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A molecular conjugate made of a free-base diphenyl porphyrin chromophore (DPP) trans-linked to two N-acridinium units has been synthesized and photophysically characterized in acetonitrile. Interestingly, the emission of both fluorophores is quenched in the array at room temperature. Steady-state and time-resolved optical analysis proved that an ultrafast electron transfer from the porphyrin to the acridinium units occurs upon excitation of either the porphyrin or the acridinium moiety. On the other hand, at low temperature (77 K) the emission of the porphyrin is completely recovered, thanks to the inhibition of the electron transfer, and a photoinduced energy transfer from the acridinium to the porphyrin component is observed.

A multi-responsive receptor consisting of two (acridinium-Zn(II) porphyrin) conjugates has been designed. The binding constant between this receptor and a ditopic guest has been modulated (i) upon addition of nucleophiles converting acridinium moieties into the non-aromatic acridane derivatives and (ii) upon oxidation of the porphyrin units. A total of eight states has been probed for this receptor resulting from the cascade of the recognition and responsive events. Moreover, the acridinium/ acridane conversion leads to a significant change of the photophysical properties, switching from electron to energy transfer processes. Interestingly, for the bis(acridinium-Zn(II) porphyrin) receptor, charge-transfer luminescence in the nearinfrared has been observed.

The increase of antimicrobial resistance to conventional antibiotics is worldwide a major health problem that requires the development of new bactericidal strategies. Antimicrobial photodynamic therapy (a-PDT) that generates reactive oxygen species acting on multiple cellular targets is unlikely to induce bacterial resistance. This localized treatment requires, for safe and efficient treatment of nonsuperficial infections, a targeting photosensitizer excited in the near IR. To this end, a new conjugate consisting of an antimicrobial peptide linked to a π-extended porphyrin photosensitizer was designed for a-PDT. Upon irradiation at 720 nm, the conjugate has shown at micromolar concentration strong bactericidal action on both Gram-positive and Gram-negative bacteria. Moreover, this conjugate allows one to reach a low minimum bactericidal concentration with near IR excitation without inducing toxicity to skin cells. Keywords: antimicrobial peptide; antimicrobial photodynamic therapy; bacteria; keratinocyte; near infrared; porphyrin.

Co-crystallization between the polycyclic aromatic hydrocarbons anthracene (A) and 9-methylanthracene (MA) with 1,4-diiodotetrafluorobenzene (I2F4) afforded three novel co-crystals, viz. A·(I2F4)2 and an unexpectedly complex system with two distinct compositions, namely MA·I2F4 and (MA)4·I2F4, which can be mechanochemically interconverted by a change in the stoichiometry of the reactive mixtures. Interestingly, all co-crystals are dual-emissive materials and exhibit different mechanisms of emission. A·(I2F4)2 and MA·I2F4 fluoresce from isolated molecules, whereas the luminescence of (MA)4·I2F4 is dominated by excimer emission. In all cases, phosphorescence at RT (RTP) is observed and interpreted as a direct consequence of the interactions between the iodine atoms of the I2F4 co-former and the π-electron density of the anthracene aromatic rings. Furthermore, [4 + 4] photoactivity within (MA)4·I2F4 was also investigated by means of FTIR/NMR spectroscopy and PXRD. The photophysical and photochemical behaviors of all solids are discussed and rationalized based on their structural features.

A novel Cu(I) cluster compound has been synthesized by reacting CuI with the 2,2′-dithiobis(5-nitropyridine) ligand under solvothermal conditions. During the reaction, the original ligand breaks into the 5-nitropyridine-2-thiolate moiety, which acts as the coordinating ligand with both N- and S-sites, leading to a distorted octahedral Cu6S6 cluster. The structure has been determined by single-crystal X-ray diffraction and FT-IR analysis, and the photophysical properties have been determined in the solid state by means of steady-state and time-resolved optical techniques. The cluster presents a near-infrared emission showing an unusual temperature dependence: when passing from 77 to 298 K, a blue-shift of the emission band is observed, associated with a decrease in its intensity. Time-dependent-density functional theory calculations suggest that the observed behavior can be ascribed to a complex interplay of excited states, basically in the triplet manifold.

