577 results on '"MASSI, MASSIMILIANO"'
Search Results
202. Gelation of La(iii) cations promoted by 5-(2-pyridyl)tetrazolate and water
- Author
-
Andrews, Philip C., primary, Junk, Peter C., additional, Massi, Massimiliano, additional, and Silberstein, Morry, additional
- Published
- 2006
- Full Text
- View/download PDF
203. Effects of Surface Chemical Composition on the Early Growth Stages of α-Sexithienyl Films on Silicon Oxide Substrates
- Author
-
Dinelli, Franco, primary, Moulin, Jean-François, additional, Loi, Maria Antonietta, additional, Da Como, Enrico, additional, Massi, Massimiliano, additional, Murgia, Mauro, additional, Muccini, Michele, additional, Biscarini, Fabio, additional, Wie, Jiang, additional, and Kingshott, Peter, additional
- Published
- 2005
- Full Text
- View/download PDF
204. Magnetic Information Storage on Polymers by Using Patterned Single‐Molecule Magnets
- Author
-
Cavallini, Massimiliano, primary, Gomez‐Segura, Jordi, additional, Ruiz‐Molina, Daniel, additional, Massi, Massimiliano, additional, Albonetti, Cristiano, additional, Rovira, Concepció, additional, Veciana, Jaume, additional, and Biscarini, Fabio, additional
- Published
- 2005
- Full Text
- View/download PDF
205. Electrochemical fabrication of cobalt and nickel tips for scanning tunneling microscopy
- Author
-
Albonetti, Cristiano, primary, Cavallini, Massimiliano, additional, Massi, Massimiliano, additional, Moulin, Jean François, additional, and Biscarini, Fabio, additional
- Published
- 2005
- Full Text
- View/download PDF
206. Fabrication of material patterns by grid-assisted deposition
- Author
-
Massi, Massimiliano, primary, Cavallini, Massimiliano, additional, Stagni, Stefano, additional, Palazzi, Antonio, additional, and Biscarini, Fabio, additional
- Published
- 2003
- Full Text
- View/download PDF
207. Luminescent Metal Complexes as Emerging Tools for Lipid Imaging
- Author
-
Schwehr, Bradley J., Hartnell, David, Massi, Massimiliano, and Hackett, Mark J.
- Abstract
Fluorescence microscopy is a key tool in the biological sciences, which finds use as a routine laboratory technique (e.g., epifluorescence microscope) or more advanced confocal, two-photon, and super-resolution applications. Through continued developments in microscopy, and other analytical methods, the importance of lipids as constituents of subcellular organelles, signalling or regulating molecules continues to emerge. The increasing recognition of the importance of lipids to fundamental cell biology (in health and disease) has prompted the development of protocols and techniques to image the distribution of lipids in cells and tissues. A diverse suite of spectroscopic and microscopy tools are continuously being developed and explored to add to the “toolbox” to study lipid biology. A relatively recent breakthrough in this field has been the development and subsequent application of metal-based luminescent complexes for imaging lipids in biological systems. These metal-based compounds appear to offer advantages with respect to their tunability of the photophysical properties, in addition to capabilities centred around selectively targeting specific lipid structures or classes of lipids. The presence of the metal centre also opens the path to alternative imaging modalities that might not be applicable to traditional organic fluorophores. This review examines the current progress and developments in metal-based luminescent complexes to study lipids, in addition to exploring potential new avenues and challenges for the field to take.
- Published
- 2022
- Full Text
- View/download PDF
208. Electrochemical preparation of cobalt tips for scanning tunneling microscopy
- Author
-
Albonetti, Cristiano, primary, Bergenti, Ilaria, additional, Cavallini, Massimiliano, additional, Dediu, Valentin, additional, Massi, Massimiliano, additional, Moulin, Jean-François, additional, and Biscarini, Fabio, additional
- Published
- 2002
- Full Text
- View/download PDF
209. Spontaneous Fabrication of Microscopic Arrays of Molecular Structures with Submicron Length Scales
- Author
-
Cavallini, Massimiliano, primary, Biscarini, Fabio, additional, Massi, Massimiliano, additional, Farran-Morales, Angeles, additional, Leigh, David A., additional, and Zerbetto, Francesco, additional
- Published
- 2002
- Full Text
- View/download PDF
210. Proton-Induced Reversible Modulation of the Luminescent Output of Rhenium(I), Iridium(III), and Ruthenium(II) Tetrazolate Complexes.
- Author
-
Werrett, Melissa V., Muzzioli, Sara, Wright, Phillip J., Palazzi, Antonio, Raiten, Paolo, Zacchini, Stefano, Massi, Massimiliano, and Stagni, Stefano
- Published
- 2014
- Full Text
- View/download PDF
211. Ligand-Induced Structural, Photophysical, and ElectrochemicalVariations in Tricarbonyl Rhenium(I) Tetrazolato Complexes.
- Author
-
Wright, Phillip J., Affleck, Mark G., Muzzioli, Sara, Skelton, Brian W., Raiteri, Paolo, Silvester, Debbie S., Stagni, Stefano, and Massi, Massimiliano
- Published
- 2013
- Full Text
- View/download PDF
212. Synthesis, Photophysicaland Electrochemical Investigationof Dinuclear Tetrazolato-Bridged Rhenium Complexes.
- Author
-
Wright, PhillipJ., Muzzioli, Sara, Werrett, Melissa V., Raiteri, Paolo, Skelton, Brian W., Silvester, Debbie S., Stagni, Stefano, and Massi, Massimiliano
- Published
- 2012
- Full Text
- View/download PDF
213. Investigating vaterite phase stabilisation by a tetrazole molecule during calcium carbonate crystallisation
- Author
-
Massi, Massimiliano, Ogden, Mark I., and Jones, Franca
- Subjects
- *
VATERITE , *TETRAZOLES , *CALCIUM carbonate , *CRYSTALLIZATION , *PHASE equilibrium , *CARBOXYLATES , *REACTION mechanisms (Chemistry) - Abstract
Abstract: Tetrazole compounds have recently been found to impact on crystal morphology but in a manner different from that of carboxylate molecules. One such molecule was found to stabilise vaterite and this was investigated by assessing the impact of systematic changes on its structure. It was found that both the tetrazole and the formyl functionalities were required for vaterite stabilisation. The mechanism of stabilisation appears to be via inhibition of vaterite dissolution. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
214. Influence of the substrate hydrophilicity on the grid assisted deposition of tris-(8-hydroxyquinolinato) aluminum(III) thin films
- Author
-
Massi, Massimiliano, Cavallini, Massimiliano, and Biscarini, Fabio
- Subjects
- *
ALUMINUM films , *TRIS(8-hydroxyquinoline) aluminum , *SURFACE coatings , *WETTING , *SUBSTRATES (Materials science) , *HYDROPHILE-lipophile balance , *NUMERICAL grid generation (Numerical analysis) - Abstract
Abstract: The influence of the substrate wetting properties on the grid assisted deposition of tris-(8-hydroxyquinolinato)aluminum(III) (Alq3) onto Si/SiO x surfaces was investigated. Different degrees of hydrophilicity/hydrophobicity on the Si/SiO x were obtained by changing the surface chemical functionalities with wet treatments. We observed that the deposited Alq3 films can be spatially controlled and assembled either into continuous grid-like stripes or ordered dots depending upon the wetting properties of the substrate. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
215. Lanthanoid β-triketonates: a new class of highly efficient NIR emitters for bright NIR-OLEDs.
- Author
-
Ogden, Mark I., Massi, Massimiliano, Reid, Brodie L., Hanan, Garry S., Stagni, Stefano, Malicka, Joanna M., and Cocchi, Massimo
- Subjects
- *
RARE earth metal metallurgy , *KETONE derivatives , *NEAR infrared radiation , *ORGANIC light emitting diodes , *YTTERBIUM compounds , *CHEMIEXCITATION - Abstract
The reaction of hydrated YbCl3 with potassium tribenzoylmethanide yields a new bimetallic tetranuclear Yb3+/K+ assembly. This species not only possesses the longest excited state lifetime and quantum yield reported for the Yb3+ diketonate family but is also suitable to be incorporated in NIR-OLEDs, whose performance outclasses any other reported lanthanoid-based device with NIR emission. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
216. Photoactive Metal Carbonyl Complexes Bearing N-Heterocyclic Carbene Ligands: Synthesis, Characterization, and Viability as Photoredox Catalysts
- Author
-
Tang, Meiqiong, Cameron, Lee, Poland, Eve M., Yu, Li-Juan, Moggach, Stephen A., Fuller, Rebecca O., Huang, Hai, Sun, Jianwei, Thickett, Stuart C., Massi, Massimiliano, Coote, Michelle L., Ho, Curtis C., and Bissember, Alex C.
