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A family of bimetallic complexes based on aurophilic interactions was synthesized, and tested for vapochromism and P–T variations. These complexes can originate cocrystals, opening the route to a new aurophilic-based crystal engineering.

Mixed mercury(II) halogenides have been known for a long time as good NLO (non-linear optic) materials. The NLO properties are due to the halogen disposition in the solid state and the electron distribution among the bonds formed by soft elements. We investigated the possibility of using HgBrI as a asymmetric tecton in the preparation of noncentrosymmetric crystalline compounds, by exploiting the coordinating power of Hg(II) toward N-donor ligands, and seven coordination complexes have been obtained. To unravel the nature of these complex systems we combined the data from different techniques: Raman spectroscopy, SC-XRD and Second Harmonic Generation, supported by a periodic DFT computational approach. In HgBrI crystalline products with low symmetry, the presence of substitutional disorder leads to a lack of the inversion center conferring NLO activity, which is absent in analogous complexes of Hg(II) halogenides. These results indicate HgBrI as an interesting tecton to obtain metallorganic NLO materials.

Shape-memory polymers and alloys are adaptable materials capable of reversing from a deformed, metastable phase, to an energetically favoured original phase in response to external stimuli. In the context of metal-organic frameworks, the term shape-memory is defined as the property of a switchable framework to stabilize the reopened pore phase after the first switching transition. Herein we describe a novel flexible terpyridine MOF which, upon desolvation, transforms into a non-porous structure that reopens into a shape-memory phase when exposed to CO2 at 195 K. Based on comprehensive in situ experimental studies (SC-XRD and PXRD) and DFT energetic considerations combined with literature reports, we recommend dividing shape-memory MOFs into two categories, viz responsive and non-responsive, depending on the transformability of the gas-free reopened pore phase into the collapsed phase. Furthermore, considering the methodological gap in discovering and understanding shape-memory porous materials, we emphasize the importance of multicycle physisorption experiments for dynamic open framework materials, including metal-organic and covalent-organic frameworks.

A discrete π-hole···σ-hole dimer is synthesized and X-ray characterized. It presents a perfect thumbtack geometry where the σ-hole of the linear [AuI

Tetrahydropyridazines are of particular interest for their versatility as intermediates in organic synthesis and display pharmacological activity in several domains. Here, we describe the photocatalytic synthesis of different tetrahydropyridazines starting from γ,δ-unsaturated N-arylsulfonylhydrazones. Simple structural changes of substrates result into three different pathways beginning from a common N-hydrazonyl radical, which evolves through a domino carboamination/dearomatization, a HAT process, or a photoinduced radical Smiles rearrangement to afford diverse tetrahydropyridazines. All reactions are carried out in very mild conditions, and the quite inexpensive [Ru(bpy)3]Cl2 is used as the catalyst. Preliminary mechanism studies are presented, among them luminescence and electrochemical characterization of the involved species. Computational studies allow to rationalize the mechanism in accord with the experimental findings.

This manuscript reports four new gold(I)-silver(I) complexes with 2-(2-pyridyl)-1,8-naphthyridine (pyNP) and terpyridine (terpy) as ancillary ligands, having formulae [Ag(pyNP)(Au(CN)

New mono-, bis-, and tris-chelate Zn(II) complexes have been synthesized starting from different Zn(II) salts and employing a fluorescent 1,3-substituted-imidazo[1,5-a]pyridine as a chelating ligand. The products have been characterized by single-crystal X-ray diffraction; mass spectrometry; and vibrational spectroscopy. The optical properties have been investigated to compare the performances of mono-, bis-, and tris-chelate forms. The collected data (in the solid state and in solution) elucidate an important modification of the ligand conformation upon metal coordination; which is responsible for a notable increase in the optical performance. An intense modification of the emission quantum yield along the series in the solid state is observed comparing mono-, bis-, and tris-chelate adducts; independently from the anionic ligand introduced by ionic exchange.

