Structural transformations in crystals induced by photochemical reactions

Structural changes induced in crystals by photochemical reactions were presented. The changes concern: a) the distances between neighbouring reactant molecules and their mutual orientation in the case of intermolecular reactions, b) the distances and angles between fragments of a molecule for intramolecular reactions, c) the position of molecules in crystals, d) geometry of hydrogen bonds, e) cell constants, and f) the content of product molecules in crystals. For most intramolecular reactions, the distances between reactive atoms are constant for a long time in phototransformation and decrease rapidly at its end (Figs. 3 and 5). In the case of intermolecular reactions, the distances between reactive atoms of reactant molecules decrease linearly along with the phototransformation of crystals (Fig. 7). Additionally, unreacted molecules become, to a certain degree, similar to product molecules in terms of their shape (Figs, 4 and 8). Reactant and product molecules do not assume a fixed place in crystals. Product molecules change their orientation towards that of which is observed in a pure product crystal and reactant molecules gradually move away from the position they took in pure reactant crystals. All this has an influence on the geometry of hydrogen bonds existing in crystals (Fig. 9). The above-mentioned structural transformations find their expression in values of cell constants (Fig. 10). The factors influencing the photoreactivity of molecules in crystals were also described. Knowledge of crystal and molecular structures of partly reacted crystals, determined thanks to X-ray structure analysis which is a branch of crystallography, reveals the behaviour of molecules in crystals in which photochemical reactions proceed and helps to understand a pathway of these reactions

DMAP and HMTA manganese(III) meso-tetraphenylporphyrin-based coordination complexes: Syntheses, physicochemical properties, structural and biological activities

International audienceThe reactions of the (triflato)(meso-tetra(para-methoxyphenyl)porphyrinato)manganese(III) ([MnIII(TMPP)(SO3CF3)] complex with an excess of 4-dimethylaminopyridine (DMAP) and hexamethylenetetramine (HMTA) have been examined. These reactions yield crystalline [MnIII(TMPP)(DMAP)2](0.1Cl)(0.9SO3CF3)•2CHCl3 (I) and [MnIII(TMPP)(HMTA)2](SO3CF3)•2CH2Cl2 (II) complexes, respectively. The hyper d-type electronic spectra of I-II are characteristic for high-spin (S = 2) Mn(III) metalloporphyrins with very redshifted Soret bands. A cyclic voltammetry investigation was carried out on these two Mn(III) coordination compounds. The crystal structures of the solid complexes I-II were determined by X-ray single-crystal diffraction and elucidated by Hirshfeld surface approach. Furthermore, bioactivity of the H2TMPP free base, the [MnIII(TMPP)(SO3CF3)] starting material and complexes I-II, was assessed by a set of in vitro tests checking for antioxidant, antibacterial and antifungal (against several strains) effects

Study on the synthesis, physicochemical, electrochemical properties, molecular structure and antifungal activities of the 4-pyrrolidinopyridine Mg(II) meso-tetratolylporphyrin complex

International audienceA novel magnesium(II) metalloporphyrin namely the bis(4-pyrrolidinopyridine)[meso-tetra(p-tolyl)porphyrinato)]magnesium(II) dichloromethane desolate complex with the formula [Mg(TTP)(4-pypo)2]·CH2Cl2 (I) has been synthetized and fully characterized by UV–Vis, fluorescence, IR, 1H NMR spectroscopy and mass spectrometry. The X-ray molecular structure shows that I presents two molecules (1 and 2) [Mg1(TTP)(4-pypo)2] and [Mg2(TTP)(4-pypo)2] in the asymmetric unit while the Hirshfeld surface analysis on this hexacoordinated Mg(II) porphyrin species indicates that the crystal lattice is mainly sustained by C__H…C, C__H…Cg (Cg is the centroid of a phenyl ring) and C__H…Cl intermolecular interactions. The cyclic voltammetry data of I is also reported. The bioactivity of the H2TTP, the [Mg(TTP)] starting material and [Mg(TTP)(4-pypo)2]·CH2Cl2 (I) was evaluated in vitro, by examining their inhibitory effect against three strains of Candida viz. C. albicans, C. glabrata and C. tropicalis with MIC values in the range 2.5 to 10 µg.mL−1. The screening of the susceptibility of M. canis and T. rubrum clinical strains on the three porphyrinic derivatives is also reported