Crystal structure, anti-fungal activity and phytotoxicity of diorganotin compounds of dihalo-substituted [(2-hydroxyphenyl) methylideneamino]thiourea

• Main Authors: Sarkar, B., Choudhury, A.K., Roy, A., Biesemans, M., Willem, R., Ng, S.W., Tiekink, E.R.T.
• Format: Article
• Published: John Wiley & Sons 2010
• Subjects: Q Science (General)
• Online Access: http://eprints.um.edu.my/11714/

Seven new diorganotin (IV) compounds (1-7) of Schiff bases derived from dihalo-substituted salicylaldehyde and thiosemicarbazide were synthesized. The general formulae for the compounds are {R2Sn[OArCH=N-N=C(NH2)S]}, where R = Me, n-Bu, Ph and Bz, and Ar = -C6H2(3-Br-, 5-Cl) or -C6H2(3,5-Br-2), and these were characterized by UV-vis, IR and NMR (H-1, C-13, Sn-119) spectroscopy and elemental analysis. Five structures were also investigated by X-ray crystallography. All molecules are mononuclear, five-coordinate with a tridentate ligand coordinating the tin atom through the thiolate-S, phenoxide-O and imino-N atoms. The coordination geometries for the n-butyl compounds approach square pyramidal arrangements with distortions towards trigonal pyramidal occurring for the di-methyl and di-phenyl compounds which display wider C-Sn-C angles. The potential of the new compounds against six fungal pathogens (Bipolaris sorokiniana, Helminthosporium oryzae, Altreneria brassicae, Alterneria kikuchiana, Stemphylium pori and Colletotrichum capsici) were investigated for six different crops (Triticum aestivum, Oryzae sativa, Brassica nigra, Brassica oleracea, Allium cepa and Capcicum annum) and demonstrated significant activity. None of the investigated compounds displayed adverse phytotoxicity at concentrations as high as 100 ppm. Copyright (C) 2010 John Wiley & Sons, Ltd.