ORGANOMETALLIC COMPLEXES WITH BIOLOGICAL MOLECULES .2. SYNTHESIS, SOLID-STATE CHARACTERIZATION AND IN-VIVO CYTOTOXICITY OF DIORGANOTIN(IV) CHLORO AND TRIORGANOTIN(IV) CHLORO DERIVATIVES OF PENICILLIN-G

Several new diorganotin(IV)chloro and triorganotin(IV)chloro penicilli n G derivatives have been prepared. The isolated compounds showed 1:1 stoichiometry, with formulae R2SnClpenG and R3SnClpenGNa, respectively (penG- = penicillin G- = 4 - thia - 1 - azabicyclo[3.2.0]heptane - 2 - carboxylate, 3,3-dimethyl-7-oxo-6-(2-phenylacetamido) anion; R = Me, Bu, Ph). The coordination environment around the tin(IV) atom, in all of the complexes, was trigonal bipyramidal. Penicillin G behaved as a monoanionic, bismonodentate ligand in R2SnClpenG through the beta-lac tamic carbonyl and unidentate ester-type carboxylate anion, and as uni dentate through the beta-lactamic carbonyl in RSnClpenGNa, as inferred on the basis of IR spectra. The rationalization of the Mossbauer para meter nuclear quadrupole splitting, DELTAE (mm s-1), according to the point-charge model formalism, supported such an hypothesis. The partia l atomic charges on tin atoms, Q(Sn), calculated for all the diorganot in(IV)chloropenG and triorganotin(IV)chloropenGNa compounds by the CHE LEQ program, correlated well with the experimental Sn-119 Mossbauer pa rameter isomer shift, delta (mm s-1). The delta/Q(Sn) data for diorgan otin(IV)chloropenG and for triorganotin(IV)chloropenGNa derivatives ha ve been correlated with the delta/Q(Sn) values of triorganotin(IV) hal ide, cyanide, thiocyanate and cyanate compounds, whose trigonal bipyra midal polymeric structure has been well established. Finally, the biol ogical activity of diorganotin(IV)chloropenG and triorganotin(IV)chlor openGNa derivatives has been tested using Ciona intestinalis fertilize d eggs at different stages of development.