FUNGICIDAL AND SPECTRAL STUDIES OF SOME TRIPHENYLTIN COMPOUNDS

In the interest of developing a more effective fungicide to combat Dut ch elm disease, our laboratories have synthesized several triphenyltin carboxylates and some 1:1 addition compounds of triphenyltin chloride using 2,3-disubstituted thiazolidin-4-ones as the ligand and screened them in vitro against Ceratocystis ulmi, the causative agent of Dutch elm disease, using a shake culture method, Elemental analyses and spe ctroscopic data indicate that the structures of the carboxylates in th e solid state are monomeric with a tetrahedral tin atom with the excep tion of the furan-2-carboxylic acid derivative, which was found to be polymeric, The triphenyltin chloride adducts are trigonal-bipyramidal with the three phenyl groups in the equatorial plane, Far-infrared dat a indicate that the three phenyl groups are not co-planar, Screening r esults for both series of organotins indicate that these two classes o f compounds are effective inhibitors of Ceratocystis ulmi, with the ad ducts having a higher activity, The furan-2-carboxylic acid derivative has a markedly decreased activity compared with the other carboxylate s and this is attributed to its polymeric structure. (C) 1998 John Wil ey & Sons, Ltd.