Spectroscopic and X‐ray structural characterization of new polymeric organotin(IV) carboxylates and their in vitro antifungal activities: Part II

Abstract

The reactions of R3SnCl (R = Me, Bu or Ph) with sodium 4‐phenylbutyrate, Na(OPhb), in EtOH yielded three polymeric triorganotin carboxylates, namely [R3Sn(OPhb)]n (R = Me (1), Bu (2) or Ph (3)). All complexes were spectroscopically characterized using Fourier transform infrared, 119Sn Mössbauer, 1H NMR, 13C{1H} NMR and 119Sn{1H} NMR spectral techniques. In addition, the crystal structures of 1 and 3 were determined using single‐crystal X‐ray diffraction. Their polymeric structures are sustained by bridging carboxylates which connect two five‐coordinate Sn(IV) centres. Each metallic cation displays a distorted trigonal bipyramidal coordination geometry (Addison's parameters ranging from 0.84 in 1 to 0.77–0.91 in 3), with the oxygen atoms occupying the apical positions and the organic groups at the equatorial corners. The one‐dimensional zigzag chains of 1 propagate along the b‐axis, whereas 3 displays wave‐like double polymeric chains along the b‐axis. For both 1 and 3, parallel one‐dimensional polymeric chains are interconnected by C─H⋅⋅⋅π interactions. The antifungal activity of 1–3 was screened against Candida albicans (ATCC 18804), C. tropicalis (ATCC 750), C. glabrata (ATCC 90030), C. parapsilosis (ATCC 22019), C. lusitaniae (CBS 6936) and C. dubliniensis (clinical isolate 28). The antifungal activity of 3 was noteworthy since it was not only more active than 1 and 2, but also more active than the control drugs (nystatin and fluconazole nitrate) in some cases.