An unprecedented chromophore, based on a nitrogen fused tricyclic heterocycle, is presented. This prototype molecule can be considered a “rigidified” monomethine cyanine dye and the central core is isoelectronic to pyridine-based BODIPY analogues, such as boron difluoride dipyridylmethene. The chromophore was synthesized and its photophysical properties examined. The new molecule can be considered the starting point to develop dyes, fluorophores or dual-emission fluorescent probes with excitation window in the green region of the spectrum.

This manuscript reports the synthesis, X-ray characterization and DFT study of three new [M(bipy)3]2[Au(CN)2]3(X) (M = Fe, Co, and Ni; bipy = 2,2′-bipyridine; X = anion) ionic compounds. These salts are composed of [M(bipy)3]2+ dications and [Au(CN)2]− anions in a 2 : 3 ratio. The positive charge is compensated by X = Cl− anions in compounds 1 (M = Fe) and 2 (M = Co) and X = OH− in 3 (M = Ni). The three tridentate bipyridine ligands define the coordination of the M2+ cation, resulting in a nearly octahedral coordination sphere. The linear dicyanoaurate(I) anions are completely surrounded by a cradle of aromatic rings with Au-ring centroid distances below the sum of van der Waals radii, evidencing the existence of a specific Au⋯π attraction. This interaction has been analyzed in terms of the role of the Au-atom (Lewis acid or Lewis base) using DFT calculations combined with the quantum theory of atoms in molecules (QTAIM), noncovalent interaction plot index (NCIplot) and natural bond orbital (NBO) computational tools. The NBO suggests that the Au⋯π interaction is an example of a coinage bond in spite of the anionic nature of the acceptor and the cationic nature of the donor.

The behavior in solution of the dicyanoaurate anion in the presence of other metal centers has so far been little explored, despite its importance in material science. The design and synthesis of systems with controlled coordination behavior, using chelating ligands and Zn

The X-ray structure of the {Cu(NH

The reactivity of “furan-ynes” in combination with pyridine and quinoline N-oxides in the presence of a Au(I) catalyst, has been studied, enabling the synthesis of three different heterocyclic scaffolds. Selective access to two out of the three possible products, a dihydropyridinone and a furan enone, has been achieved through the fine-tuning of the reaction conditions. The reactions proceed smoothly at room temperature and open-air, and were further extended to a broad substrate scope, thus affording functionalized dihydropyridinones and pyranones.

Tetrahydropyridazines are of particular interest for their versatility as intermediates in organic synthesis and display pharmacological activity in several domains. Here, we describe the photocatalytic synthesis of different tetrahydropyridazines starting from γ,δ-unsaturated

The reactivity of "furan-ynes" in combination with pyridine and quinoline N-oxides in the presence of a Au(I) catalyst, has been studied, enabling the synthesis of three different heterocyclic scaffolds. Selective access to two out of the three possible products, a dihydropyridinone and a furan enone, has been achieved through the fine-tuning of the reaction conditions. The reactions proceed smoothly at room temperature and open-air, and were further extended to a broad substrate scope, thus affording functionalized dihydropyridinones and pyranones.

A study of the effect of flexibility of tri-chelating ligands on the overall topology of CuCN derivatives is reported. In particular, we selected two ligands with different degree of aromatic condensation: 2,2′:6′,2′’-terpyridine (tpy) and 2-(2′-pyridyl)-1,8-naphthyridine (pyNP). We obtained a new coordination polymer of pyNP [(CuCN)3(pyNP)]n (1), three coordination polymers of tpy ([(CuCN)3(tpy)]n (2), [(CuCN)(tpy)]n (3) and {[Cu(tpy)][Cu(CN)3]}n (4)), and one molecular compound, [Cu2Cl(CN)(pyNP)] (5). All products have been characterized by SC-XRD and Raman/IR spectroscopies. Results indicate that an hexagonal net can be obtained, but the two ligands show different effects on the topological fragments of cyanocuprate. An accurate vibrational analysis demonstrated to be diagnostic of the structural patterns in these systems, especially for cyanide stretching modes. We observed different behavior between tpy and pyNP in solvothermal condition. In the first case it was not possible to obtain a pure product, and Cu(II) derivatives have been identified; while using pyNP a pure phase was obtained, that suggests a preference toward Cu(I) coordination. It was also observed that the addition of CN ions promotes CuCN solubilization, increasing products yields, with effects on the nature and crystallinity of the obtained products.

