Orthorhombic Cmc2 Research Articles

Structural and biological studies of organotin(IV) derivatives with 2-mercapto-benzoic acid and 2-mercapto-4-methyl-pyrimidine

Four organotin(IV) complexes with the heterocyclic thioamides 2-mercapto-4-methyl-pyrimidine hydrochloride (H 2MPMT +Cl −, C 5H 7N 2SCl) and 2-mercapto-benzoic acid (H 2MBA, C 7H 6O 2S), of the formulae [Ph 3Sn(MPMT)] ( 1), [Me 2Sn(MPMT) 2] ( 2), {[( n-Bu) 2Sn(MBA)] 2} n ( 3), already reported in the literature, and {[Me 2Sn(MBA)] 2} n ( 4), with a different structure to the one already reported, have been used to study their influence upon the catalytic peroxidation of linoleic acid by the enzyme lipoxygenase (LOX). The IC 50 values found lie in the range 20–30 μΜ. The crystal structure of 4 was determined by X-ray diffraction at room temperature (293(2) K). The structure of 4 is polymeric and it consists of {[Me 2Sn(MBA)] 2} dimeric building blocks in contrast to the complex of the same formula reported earlier which has a hexameric cyclic structure. Intermolecular Sn–O bonding interactions between these units in 4 lead to the formation of infinite chains with helical conformations. In addition the crystal structure of 3, previously reported with R = 9.9%, was now reduced to R = 6.1%. Comparison with the already reported hexanuclear macrocycle complexes {[( n-Bu) 2Sn(MBA)] 6} ( 5) and {[Me 2Sn(MBA)] 6 H 2O} ( 6) to the helical polymeric 3 and 4 was made. DFT calculations performed for the hexameric complex 6 and helical polymeric complex 4 have shown that the energy (Δ Ε) difference between the two polymeric and hexanuclear conformers is only 1.65 Kcal/mol. Finally, the crystal structure of complex 2, previously solved in the orthorhombic Cmc2 1 space group, was now solved in the monoclinic P2 1/ n space group.

Synthesis, X-ray diffraction study and physico-chemical characterizations of KLaP 4O 12

Crystals of KLaP 4O 12 have been synthesized by flux technique and characterized by single-crystal X-ray diffraction. This material crystallizes in the orthorhombic Cmc2 1 space group with lattice parameters: a = 8.547(3) Å, b = 11.668(1) Å, c = 13.351(2) Å, V = 1331.4(5) Å 3 and Z = 4. The crystal structure has been refined yielding a final R( F) = 0.015 and w R ( F 2 ) = 0.039 for 1303 independent reflections. The three-dimensional framework with intersecting tunnels of KLaP 4O 12 can be regarded as a succession of alternated [P 4O 12] 4− anionic and K +, La 3+ cationic layers parallel to the (a and b) plane which are centered by the planes z = 0, 1/2 and 1/4, 3/4, respectively. The title compound has been also characterized by different physico-chemical techniques: IR, NMR and CI spectroscopies and DTA–TGA–DSC thermal analysis.

Sur un nouveau compose doubleur de frequence, synthese, et structure du nitrate-bis-nitratotrifluoroantimonate de potassium K 2SbF 3(NO 3) 2·KNO 3

The study of the KNO 3SbF 3 system shows a 3:1 stoichiometric complex the structure of which has been solved from single-crystal X-ray diffraction data (orthorhombic Cmc2 1, R = 0.045 for 882 planes). It is a potassium nitrate bis-nitratotrifluoroantimonate. Antimony atoms present an intermediary coordination between AX 3 E and AX 5 E types. Infrared and Raman spectra are discussed taking into account crystallographic results. A nonlinear optical test using a powder sample shows a signal with an intensity near that of KDP.