The polycyclic aromatic hydrocarbon (PAH) triphenylene (TP) has been reacted with halo-pentafluorobenzene (XF5, X = Br, I) and 1,4-dihalo-tetrafluorobenzene (X2F4, X = Br, I) to yield the corresponding cocrystals TP center dot BrF5, TP center dot Br2F4, TP center dot IF5, and TP center dot I2F4 form I. These materials have been synthesized by dissolving TP into an excess of liquid or molten coformer, and single crystals have been grown via seeding chloroform solutions. They have been fully characterized by a combination of techniques including X-ray diffraction, Raman spectroscopy, and luminescence spectroscopy in the solid state. TP center dot I2F4 form I was found to undergo a single-crystal to single-crystal (SCSC) polymorphic phase transition induced by temperature (when cooled down to 100 K) leading to the new form TP center dot I2F4 form II, which is transformed back into the first structure when brought again at RT. This behavior was confirmed also by Raman spectroscopy. Upon cocrystallization and as a result of the external heavy atom effect, all crystalline materials exhibited bright room temperature phosphorescence clearly visible by the naked eye. The latter was almost exclusive for cocrystal TP center dot I2F4, whereas for TP center dot Br2F4 both fluorescence and phosphorescence were detected. In TP center dot Br2F4, the phosphorescence lifetime was on the order of 200 ms, and with the visual outcome of an orange phosphorescence lasting for a couple of seconds upon ceasing the excitation, that makes this compound classifiable as an ultralong organic phosphorescent (UOP) material. The results evidenced the role of the nature of the heavy atom in governing the phosphorescence output from organic cocrystals.

Tetraphenylmethane appended with four pyridylpyridinium units works as a scaffold to self-assemble four ruthenium porphyrins in a tetrahedral shape-persistent giant architecture. The resulting supramolecular structure has been characterised in the solid state by X-ray single crystal analysis and in solution by various techniques. Multinuclear NMR spectroscopy confirms the 1 : 4 stoichiometry with the formation of a highly symmetric structure. The self-assembly process can be monitored by changes of the redox potentials, as well as by modifications in the visible absorption spectrum of the ruthenium porphyrin and by a complete quenching of both the bright fluorescence of the tetracationic scaffold and the weak phosphorescence of the ruthenium porphyrin. An ultrafast photoinduced electron transfer is responsible for this quenching process. The lifetime of the resulting charge separated state (800 ps) is about four times longer in the giant supramolecular structure compared to the model 1 : 1 complex formed by the ruthenium porphyrin and a single pyridylpyridinium unit. Electron delocalization over the tetrameric pyridinium structure is likely to be responsible for this effect.

The fluorescent dye perylene-3,4,9,10-tetracarboxylic dianhydride (PBA) was immobilized onto polysulfone hollow fibers by means of a wet coating procedure. After immobilization, PBA was able to react with primary amines through a double anhydride ring opening reaction. The in situ amine coupling was further revealed by fluorescence analysis. Both emission (534 nm →538 nm) and fluorescence lifetime changes (2.7 ns →3.3 ns) of the dye are a useful tool to detect and visualize the occurrence of the reaction. The successful implementation of amine coupling with a reporting function on polysulfone fibers holds great interest for biomedical applications.

The documents contain the poster and the program of the "Society 2019" event for the European Researchers Night in Bologna, Italy. The event took place on September 27, 2019.

International audience; The photophysical properties of heteroleptic rotor-like Ru(II) complexes containing both a cyclopentadienyl-type ligand and a hydrotris(indazolyl)borate chelating unit with a piano stool structure (Ar5L1-Ru-S1 and L3-Ru-S1) and their corresponding subunits have been investigated. The complexes show peculiar absorption features when compared with their related ligands or fragments. L3-Ru-S1 was found to be non-emissive, while Ar5L1-Ru-S1 showed a weak emission with a quantum yield of 0.27%. With the help of DFT calculations, we demonstrate that the new absorption features can be attributed to ruthenium-based charge transfer transitions which involve the π* orbitals of the phenyl substituents of the cyclopentadienyl ligand.

With reference to the newly launched Horizon Europe MSCA Postoctoral Felloships call, and based on personal experiences on the supervision of postdoctoral projects within the previous Horizon 2020 Program, I will draw an overview of the process of proposal's writing with suggestions to improve the efficacy of the text and avoid errors that can reduce the chance of success.

Dynamics of the exited state of three complexes C1, C2 and C3 in dichloromethane have been probed by Transient Absorption Spectroscopy in the femtosecond time domain at different excitation wavelengths. The three complexes, regardless to the substitution pattern of corresponding free ligands (Figure I), revealed almost identical photophysical behaviour. In all case the excited complexes from an initially 1(M+X)LCT state either relax to the ground state or undergo fast Intersystem Crossing to 3(M+X)LCT within ~1 ps. In these dimeric systems the radiationless relaxation from 3(M+X)LCT occurs within the very fast time constant of ~25 ps. This unusual fast spin forbidden deactivation can be explained by Energy Gap Law through nested Potential Energy Sutrfaces of T1 and S0. When samples were excited at higher energies (440 nm) some photodegredation with ligand dissociation was observed. Despite of similar photophysical behaviour the extent of photodegredation is significantly reduced by introduction of NO2 group in acenaphthene moiety of the free ligands. This functionalization made us possible to study the deactivation dynamics of the excited states in halide-bridged dimeric Cu(I) complexes bearing Ar-BIAN ligands.