Among GRAS molecules, α-amino acids have been extensively used to produce molecular salts and cocrystals of APIs thanks to their nontoxicity, ready availability, cheapness, and their zwitterionic n...

The X-ray structure of the {Cu(NH3)4[Au(CN)2]}+[Au(CN)2]− salt is reported showing an unprecedented [d9]Cu⋯[d10]Au coinage bond. The physical nature of the interaction has been studied using DFT calculations, including the quantum theory of atoms-in-molecules, the noncovalent interaction plot and the natural bond orbital analysis, revealing the nucleophilic role of the [d10]Au metal and the electrophilic role of [d9]Cu metal.

The selective formation of the heterocyclic salt ((1,4-dioxane-2,5-diyl)-bis-(methylene))-bis-(triphenylphosphonium) chloride was observed when epichlorohydrin and triphenylphosphine were reacted in CH2Cl2 at room temperature. Slow evaporation from a mixture of ethanol and ethyl acetate allows to isolate monocrystals of the heterocyclic phosphonium salt. Mechanistic investigations point to the formation of the zwitterionic intermediate 1-chloro-3-(triphenylphosphonio)-propan-2-olate, which can dimerize and generate the 1,4-dioxane derivative. In the exclusive presence of a Brønsted acid as HCl, which usually facilitates epoxide ring opening, the exclusive formation of 1,3-dichloro-2-propanol was although observed. Also, when epichlorohydrin, PPh3, and a stoichiometric amount of HCl were mixed, (2-chloro-3-hydroxypropyl)-triphenylphosphonium chloride was formed and its isolation in pure form provides monocrystals subjectable to X-ray analysis.

Cement composites were realized containing graphene-based materials having different oxygen content (from 0 to 45%). It was found that the polarity of the reinforcement influences both the dispersion in water and the chemical interaction with the hydrated cement matrix, and thus the mechanical performance of the composites. In particular, the reinforcements with the highest oxygen content result aggregated while the cement with the highest strength is obtained with functionalized graphene, containing 5% oxygen, where the surface has sufficient polar groups to guarantee proper dispersion and interaction with the hydrated cement.

A novel approach for the analysis of extended X-ray absorption fine structure (EXAFS) spectra is developed exploiting an inverse machine learning-based algorithm. Through this approach, it is possible to explore and account for, in a precise way, the nonlinear geometry dependence of the photoelectron backscattering phases and amplitudes of single and multiple scattering paths. In addition, the determined parameters are directly related to the 3D atomic structure, without the need to use complex parametrization as in the classical fitting approach. The applicability of the approach, its potential and the advantages over the classical fit were demonstrated by fitting the EXAFS data of two molecular systems, namely, the KAu (CN)2 and the [RuCl2(CO)3]2 complexes. ispartof: JOURNAL OF PHYSICAL CHEMISTRY A vol:125 issue:32 pages:7080-7091 ispartof: location:United States status: published

