Syntheses and electrochemistry of metal complexes of a bulky pyridine-thiolate ligand

Reactions of Li(tBuL-NS) (lithium bis(4-t-butylphenyl)-2-pyridylmethanthiolate(1-)) with MCl2(M = Ni, Zn, Pt) afforded the respective M(tBuL-NS)2complexes in good yields. Treatment of CuCl2, Cu(OTf)2(OTf = triflate) and PdCl2(PhCN)2with Li(tBuL-NS) led to the formation of the dimeric compounds [Cu(tBuL-NS)Cl]2·2H2O, Cu2(tBuL-NS)3(OTf) and [Pd(tBuL-NS)Cl]2, respectively. The interaction of Li(t-BuL-NS) with [Ru(CO)2Cl2]n, [Rh(COD)Cl]2(COD = 1,5-cyclooctadiene) and Re(CO)5Cl gave cis-Ru(tBuL-NS)2(CO)2, Rh(tBuL-NS)(COD) and Re(tBuL-NS)(CO)4, respectively. The structure of Rh(tBuL-NS)(COD) has been established by X-ray crystallography. The geometry around Rh is square planar with Rh-N and Rh-S distances of 2.114 (5) and 2.250 (2) Å, respectively. Reaction of Ni(PMe3)2(CH3)Cl with Li(tBuL-NS) afforded Ni(tBuL-NS)(PMe3)CH3, which undergoes CO insertion to give the acyl complex Ni(tBuL-NS)(PMe3)(COCH3). The cyclic voltammogram of Pt(tBuL-NS)2exhibits a reversible 1-electron couple at 0.3 V vs ferrocenium-ferrocene, which is assigned as the ligand-centered oxidation.