Online event: seminar and discussion with the audience, in the frame of the European Researchers' Night 2020, 27 November 2020, from 20:00 pm to 23:00 pm.

With the aim of developing new molecular theranostic agents, pi-extended Zn(II) porphyrin as photosensitizer for photodynamic therapy (PDT) linked to two GdDOTA-type complexes for magnetic resonance imaging (MRI) detection was synthesized. The relaxivity studies revealed a much higher relaxivity value per Gd ion for this medium sized molecule (19.32 mM(-1) s(-1) at 20 MHz and 298 K) compared to clinical contrast agents-a value which strongly increases in the presence of bovine serum albumin, reaching 25.22 mM(-1) s(-1). Moreover, the photophysical studies showed the strong ability of the molecule to absorb light in the deep red (670 nm, epsilon approximate to 60000 M-1 cm(-1)) and in the near-infrared following two-photon excitation (920 nm, sigma(2) approximate to 650 GM). The conjugate is also able to generate singlet oxygen, with a quantum yield of 0.58 in DMSO. Promising results were obtained in cellular studies, demonstrating that the conjugate is internalized in HeLa cells at micromolar concentration and leads to 70% of cell death following 30 min irradiation at 660 nm. These results confirm the potential of the designed molecule as an imaging and therapeutic agent.

In this work, different materials were fabricated from cellulose acetate, loaded with rhodamine B hydrazide and tested as Cu(II) optical sensor. We prepared membranes displaying a sub-micron porous structure using the phase inversion technique, clusters of fibers with varying diameter depending on the preparation procedure using electrospinning, and casted films presenting a smooth non porous structure. Loading of rhodamine B hydrazide on the fabrics after their production was found to be the best procedure to ensure the stability of the dye in the polymeric materials. Absorption and emission analysis of the solid substrates revealed the presence of the dye on the porous fabrics and allowed to choose the most suited materials and loading conditions to test their response towards Cu(II) ions. Reaction of the loaded rhodamine B hydrazide with Cu(II) was confirmed by absorption and emission spectroscopies and by confocal fluorescence imaging, through detection of the product rhodamine B. The results point to promising sensing applications of the prepared composite materials.

Three new coordination polymers (CPs) named [Cu(6mna)]n (CP1), [CuCl(H6mna)(H2O)0.33]n (CP2), and {[(CuI)2H2dtdn].MeCN}n (CP3), (H6mna = 6-mercaptonicotinic acid, and H2dtdn = 6,6’-dithiodinicotinic acid) have been synthesized and their structures determined by single-crystal X-ray diffraction. Complexes 1 and 3 are 2D-CPs while complex 2 is a 1D-CP. The optical properties of these complexes have been evaluated in the solid state, at room temperature and at 77 K, and compared with those of the starting ligands. The electrical conductivity of CPs 1–3 has been evaluated and their thermal stabilities have been studied. CP2 shows an interesting crystal arrangement, where the connection between the ligand and the copper forms a channel-like structure characterized by an intrinsic disorder. Crystal data collected at low temperatures for this complex revealed minor structural changes in the Cu⋯Cu distances and Cu–S–Cu angles along the chain, excluding phase transition. In CP1, the N and S atoms are involved in metal coordination bonds giving rise to a 2D coordination polymer. In CP3, the Cu-I bonds compose double ladder-like structures, bridged by H2dtdn ligands. The electrical conductivities of CPs 1–3 suggest their semiconductive behavior.

The complexation processes of N,N'-dibutyl-1,4,5,8-naphthalene diimide (NDI) into two types of ?-electron-rich molecular containers consisting of two Zn(II)-porphyrins connected by four flexible linkers of two different lengths, were characterized by means of absorption and emission spectroscopies and molecular dynamics simulation. Notably, the addition of NDI leads to a strong quenching of the fluorescence of both cages only when they are in an open conformation suitable for guest encapsulation, a situation triggered by silver(I) ions binding to the lateral triazoles. Molecular dynamics simulations confirm the fast binding of NDI, likely assisted by NDI-silver(I) interactions. Upon NDI complexation, the two porphyrin macrocycles get closer, with an optimized face to face orientation, suggesting an induced-fit mechanism through ?-? interactions with the NDI aromatic cycle. Ultrafast transient absorption experiments allowed to identify the process of quenching of the Zn-porphyrin fluorescence as an efficient photoinduced electron transfer reaction between the cage porphyrin and the included NDI guest. The process occurs on fast and ultrafast time scales in the two complexes (1.5 ps and

