Alkyl-sulfur versus aryl-sulfur bond cleavage in tridentate alkylthiophenylazonaphthols by group 9 metal ions

The reactions of monoanionic tridentate alkylthiophenylazonaphthols featuring both C(sp(3))-S and aryl C(sp(2))-S bonds with low-valent group 9 metal compounds afforded monomeric metal complexes via either C(sp2)-S or C(sp3)-S cleavage. Rhodium(I) and iridium(I) selectively cleave C(sp2)-S bond of 2-hydroxy-1-(2'-alkylthiophenylazo) naphthalenes (HL1-HL5) and 1-hydroxy-2-(2'-alkylthiophenylazo) naphthalenes (HL6-HL10) with concomitant two-electron metal based oxidation resulting in the formation of novel M(III) cyclometallates. The molecular structures of the resulting complexes have been determined by single crystal X-ray crystallography. Rhodium(III) or iridium(III) binds desulfurized modified HL1-HL10 ligands via O, N, C(aryl) donor set. Cobalt(I), the remaining member of the group 9, regiospecifically cleaves the C(sp3)-S bond of the diazene ligands with concomitant two-electron oxidation leading to the formation of novel cobalt(III) complexes. The molecular structures of one of the resulting cobalt(III) complex has been determined by single crystal X-ray crystallography. The cobalt(III) center binds one monoanionic ligand (HL) via O, N, S donor set along with a dianionic modified HL through O, N, S(thiolato) donor set. (C) 2018 Elsevier B.V. All rights reserved.