Synthesis and Antifungal Activity of Some Organotin(IV) Carboxylates

Six diorganotin(IV) carboxylates prepared by reacting diorganotin(IV) dichlorides with the respective silver carboxylate have been tested for antifungal activity against Aspergillus. niger, Aspergilluus flavus and Pencillium. citrinum in Sabourand dextrose broth. The compounds generally exhibit greater fungitoxicity than the diorganotin(IV) dichlorides and the carboxylic acids from which they were synthesized. In keeping with the generally accepted notion that the organotin moiety plays an important role in deciding the antifungal activity of an organotin compound, the diphenyltin(IV) compounds were more active than their di-n-butyltin(IV) analogues. However, the order of increasing fungitoxicity of the compounds parallels that of the uncomplexed carboxylic acids. The implications of the results are discussed

Reduction of dodecatungstocobaltate(III) by aqueous solutions of hydrazinium ion

The kinetics of the reduction of dodecatungstocobaltate (III) anion by hydrazinium ion has been studied in aqueous hydrochloric acid. The data are consistent with the rate law {A figure is presented} with k2 = (1.80 ± 0.05) X 10-2 mol-1 dm3 S-1 , ΔH ‡ = 46.7 ± 0.8 kJ molp-1, and ΔS ‡ = -121 ±5 J K-1 mol-1 at I = 2.0 mol dm-3 (NaCl), [H+] = 0.1- 1.5 mol dm-3 and T = 24.5 °C. Added copper(II) ions catalysed the rate and the reduction is interpreted in terms of the outer-sphere mechanism