Proton-coupled electron transfer (PCET) plays a key role in many biological processes, and a thorough comprehension of its subtle mechanistic complexity requires the synthesis and characterization of suitable artificial systems capable of mimicking this fundamental, elementary step. Herein, we report on a detailed photophysical investigation of conjugate 1, based on a tin(IV) tetraphenylporphyrin (SnTPP) chromophore bound to two l-tyrosinato amino acids, in CH2Cl2 in combination with organic bases of different strength and the preparation of a novel conjugate 3, based on a tin(IV) octaethylporphyrin (SnOEP) in place of the tetraphenyl analogue, and its photophysical characterization in CH2Cl2 in the presence of pyrrolidine. In the case of compound 1 with all bases examined, quenching of both the singlet and triplet excited states is observed and attributed to the occurrence of concerted proton-electron transfer (CPET). Rates and quenching yields decrease with the strength of the base used, consistent with the decrease of the driving force for the CPET process. Conjugate 3 with pyrrolidine is quenched only at the triplet level by CPET, albeit with slower rates than its parent compound 1, ascribable to the smaller driving force as a result of SnOEP being more difficult to reduce than SnTPP. For both systems, the quenching mechanism is confirmed by suitable blank experiments, specific kinetic treatments, and the observation of kinetic isotope effects (KIEs). Differently from what has been previously proposed, a detailed reinvestigation of the triplet quenching of 1 with pyrrolidine shows that no long-lived radical pair state is formed, as diradical recombination is always faster than formation. This is true for both 1 and 3 and for all bases examined. The kinetics of the CPET pathways can be well described according to Marcus theory and point toward the involvement of substantial reorganization energy as typically observed for PCET processes of concerted nature.

Polysulfone-based materials were fabricated as casted films, porous membranes, and nanofibers by solution casting, phase inversion process, and electrospinning technique, respectively. Photoactive rhodamine B hydrazide molecules were loaded into the fabrics either in preloading or postloading processes. The morphological structure of the fabrics was investigated by scanning electron microscopy and the wettability was determined by contact angle measurements. Detailed spectroscopic characterizations of the closed and open forms of rhodamine B was performed both in solution and in the solid-state composite materials. Theoretical investigations supported the depiction of the absorption and emission features of the two forms. The response of the prepared composite materials to Cu(II) ions has been tested by absorption and emission spectroscopy and confocal fluorescence imaging. The most effective materials for Cu(II) detection were found to be polysulfone films prepared by phase inversion and postloaded with 10% rhodamine B hydrazide. These results open the way to the development of composite sensory membranes. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48408.

International audience; A molecular theranostic agent designed for photodynamic therapy (PDT) treatment in the near-infrared and for imaging tissue tumors with magnetic resonance imaging (MRI) is reported. It consists of a linear pi-conjugated Zn(II) porphyrin dimer linked at each extremity to a GdDOTA-type complex. This agent has shown very promising potential for PDT applications with good singlet oxygen generation in DMSO and high linear absorption in the near- infrared (lambda(max) = 746 nm, epsilon approximate to 10(5) M-1 cm(-1)). Moreover, this molecule has a propensity for two-photon excited PDT with high two-photon cross sections (similar to 8000 GM in 880-930 nm range), which should allow for deeper tumor treatments and higher spatial precision as compared to conventional one-photon PDT. Regarding the MRI contrast agent properties, the molecule has shown superior relaxivity (14.4 mM(-1) s(-1) at 40 MHz, 298 K) in comparison to clinical contrast agents and the ability to be internalized in cells, thanks to its amphiphilic character. Irradiation of HeLa cells using either one-photon (740 nm) or two-photon excitation (910 nm) has led in both cases to important cell death.

Two hybrid dyes possessing tetraphenylethylene moieties weakly conjugated with a pyrrolo[3,2-b]pyrrole core have been synthesized. Both dyes display a weak emission in solution, however, in the solid state a similar to 100-fold increase in the fluorescence quantum yield is observed. The position of the molecular rotors about the core greatly influences the photophysical characteristics. The variances in emission properties were assigned to entirely different changes in dihedral angles upon excitation, which in turn have substantial effects on radiative rate constants, allowed transitions, and HOMO/LUMO distribution.

trans-A(2)B-Corroles with amide substituents at different positions versus the macrocyclic core have been synthesized. Their self-organizing properties have been comprehensively evaluated both in solid-state and in solution. The rigid arrangement of the amide functionality with the corrole ring led to the formation of strong intramolecular interactions and precluded intermolecular interactions. Replacement of sterically hindered C6F5 substituents at positions 5 and 15 with smaller electron-withdrawing CO2Me groups resulted in significant changes in the self-assembly pattern. With these substituents, tetramers formed in a crystalline state, in which one of the H-pyrrole subunits is out of the corrole plane. This allows the N-H group to form a hydrogen bond with a neighboring carbonyl group of the n-butyl amide fragment. DOSY NMR studies showed that amido-corroles bearing the OCH(2)CONHnBu motif formed dimers in millimolar solutions in nonpolar solvents and the dimers existed in equilibrium with monomers. However, the corroles possessing meso-ester groups did not form dimers in polar tetrahydrofuran. Comprehensive optical studies allowed the absorption and emission features of the monomer corroles to be characterized in dilute solutions.