The novel rhenium complexes fac-Re(pdbpy)(CO)3Cl (pdbpy = 4-phenyl-6-(phenyl-2,6-diol)-2,2′-bipyridine), 1, and fac-Re(ptbpy)(CO)3Cl (ptbpy = 4-phenyl-6-(phenyl-3,4,5-triol)-2,2′-bipyridine), 2, have been synthesized, and the single crystal X-ray diffraction (SC-XRD) structure of 1 was solved. The electrochemical behaviors of the complexes in acetonitrile under Ar and their catalytic performances for CO2 reduction with added water and MeOH are discussed. A detailed IR spectroelectrochemical study under Ar and CO2 atmospheres coupled with DFT calculations allows the identification of reduced species and the interpretation of the reduction mechanisms. Comparison between the rhenium complexes and the corresponding Mn derivatives Mn(pdbpy)(CO)3Br, 3, and Mn(ptbpy)(CO)3Br, 4, has been also considered. Finally, photostimulated conversion of the CO2 was investigated with catalysts (1, 3, and 4) under visible light irradiation (λ > 420 nm) in acetonitrile as solvent. Remarkably, 1 and 3 catalysts were active towa...

The formation of a codrug, a cocrystal formed by two active pharmaceutical ingredients (APIs), between theophylline (THEO) and pyridoxine·HCl (PyrH+Cl–) is reported. The THEO PyrH+Cl– drug–drug cocrystal could turn out to be interesting in the pharmaceutical field because these two APIs are concurrently administered for asthma treatment. The codrug was characterized by a combined experimental and computational investigation by means of single crystal X-ray diffraction (SCXRD), solid-state NMR (SSNMR), and density functional theory (DFT) calculations. An exhaustive SSNMR study was performed to unravel the complex network of hydrogen bond interactions which was poorly defined by SCXRD. Several advanced two-dimensional SSNMR spectra such as 1H DQ MAS, 13C–1H HETCOR, 14N–1H J- and D-HMQC were acquired, taking advantage of the resolution and sensitivity improvement provided by indirect detection pulse sequences and very fast MAS at 70 kHz. These experiments, supported and completed by DFT calculations, were fu...

A facile double condensation procedure, through both standard and microwave heating, provides a versatile one step approach for the synthesis of multidentate nitrogen heterocyclic ligands containing the imidazo[1,5-a]pyridine moiety. The obtained compounds show interesting optical properties: blue fluorescent emissions, moderate quantum yields and large Stokes shifts, enabling their technological application.

We report on the preparation, characterization, and bioavailability properties of three new crystal forms of ethionamide, an antitubercular agent used in the treatment of drug-resistant tuberculosis. The new adducts were obtained by combining the active pharmaceutical ingredient with three dicarboxylic acids, namely glutaric, malonic and tartaric acid, in equimolar ratios. Crystal structures were obtained for all three adducts and were compared with two previously reported multicomponent systems of ethionamide with maleic and fumaric acid. The ethionamide-glutaric acid and the ethionamide-malonic acid adducts were thoroughly characterized by means of solid-state NMR (13C and 15N Cross-Polarization Magic Angle Spinning or CPMAS) to confirm the position of the carboxylic proton, and they were found to be a cocrystal and a salt, respectively, they were compared with two previously reported multicomponent systems of ethionamide with maleic and fumaric acid. Ethionamide-tartaric acid was found to be a rare example of kryptoracemic cocrystal. In vitro bioavailability enhancements up to a factor 3 compared to pure ethionamide were assessed for all obtained adducts.

Herein is presented a rare example of salt/cocrystal polymorphism involving the adduct between ethionamide (ETH) and salicylic acid (SAL). Both the salt and cocrystal forms have the same stoichiometry and composition and are both stable at room temperature. The synthetic procedure was successfully optimized in order to selectively obtain both polymorphs. The two adducts' structures were thoroughly investigated by means of single-crystal X-ray diffraction, solid-state NMR spectroscopy, and density functional theory (DFT) calculations. From the solid-state NMR point of view, the combination of mono- and multinuclear experiments (1H MAS, 13C and 15N CPMAS, 1H-{14N} D-HMQC, 1H-14N PM-S-RESPDOR) provided undoubted spectroscopic evidence about the different positions of the hydrogen atom along the main N···H···O interaction. In particular, the 1H-14N PM-S-RESPDOR allowed N-H distance measurements through the 1H detected signal at a very high spinning speed (70 kHz), which remarkably agree with those derived by DFT optimized X-ray diffraction, even on a natural abundance real system. The thermodynamic relationship between the salt and the cocrystal was inquired from the experimental and computational points of view, enabling the characterization of the two polymorphs as enantiotropically related. The performances of the two forms in terms of dissolution rate are comparable to each other but significantly higher with respect to the pure ETH.

