Synthesis and X-ray structure of (η-C5H5)2W2Ir2(CO)7(CHCO2Et)2, a tetrahedral heterometal cluster with two different environments for ethylcarboxylatocarbene ligands
Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14214 U.S.A.
Department of Chemistry and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 U.S.A.
Abstract:
The tetrahedral heteronuclear cluster complex (η5-C5H5)2W2Ir2(CO)10 reacts with N2CHCO2R (R = Et, Me) at room temperature to form the dicarbene species (η5-C5H5)2W2Ir2(CO)7(CHCO2R)2. An X-ray diffraction study (R = Et) shows an intact tetrahedral metal framework with two distinct sites for the CHCO2Et ligands. The first uses its carbon atom to bridge the Ir---Ir bond; the second uses its carbon atom to bridge an Ir---W bond and, additionally, forms a donor bond from a carbonyl oxygen atom to the second tungsten atom.