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 RnSnCl4−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 Mössbauer 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 Mössbauer 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.