- Abstract
This report details the synthesis and characterization of a small family of previously unreported, structurally related chromium, molybdenum, tungsten, manganese, and iron complexes bearing N-heterocyclic carbene and carbonyl supporting ligands. These complexes have the general form [ML(CO)3X] or [ML(CO)3], where X = CO or Br and L = 1-phenyl-3-(2-pyridyl)imidazolin-2-ylidene. Where possible, the solid-state, spectroscopic, electrochemical, and photophysical properties of these molecules were studied using a combination of experiment and theory. Photophysical studies reveal that decarbonylation occurs when these complexes are exposed to ultraviolet light, with the CO ligand being replaced with a labile acetonitrile solvent molecule. To obtain insights into the potential utility, scope, and applications of these complexes in visible-light-mediated photoredox catalysis, their capacity to facilitate a range of photoinduced reactions via the reductive or oxidative functionalization of organic molecules was investigated. These chromium, molybdenum, and manganese catalysts efficiently facilitated atom-transfer radical addition processes. In light of their photolability, these types of catalysts may potentially allow for the development of photoinduced reactions involving less conventional inner-sphere electron-transfer pathways.
- Published
- 2022
- Full Text
- View/download PDF
217. 2,7- and 4,9-Dialkynyldihydropyrene Molecular Switches: Syntheses, Properties, and Charge Transport in Single-Molecule Junctions
- Author
-
Roemer, Max, Gillespie, Angus, Jago, David, Costa-Milan, David, Alqahtani, Jehan, Hurtado-Gallego, Juan, Sadeghi, Hatef, Lambert, Colin J., Spackman, Peter R., Sobolev, Alexandre N., Skelton, Brian W., Grosjean, Arnaud, Walkey, Mark, Kampmann, Sven, Vezzoli, Andrea, Simpson, Peter V., Massi, Massimiliano, Planje, Inco, Rubio-Bollinger, Gabino, Agraït, Nicolás, Higgins, Simon J., Sangtarash, Sara, Piggott, Matthew J., Nichols, Richard J., and Koutsantonis, George A.
- Abstract
This paper describes the syntheses of several functionalized dihydropyrene (DHP) molecular switches with different substitution patterns. Regioselective nucleophilic alkylation of a 5-substituted dimethyl isophthalate allowed the development of a workable synthetic protocol for the preparation of 2,7-alkyne-functionalized DHPs. Synthesis of DHPs with surface-anchoring groups in the 2,7- and 4,9-positions is described. The molecular structures of several intermediates and DHPs were elucidated by X-ray single-crystal diffraction. Molecular properties and switching capabilities of both types of DHPs were assessed by light irradiation experiments, spectroelectrochemistry, and cyclic voltammetry. Spectroelectrochemistry, in combination with density functional theory (DFT) calculations, shows reversible electrochemical switching from the DHP forms to the cyclophanediene (CPD) forms. Charge-transport behavior was assessed in single-molecule scanning tunneling microscope (STM) break junctions, combined with density functional theory-based quantum transport calculations. All DHPs with surface-contacting groups form stable molecular junctions. Experiments show that the molecular conductance depends on the substitution pattern of the DHP motif. The conductance was found to decrease with increasing applied bias.
- Published
- 2022
- Full Text
- View/download PDF
218. Fluorescent probes for neuroscience: imaging ex vivo brain tissue sections.
- Author
-
Schwehr, Bradley J., Hartnell, David, Ellison, Gaewyn, Hindes, Madison T., Milford, Breah, Dallerba, Elena, Hickey, Shane M., Pfeffer, Frederick M., Brooks, Doug A., Massi, Massimiliano, and Hackett, Mark J.
- Subjects
- *
FLUORESCENT probes , *DRUG target , *FLUORESCENCE microscopy , *CHEMICAL species , *METAL ions - Abstract
Neurobiological research relies heavily on imaging techniques, such as fluorescence microscopy, to understand neurological function and disease processes. However, the number and variety of fluorescent probes available for ex vivo tissue section imaging limits the advance of research in the field. In this review, we outline the current range of fluorescent probes that are available to researchers for ex vivo brain section imaging, including their physical and chemical characteristics, staining targets, and examples of discoveries for which they have been used. This review is organised into sections based on the biological target of the probe, including subcellular organelles, chemical species (e.g., labile metal ions), and pathological phenomenon (e.g., degenerating cells, aggregated proteins). We hope to inspire further development in this field, given the considerable benefits to be gained by the greater availability of suitably sensitive probes that have specificity for important brain tissue targets. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
219. Elucidating the Mechanism of Efficient Eu(III) and Yb(III) Sensitisation from a Re(I) Tetrazolato Triangular Assembly.
- Author
-
Wright, Phillip J., Pfrunder, Michael C., Etchells, Isaac M., Haghighatbin, Mohammad A., Raiteri, Paolo, Ogden, Mark I., Stagni, Stefano, Hogan, Conor F., Cameron, Lee J., Moore, Evan G., and Massi, Massimiliano
- Subjects
- *
ENERGY transfer , *EXCITED states , *YTTERBIUM , *EUROPIUM , *LUMINESCENCE - Abstract
The reaction of Re(CO)5Br with deprotonated 1H‐(5‐(2,2′:6′,2′′‐terpyridine)pyrid‐2‐yl)tetrazole yields a triangular assembly formed by tricarbonyl Re(I) vertices. Photophysical measurements reveal blue‐green emission with a maximum at 520 nm, 32 % quantum yield, and 2430 ns long‐lived excited state decay lifetime in deaerated dichloromethane solution. Coordination of lanthanoid ions to the terpyridine units red‐shifts the emission to 570 nm and also reveals efficient (90 %) and fast sensitisation of both Eu(III) and Yb(III) at room temperature, with a similar rate constant kET on the order of 107 s−1. Efficient sensitisation of Eu(III) from Re(I) is unprecedented, especially when considering the close proximity in energy between the donor and acceptor excited states. On the other hand, comparative measurements at 77 K reveal that energy transfer to Yb(III) is two orders of magnitude slower than that to Eu(III). A two‐step mechanism of sensitisation is therefore proposed, whereby the rate‐determining step is a thermally activated energy transfer step between the Re(I) centre and the terpyridine functionality, followed by rapid energy transfer to the respective Ln(III) excited states. At 77 K, the direct Re(I) to Eu(III) energy transfer seems to proceed via a ligand‐mediated superexchange Dexter‐type mechanism. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
220. Correlative multimodal optical and X-ray fluorescence imaging of brominated fluorophores.
- Author
-
Adair, Liam D., Graziotto, Marcus E., Koh, Terry, Kidman, Clinton J., Schwehr, Bradley J., Hackett, Mark J., Massi, Massimiliano, Harris, Hugh H., and New, Elizabeth J.
- Subjects
- *
X-ray imaging , *X-ray fluorescence , *FLUOROPHORES , *X-ray microscopy , *FLUORESCENCE microscopy , *STAINS & staining (Microscopy) - Abstract
Imaging with multiple modalities can maximise the information gained from the analysis of a single sample. probes for optical fluorescence and X-ray fluorescence microscopy based on brominated 4-amino-1,8-naphthalimide and BODIPY scaffolds have been successfully designed and synthesised. Herein we show that these prototype probes, based on each of these scaffolds, can be imaged in two different cancer cell lines, and that the respective optical fluorescence and X-ray fluorescence signals are well correlated in these images. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
221. Lanthanoid Semiquinonate/Tropolonate Complexes: Redox Chemistry and Luminescence.
- Author
-
Dunstan, Maja A., Suryadevara, Nithin, Cameron, Lee, Gable, Robert W., Massi, Massimiliano, and Boskovic, Colette
- Subjects
- *
COMPLEX compounds , *LUMINESCENCE , *ANTENNAS (Electronics) , *ELECTROCHEMISTRY , *COORDINATION polymers , *VISIBLE spectra - Abstract
Heteroleptic lanthanoid (Ln = Eu, Gd, Tb, Dy, Ho and Yb) complexes featuring hydro‐tris(1‐pyrazolyl)borate (Tp−) ligands combined with the bidentate O‐donor ligands tropolonate (trop−) or 3,5‐di‐tertbutylseminquinonate (dbsq⋅−) have been synthesized and investigated. Despite the similarity of the bidentate O‐donor trop− and dbsq⋅− ligands, and the lanthanoid coordination geometries, the complexes [LnTp2dbsq] (Ln‐dbsq) and [LnTp2trop] (Ln‐trop) exhibit markedly different redox and photophysical properties. The electrochemistry of Ln‐dbsq is dominated by processes associated with the readily redox‐active dbsq⋅− moiety. In contrast, the relative redox inactivity of Ln‐trop allows for the observation of the Eu(III) to Eu(II) reduction process. Photophysical measurements reveal no sensitized emission for the Ln‐dbsq family, while the trop− antenna ligand is able to sensitize emission in the visible range for Eu(III) and Ho(III), and in the near‐infrared for Ho(III) and Yb(III). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
222. Inside Cover.
- Author
-
Lazniewska, Joanna, Darby, Jack R. T., Holman, Stacey L., Sorvina, Alexandra, Plush, Sally E., Massi, Massimiliano, Brooks, Doug A., and Morrison, Janna L.
