Synthesis and Biocidal Activity of Isothiocyanato-Chromium(III) Complexes of Some Newly Synthesized Heterocyclic Schiff Bases

Abstract

Eight new bidentate Schiff bases were synthesized by reaction of 2-aminobenzothiazole or 2-amino-4-phenyl-5-phenylazothiazole with 2-hydroxy-1-naphthaldehyde or substituted (2-hydroxy-, 4-hydroxy-, 3-methoxy-4-hydroxy-) benzaldehyde. The reaction products of these Schiff bases with potassium hexathiocyanatochromium(III) were of the type: K[Cr(NCS)₂(B₁)₂] and K[Cr(NCS)₄(B₂)], where HB₁ [dbnd] N, O donor monobasic bidentate Schiff bases and B₂ [dbnd] N, N donor bidentate Schiff bases. They were characterized on the basis of elemental analysis, molecular mass determination, conductance, magnetic measurements, infrared and UV-visible spectral studies. The complexes were of octahedral structure. Different ligand field parameters 10Dq, B, β₃₅ and C.F.S.E. were calculated and discussed. The Schiff bases and the complexes were also screened for microbiological activity against the fungi Aspergillus niger, Alternaria alternata and bacterium Escherichia coli. The mixed ligand complexes were found more active than the Schiff bases.