The synthesis and photophysical properties of two multichromophoric systems, Pt(II)/B(III) and Pt(II)/Ir(III), based on novel N^O-julolidine ligands are reported. The functionalization of the julolidine core enables the introduction of two different anchoring sites, a terminal acetylene and an N^O chelating moiety, which allow the assembling of two different chromophoric centers. The complex photophysical behavior of these multicomponent arrays is rationalized by investigating a series of model compounds, which are prepared through specific synthetic pathways. The photophysical properties of the final multicomponent arrays are investigated in parallel with the models. The multichromophoric system, composed by a platinum(II) and an iridium(III) chromophore connected through a modified julolidine ditopic ligand, displays a peculiar excitation wavelength dependent luminescence behavior. It exhibits tuning of the emission color from blue to orange, passing through pure and warm white.

The interlocking of ring and axle molecular components in rotaxanes provides a way to combine chromophoric, electron-donor and electron-acceptor moieties in the same molecular entity, in order to reproduce the features of photosynthetic reaction centers. To this aim, the photoinduced electron transfer processes involving a 1,8-naphthalimide chromophore, embedded in several rotaxane-based dyads, were investigated by steady-state and time-resolved absorption and luminescence spectroscopic experiments in the 300 fs-10 ns time window. Different rotaxanes built around the dialkylammonium/ dibenzo[24]crown-8 ether supramolecular motif were designed and synthesized to decipher the relevance of key structural factors, such as the chemical deactivation of the ammonium-crown ether recognition, the presence of a secondary site for the ring along the axle, and the covalent functionalization of the macrocycle with a phenothiazine electron donor. Indeed, the conformational freedom of these compounds gives rise to a rich dynamic behavior induced by light and may provide opportunities for investigating and understanding phenomena that take place in complex (bio)molecular architectures.

Poster presented at the "European Reserachers' Night 2018", in the frame of the activity "TEC01: I MOF come sensori chimici e adsorbenti di inquinanti", 28 September 2018, Bologna, Italy

Coordination polymers (CPs) or metal-organic frameworks (MOFs), consisting of metal ions and bridging organic ligands, have attracted considerable interest as a potential source of functional materials that can bring display remarkable physical properties such as luminescence, magnetism, electrical conductivity, or a combination of more than one physical properties.[1] The properties of CPs/MOFs, basically, depend on the suitable selection of their main molecular components, i.e. the metal ion or cluster and the multidentate organic ligand, and on how they align arrange to form the final solid state structure. We are interested in the application of CPs/MOFs as chemical sensors which require signal transduction based on the dynamics of the analyte interacting with the CPs/MOF network. We honed from the design principles of previous research in the field of optical and/or conductive CPs/MOFs to select starting building blocks (Scheme 1) that can be employed to produce CPs/MOFs with remarkable optical and conductivity features. In that regard, copper(I) based CPs/MOFs have attracted great attention as potential candidates for optical, electronic, and optoelectronic applications. Copper(I), with a d10 electronic configuration, is well known for its diverse coordination geometries, which afforded CPs with unprecedented structural motifs and physico-chemical properties.[2] On the other hand, Copper(I) complexes with nitrogen-sulfur donor ligands has drawn much attention as suitable building units to construct new multifunctional materials with fascinating structure and properties where they adopt a wide range of coordination modes.[3] The selected units will offer extensive connectivity, flexibility, tunable porosity and functionalization of the inner surface of the network, with groups interacting with the analytes by means of coordination bonds, p-p interactions or hydrogen bonds.

Coordination polymers (CPs) are polymeric structures containing metal centers linked, in an infinite one-, two-, or three-dimensional network, by suitable organic ligands. They are particularly attractive for their diverse structural motifs and physico-chemical properties. [1] Copper(I) based coordination polymers, in particular, offer a rich coordination ability combined with excellent photophysical and electronic properties. [2] The selection of the ligands is of crucial importance for tuning the final architecture of the materials, and their optical and electrical behaviour. We are interested in the application of coordination polymers as chemical sensors, where the signal transduction is based on the interaction of the analyte with the CP network. Both optical and electrical changes are foreseen to be used as effective recognition signals. In this work, we have selected nitrogen-sulfur heterocyclic units as chelating ligands. These multifunctional ligands contain a carboxylic group, a thiol group and a pyridinic nitrogen. Thus, they can exhibit different coordination sites for copper(I) and different final structural motifs. Three new coordination polymers have been obtained by the assembly of these ligands with Cu(I) ions. Two of them are two-dimensional CPs while one is a one-dimensional CP and their crystal structures differ in the coordination geometry. The optical properties of the complexes, evaluated in the solid state at room temperature and at 77K, will be presented and discussed.