- Abstract
Sheep models of intrauterine growth restriction (IUGR) were utilised to investigate metabolic changes in fetal perirenal adipose tissue (PAT). Using two‐photon microscopy, a decreased redox ratio was detected in IUGR fat. This was accompanied by changes in lipid droplet morphology, detected by confocal microscopy, and by altered expression of metabolic‐related genes. The results indicate that metabolic imbalance of fetal PAT may increase the chance of survival of growth‐restricted neonates. Further details can be found in the article by Joanna Lazniewska, Jack R. T. Darby, Stacey L. Holman, Alexandra Sorvina, Sally E. Plush, Massimiliano Massi, Doug A. Brooks, and Janna L. Morrison (e202000322). [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
223. Formation of HoIII Trinuclear Clusters and GdIII Monodimensional Polymers Induced by ortho and para Regioisomers of Pyridyl-Functionalised β-Diketones: Synthesis, Structure, and Magnetic Properties
- Author
-
Andrews, Philip C., Deacon, Glen B., Frank, René, Fraser, Benjamin H., Junk, Peter C., MacLellan, Jonathan G., Massi, Massimiliano, Moubaraki, Boujemaa, Murray, Keith S., and Silberstein, Morry
- Abstract
Reaction of GdCl3H2O6and 1,3bispyridin4ylpropane1,3dione in methanol with an excess of triethylamine produced a monodimensional polymeric chain [Gdpdppd3H2O]∞, whereas treatment of HoCl3H2O6with 1,3bispyridin2ylpropane1,3dione yielded a trinuclear cluster [Ho3odppd3μ3OH2H2O4Cl2]Cl2. The compounds were characterised by elemental analysis, IR spectroscopy and magnetism, and their structures were investigated by Xray crystallography. The 8.20μBmagneticmoment value of the polymeric [Gdpdppd3H2O]∞, between 300 and 20 K, and the magnetisation isotherms 2–20 K; fields 0–5 T, are in agreement with essentially uncoupled singleion Gd3+f7centres, a small decrease in μeffbelow 20 K being indicative of zerofield splitting. A temperaturedependent dcsusceptibility and magnetisation investigation of the trinuclear triangular [Ho3odppd3μ3OH2H2O4Cl2]Cl2revealed that spinorbit and ligandfield effects on the Ho3+centres, leading to thermal depopulation of Zeeman levels and consequent decreases in μeffvalues with decreasing temperature, are occurring rather than weak intracluster antiferromagnetic coupling. Frequency and temperaturedependent acsusceptibility studies on this homometallic Ho3+cluster did not show clear evidence for slow magnetisation reversal, characteristic of singlemolecule magnetism SMM, and this contrasts with such behaviour recently reported, elsewhere, for a Dy3+triangle having the same core structure but with different chelating {O,O} ligands.© WileyVCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009
- Published
- 2009
- Full Text
- View/download PDF
224. Frontispiece: Fluorine‐18 Radiolabelling and Photophysical Characteristics of Multimodal PET–Fluorescence Molecular Probes.
- Author
-
Klenner, Mitchell A., Pascali, Giancarlo, Massi, Massimiliano, and Fraser, Benjamin H.
- Subjects
MOLECULAR probes ,RADIOLABELING - Abstract
Keywords: fluorescence; fluorine-18; multimodality; PET; photophysics EN fluorescence fluorine-18 multimodality PET photophysics 1 1 1 01/18/21 20210113 NES 210113 B PET-fluorescence multimodal probes b provide complimentary information for medical diagnoses. Such probes enable specific functional imaging of a disease state from initial diagnostic positron emission tomography (PET) scans, followed by high spatial resolution, real-time fluorescence imaging during intraoperative excision of the diseased tissue. Fluorescence, fluorine-18, multimodality, PET, photophysics. [Extracted from the article]
- Published
- 2021
- Full Text
- View/download PDF
225. Tetrazole functional copolymers: Facile access to well-defined Rhenium(I)-Polymeric luminescent materials.
- Author
-
Dallerba, Elena, Massi, Massimiliano, and Lowe, Andrew B.
- Subjects
- *
RANDOM copolymers , *COPOLYMERS , *TETRAZOLES , *ESTERS , *GEL permeation chromatography , *RHENIUM , *FOURIER transform infrared spectroscopy , *DIBLOCK copolymers - Abstract
Well-defined random copolymers containing tetrazole functional groups were prepared by a combination of reversible addition-fragmentation chain transfer (RAFT) radical homopolymerisation of pentafluorophenyl acrylate (PFPA), end-group modification and post-polymerisation modification of the activated ester side-groups with primary amines. PolyPFPA with a size exclusion chromatography (SEC) measured M n of 10,800 and dispersity, Ð , of 1.05 was prepared with 2-cyano-2-propyl benzodithioate as the RAFT chain transfer agent and 2,2′-azobisisobutyronitrile (AIBN) as the source of primary radicals in 1,4-dioxane. Prior to modification of the pentafluorophenyl (PFP) ester side-groups, the thiocarbonylthio end-group was removed via a radical-mediated desulfurisation employing two equivalents of AIBN. Complete removal of the end-group was successful as judged by UV–vis spectroscopy with no effect on the molecular weight distribution of the parent homopolymer based on SEC analysis. The pendent PFP ester groups were subsequently modified in a sequential manner with n -butylamine and 5-aminotetrazole yielding the corresponding random amide species quantitatively, as judged by 19F NMR and FTIR spectroscopies, and of varying molar composition as determined by 1H NMR spectroscopy. The reaction of the tetrazole functional copolymers with Re(CO) 3 (phen)Br (phen = 1,10-phenanthroline) yielded the corresponding rhenium-polymer hybrids via coordination through the pendent tetrazole functional group. Successful, and quantitative coordination was confirmed by FTIR spectroscopy and detailed photophysical studies. In the case of the latter, the absorption profiles of all hybrid materials possessed broad bands centred around ca. 370 nm associated with metal-to-ligand charge transfer (MLCT) transitions; excitation as this wavelength results in a broad emission centred at 606 nm for all hybrid species and is due to emission from the triplet MLCT excited states. Image 1 • Tetrazole functional copolymers are readily obtained from poly(pentafluorophenyl acrylate) and 5-aminotetrazole. • Copolymers with pendent tetrazole groups act as macroligands for the attachment of rhenium(I) fragments. • The metal-polymer hybrids retain the photophysical properties of the rhenium species. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
226. Photophysical and Biological Properties of Iridium Tetrazolato Complexes Functionalised with Fatty Acid Chains.
- Author
-
Caporale, Chiara, Ranieri, Anna Maria, Paternoster, Silvano, Bader, Christie A., Falasca, Marco, Plush, Sally E., Brooks, Douglas A., Stagni, Stefano, and Massi, Massimiliano
- Subjects
FATTY acids ,IRIDIUM ,CELL imaging ,PALMITIC acid ,EXCITED states ,OLEIC acid - Abstract
Five cyclometalated Ir(III) tetrazolato complexes functionalised with fatty acid chains (octanoic, palmitic, stearic, palmitoleic, and oleic) have been synthesised. The fatty acids were chosen to evaluate the potential effect of the length and degree of unsaturation on the biological properties of the complexes for use as cellular imaging agents. The complexes were analysed in both organic and aqueous media to determine if the presence and nature of the fatty acid chains had a significant effect on their photophysical properties. The complexes display green–yellow emission in dichloromethane solutions with relatively long excited state decays, within the range 360–393 ns, and quantum yields between 5.4% and 6.7% (from degassed solutions). Temperature-dependent photophysical studies suggest that the emitting excited states of the complexes might be quenched by the thermal population of dark states. In water, the quantum yields drop within the range of 0.5%–2.4%, and the photophysical measurements are influenced by the variable degrees of aggregation. In general, the entire series displayed low cytotoxicity and relatively high photostability, which are favourable attributes in the design of cellular imaging agents. Images of live HeLa cells were obtained for all the complexes, but those functionalised with palmitic and stearic acids had limitations due the lower solubility conferred by the saturated aliphatic chains. The complexes were mainly detected within the endoplasmic reticulum. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
227. Rhenium(I)-tetrazolato functional luminescent polymers: Organic-inorganic hybrids via RAFT and post-polymerization modification.
