Organometallic Complexes with Biological Molecules, VI. Diorganotin(IV) and Triorganotin(IV) Ampicillin and Methicillin Derivatives: Spectroscopic Investigations in the Solid State

✍ Scribed by Lorenzo Pellerito; Francesco Maggio; Tiziana Fiore; Alessandro Pellerito

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 707 KB
• Volume: 10
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/(sici)1099-0739(199608)10:6<393::aid-aoc489>3.0.co;2-s

✦ Synopsis

Derivatives of D(-)-a-aminobenzylpedcillin (ampicillin) and of 2,6-dimethoxyphenylpniciUin (methicillin) with diorgano-and triorgano-tin(IV) moieties have been synthesized. The stoichiometries of the compounds obtained were of the type R2 S n C L H 2 0, R3 SnClLNaaH2 0 IL=ampiciUn or methicillin monoanion; R=Me, Bu, Ph] and RzSnampicz . 2 H 2 0 (ampic=ampicillin; R=Me, Bu, Ph). For R2SnClL.H20 and R$3nClLNa.-H20, infrared (IR) data suggest fivecoordination around the tin(IV) atom; in RzSnampic2.2H20 sixcoordination is most likely to occur. Thermogravimetric (TG) analysis excludes any involvement in the coordination of tin(1V) by water molecules, in any of the compounds. Trigonal bipyramidal configurations in the solid state are proposed for both R2SnClL-H20 and R3SnClLNa.H20 @,=ampicillin or methicillin) on the basis of the abovementioned IR and Mossbauer data.

As far as R2Snampic2.2H20 compounds are concerned, the coordination geometry at tin could be, as previously reported for analogous R2Sna-mox2.2H20 derivatives, skew-trapezoidal bipyramidal, the monoanionic bidentate chelating ampicillin residue being in the trapezoidal plane and having bent axial organic groups.

Electronegativity equalization procedures have been applied to idealized trigonal bipyramidal structures for R2SnClLaH20 and R3SnClLNaaH20 (L=ampicillin or methicillin) and to octahedral trans-Rz for R2Snampic2.2H20, to estimate the partial atomic charges on the tin atoms, Qs,, which have been correlated with the isomer shift (6) Mossbauer parameter.