Preparation of mononuclear and dinuclear Rh hydrotris(pyrazolyl)borato complexes containing arenethiolato ligands and conversion of the mononuclear complexes into dinuclear Rh–Rh and Rh–Ir complexes with bridging arenethiolato ligands

Dalton Transactions Pub Date: 2004-09-29 DOI: 10.1039/B409623A

Abstract

Reactions of [Tp*Rh(coe)(MeCN)] (1; Tp* = HB(3,5-dimethylpyrazol-1-yl)3; coe = cyclooctene) with one equiv. of the organic disulfides, PhSSPh, TolSSTol (Tol = 4-MeC6H4), PySSPy (Py = 2-pyridyl), and tetraethylthiuram disulfide in THF at room temperature afforded the mononuclear RhIII complexes [Tp*Rh(SPh)2(MeCN)] (3a), [Tp*Rh(STol)2(MeCN)] (3b), [Tp*Rh(η2-SPy)(η1-SPy)] (6), and [Tp*Rh(η2-S2CNEt2)(η1-S2CNEt2)] (7), respectively, via the oxidative addition of the organic disulfides to the RhI center in 1. For the Tp analogue [TpRh(coe)(MeCN)] (2, Tp = HB(pyrazol-1-yl)3), the reaction with TolSSTol proceeded similarly to give the bis(thiolato) complex [TpRh(STol)2(MeCN)] (4) as a major product but the dinuclear complex [{TpRh(STol)}2(μ-STol)2] (5) was also obtained in low yield. Complex 3 was treated further with the RhIII or IrIII complexes [(Cp*MCl)2(μ-Cl)2] (Cp* = η5-C5Me5) in THF at room temperature, yielding the thiolato-bridged dinuclear complexes [Tp*RhCl(μ-SPh)2MCp*Cl] (8a: M = Rh, 8b: M = Ir). Dirhodium complex [TpRhCl(μ-STol)2RhCp*Cl] (9) was obtained similarly from 4 and [(Cp*RhCl)2(μ-Cl)2]. Anion metathesis of 8a proceeds only at the Rh atom with the Cp* ligand to yield [Tp*RhCl(μ-SPh)2RhCp*(MeCN)][PF6] (10), when treated with excess KPF6 in CH2Cl2–MeCN. The X-ray analyses have been undertaken to determine the detailed structures of 3b, 4, 5, 6, 7, 8a, 9, and 10.

Graphical abstract: Preparation of mononuclear and dinuclear Rh hydrotris(pyrazolyl)borato complexes containing arenethiolato ligands and conversion of the mononuclear complexes into dinuclear Rh–Rh and Rh–Ir complexes with bridging arenethiolato ligands
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