Komplekse van chroom (O) met karbeenligande

Abstract

This study comprises the syntheses, reactions and structures of some new metallocyclic chelates of chromium(O) with N, Sand O donor-atoms. Reactions of .£_-lithiated organoreagents Q-RXC 6H4Li;X=O,S,NMe and R=Me) with Cr(C0) 6 followed by alkylation with [Et3o] [BF 4], gave a new series of neutral penta- and tetracarbonyl(carbene)chromium(O) complexes of general formulae Cr{C(0Et)C 6H4XR-.£_}(C0) 5 and Cr{C(OEt)C 6H4XR-.£_}(C0) 4. These complexes could also be made photochemically. A crystal structure determination was undertaken for the complex Cr{C(OEt)C 6H4NMe 2-~}(C0) 4. The carbene unit in the tetracarbonyl complexes, Cr{C(OEt)C 6H4XR-~}(C0) 4, reacts with NH 3 to yield the chelate complexes Cr{C(NH 2)C 6H4XR-.£_}(C0) 4. N,N-dimethylhydrazine reacts with Cr{C(OEt)C 6H4SMe-.£_}(C0) 4 via formal NH insertion into the metal-carbene bond, to yield the chelate complex Cr{NHC(OEt)C 6H4SMe-.£_}(C0) 4. Reaction of 13-lithiated sulphide (PhSCH = CH - Li+) with Cr(C0)6 and subse= quent alkylation with [Et 3 0] [BF 4] results in neutral (carbene-thio) che= lates Cr{C(OEt)C(OEt) =CHCH2S(Ph)}(C0)4 and Cr{C(OEt)CH =CHS(Ph)}(C0) 4 The sulphide, PhCH 2SH, was reacted in a carbene substitution reaction with the carbene complex Cr{C(OEt)Ph}(C0)5 to produce the corresponding neutralpentacarbonyl(thiocarbene)chromium(O) complexes of general formulae Cr{C(SCH 2Ph)Ph}(C0)5 and Cr{C(SCH 2Ph) 2}(C0) 5.