Lotz, Simon2024-11-272024-11-2722/01/211986http://hdl.handle.net/2263/99494Dissertation (MSc (Chemistry))--University of Pretoria, 1986.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.Afr© 2024 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.Chroom (o)KarbeenligandeUCTDDissertation