- Author
-
Dallerba, Elena, Massi, Massimiliano, and Lowe, Andrew B.
- Subjects
- *
TETRAZOLES , *POLYMERS , *RHENIUM , *GEL permeation chromatography , *CYANO group , *INFRARED spectroscopy , *COORDINATION polymers - Abstract
• Well-defined copolymers of styrene with 4-cyanostyrene. • Post-polymerization modification to yield analogous tetrazole functional copolymers. • Coordination of rhenium(I) complexes to functional polymeric backbone via the tetrazole functional group. • Formation of novel hybrid metal-polymer luminescent materials. A series of well-defined tetrazole-functionalized (co)polymers based on the styrenic structural motif that are able to serve as macromolecular ligands for the coordination of a luminescent rhenium(I) complex are presented. Copolymers of styrene with 4-cyanostyrene containing different ratios of cyano appended groups have been synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Post-polymerization modification of the cyano groups via reaction with NaN 3 yielded the corresponding tetrazole functionalized copolymers. These tetrazole functional materials are able to serve as macromolecular ligands for the coordination of metal complexes: a rhenium(I) species has been incorporated into the polymeric structure by coordination to the tetrazole groups on the copolymers. The parent (co)polymers have been characterised by size exclusion chromatography (SEC), while inverse-gated proton decoupled 13C NMR spectroscopy and infrared spectroscopy confirmed the formation of the tetrazole functional group and subsequent metal coordination. The photophysical properties of the copolymer-rhenium(I) hybrid luminescent materials have been fully investigated. Absorption and emission profiles confirmed coordination between the tetrazole functionality appended to the polymer material and the rhenium(I) precursor complex. Lifetime measurements and quantum yields confirmed that the presence of the polymeric scaffold does not interfere with the luminescent properties of the rhenium(I) complex. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
228. Neutral rhenium(I) tricarbonyl complexes with sulfur-donor ligands: anti-proliferative activity and cellular localization.
- Author
-
Levina, Aviva, Wardhani, Kartika, Stephens, Liam J., Werrett, Melissa V., Caporale, Chiara, Dallerba, Elena, Blair, Victoria L., Massi, Massimiliano, Lay, Peter A., and Andrews, Philip C.
- Subjects
- *
LIGANDS (Chemistry) , *RHENIUM , *X-ray fluorescence , *X-ray microscopy , *CELL imaging , *FLUORESCENCE microscopy , *THIOLS - Abstract
Rhenium(I) tricarbonyl complexes are widely studied for their cell imaging properties and anti-cancer and anti-microbial activities, but the complexes with S-donor ligands remain relatively unexplored. A series of six fac-[Re(NN)(CO)3(SR)] complexes, where (NN) is 2,2′-bipyridyl (bipy) or 1,10-phenanthroline (phen), and RSH is a series of thiocarboxylic acid methyl esters, have been synthesized and characterized. Cellular uptake and anti-proliferative activities of these complexes in human breast cancer cell lines (MDA-MB-231 and MCF-7) were generally lower than those of the previously described fac-[Re(NN)(CO)3(OH2)]+ complexes; however, one of the complexes, fac-[Re(CO)3(phen)(SC(Ph)CH2C(O)OMe)] (3b), was active (IC50 ∼ 10 μM at 72 h treatment) in thiol-depleted MDA-MB-231 cells. Moreover, unlike fac-[Re(CO)3(phen)(OH2)]+, this complex did not lose activity in the presence of extracellular glutathione. Taken together these properties show promise for further development of 3b and its analogues as potential anti-cancer drugs for co-treatment with thiol-depleting agents. Conversely, the stable and non-toxic complex, fac-[Re(bipy)(CO)3(SC(Me)C(O)OMe)] (1a), predominantly localized in the lysosomes of MDA-MB-231 cells, as shown by live cell confocal microscopy (λex = 405 nm, λem = 470–570 nm). It is strongly localized in a subset of lysosomes (25 μM Re, 4 h treatment), as shown by co-localization with a Lysotracker dye. Longer treatment times with 1a (25 μM Re for 48 h) resulted in partial migration of the probe into the mitochondria, as shown by co-localization with a Mitotracker dye. These properties make complex 1a an attractive target for further development as an organelle probe for multimodal imaging, including phosphorescence, carbonyl tag for vibrational spectroscopy, and Re tag for X-ray fluorescence microscopy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
229. Designing Ionic Ir(III) Cyclometalated Complexes as Photocatalysts for Light Assisted ATRP of MMA. A Combined Experimental and Mechanistic Study.
- Author
-
Vigarani, Giulia, Marchini, Edoardo, Previati, Eleonora, Giorgini, Loris, Zacchini, Stefano, Argazzi, Roberto, Massi, Massimiliano, Fiorini, Valentina, Caramori, Stefano, and Stagni, Stefano
- Subjects
- *
PHOTOCATALYSTS , *PHOSPHORESCENCE , *ELECTRON donors , *VISIBLE spectra , *PHOTOPOLYMERIZATION , *POLYMERIZATION , *ION pairs - Abstract
A new family of ionic Ir(III) cyclometalated complexes with general formula [Ir(CN)2(NN)][Br], was designed and prepared to be assessed as photocalysts for the visible light assisted ATRP polymerization of MMA. To this purpose, our design strategy involved both: i) the decoration of the cyclometalating (CN) and the ancillary (NN) ligands with various electron withdrawing and/or electron donor substituents and, ii) the use of Br− as the counter anion for these cationic Ir(III) species. After an extensive screening in which the [Ir(CN)2(NN)][Br]‐type compounds were compared to the model neutral complex fac‐[Ir(ppy)3], the "fully" amino‐substituted ion pairs abbreviated as [10][Br] and [11][Br], exhibited the best photocatalytic performances under irradiation with CFL lamps. It is worth noting that the outcomes of transient absorption spectroscopy (TAS) experiments combined with theoretical DFT calculations, enlightened the role played by the Ir(III) complexes in the mechanism of the photoATRP process, and suggested the rationalization of the different performances that were highlighted by our Ir(III) catalyst in the visible light assisted photopolymerization of MMA. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
230. Front Cover.
- Author
-
Cingolani, Andrea, Zanotti, Valerio, Zacchini, Stefano, Massi, Massimiliano, Simpson, Peter V., Maheshkumar Desai, Nima, Casari, Ilaria, Falasca, Marco, Rigamonti, Luca, and Mazzoni, Rita
- Subjects
LIGANDS (Chemistry) ,IRON ,CREDIT ,IMAGE - Abstract
The cover image is based on the Full Paper Synthesis, reactivity and preliminary biological activity of iron(0) complexes with cyclopentadienone and amino‐appended N‐heterocyclic carbene ligands by Andrea Cingolani et al., https://doi.org/10.1002/aoc.4779. Illustration Credit: Rita Mazzoni. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
231. Synthesis, reactivity and preliminary biological activity of iron(0) complexes with cyclopentadienone and amino‐appended N‐heterocyclic carbene ligands.
- Author
-
Cingolani, Andrea, Zanotti, Valerio, Zacchini, Stefano, Massi, Massimiliano, Simpson, Peter V., Maheshkumar Desai, Nima, Casari, Ilaria, Falasca, Marco, Rigamonti, Luca, and Mazzoni, Rita
- Subjects
LIPOPHILICITY ,IRON ,MOLECULAR structure ,CHEMICAL speciation ,AMINO group ,BUFFER solutions - Abstract
Neutral and cationic cyclopentadienone (CpO) N‐heterocyclic carbene (NHC) bis‐carbonyl iron(0) complexes bearing, appended to the NHC ligand, either a terminal amino group on the lateral chain, [Fe(η4‐CpO)(CO)2(κC‐NHC(CH2)nNH2)] with n = 2 (2a) and 3 (2b), or a cationic NMe3+ fragment, [Fe(η4‐CpO)(CO)2(κC‐NHC(CH2)2NMe3)](I) (3), were prepared and characterized in terms of their structure, stability and reactivity. The photochemical properties of 2a and 2b were examined both in organic solvents and in water, revealing the photoactivated release of one CO ligand followed by the formation of the chelated complex [Fe(η4‐CpO)(CO)(κ2C,N‐NHC(CH2)2NH2)] (4), whose molecular structure was confirmed by single crystal X‐ray diffraction studies. This metallacyclization occurs only in the case of 2a, with the ethylene spacer between NHC ring and NH2 group in the lateral chain, allowing the formation of a stable 6‐membered ring. On the other hand, 2b undergoes decomposition upon irradiation. The reactivity in aqueous solutions revealed the chemical speciation of the complexes at different pH and especially under physiological conditions (phosphate buffer solution at pH 7.4 and 37 °C). The lack of data on the biological properties of iron(0) complexes prompted us to preliminarily investigate their cytotoxicity against model cancer cells (AsPC‐1 and HPAF‐II), along with a determination of their lipophilicity. Cyclopentadienone iron(0) complexes bearing an amino functionality on the lateral chain of the ancillary N‐heterocyclic carbene ligand show cytotoxicity properties against pancreatic cancer AsPC‐1 and HPAF‐II cells comparable to carboplatin. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
232. Front Cover: Analyzing the Relation between Structure and Aggregation Induced Emission (AIE) Properties of Iridium(III) Complexes through Modification of Non‐Chromophoric Ancillary Ligands (Eur. J. Inorg. Chem. 2/2018).
