A new pentanuclear cyano-bridged complex [(Fe(II)(tetraazamacrocycle))3{mu-NC-FeIII(CN)5)2]: synthesis, spectroscopic and magnetic characterization

Hexacyanoferrate(III) reacts with [FeII(meso)(CH3CN)2](ClO4)2.2CH3CN (meso=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) in acetonitrile/water mixture producing the title complex, where three [Fe(meso)]2+ units are connected by two [Fe(CN)6](3-) anions. Molecular modeling (MM+) shows a fairly linear molecule and M?ssbauer data are consistent with two terminal pentacoordinated low spin iron(II)-meso units linked to one hexacoordinated low spin iron(II)-meso through two hexacoordinated low spin iron(III) units. Spectroscopic characterization showed a typical mixed-valence charge transfer band and the degree of electron coupling was calculated to be H(AB)=678 cm(-1). Magnetic properties exhibited an antiferromagnetic exchange interaction between the iron(III) ions with a coupling constant J= -44 cm(-1).     

Synthesis, spectral characterization and biological studies of some organotin(IV) complexes of L-proline, trans-hydroxy-L-proline and L-glutamine

New organotin(IV) complexes of the general formula R3Sn(L) (where R=Me, n-Bu and HL=L-proline; R=Me, Ph and HL=trans-hydroxy-L-proline and L-glutamine) and R2Sn(L)2 (where R=n-Bu, Ph and HL=L-proline; R=Ph, HL=trans-hydroxy-L-proline) have been synthesized by the reaction of RnSnCl(4-n) (where n=2 or 3) with sodium salt of the amino acid (HL). n-Bu2Sn(Pro)2 was synthesized by the reaction of n-Bu2SnO with L-proline under azeotropic removal of water. The bonding and coordination behavior in these complexes have been discussed on the basis of IR and 119Sn M?ssbauer spectroscopic studies in the solid-state. Their coordination behavior in solution has been discussed with the help of multinuclear (1H, 13C and 119Sn) NMR spectral studies. The 119Sn M?ssbauer and IR studies indicate that L-proline and trans-hydroxy-L-proline show similar coordination behavior towards organotin(IV) compounds. Pentacoordinate trigonal-bipyramidal and hexacoordinate octahedral structures, respectively, have been proposed for the tri- and diorganotin(IV) complexes of L-proline and trans-hydroxy-L-proline, in which the carboxylate group acts as bidentate group. L-glutamine shows different coordination behavior towards organotin(IV) compounds, it acts as monoanionic bidentate ligand coordinating through carboxylate and amino group. The triorganotin(IV) complexes of L-glutamine have been proposed to have trigonal-bipyramidal environment around tin. The newly synthesized complexes have been tested for their antiinflammatory and cardiovascular activities. Their LD50 values are >1000 mg kg-1.     

Organometallic complexes with biological molecues,part 3. in vivo cytotoxicity of diorganotin (IV) chloro and triorganotin (IV) chloro derivatives of penicillin g on chromosomes of aphanius fasciatus (pisces,cyprinodontiformes)

In order to obtain a continuous source of mitotic metaphases, gill tissue of Aphaius fasciatus (Pisces, Cyprinodontiformes) has been successfully employed. Results gathered after exposure of fish to R₂SnClpenG, R₃SnClpenGNa, to the parents R₂SnCl₂, R₃SnCl and to penGNa (penGNa = penicillinGNa; R = methyl, butyl and phenyl) suggest that both the parent organotin (IV) chloride and organotin (IV) chloropenG derivatives are toxic while penGNa exerts no significant toxic activity. Essentially, all of the chromosome abnormalities are classifiable as irregularly staining of chromosomes, breakages, side-arm bridges or pseudochiasmata.     

Biocidal organotin compounds: Part 1. Preparation and characterization of triorganotin(IV) 4-pyridyl- and 2-pyrimidyl- thioacetates and the crystal structure of triphenyltin(2-pyrimidylthioacetate)

The preparation and spectroscopic characterization of [R₃Sn(O₂CCH₂SC₅H₄N-4)], R == Ph, benzyl (Bz), cyclohexyl (c-Hex) and n-Bu, and of [R₃Sn(O₂CCH₂SC₄H₃N₂-2,6)], R == Me, Ph and n-Bu, are reported. The 2-pyrimidyl compounds feature trigonal bipyramidal tin centres with trans-R₃SnO₂ geometries as was confirmed by X-ray crystallography for [Ph₃Sn(O₂CCH₂SC₄H₃N₂-2,6)]. ¶ By contrast the 4-pyridyl compounds have trigonal bipyramidal geometries in the solid state (arising from intermolecular Sn…N interaction) and tetrahedral geometries in solution. The biocidal activity of these compounds against the fungi Helminthosporium maydis (ITCC 2675) and H. oryzae (ITCC 2675), both of which damage crops such as maize and rice, shows promise. Encouraging is the observation that the compounds show no adverse phytotoxicity at concentrations to 10^?3M.