Übergangsmetall-carbin-komplexe: XCI. Synthese isonitril-substituierter, neutraler und kationaischer diethylaminocarbin-komplexe des wolframs in niedriger und mittlerer oxidationszahl

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The pyridine ligands in cis-I(CO) 2(py) 2CNEt 2 (I) can be readily replaced by CH 3NC or t-C 4H 9NC to yield the stable, neutral carbyne complxes cis-I(CO) 2(RNC) 2WCNEt 2 (R = CH 3 (II), t-C 4H 9 (III0). Upon oxidative decarbonylation with iodine, II and III are quantitatively transformed to the reactive to the reactive seven-coordinated carbonyl-containing carbyne complexes (I) 3(CO)(RNC) 2WCNEt 2 (R = CH 3(IV), t-C 4H 9 (V)) with tungsten in a higher oxidation state. Compounds IV and V react with an excess of RNC (R = CH 3, t-C 4H 9) upon elimination of the CO ligand and displacement of one iodine ligand from the coordination sphere to form the seven-coordinated cationic carbyne complexes [(I) 2(RNC) 4WCNEt 2] +I − R = CH 3 (VI), t-C 4H 9 (VII). The composition and structure of the new compounds were determined by elemental analyses and by IR, 1H NMR, and 13C NMR spectroscopy.