Poster presented at the "European Reserachers' Night 2017", in the frame of the activity "Nanotecnologie per combattere i super-batteri e rivelare sostanze organiche volatili", 29 September 2017, Opificio Golinelli, Bologna, Italy.

Poster presented at the "Annual Congress of the Italian Society of Photobiology - SIFB2019", 19-21 June 2019, CNR-ISOF, Bologna, Italy.

Access to clean water continues to be the most urgent and pressing global issue. The increasing scarcity of freshwater sources and the global demand for water is expected to grow in the oncoming decades which urge the need to develop alternative water supplies, including seawater desalination, reuse and recycling of wastewater. Membrane-based separations for water treatment and desalination are playing an increasingly important role to provide adequate water resources of desirable quality for a wide spectrum of designated applications. H2020-MSCA-IF-project "Enhanced-MUMs" targets the development of advanced multifunctional and low-cost polymeric membranes for water treatment and desalination. The project is a multidisciplinary one and its main innovation resides in the combination of (1) enhanced structural properties: high porosity and reinforcement, for improved water treatment and desalination characteristics and (2) light-induced antifouling and antimicrobial activity based on the loading of photosensitizers in the polymeric membrane. The current work represents optimization of the preparation conditions of cellulose acetate membranes by phase inversion technique using automatic film applicator and water as a coagulation medium. The prepared bare membranes have a well-defined anisotropic microscopic structure with a pure water flux range from 150 L/m2.h to 990 L/m2.h using different membrane thickness and under different applied pressure. Modified membranes have been prepared using salt coagulation bath as well as in-situ salt addition to the polymer solution during the membrane fabrication. It was found that the preparation conditions greatly affect the microscopic and surface characteristics. The project also aims to: improve the microscopic structure with regard to the pore size and structure and improve the mechanical properties of the modified membranes. In addition, the project aims also to study and control the fouling characteristics of the membranes by imparting photo-induced properties for enhanced antimicrobial and antifouling effects.

Access to clean water continues to be the most urgent and pressing global issue The increasing scarcity of freshwater sources and the global demand for water is expected to grow in the oncoming decades which urge the need to develop alternative water supplies, including seawater desalination, reuse and recycling of wastewater. H2020 MSCA IF project "Enhanced MUMs" targets the development of advanced multifunctional and low cost polymeric membranes for water treatment and desalination The project is a multidisciplinary one and its main innovation resides in the combination of (1) enhanced structural properties high porosity and reinforcement, for improved water treatment and desalination characteristics and (2) light induced antifouling and antimicrobial activity based on the loading of photosensitizers in the polymeric membrane. The current work represents optimization of the preparation conditions of cellulose acetate membranes by phase inversion technique using automatic film applicator and water as a coagulation medium.

In-depth photophysical studies of four flexible covalent cages bearing either two free-base porphyrins or one free-base porphyrin and one Zn(II) porphyrin, connected by linkers of different lengths, are reported. In the case of the cages with two free-base porphyrins, exciton coupling between the porphyrins is evidenced by large and split Soret bands in the absorption spectra, but the different length of the linkers has only a slight effect on their emission properties. Strong electronic interactions between the porphyrins are also evidenced for the cages that incorporate a free-base porphyrin and a Zn(II) porphyrin, with a more pronounced splitting of the Soret band for the system with longer linkers. In these cages, following excitation of the Zn-porphyrin component, an almost quantitative energy transfer to the free-base unit occurs, with a rate 1.4 times faster in the cage with longer linkers (1.4 × 10[Formula: see text] s[Formula: see text] vs. 1.0 × 10[Formula: see text] s[Formula: see text]. This difference might reflect the more flattened conformation adopted by the cage equipped with longer and more flexible linkers, the latter allowing for a shorter interplanar distance between the porphyrins. The results are discussed in terms of classical and short-range energy transfer mechanisms.