Synthesis and characterization of fourteen new 2,2’-bipyridine metal complexes fac-M(bpy-R)(CO)3X (where M = Mn, X = Br or M = Re, X = Cl and R = -CF3, -CN, -Ph, -PhOH, -NMe2) are reported. The complexes have been characterized by NMR, IR spectroscopy and elemental analysis. Single crystal X-Ray diffraction structures have been solved for Re(dpbpy)(CO)3Cl (dpbpy = 4,6-diphenyl-2,2'-bipyridine) and Re(hpbpy)(CO)3Cl (hpbpy = 4-(2-hydroxy-phenyl)-6-phenyl-2,2'-bipyridine). Electrochemical behaviors of the complexes in acetonitrile under Ar and their catalytic performances for CO2 reduction with added water and MeOH have been investigated by cyclic voltammetry and controlled potential electrolysis. The role of the substituents on the electrochemical properties and the related overpotentials required for CO2 transformation have been analyzed. The complexes carrying only electron withdrawing groups like -CF3, -CN totally lose their catalytic activities towards CO2 reduction, whereas the symmetric -NMe2 substituted and push-pull systems (containing both -NMe2 and -CF3) still display electrocatalytic current enhancement under CO2 atmosphere. The complexes carrying a phenyl or a phenol group in position 4 show catalytic behaviors similar to those of simple M-bpy systems. The only detected reduction product by GC analysis is CO: for example, fac-Re (bpy-4,4’-NMe2)(CO)3Cl gives CO with high faradic efficiency and a TON of 18 and 31, in absence of external proton source and with 5% MeOH, respectively. DFT calculations were carried out to highlight the electronic properties of the complexes; results are in agreement with experimental electrochemical data.

This work follows the recent discovery of a zinc-bearing Egyptian blue (EB) pigment widely used for the production of the early medieval mural paintings cycle in Santa Maria foris portas Church at Castelseprio (Lombardy Region, Italy). The inclusion of zinc in the synthesis of EB has been studied for the first time trying to evaluate whether its addition could be casual or deliberate. Historical reconstructions of the pigment have been carried out with a special focus on the use of zinc besides copper, using the different production methods. The influence of zinc on the pigment’s NIR photoluminescence and VIS-NIR reflectance has been characterized using FORS spectroscopy, X-ray diffraction, optical microscopy, and scanning electron microscopy-energy dispersive X-ray spectroscopy. A comparison of the production methods including salt-flux, solid-state, and Zn-rich syntheses showed that the solid-state synthesis results in particularly efficient NIR photoluminescence and VIS-NIR reflectance. Modern replicas were compared with an ancient sample in order to understand the zinc environment inside the structure of the Zn-enriched EB. Zn was found to be concentrated in a glass-based matrix surrounding cuprorivaite crystals, the main mineral associated with the EB pigment, and not included in a hypothetical Zn-doped cuprorivaite with formula CaCu1−xZnxSi4O10. The Zn-rich synthesis opens up the possibility of producing EB from brass and demonstrates that EB used in Castelseprio’s mural paintings could have been produced in this way. The relationship between the microstructure and the NIR photoluminescence of cuprorivaite-like pigments is of interest also for applications in modern and future technologies.

