Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Several new diorganotin(IV)chloro and triorganotin(IV)chloro penicillin 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-phenylacet-amido) anion; R = Me, Bu, Ph). The coordination environment around the the tin(IV) atom, in all of the complexes, was trigonal bipyramidal. Penicillin G behaved as a monoanionic, bismonodentate ligand in R2SnClpenG through the β-lactamic carbonyl and unidentate ester-type carboxylate anion, and as unidentate through the β-lactamic carbonyl in R3SnClpenGNa, as inferred on the basis of IR spectra.The rationalization of the Mössbauer parameter nuclear quadrupole splitting, ΔE (mm s-1), according to the point-charge model formalism, supported such an hypothesis.The partial atomic charges on tin atoms, QSn, calculated for all the diorganotin(IV)chloropenG and triorganotin(IV)chloropenGNa compounds by the CHELEQ program, correlated well with the experimental 119Sn Mössbauer parameter isomer shift, δ (mm s-1). The δ/QSn data for diorganotin(IV)chloropenG and for triorganotin(IV)-chloropenGNa dervatives have been correlated with the δ/QSn values of triorganotin(IV) halide, cyanide, thiocyanate and cyanate compounds, whose trigonal bipyramidal polymeric structure has been well established.Finally, the biological activity of diorganotin(IV)chloropenG and triorganotin(IV)chloropenGNa derivatives has been tested using Ciona intestinalis fertilized eggs at different stages of development.
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