- Author
-
Galán, Laura Abad, Cordes, David B., Slawin, Alexandra M. Z., Jacquemin, Denis, Ogden, Mark I., Massi, Massimiliano, and Zysman‐Colman, Eli
- Subjects
IRIDIUM ,LIGANDS (Chemistry) ,PHOSPHORESCENCE ,CRYSTAL structure ,IRRADIATION - Abstract
The Front Cover shows the two Ir complexes bearing β‐diketone/triketonate ligands. Upon UV light irradiation in the solid state, both molecules show visible emission ranging from yellow to red. This emission is negligible in solution, confirming that these compounds are aggregation‐induced emitters (AIE). The molecular packing in the crystal and the alteration of the π–π stacking involving the ancillary ligands determines the nature of the emission. The importance of structural parameters in comprehending the solid‐state phosphorescence of Ir complexes is highlighted by merging the experimental solid‐state emissions and crystal structures of the complexes. More information can be found in the Full Paper by D. Jacquemin, M. I. Ogden, M. Massi, E. Zysman‐Colman et al. For more on the story behind the cover research, see the Cover Profile. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
233. Comparison of the impact of ozone, chlorine dioxide, ferrate and permanganate pre-oxidation on organic disinfection byproduct formation during post-chlorination
- Author
-
Rouge, Valentin, von Gunten, Urs, de Sentenac, Mariette Lafont, Massi, Massimiliano, Wright, Phillip J., Croue, Jean-Philippe, and Allard, Sebastien
- Subjects
haloacetic acid ,oxidation ,solid-phase microextraction ,drinking-water ,bromate formation ,trihalomethane formation ,bromide-containing waters ,model compounds ,rate constants ,dbp formation - Abstract
Pre-oxidation is commonly used to mitigate the formation of byproducts during post-disinfection. A comparative study of the impact of four pre-oxidants, ozone (O-3), chlorine dioxide (ClO2), permanganate (Mn(vii)) and ferrate (Fe(vi)), on the formation of trihalomethanes (THMs), haloacetonitriles (HANs) and adsorbable organic halogens (AOX) in chlorinated synthetic and real waters was conducted. The pre-oxidant doses were based on their impact on natural organic matter reactivity measured by the electron donating capacity before chlorination. The influence of pH (6.5-8.1) and bromide (0-500 mu g L-1) was evaluated in terms of disinfection byproduct (DBP) formation and theoretical toxicity assessment (based on THM and HAN formation). All oxidants were efficient in mitigating chlorinated DBPs, except Mn(vii) which had little impact on THM formation. O(3)was generally more efficient than the other oxidants in mitigating AOX and THM formation, all pre-oxidants readily reduced the formation of HANs (>45% reduction at high dose). pH depression improved AOX mitigation by O(3)and Fe(vi) but diminished Mn(vii) efficiency for all DBPs. Pre-oxidation was less efficient in mitigating brominated DBPs and generally enhanced the bromine substitution factor. Although HANs were formed at low concentrations compared to THMs, they dominated the calculated toxicity, particularly the brominated HANs. The increased dibromoacetonitrile formation after pre-oxidation was a major factor counteracting the benefits of the overall DBP mitigation. In the presence of bromide, the pre-oxidant dose should be optimized to decrease the reactivity of the matrix while controlling the toxicity induced by formation of brominated DBPs, notably brominated HANs.
234. Synthesis and cellular uptake of neutral rhenium(I) morpholine complexes.
- Author
-
Bader, Christie A., Simpson, Peter V., Dallerba, Elena, Stagni, Stefano, Johnson, Ian R. D., Hickey, Shane M., Sorvina, Alexandra, Hackett, Mark, Sobolev, Alexandre N., Brooks, Doug A., Massi, Massimiliano, and Plush, Sally E.
- Subjects
- *
MORPHOLINE , *RHENIUM , *STOKES shift , *CELL imaging , *ORGANIC bases , *LYSOSOMES - Abstract
Morpholine motifs have been used extensively as targeting moieties for lysosomes, primarily in fluorescence imaging agents. Traditionally these imaging agents are based on organic molecules which have several shortcomings including small Stokes shifts, short emission lifetimes, and susceptibility to photobleaching. To explore alternative lysosome targeting imaging agents we have used a rhenium based phosphorescent platform which has been previously demonstrated to have an improved Stokes shift, a long lifetime emission, and is highly photostable. Rhenium complexes containing morpholine substituted ligands were designed to accumulate in acidic compartments. Two of the three complexes prepared exhibited bright emission in cells, when incubated at low concentrations (20 μM) and were non-toxic at concentrations as high as 100 μM, making them suitable for live cell imaging. We show that the rhenium complexes are amenable to chemical modification and that the morpholine targeted derivatives can be used for live cell confocal fluorescence imaging of endosomes–lysosomes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
235. Antibacterial activity of a new class of tris homoleptic Ru (II)‐complexes with alkyl‐tetrazoles as diimine‐type ligands.
- Author
-
Monti, Nicola, Zacchini, Stefano, Massi, Massimiliano, Hochkoeppler, Alejandro, Giorgini, Loris, Fiorini, Valentina, Stefan, Alessandra, and Stagni, Stefano
- Subjects
- *
TETRAZOLES , *DEINOCOCCUS radiodurans , *DISC diffusion tests (Microbiology) , *CLASSROOM activities , *GRAM-negative bacteria , *X-ray crystallography - Abstract
Herein, we describe a new family of tris chelate homoleptic Ru (II) complexes, [Ru(N^N)3]2+, where the role of the diimine‐type ligands (N^N) was fulfilled by 2‐pyridyl (PTZ) or 2‐quinolyl tetrazole (QTZ) derivatives decorated with various alkyl substituents at the N‐2 position of the tetrazole ring. The new Ru (II) complexes with general formula [Ru (PTZ‐R)3]2+ and [Ru (QTZ‐R)3]2+, were obtained as mixtures of facial (fac) and meridional (mer) isomers, as suggested by NMR (1H, 13C) experiments, and confirmed in the case of mer‐[Ru (QTZ‐Me)3]2+, by X‐ray crystallography. The photophysical behavior of the tetrazole‐based [Ru(N^N)3]2+ type species was investigated by UV–vis absorption spectroscopy, providing trends typical of polypyridyl Ru (II) complexes. The new homoleptic complexes fac/mer‐[Ru (PTZ‐R)3]2+ and fac/mer‐[Ru (QTZ‐R)3]2+ have been assessed for any eventual antimicrobial activity towards two different bacteria such as Gram‐negative Escherichia coli and Gram‐positive Deinococcus radiodurans. Whereas being inactive toward E. coli, the response of agar disks diffusion tests suggested that some of the new fac/mer Ru (II) complexes could inhibit the growth of D. radiodurans. This effect was further investigated by determining the growth kinetics in liquid medium of D. radiodurans exposed to the fac/mer‐[Ru (PTZ‐R)3]2+ and fac/mer‐[Ru (QTZ‐R)3]2+ complexes at different concentrations. The outcome of these experiments highlighted that the turn‐on of the growth inhibitory effect took place as the linear hexyl chain was appended to the PTZ or QTZ scaffold, suggesting also how the inhibitory activity appeared more pronouncedly exerted by the facial isomers fac‐[Ru (PTZ‐Hex)3]2+ and fac‐[Ru (QTZ‐Hex)3]2+ (MIC = ca. 3.0 μg/ml) with respect to the corresponding meridional isomers (MIC = ca. 6.0 μg/ml). [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
236. Luminescent Copolymer‐Rhenium(I) Hybrid Materials via Picolylamine‐Modified Poly(pentafluorophenyl acrylate).
- Author
-
Fantini, Gregorio, Dallerba, Elena, Massi, Massimiliano, and Lowe, Andrew B.
