Synthesis and Reactivity of N,N,N’,N’-Tetramethyldiaminomethane (TMDM) Complexes of Tricarbonylrhenium(I). X-Ray Molecular Structures of [ReBr(CO)₃(TMDM)] and [{Re(bipy)(CO)₃}₂(μ-OH)][SbF₆].
N,N,N′,N′-Tetramethyldiaminomethane (TMDM) is known to act as a source of Me₂NCH in carbonyl substitution reactions, but the reaction of TMDM with the neutral halogenopentacarbonylrhenium(I) compounds gave unexpectedly fac-[ReX(CO)₃(TMDM)] (X=Cl, Br or I), in which the intact TMDM ligand acts in a chelating fashion. The complexes are stable both in the solid-state and in solution, but rapidly decompose on dehalogenation, yielding Re metal. Under anaerobic conditions, the reaction of TMDM with [Re(CO)₃(bipy)]⁺also leads to decomposition. In the presence of oxygen the system is stable. Three Re(bipy) containing species were identified in the reaction mixture: [{Re(CO)₃(bipy)}₂(μ-OH)][SbF₆] (1), which was characterised by X-ray crystallography, [{Re(CO)₃(bipy)}₂(μOH)₂][SbF₆]₂(2) and [Re(OH)(CO)₃(bipy)] (3). Graphical Abstract Reaction of neutral [ReX(CO)₅] (X=Cl, Br or I) with N,N,N′,N′-tetramethyldiaminomethane ((TMDM)) gave unexpectedly fac-[ReX(CO)₃(TMDM)] (X=Cl, Br or I), in which the intact TMDM ligand acts in a chelating fashion. Reaction of TMDM with [Re(CO)₃(bipy)]⁺ under aerobic conditions yields three complexes: [{Re(CO)₃(bipy)}₂(μ-OH)][SbF₆] (1), which was characterised by X-ray crystallography, [{Re(CO)₃(bipy)}₂(μOH₂)][SbF₆]₂(2) and [Re(OH)(CO)₃(bipy)] (3)