A series of 1,3-diarylated imidazo[1,5- a ]pyridine derivatives were synthesized in high yields by a one-pot, three components, condensation of phenyl(pyridin-2-yl)methanone with several aldehydes in the presence of ammonium acetate. These compounds were characterized by spectroscopic and crystallographic techniques and their optical properties were discussed in relation to their chemical structures. Absorption and fluorescence spectra generally show two absorption maxima around 310 nm and 350 nm and an emission maximum between 460 and 550 nm with a remarkable Stokes' shift range of 90–166 nm. Moreover, depending on the chemical structure of the substituent in position 3, we were able to tune the quantum yields (Φ) in solution from 6.4% to 38.5%. Finally, the 1-phenylimidazo[1,5- a ]pyridine substituted with a 3-(2-methoxyphenyl) group (large Stokes' shift, high Φ) was dispersed in a transparent thermosetting polyurethane resin giving a luminescent low cost material.

Herein, we investigate the photophysical features of new zinc(II) chlorido complexes containing fluorescent 1,3-substituted imidazo[1,5-a]pyridines as ligands. The derivatives introduce electron-donating or electron-withdrawing moieties in position 3 on the ligand skeleton. The obtained compounds have been characterized with different spectroscopic techniques, their structure has been defined by single-crystal X-ray diffraction and mass spectrometry and their optical properties have been discussed in relation to the chemical structure. The comparison between the emission spectra of the free ligands and of the corresponding zinc(II) chlorido complexes shows an intense hypsochromic shift, due to the modification of the ligands conformation upon metal coordination, and a significant increase of the quantum yield after complexation.

A novel thorium(IV) metal–organic framework (MOF), Th(2,6-naphtalenedicarboxylate)2, has been synthesized via solvothermal reaction of thorium nitrate and 2,6-naphtalendicarboxilyc acid. This compound shows a new structural arrangement with an interesting topology and an excellent thermal resistance, as the framework is stable in air up to 450 °C. Most notably, this MOF, combining the radioactivity of its metal center and the scintillation property of the ligand, has been proven capable of spontaneous photon emission.

We report here the synthesis and structural, thermal and vibrational characterization of five complexes of the 2,2′-bipyrimidine ligand (bpym) with HgX2, X = Cl, Br, I, CN, SCN, with the aim of investigating the factors that could influence the supramolecular chemistry of mercury(II). The combination of the 2,2′-bpym ligand, a bidentate molecule and bridging anions together with a d10 metal like mercury(II) has given different polymeric structures with 1D and 3D dimensionalities. A computational modelling, compared to statistical analysis of the reported structures, has allowed the rationalisation of the differing contributions of the bpym, halide and pseudohalide ligands to the supramolecular architecture. The solid state photoluminescent properties of the complexes have been investigated and an interpretation based on computational models has been proposed.

This communication reports the solvent-free synthesis of a series of copper(I) cyanide (CuCN) -based coordination polymers showing interesting luminescence properties and specific three-dimensional structures. The new compounds have been achieved by directly grinding CuCN together with thiourea (tu), N-methylthiourea (mtu), N-phenylthiourea (ptu), N,N′-diphenylthiourea (dptu), and 2,4-difluorophenylthiourea (fptu). The resulting compounds are [(CuCN)2(tu)]n, [(CuCN)5(mtu)3]n, [(CuCN)3(mtu)2]n, [CuCN(ptu)]n, [CuCN(dptu)]n, and [(CuCN)3(fptu)2]n. “Seeding” crystallization was successful for [(CuCN)2(tu)]n, [CuCN(ptu)]n, [CuCN(dptu)]n, and [(CuCN)3(fptu)2]n, and their structures have been resolved using X-ray single crystal diffraction. Owing to the microcrystalline powdered nature of compounds [(CuCN)5(mtu)3]n and [(CuCN)3(mtu)2]n, their characterization was mainly based on solid-state NMR, via 13C cross polarization magic angle spinning for ligand coordination and 1H magic angle spinning for the weak inter...