Molecular cages incorporating two or more porphyrins have shown the ability to respond to light and to work as nanoreceptors or nanoreactors, depending on the specific geometrical arrangement of the porphyrins [1]. Here, a combined spectroscopic and computational approach is presented to study two covalent cages consisting of two zinc(II) tetraphenylporphyrins connected by four flexible spacers of different length and their corresponding silver(I)-complexed cages [2]. The essential features of the experimental Soret bands of the porphyrinic cages are for the first time interpreted and characterized at a molecular level by means of a mixed quantum/classical procedure based on molecular dynamics (MD) simulation and the perturbed matrix method (PMM) [3]. Despite the zinc-to-zinc distance is found to be similar in both cages, the MD-PMM calculations show that the conformation adopted by the cage with longer linkers corresponds to more slipped porphyrins, giving rise to a redshifted (7-8 nm), broader and slightly splitted Soret peak with respect to the cage with shorter linkers. The same method allows also for a comprehensive interpretation of the changes in the UV-visible absorbance of the cages upon silver(I) complexation to the peripheral binding sites. The process of silver(I) complexation separates the two porphyrins in a face-to-face conformation in both cages resulting in narrower (and more similar) Soret bands due to a reduced excitonic coupling. The very good agreement between experimental and theoretical results gives high credence to this method to get geometrical data of interacting porphyrins in complex architectures, simply from their absorption spectra.

Access to clean water continues to be the most urgent and pressing global issue. The increasing scarcity of fresh water sources and the global demand for water is expected to grow in the oncoming decades, whith the urgent need to develop alternative water supplies, including seawater desalination, reuse and recycling of wastewater. Membrane-based separations for water treatment and desalination are playing an increasingly important role to provide adequate water resources of desirable quality for a wide spectrum of designated applications. H2020-MSCA-IF-project 'Enhanced-MUMs' is a multidisciplinary project that aims at bringing high innovation in the forefront research area of water treatment and desalination. Enhanced-MUMs targets the development of advanced multifunctional and low-cost polymeric membranes for water treatment and desalination. The main innovation resides in the combination of enhanced structural properties (high porosity and reinforcement) for improved desalination characteristics and light-induced antifouling and antimicrobial activity based on the loading of photosensitizers in the polymeric membrane. The current work represents optimization of the preparation conditions of cellulose acetate membranes by phase inversion technique using automatic film applicator and water as a coagulation medium. The prepared bare membranes have a well-defined anisotropic microscopic structure with a pure water flux range from 150 L/m2.h to 990 L/m2.h using different membrane thickness and under different applied pressures. Modified membranes have been prepared using salt coagulation bath as well as in-situ salt addition to the polymer solution during the membrane fabrication. It was found that the preparation conditions greatly affect the microscopic and surface characteristics. The project also aims to: improve the microscopic structure with regard to the pore size and structure and improve the mechanical properties of the modified membranes. In addition, the project aims also to study and control the fouling characteristics of the membranes by imparting photo-induced antimicrobial and antifouling effects.

Melanoma is an aggressive cancer with a high rate of mortality and morbidity due to its unresponsiveness to conventional radiotherapy and chemotherapy. Photodynamic Therapy (PDT) is a minimally-invasive technique that combines a photosensitiser, light and oxygen to induce cell death. Although an established modality for non-melanoma skin cancers, it is currently not suitable for melanoma since the (visible) activating light has very limited penetration due to the high tumour pigmentation. This limitation can be overcome by using an innovative strategy based on two-photon excitation photodynamic therapy (TPE-PDT) for the destruction of melanoma.[1] It requires the design of specific two-photon absorbing photosensitisers that bypass the absorption of the high melanin content of melanomas and the use of excitation in the near-infrared (NIR) for a deep penetration of light, to perform an efficient treatment. Porphyrin derivatives were developed in the group as TP photosensitisers to perform PDT in the NIR.[2] They have very appealing features for TP-PDT, a large TP absorption cross-section (s2 > 1000 GM) in the NIR and significant singlet oxygen production (0.5-0.6 in DMSO). TP excitation at 910 nm performed on cancer cells incubated with such molecules led to important cell death.[3] Based on these results, a new family of PSs with a large ?-delocalized system and using folic acid as a vector was designed within sight of treating melanoma cancer.

Coordination polymers (CPs), consisting of metal ions and bridging organic ligands, have attracted considerable interest as a potential source of functional materials that can bring display remarkable physical properties such as luminescence, magnetism, electrical conductivity, or a combination of more than one physical properties.1 The properties of CPs/MOFs, basically, depend on the suitable selection of their main molecular components, and on how they align arrange to form the final solid state structure. We are interested in the application of CPs and metal-organic frameworks (MOFs; porous coordination polymers) as chemical sensors which require signal transduction based on the dynamics of the analyte interacting with the CPs/MOF network. We honed from the design principles of previous research in the field of optical and/or conductive CPs/MOFs to select starting building blocks (Scheme 1) that can be employed to produce CPs/MOFs with remarkable optical and conductivity features. In that regard, copper(I) based CPs/MOFs have attracted great attention as potential candidates for optical, electronic, and optoelectronic applications. Copper(I), with a d10 electronic configuration, is well known for its diverse coordination geometries, which afforded CPs with unprecedented structural motifs and physico-chemical properties.2 We present here copper(I) complexes with nitrogen-sulfur donor ligands has drawn much attention as suitable building units to construct new multifunctional materials with fascinating structure and properties where they adopt a wide range of coordination modes.3 The selected units offer extensive connectivity, flexibility, and free functional groups that may interacting with the analytes by means of coordination bonds, p-p interactions or hydrogen bonds.

