Synthesis and characterisation of a new class of phosphine-phosphonite ferrocenediyl dinuclear rhodium complexes

We previously reported the easy access to mixed ferrocenediyl ligands bearing phosphine and phosphonite moieties. Using this strategy, a new enantiopure phosphine-menthylphosphonite ferrocenediyl has been synthesised. This mixed ligand leads to original unsymmetrical dinuclear rhodium coordination-complexes. One example of this new class of quasi-close bridging A frame dinuclear rhodium complexes, fully characterised by multinuclear H-1, C-13, P-31 and Rh-103 NMR and optical rotation measurements, is presented. Preliminary tests have shown an activity improvement in the hydroformylation of oct-1-ene using the phosphine-menthylphosphonite ferrocenediyl auxiliary compared to known phosphine-phosphonite ligands. (C) 2003 Elsevier B.V. All rights reserved.