Metal chelates of α-diimines containing a benzothiazole moiety. I. Complexes of 2-(2-pyridyl)benzothiazole

Abstract

2-(2-pyridyl)benzothiazole (pbt) acts as a bidentate ligand, coordinating through both nitrogen atoms. Cobalt(II) forms the tetrahedral complexes CoX 2(pbt) (X = Cl, Br) and the high-spin octahedral complexes CoX 2(pbt) 2 (X = Cl, Br, I) and [Co(pbt)(H 2O) 4]SO 4 Nickel(II) forms mono-, bis-, and tris-ligand complexes. The tris complex [Ni(pbt) 3](ClO 4) 2 and the bis complexes NiX 2(pbt) 2 (X = Cl, Br, SCN, NO 3) are octahedral with moments in the range 3.1–3.3 B.M. The mono complexes NiCl 2(pbt) and Ni(CH 3CO 2) 2(pbt)(H 2)) 2 have moments in the range 3.3–3.6 B.M.; the spectrum of NiCl 2(pbt) indicates that the complex is tetragonal and polymeric with chloro bridges. The mono complex [Ni(pbt)(H 2O) 4SO 4 was also isolated. With palladium(II) and platinum(II) the mono complexes MX 2(pbt) (M = Pd, X = Cl, Br, SCN, NO 2; M = Pt, X = Cl, Br, SCN) and one bis complex PtI 2(pbt) 2 were obtained. The copper(II) complex Cu(pbt) 2 (ClO 4) 2. H 2O has one perchlorate group coordinated in the solid state and in nitrobenzene solution. The spectra of the mono complexes CuX 2(pbt) (X = Cl, Br, SCN, NO 3) indicate five- or six-coordination. The thiocyanato complex contains a bridging SCN group. The insoluble copper(I) complex CuI(pbt) is probably dimeric with iodo bridges. Mono complexes MX 2(pbt) (M = Zn, X = Br, I; M = Cd, X = Cl, Br, I, SCN) and bis complexes Zn(SCN) 2(pbt) 2 and CdI 2(pbt) 2 were isolated. The spectra of Zn(pbt) 2(ClO 4) 2.H 2O and Cd(pbt) 2(ClO 4) 2 indicate perchlorate coordination.