- Subjects
- *
FUNCTIONAL groups , *RHENIUM , *MATERIALS , *COPOLYMERS - Abstract
The synthesis and photophysical properties of well‐defined polymer‐rhenium(I) hybrid materials is described. Reversible addition‐fragmentation chain transfer polymerization of pentafluorophenyl acrylate yields a parent homopolymer that serves as a reactive scaffold for the preparation of a series of new statistical copolymers containing pendent pyridyl functional groups in conjunction with various other repeat unit species. Attachment of [Re(CO)3(phen)]+ fragments via coordination through the pendent pyridyl groups yields the hybrid metal‐copolymer materials. Photophysical studies confirm successful rhenium coordination as judged from the absorption and emission profiles of the hybrid materials and further verify that the polymeric scaffold has no discernable effect on the luminescent properties of the coordinated rhenium species. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
237. Synthesis and characterisation of homoleptic 2,9-diaryl-1,10-phenanthroline copper(i) complexes: influencing selectivity in photoredox-catalysed atom-transfer radical addition reactions.
- Author
-
Nicholls, Thomas P., Caporale, Chiara, Massi, Massimiliano, Gardiner, Michael G., and Bissember, Alex C.
- Subjects
- *
ADDITION reactions , *COPPER - Abstract
This report details the synthesis and characterisation of eight homoleptic bis(2,9-diaryl-1,10-phenanthroline)copper(i) complexes, seven of which are previously unreported {aryl = p-CF3C6H4, p-FC6H4, m,p-(OMe)2C6H3, o,p-(OMe)2C6H3, p-OMe-m,m-Me2C6H2, p-OMe-m,m-(t-Bu)2C6H2, 9,9-dimethyl-9H-fluoren-2-yl, 4-(9H-carbazol-9-yl)phenyl)}. Where possible the solid state, photophysical and electrochemical properties of these complexes were studied. In order to obtain insights into the influence of the intrinsic features of these copper(i) complexes on their reactivity in visible light-mediated photoredox catalysis, their capacity to promote a known atom-transfer radical addition process was evaluated. This specific transformation was identified as a suitable model system as it is reported to proceed via a mechanism consistent with the inner-sphere reactivity enabled by coordinatively unsaturated phenanthroline-based copper(i) species. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
238. Synthesis and the photophysical and biological properties of tricarbonyl Re(I) diimine complexes bound to thiotetrazolato ligands.
- Author
-
Stephens, Liam J., Dallerba, Elena, Kelderman, Jenisi T. A., Levina, Aviva, Werrett, Melissa V., Lay, Peter A., Massi, Massimiliano, and Andrews, Philip C.
- Subjects
- *
BIOSYNTHESIS , *METHICILLIN-resistant staphylococcus aureus , *ESCHERICHIA coli , *CELL imaging , *LIGAND binding (Biochemistry) , *CHARGE transfer , *LIGANDS (Chemistry) , *PHOTOLUMINESCENT polymers - Abstract
Twelve Re(I) tricarbonyl diimine (2,2′-bipyridine and 1,10-phenanthroline) complexes with thiotetrazolato ligands have been synthesised and fully characterised. Structural characterisation revealed the capacity of the tetrazolato ligand to bind to the Re(I) centre through either the S atom or the N atom with crystallography revealing most complexes being bound to the N atom. However, an example where the Re(I) centre is linked via the S atom has been identified. In solution, the complexes exist as an equilibrating mixture of linkage isomers, as suggested by comparison of their NMR spectra at room temperature and 373 K, as well as 2D exchange spectroscopy. The complexes are photoluminescent in fluid solution at room temperature, with emission either at 625 or 640 nm from the metal-to-ligand charge transfer excited states of triplet multiplicity, which seems to be exclusively dependent on the nature of the diimine ligand. The oxygen-sensitive excited state lifetime decay ranges between 12.5 and 27.5 ns for the complexes bound to 2,2′-bipyrdine, or between 130.6 and 155.2 ns for those bound to 1.10-phenanthroline. Quantum yields were measured within 0.4 and 1.5%. The complexes were incubated with human lung (A549), brain (T98g), and breast (MDA-MB-231) cancer cells, as well as with normal human skin fibroblasts (HFF-1), revealing low to moderate cytotoxicity, which for some compounds exceeded that of a standard anti-cancer drug, cisplatin. Low cytotoxicity combined with significant cellular uptake and photoluminescence properties provides potential for their use as cellular imaging agents. Furthermore, the complexes were assessed in disc diffusion and broth microdilution assays against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), Escherichia coli (E. coli), and Pseudomonas aeruginosa (P. aeruginosa) bacterial strains, which revealed negligible antibacterial activity in the dark or after irradiation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
239. Preliminary investigations into the use of the ancient pigments Han blue and Han purple as luminescent dusting powders for the detection of latent fingermarks.
- Author
-
La Rocca, Ruby, Pitman, Rebecca, Shahbazi, Sorour, Lópes, Thais, Dallerba, Elena, Massi, Massimiliano, Smith, Gregory D., and Lewis, Simon W.
- Subjects
- *
SWEEPING & dusting , *LUMINESCENCE , *NEAR infrared radiation , *SUSTAINABLE development , *ULTRAVIOLET radiation - Abstract
Here we present our preliminary studies into the inorganic pigments Han blue (BaCuSi 4 O 10) and Han purple (BaCuSi 2 O 6) as near-infrared luminescent fingerprint dusting powders. These pigments were developed in ancient China around 800 BCE and both show luminescence in the NIR region. There remains, however, ambiguity in the literature concerning their photophysical properties. Samples of Han blue and Han purple artist's pigments were characterized by optical microscopy, infrared, ultraviolet-visible absorbance and luminescence spectroscopy. Their performance as fingerprint dusting powders, without any further treatment, on non-porous surfaces were compared to exfoliated lipophilic coated Egyptian blue and commercial fluorescent powders in a pilot study. These results demonstrate for the first time that both ancient pigments show promise as alternative dusting powders for latent fingermarks. [Display omitted] • Ancient pigments Han blue and Han purple investigated as dusting powders for latent fingermarks. • Comprehensive spectroscopic characterization of commercially available pigments carried out. • Both ancient pigments demonstrate promise as alternative dusting powders for latent fingermarks. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
240. Preclinical pharmacokinetics, pharmacodynamics, and toxicity of novel small-molecule GPR119 agonists to treat type-2 diabetes and obesity.
- Author
-
Patil, Mohan, Casari, Ilaria, Thapa, Dinesh, Warne, Leon N., Dallerba, Elena, Massi, Massimiliano, Carlessi, Rodrigo, and Falasca, Marco
- Subjects
- *
TYPE 2 diabetes , *GASTRIC inhibitory polypeptide , *PHARMACOKINETICS , *DRUG accessibility , *DRUG bioavailability , *PHARMACODYNAMICS - Abstract
The escalating global prevalence of type-2 diabetes (T2D) and obesity necessitates the development of novel oral medications. Agonism at G-protein coupled receptor-119 (GPR119) has been recognized for modulation of metabolic homeostasis in T2D, obesity, and fatty liver disease. However, off-target effects have impeded the advancement of synthetic GPR119 agonist drug candidates. Non-systemic, gut-restricted GPR119 agonism is suggested as an alternative strategy that may locally stimulate intestinal enteroendocrine cells (EEC) for incretin secretion, without the need for systemic drug availability, consequently alleviating conventional class-related side effects. Herein, we report the preclinical acute safety, efficacy, and pharmacokinetics (PK) of novel GPR119 agonist compounds ps297 and ps318 that potentially target gut EEC for incretin secretion. In a proof-of-efficacy study, both compounds demonstrated glucagon-like peptide-1 (GLP-1) secretion capability during glucose and mixed-meal tolerance tests in healthy mice. Furthermore, co-administration of sitagliptin with investigational compounds in diabetic db/db mice resulted in synergism, with GLP-1 concentrations rising by three-fold. Both ps297 and ps318 exhibited low gut permeability assessed in the in-vitro Caco-2 cell model. A single oral dose PK study conducted on healthy mice demonstrated poor systemic bioavailability of both agents. PK measures (mean ± SD) for compound ps297 (C max 23 ± 19 ng/mL, T max range 0.5 – 1 h, AUC 0–24 h 19.6 ± 21 h*ng/mL) and ps318 (C max 75 ± 22 ng/mL, T max range 0.25 – 0.5 h, AUC 0–24 h 35 ± 23 h*ng/mL) suggest poor oral absorption. Additionally, examinations of drug excretion patterns in mice revealed that around 25 % (ps297) and 4 % (ps318) of the drugs were excreted through faeces as an unchanged form, while negligible drug concentrations (<0.005 %) were excreted in the urine. These acute PK/PD assessments suggest the gut is a primary site of action for both agents. Toxicity assessments conducted in the zebrafish and healthy mice models confirmed the safety and tolerability of both compounds. Future chronic in-vivo studies in relevant disease models will be essential to confirm the long-term safety and efficacy of these novel compounds. [Display omitted] • Novel synthetic O-LPI mimetic compounds, ps297 and ps318 acts as GPR119 agonist. • Showed low gut permeability in vitro and minimal systemic availability in vivo. • In GTT, both agents corrected glucose excursion and modulated GLP-1 secretion. • Suggesting gut-restricted incretin modulation. • Appeared safe and tolerable in mice and zebrafish model. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
241. Well‐Defined Tetrazole‐Functional Copolymers as Macromolecular Ligands for Luminescent Ir(III) and Re(I) Metal Species: Synthesis, Photophysical Properties and Application in Bioimaging.
