THE CHEMICAL-REACTIVITY OF PHOSPHORUS-BRIDGING CARBONYL-COMPOUNDS - ANOVEL-APPROACH TO HOMOGENEOUS CATALYSIS

The use of a bicyclic metal carbonyl matrix allows the stabilization o f phosphorus-bridging carbonyl groups in air-stable, readily synthesiz ed iron carbonyl derivatives of the general type (R2NP)(2)COFe2(CO)(6) (R2N=bulky dialkylamino group, particularly iPr(2)N). Such phosphorus -bridging carbonyl derivatives readily undergo extrusion of the phosph orus-bridging carbonyl group at similar to 100 degrees C to give a (R2 NP)(2)Fe-2(CO)(6) unit with reactive sites on the phosphorus atoms whi ch can be trapped by a variety of reagents. For example, alcohols trap (iPr(2)NP)(2)Fe-2(CO)(6) as (ROPN-iPr(2))(iPr(2)NPH)Fe-2(CO)(6) where as the (iPr(2)NP)(2)Fe-2(CO)(6) unit can also add to the C=N of aceton itrile or benzonitrile, the C=O of aldehydes, ketones, or even maleic anhydride, and the C=C of acrylonitrile. The phosphorus-bridging carbo nyl extrusion chemistry of (iPr(2)NP)(2)COFe2(CO)(6) suggests the poss ibility of designing novel synergistic catalyst systems in which react ive vacant sites are generated at phosphorus atoms adjacent to vacant sites on transition metal atoms. (C) 1998 Elsevier Science S.A. All ri ghts reserved.