New water-soluble rhodium(I) complexes containing 1-methyl-1-azonia-3,5-diaza-7-phosphaadamantane iodide

Abstract

Reaction of [Rh₂Cl₂(CO)₄] with stoichiometric quantities of 1-methyl-1-azonia-3,5-diaza-7-phosphaadamantane iodide (mtpa⁺I^-) in MeOH and H₂O yields square-planar [RhI(CO)(mtpa⁺I^-)₂] 1 and trigonal-bipyramidal [RhI(CO)(mtpa⁺I^-)₃]·4H₂O 2, respectively. The complexes are stable in aqueous solution under inert atmosphere and catalyse the hydroformylation and the hydrocarboxylation of alkenes and the hydrogenation of aldehydes and alkenes. An X-ray crystallography study revealed that 2 has a TBPY-5 structure. The coordination around the Rh atom forms a nearly ideal trigonal bipyramid [a=15.705(3) Å, b=13.219(3) Å, c=20.894(4) Å, monoclinic, space group P2₁/c, Z=4, β=110.72(3)°].