- Author
-
Dallerba, Elena, Hartnell, David, Hackett, Mark J., Massi, Massimiliano, and Lowe, Andrew B.
- Subjects
- *
HYBRID materials , *COPOLYMERS , *METALS , *LIGANDS (Chemistry) , *ULTRAVIOLET-visible spectroscopy , *POLYMERS , *METAL complexes - Abstract
Well‐defined copolymers containing luminescent iridium and hybrid iridium/rhenium fragments are prepared utilizing parent poly(n‐butyl acrylamide‐co‐N‐(1H‐tetrazol‐5‐yl) acrylamide) as macromolecular chelating species. The parent (co)polymers are prepared via the modification of a precursor poly(pentafluorophenyl acrylate) (polyPFPA) homopolymer, prepared by reversible addition‐fragmentation chain transfer polymerization, with n‐butylamine and 5‐aminotetrazole. Reaction of the parent copolymers with [Ir2(ppy)4(μ−Cl2)] (ppy = 2‐phenylpyridine) yields modified copolymers containing the Ir(ppy)2 fragment as a pendent group. Attachment of the Ir species is confirmed by a combination of photophysical studies, UV–Vis spectroscopy, and visually under irradiation with UV light. Importantly, it is demonstrated that the chelation of the Ir(ppy)2 fragment to a polymeric scaffold does not impact the fundamental photophysical properties of the Ir species. Attachment of a second luminescent metal species, Re(CO)3(phen) (phen = 1,10‐phenanthroline), gives hybrid materials containing Re(I) and Ir(III). The photophysical properties of these hybrid materials are consistent with the presence of both metal species and indicate the occurrence of energy transfer phenomena from the polymer‐bound Ir to Re metal centers. Finally, it is demonstrated that the Ir modified polymers and the Ir/Re hybrid materials offer potential in tissue imaging applications with scope to tune both luminescent properties and biological specificity as evidenced from preliminary brain tissue staining experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
242. Bottom–up nanofabrication of materials for organic electronics
- Author
-
Cavallini, Massimiliano, Facchini, Massimo, Massi, Massimiliano, and Biscarini, Fabio
- Subjects
- *
SURFACE chemistry , *PHYSICAL & theoretical chemistry , *CRYSTALLIZATION , *EVAPORATION (Chemistry) - Abstract
Self-organising functional systems and devices are the ultimate aim of bottom-up fabrication. Here, we show how spontaneous organisation can be exploited for patterning a variety of materials, relevant to organic electronics, into arrays of lines or dots by means of a stamp-assisted deposition method, termed lithographically controlled wetting (LCW). LCW is a versatile bottom-up method, able to exploit the spontaneous properties of materials; a stamp is gently placed on a solution layer cast on a substrate. Capillary forces pin the layer to the stamp protrusions, and the hydrodynamic flow during solvent evaporation moves the solution under the protrusions. As the critical concentration is achieved, the solute precipitates only in the regions where the solution is confined by the menisci, and the pattern exhibits the motif of the stamp. By changing concentration or stamp–substrate distance, it is possible to downscale the feature size down to sub-100nm length scale. Spatially organised nanodots or crystallites can be fabricated by exploiting dewetting, ripening and crystallization. [Copyright &y& Elsevier]
- Published
- 2004
- Full Text
- View/download PDF
243. Spectroscopic and Molecular Docking Study of the Interaction between Neutral Re(I) Tetrazolate Complexes and Bovine Serum Albumin.
- Author
-
Lazniewska, Joanna, Agostino, Mark, Hickey, Shane M., Parkinson‐Lawrence, Emma, Stagni, Stefano, Massi, Massimiliano, Brooks, Douglas A., and Plush, Sally E.
- Subjects
- *
SERUM albumin , *MOLECULAR docking , *FLUORESCENCE resonance energy transfer , *CARRIER proteins , *BOS , *MOLECULAR interactions - Abstract
Re(I) complexes have potential in biomedical sciences as imaging agents, diagnostics and therapeutics. Thus, it is crucial to understand how Re(I) complexes interact with carrier proteins, like serum albumins. Here, two neutral Re(I) complexes were used (fac‐[Re(CO)3(1,10‐phenanthroline)L], in which L is either 4‐cyanophenyltetrazolate (1) or 4‐methoxycarbonylphenyltetrazole ester (2), to study the interactions with bovine serum albumin (BSA). Spectroscopic measurements, calculations of thermodynamic and Förster resonance energy transfer parameters, as well as molecular modelling, were performed to study differential binding between BSA and complex 1 and 2. Induced‐fit docking combined with quantum‐polarised ligand docking were employed in what is believed to be a first for a Re(I) complex as a ligand for BSA. Our findings provide a basis for other molecular interaction studies and suggest that subtle functional group alterations at the terminal region of the Re(I) complex have a significant impact on the ability of this class of compounds to interact with BSA. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
244. Structure illumination microscopy imaging of lipid vesicles in live bacteria with naphthalimide-appended organometallic complexes.
- Author
-
Maria Ranieri, Anna, Vezzelli, Matteo, Leslie, Kathryn G., Huang, Song, Stagni, Stefano, Jacquemin, Denis, Jiang, Haibo, Hubbard, Alysia, Rigamonti, Luca, Watkin, Elizabeth L. J., Ogden, Mark I., New, Elizabeth J., and Massi, Massimiliano
- Subjects
- *
LUMINESCENT probes , *MOLECULAR probes , *MICROSCOPY , *BACILLUS cereus , *CHEMICAL stability - Abstract
There is a lack of molecular probes for imaging bacteria, in comparison to the array of such tools available for the imaging of mammalian cells. Here, organometallic molecular probes have been developed and assessed for bacterial imaging, designed to have the potential to support multiple imaging modalities. The chemical structure of the probes is designed around a metal-naphthalimide structure. The 4-amino-1,8-naphthalimide moiety, covalently appended through a pyridine ancillary ligand, acts as a luminescent probe for super-resolution microscopy. On the other hand, the metal centre, rhenium(I) or platinum(II) in the current study, enables techniques such as nanoSIMS. While the rhenium(I) complex was not sufficiently stable to be used as a probe, the platinum(II) analogue showed good chemical and biological stability. Structured illumination microscopy (SIM) imaging on live Bacillus cereus confirmed the suitability of the probe for super-resolution microscopy. NanoSIMS analysis was used to monitor the uptake of the platinum(II) complex within the bacteria and demonstrate the potential of this chemical architecture to enable multimodal imaging. The successful combination of these two moieties introduces a platform that could lead to a versatile range of multi-functional probes for bacteria. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
245. Mapping sub-cellular protein aggregates and lipid inclusions using synchrotron ATR-FTIR microspectroscopy.
- Author
-
Hartnell, David, Hollings, Ashley, Ranieri, Anna Maria, Lamichhane, Hum Bahadur, Becker, Thomas, Sylvain, Nicole J., Hou, Huishu, Pushie, M. Jake, Watkin, Elizabeth, Bambery, Keith R., Tobin, Mark J., Kelly, Michael E., Massi, Massimiliano, Vongsvivut, Jitraporn, and Hackett, Mark J.
- Subjects
- *
FOCAL plane arrays sensors , *LIFE sciences , *BIOTIC communities , *BIOMARKERS , *SYNCHROTRON radiation , *CELL aggregation - Abstract
Visualising direct biochemical markers of cell physiology and disease pathology at the sub-cellular level is an ongoing challenge in the biological sciences. A suite of microscopies exists to either visualise sub-cellular architecture or to indirectly view biochemical markers (e.g. histochemistry), but further technique developments and innovations are required to increase the range of biochemical parameters that can be imaged directly, in situ, within cells and tissue. Here, we report our continued advancements in the application of synchrotron radiation attenuated total reflectance Fourier transform infrared (SR-ATR-FTIR) microspectroscopy to study sub-cellular biochemistry. Our recent applications demonstrate the much needed capability to map or image directly sub-cellular protein aggregates within degenerating neurons as well as lipid inclusions within bacterial cells. We also characterise the effect of spectral acquisition parameters on speed of data collection and the associated trade-offs between a realistic experimental time frame and spectral/image quality. Specifically, the study highlights that the choice of 8 cm−1 spectral resolutions provide a suitable trade-off between spectral quality and collection time, enabling identification of important spectroscopic markers, while increasing image acquisition by ∼30% (relative to 4 cm−1 spectral resolution). Further, this study explores coupling a focal plane array detector with SR-ATR-FTIR, revealing a modest time improvement in image acquisition time (factor of 2.8). Such information continues to lay the foundation for these spectroscopic methods to be readily available for, and adopted by, the biological science community to facilitate new interdisciplinary endeavours to unravel complex biochemical questions and expand emerging areas of study. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
246. Structure, derivatisation, and metal complexation of p-cyclohexylcalix[4]arene.
- Author
-
Shen, Chao, Phe, Rene Z. H., Fong, Isabella, Sobolev, Alexandre N., Mocerino, Mauro, Massi, Massimiliano, and Ogden, Mark I.