WOS:000437813700033; A series of new dyes based on the fluorescent imidazo[1,5-alpha]pyridine moiety has been designed and synthesized specifically for fluorescence cell imaging application. The obtained molecules contain a carboxylic functional group inserted to increase the water solubility and to provide an effective conjugation site. Their structural and optical properties have been deeply investigated and compared with theoretical calculations. The suitability of the products as fluorescent labels for cell imaging applications has been investigated by laser scanning confocal microscopy, both in vivo on Arabidopsis thaliana seedlings and in vitro, on mouse fibroblast cells. The compounds displayed good permeability to the plant cell wall and plasma membrane, they were efficiently internalized in the inner plant tissues, and retained a strong fluorescence in aqueous media.

A series of halogenated imidazo[1,5-a]pyridines was prepared and their structural and optical properties investigated. The products were characterized by spectroscopic techniques and their optical properties discussed in relation to their chemical structure. We were able to triplicate the luminescence quantum yields (φ) in solution for three different imidazo[1,5-a]pyridine derivatives, depending on the halogen nature of the substituent on the imidazo[1,5-a]pyridine moiety. The effect of the halogen and of the geometrical and chemical characteristics of the molecular skeleton on the crystal packing was studied in the solid state by single crystal X-ray diffraction. At the same time, the possible presence of halogen bonds was evaluated through solid-state NMR analysis.

The synthesis and structural characterization of a new coordination polymer [Pb(OH)]n[Ag(SCN)(CN)]n, formed by an anionic layer [Ag(CN)(μ3-SCN)]nn− linked to the 1D cationic fragment [Pb(OH)]n through a bridging cyanide, is reported. We have obtained a rational combination of the pattern of laurionite-type structures (Pb(OH)X, with X = halogen, SCN) with the 2D hexagonal pattern of the silver thiocyanate. The title compound shows luminescent behaviour, and the analysis of the computed band structure allows us to describe the electronic transitions.

The effect of a local proton source on the activity of a bromotricarbonyl Mn redox catalyst for CO2 reduction has been investigated. The electrochemical behaviour of the novel complex [fac-Mn(dhbpy)(CO)3Br] (dhbpy = 4-phenyl-6-(1,3-dihydroxybenzen-2-yl) 2,2'-bipyridine), containing two acidic OH groups in the proximity of the metal centre, under a CO2 atmosphere showed a sustained catalysis in homogeneous solution even in the absence of Brønsted acids.

This article reports on the preparation and solid-state characterization of an indomethacin−caffeine drug−drug cocrystal (or codrug) in a 1:1 stoichiometry. These two active ingredients are frequently coadministered as part of a therapy against strong migraines, in a commercially available fixed dose combination formulation. The X-ray crystal structure of the codrug is characterized by a hydrogen bond interaction between the carboxylic moiety of indomethacin and the purinic nitrogen atom of caffeine. The combination of multinuclear and multidimensional solid-state NMR measurements (1H MAS, 13C and 15N CPMAS, 1H DQ MAS, 13C−1H HETCOR, 14N−1H J- and D-HMQC), as well as IR data, provided spectroscopic evidence about the hydrogen atom position along the hydrogen bond axis, thereby confirming the neutral nature of the cocrystal. Furthermore, dissolution kinetic tests revealed superior bioavailability of indomethacin in the codrug compared to indomethacin alone and to an indomethacin−caffeine physical mixture. On the other hand, the melting point of indomethacin was slightly lower in the cocrystal rather than in the pure drug.

