Sulphur-nitrogen chelating agents. I. Metal complexes of 8-methylthioquinoline.

8-Methylthioquinoline (N-SMe) has been prepared and complexes with nickel(II), palladium(11), platinum(11), copper(11), copper(1), silver(1), and mercury(II) have been obtained. The complexes NiX2(N-SMe)2 (X = Cl, Br, I, NCS) are high-spin and presumably octahedral. The mono-chelated complexes MX2(X-SMe) (M = Pd, Pt, Cu; X = Cl, Br) were isolated; the sulphato-complex CuSO,(X-SMe), 2H,O is probably dimerio with bridging sulphato groups. The bis-chelated copper(II) complex [Cu(X-SMe)2](ClO4)2 was obtained but attempts to isolate analogous complexes of nicke1(II), palladium(11), and platinum(II) were unsuccessful. The complexes CuI(R'-SMe), [Ag(X-SMe)2]ClO4. and HgCl2(X-SMe) were also characterized. The paramagnetic red nickel(II) complex Ni(N-S)2 (N-SH = 8-mercapto-quinoline) was reinvestigated: a temperature-dependent magnetic study shows that the moment does not vary with temperature. It is suggested that this compound is polymeric and tetragonal. Attempts to prepare a gold(III) complex of 8-methylthioquinoline led to demethylation of the ligand and the isolation of AuCl2(N-S).