- Subjects
- *
METALS , *EUROPIUM , *AROMATIC compounds , *DIMETHYLFORMAMIDE , *DICHLOROMETHANE - Abstract
Driven by an interest in the impact of the para-substituent of calix[4]arenes on metal complexation and structural chemistry, studies of p-cyclohexylcalix[4]arene (L) have been carried out. The 1:1 dichloromethane and dimethylformamide solvates were found to be isostructural, and different to the typical bilayer structure often observed for p-t-butylcalix[4]arene solvates. The methanol solvate, in contrast, does form a bilayered structure but is also a 1:1 solvate, unlike the p-t-butylcalix[4]arene·2MeOH system. Lanthanoid complexation was investigated, resulting in the structural characterisation of two different DMF solvates of a 2:2 dimeric europium complex, Eu2(L–3H)2(DMF)4. A tetrazole derivative, 5,11,17,23-tetracyclohexyl-25,27-dihydroxy-26,28-bis(tetrazole-5-ylmethoxy)calix[4]arene, has been synthesised via the intermediate 5,11,17,23-tetracyclohexyl-25,27-dihydroxy-26,28-dicyanomethoxycalix[4]arene, with the latter compound being structurally characterised. Attempts to isolate lanthanoid clusters supported by the tetrazole derivative under conditions known to form Ln19 clusters with the p-t-butyl analogue were unsuccessful, resulting only in isolation of the ligand from the reaction mixture. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
247. Accessing Lanthanide‐to‐Lanthanide Energy Transfer in a Family of Site‐Resolved [LnIIILnIII′] Heterodimetallic Complexes.
- Author
-
Abad Galán, Laura, Aguilà, David, Guyot, Yannick, Velasco, Verónica, Roubeau, Olivier, Teat, Simon J., Massi, Massimiliano, and Aromí, Guillem
- Subjects
- *
ENERGY transfer , *COORDINATE covalent bond , *LUMINESCENCE - Abstract
The ligand H3L (6‐[3‐oxo‐3‐(2‐hydroxyphenyl)propionyl]pyridine‐2‐carboxylic acid), which exhibits two different coordination pockets, has been exploited to engender and study energy transfer (ET) in two dinuclear [LnIIILnIII′] analogues of interest, [EuYb] and [NdYb]. Their structural and physical properties have been compared with newly synthesised analogues featuring no possible ET ([EuLu], [NdLu], and [GdYb]) and with the corresponding homometallic [EuEu] and [NdNd] analogues, which have been previously reported. Photophysical data suggest that ET between EuIII and YbIII does not occur to a significant extent, whereas emission from YbIII originates from sensitisation of the ligand. In contrast, energy migration seems to be occurring between the two NdIII centres in [NdNd], as well as in [NdYb], in which YbIII luminescence is thus, in part, sensitised by ET from Nd. This study shows the versatility of this molecular platform to further the investigation of lanthanide‐to‐lanthanide ET phenomena in defined molecular systems. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
248. Lanthanoid pyridyl-β-diketonate 'triangles'. New examples of single molecule toroics.
- Author
-
Caporale, Chiara, Sobolev, Alexandre N., Phonsri, Wasinee, Murray, Keith S., Swain, Abinash, Rajaraman, Gopalan, Ogden, Mark I., Massi, Massimiliano, and Fuller, Rebecca O.
- Subjects
- *
MAGNETIC relaxation , *TRIANGLES , *FORECASTING , *ANISOTROPY - Abstract
Trinuclear lanthanoid clusters have been synthesised and investigated as toroidal spin systems. A pyridyl functionalised β-diketonate, 1,3-bis(pyridin-2-yl)propane-1,3-dione (o-dppdH) has been used to synthesise a family of clusters of the form [Dy3(OH)2(o-dppd)3Cl2(H2O)4]Cl2·7H2O (1), [Tb3(o-dppd)3(μ3-OH)2(CH3CH2OH)3Cl3][Tb3(o-dppd)3(μ3-OH)2(H2O)(CH3CH2OH)2Cl3]Cl2·H2O (2), [Ho3(OH)2(o-dppd)3Cl(H2O)5]Cl3·3H2O (3) and [Er3(OH)2(o-dppd)3Cl2(H2O)3(CH3OH)]Cl2·3H2O·CH3OH (4). Despite the previous occurrence of this structural motif in the literature, these systems have not been widely investigated in terms of torodic behaviour. Magnetic studies were used to further characterise the complexes. DC susceptibility studies support weak antiferromagnetic exchange in the complexes. Slow magnetic relaxation behaviour is observed in the dynamic AC magnetic studies for complex 1. Theoretical studies predict that complex 1 and 3 have a non-magnetic ground state based on a toroidal arrangement of spins. Changes to the coordination environment in 2 do not support a toroic spin state. The prolate nature of the ErIII centres in complex 4 and large transverse anisotropy do not support the toroidal arrangement of lanthanoid spins in the complex. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
249. Rhenium N-heterocyclic carbene complexes block growth of aggressive cancers by inhibiting FGFR- and SRC-mediated signalling.
- Author
-
Domenichini, Alice, Casari, Ilaria, Simpson, Peter V., Desai, Nima Maheshkumar, Chen, Lingfeng, Dustin, Christopher, Edmands, Jeanne S., van der Vliet, Albert, Mohammadi, Moosa, Massi, Massimiliano, and Falasca, Marco
- Abstract
Background: Platinum-based anticancer drugs have been at the frontline of cancer therapy for the last 40 years, and are used in more than half of all treatments for different cancer types. However, they are not universally effective, and patients often suffer severe side effects because of their lack of cellular selectivity. There is therefore a compelling need to investigate the anticancer activity of alternative metal complexes. Here we describe the potential anticancer activity of rhenium-based complexes with preclinical efficacy in different types of solid malignancies. Methods: Kinase profile assay of rhenium complexes. Toxicology studies using zebrafish. Analysis of the growth of pancreatic cancer cell line-derived xenografts generated in zebrafish and in mice upon exposure to rhenium compounds. Results: We describe rhenium complexes which block cancer proliferation in vitro by inhibiting the signalling cascade induced by FGFR and Src. Initially, we tested the toxicity of rhenium complexes in vivo using a zebrafish model and identified one compound that displays anticancer activity with low toxicity even in the high micromolar range. Notably, the rhenium complex has anticancer activity in very aggressive cancers such as pancreatic ductal adenocarcinoma and neuroblastoma. We demonstrate the potential efficacy of this complex via a significant reduction in cancer growth in mouse xenografts. Conclusions: Our findings provide a basis for the development of rhenium-based chemotherapy agents with enhanced selectivity and limited side effects compared to standard platinum-based drugs. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
250. Dendronised Polymers as Templates for In Situ Quantum Dot Synthesis.
- Author
-
Munshi, Alaa M., Kretzmann, Jessica A., Evans, Cameron W., Ranieri, Anna M., Schildkraut, Zibeon, Massi, Massimiliano, Norret, Marck, Saunders, Martin, and Iyer, K. Swaminathan
- Subjects
- *
QUANTUM dot synthesis , *POLYAMIDOAMINE dendrimers , *POLYMERIC nanocomposites , *POLYMERS , *TARGETED drug delivery , *MOLECULAR weights - Abstract
The utility of dendrimers as effective carriers for targeted drug delivery and imaging has been facilitated by a high degree of molecular uniformity, narrow molecular weight distribution, tunable size and shape characteristics, and multivalency. Dendrimer–quantum dot (QD) nanocomposites have traditionally been synthesised by electrostatic self-assembly of preformed dendrimers and QDs, but higher generations are associated with limited flexibility and increased cytotoxicity. In this paper, we report the fabrication of CdTe QD nanoparticles using a dendronised linear copolymer bearing thiolated fourth-generation poly(amido amine) (PAMAM) dendrons as the capping and stabilising agent. We demonstrate this approach enables synthesis of nanocomposites with aqueous and photophysical stability. This paper describes the synthesis of green and yellow CdTe QD–dendronised polymer nanocomposites in situ using a partially thiolated dendronised polymer as capping agent and stabiliser. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.