Grafting {Cp*Rh}2+ on the surface of Nb and Ta Lindqvist-type POM

Abstract

New hybrid POM based on Lindqvist-type polyoxometalates [M₆O₁₉]⁸⁻ (M = Nb, Ta) and organometallic fragment {Cp*Rh}²⁺ have been isolated and characterized. X-ray quality crystals of K₄[(Cp*Rh)₂Nb₆O₁₉]·20H₂O (1) and Cs₄[(Cp*Rh)₂Ta₆O₁₉]·18H₂O (2) were obtained from solutions with {Cp*Rh} : [M₆O₁₉]⁸⁻ stoichiometry 2 : 1. The solution behavior of the hybrid polyoxoanions was studied with ESI-MS and ¹H DOSY NMR. Amongst the poorly investigated chemistry of polyoxotantalates, complex 2 is the first complex bearing a grafted organometallic fragment. The formation of 1 : 1 complexes was detected by ESI-MS techniques.