Reversible molecular encapsulation constitutes a strategy to control the environment and the encounters of molecules. The isolation from the bulk phase provided by the encapsulation process has a profound impact on the physical and chemical properties of the bound molecular identity such as reactive intermediates can be stabilised, the typical course/rate of chemical reactions occurring in the bulk solution can be altered, reactions can be performed in solvents where reactants are not soluble, etc... Molecular encapsulation is a key strategy also for the selective extraction of neutral molecules, ions and ion-pairs from mixtures. In addition the synthesis of photoactive entities can lead to applications such as "artificial enzyme" catalysis, hazardous chemical capture and reactive intermediate stabilization, drug delivery and release or molecular sensing.

International audience; Despite the advantages of photodynamic therapy (PDT) over chemotherapy or radiotherapy such as low side effects, lack of treatment resistance and spatial selectivity inherent to light activation of the drug, several limitations especially related to the photosensitiser (PS) prevent PDT from becoming widespread in oncology. Herein, new folic acid- and biotin-conjugated PSs for tumour-targeting PDT are reported, with promising properties related to PDT such as intense absorption following one-photon excitation in the red or two-photon excitation in the near-infrared, and also high singlet oxygen quantum yield (close to 70% in DMSO). Cellular studies demonstrated that both targeted PSs induced phototoxicity, the folate-targeted PS being the most effective one with 80% of cell death following 30 min of irradiation and a phototoxicity four times higher than that of the non-targeted PS. This result is in accordance with the uptake of the folate-targeted PS in HeLa cells, mediated by the folate receptors. Moreover, this folate-targeted PS was also phototoxic following two-photon excitation at 920 nm, opening new perspectives for highly selective PDT treatment of small and deep tumours.

The essential features of the experimental Soret bands of two covalent cages, consisting of two zinc-porphyrins connected by four flexible spacers, are for the first time interpreted and characterized at a molecular level by means of a mixed quantum/classical procedure based on molecular dynamics (MD) simulation and the perturbed matrix method (PMM). The same method allows also for a comprehensive interpretation of the changes in the UV−visible absorbance of the cages upon silver(I) complexation to the peripheral binding sites. Although the zinc-to-zinc distance is found to be similar in both cages, the MD-PMM calculations show that the conformation adopted by the cage with longer linkers corresponds to more slipped porphyrins, giving rise to a red-shifted (7−8 nm), broader, and slightly split Soret peak with respect to the cage with shorter linkers. The process of silver(I) complexation separates the two porphyrins in a face-to-face conformation in both cages, resulting in narrower (and more similar) Soret bands due to a reduced excitonic coupling. Despite the similar features of the spectra of the two silver(I)-complexed cages, a slight difference in the peak maxima of about 2 nm is observed, arising from a slightly shorter zinc-to-zinc distance in the cage with longer linkers. These results show that the MD-PMM methodology is a reliable method to obtain information on the relative disposition and exciton coupling interaction of porphyrins in flexible systems in solution, from the analysis of their absorption spectra.

[object Object]A three-step synthetic route to a structurally unique p-expanded pyrrolo[3,2-b]pyrrole derived bisketone has been developed. In contrast to all previous ladder-type pyrrolopyrroles, the new dye exhibits a low-energy absorption band in the visible region which is responsible for its red-purple color. Interestingly, even though the compound is centrosymmetric, this band coincides with the lowest energy two-photon absorption (TPA) transition. This non-typical behaviour has been computationally rationalized by finding two close lying excited states, one of which (S1) is active for OPA and the other (S2) for TPA processes, which arise from the mixing of two symmetric partial charge-transfer states. The ultrafast excited-state dynamics was characterized by means of transient absorption analysis. A relaxation process involving S1 symmetry breaking occurs in a few ps, leading to the formation of the lowest energy charge-transfer state. This is weakly emitting, with a measured lifetime in the order of tens of picoseconds. Interestingly, two-photon polymerization has been achieved using this new ketone. The high yield of radical photo-initiation upon two-photon excitation was demonstrated by the fabrication of woodpile photonic crystal templates by direct laser writing using a zirconium-silicon hybrid composite.

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