Mono- and Dinuclear Carbonyl Complexes of (1,4,7-Trimethyl-1,4,7-triazacyclononane)rhodium(I): Facile Migration of a C(O)OMe Ligand at a Dinuclear Rh(μ-CO)2Rh Core

This is the authors' abstract. We don't add key points for this paper.

The reaction of 1,4,7-trimethyl-1,4,7-triazacyclononane (Cn*) with [{(CO)2Rh(μ-Cl)}2] in methanol at 0°C, followed by the addition of NH4PF6, results in the formation of the mononuclear carbonyl complex [Cn*Rh(μ-CO)2]PF6 ([1]PF6), the dinuclear carbonyl complex [Cn*Rh(μ-CO)3RhCn*](PF6)2 {[2](PF6)2} and the dinuclear methoxycarbonyl complex [Cn*Rh(C(O)OMe)(μ-CO)2RhCn*]PF6 ([3]PF6). The reaction of [2](PF6)2 with NaOMe results in formation of [3]PF6 by the attack of the methoxide at a bridging carbonyl. Treatment of [3]PF6 with NH4PF6 regenerates [2](PF6)2, thus showing that the methoxylation of [2](PF6)2 is reversible. The structures of [1]PF6, [2](PF6)2 and [3]PF6 have been determined by single-crystal X-ray diffraction. For [3]PF6 an unprecendented facile, reversible, migration of the C(O)OMe ligand between the two rhodium centres of the Rh(μ-CO)2Rh core is observed.