Herein, we report the synthesis and characterization of a series of complexes of the asymmetric ligand 2-(2′-pyridyl)-1,8-naphthyridine (pyNP, 1 ) with different closed-shell metals. For the first time ligand pyNP has been structurally and vibrationally characterized. The geometry of the pyNP ligand, with 3 N donor sites, can favor metallophilic interaction in complexes, so we performed a study on its coordination chemistry with different metals (Ag(I), Hg(II) and Pb(II)). Twelve new complexes, namely [Ag 2 (pyNP) 2 (NO 3 ) 2 ] ( 2 ), [Hg(pyNP)X 2 ](X = Cl( 3 ), Br( 4 ), I( 5 ), CN( 6 ), SCN( 7 , 8 )), [Pb(pyNP) 2 (NO 3 ) 2 ] ( 9 ), [Pb(pyNP)(NO 3 ) 2 ] 2 ( 10 ), [Cu(pyNP)Cl 2 (H 2 O)] ( 11 ), [Cu(pyNP) 2 (H 2 O)][Hg 2 (CN) 4 Cl 2 ]-H 2 O ( 12 ) and [Cu(pyNP)(H 2 O) 2 (μ-CN)Hg 2 (CN) 3 Cl 2 ]-H 2 O ( 13 ), have been synthesized and characterized by single crystal X-ray diffraction, Raman, FTIR and electronic spectroscopies. Structure of complex 2 shows a supported argentophilic interaction, and is the first structure in which pyNP bonds two previously unbounded metal centers.

In this paper, we synthesized and evaluated the biological activity of structural analogues of natural strigolactones in which the butenolide D-ring has been replaced with a γ-lactam. The key step to obtain the α,β-unsaturated-γ-lactam was an RCM on suitably substituted amides. Strigolactones (SLs) are plant hormones with various developmental functions. As soil signaling chemicals, they are required for establishing beneficial mycorrhizal plant/fungus symbiosis. Beside these auxinic roles, recently SLs have been successfully investigated as antitumoral agents. Peculiar to the SL perception system is the enzymatic activity of the hormone receptor. SARs data have shown that the presence of the butenolide D-ring is crucial to retain the biological activity. The substitution of the butenolide with a lactam might shed light on the mechanism of perception. In the following, a dedicated in silico study suggested the binding modes of the synthesized compounds to the receptor of SLs in plants.

Herein, we report the characterization of a series of CuCN-based coordination polymers that display different crystal packing and electronic properties, namely, [Na2Cu(CN)3·3H2O]n (1), [Cu4(CN)5(NH3)2(H2O)]n (2), [Cu3(CN)4(NH3)3]n (3), [Cu3(CN)3(O)0.25(NH3)]n (4), [Cu5(CN)6(NH3)4]n (5), and [Cu5(CN)6(NH3)2]n (6). Spectroscopic evidence of the presence of ammonia molecules coordinated to the metal centers is provided, in particular for 4, which is a new structure. The characterization has been performed by single-crystal XRD (SCXRD), micro- IR spectroscopy, micro-Raman spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The photophysical properties have been studied through solid-state luminescence spectroscopy by acquiring the emission and excitation spectra and evaluating the emission quantum yields, which is an approach that has recently grown in importance in the solid-state field. The goals of this work are (1) to elucidate the correlation between the luminescence properties and the presence of either CuI or mixed CuI/CuII oxidation states, (2) to evaluate the presence of NH3, H2O, or both in the polymers through a combined crystallographic–spectroscopic study, and (3) to rationalize the supramolecular architecture and its influence on the resulting luminescence.

The complex [Ag(PPh3)4][(PPh3)CdCl3] was synthesized and its crystal structure was determined. Solid state properties of the complex were further studied by 31P SS-NMR, Raman and IR spectroscopies. This compound presents one of the rare cases of monomeric trichlorocadmate, the first reported with a phosphorus ligand. We can obtain this thanks to the use of a big spherical cation like [Ag(PPh3)4]+. In the same time we analyze the structural effects that govern the crystallochemistry of analogous compounds. The absorption and emission properties of this compound in the solid state were analyzed by a computational modeling. For the rarity of the complex, we use the ESI-MS and 31P NMR techniques to check the properties of this anion in ethanolic solution, and the results are useful to evaluate the stability of [(PPh3)CdCl3]− ion and the role of [Ag(PPh3)4]+ ion in organizing the crystal structure during the crystal growth.