Synthesis and dynamic nuclear magnetic resonance studies of co-ordinatively unsaturated alkyne complexes of tungsten(II)

Laurence Carlton, Jack L. Davidson

Research output: Contribution to journalArticle

Abstract

Complexes [{WBr2(CO)(RC=CR')2}2] react with NaS2PMe2, NaS2CNMe2, or Tl(2-SC5H4N) to give monoalkyne [W(LL')2(CO)(RC=CR')](R = R' = Me, LL' = S2CNMe2 or 2-SC5H4N; R = Ph, R' = Me, LL' = S2CNMe2 or S2PMe2; R = R' = Ph, LL' = S2PMe2) or bis-alkyne derivatives [W(2-SC5H4N)2(PhC=CPh)2]. Dynamic n.m.r. studies of the monoalkyne complexes reveal fluxional behaviour due to propeller rotation of the co-ordinated alkyne (R = R' = Me, LL' = S2CNMe2 or 2-SC5H4N) whereas with R = Ph, R' = Me or Ph, LL' = S2PMe2 an alternative process attributed to dechelation of the chelate ligand is also observed. The S2PMe2 derivatives react with ligands L = CNBut, PMe2Ph, or P(OMe)3 to give 1:1 adducts [W(S2PMe2)2(CO)(PhC=CR)(L)] [R = Me, L = CNBut, PMe2Ph, or P(OMe)3; R = Ph, L = PMe2Ph or P(OMe)3] some of which, L = P(OMe)3, dissociate in solution to give the equilibrium (i). 13C N.m.r. studies of [W(S2PMe2)2(CO)(PhC=CMe){P(OMe) 3}] are [W(S2PMe2)2(CO)(PhC=CR)(L)] ? [W(S2PMe2)2(CO)(PhC=CR)] + L (i) interpreted in terms of a six-co-ordinate structure containing one monodentate and one bidentate S2PMe2 ligand, rather than a seven-co-ordinate bis-chelate structure.

Original languageEnglish
Pages (from-to)2071-2076
Number of pages6
JournalJournal of the Chemical Society, Dalton Transactions
Issue number8
DOIs
Publication statusPublished - 1988

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