126608-95-5Relevant academic research and scientific papers
Proton-Induced Coupling of one tert-Butylisonitrile with one Phenylcarbyne Ligand at Tungsten
Filippou, Alexander Constantin,Gruenleitner, Walter
, p. 1023 - 1034 (2007/10/02)
A good entry to highly substituted phenylcarbyne complexes of tungsten containing tert-butylisonitrile ligands is provided via Br(CO)2(pic)2WCC6H5 (1) (pic: γ-picoline).The first step includes the replacement of the picoline ligands in 1 by t-BuNC in refluxing CH2Cl2 to give Br(CO)2(t-BuNC)2WCC6H5 (2) in high yield.Complex 2 is then transformed with excess t-BuNC in toluene at 90 deg C to the carbonyl free carbyne complex trans-Br(t-BuNC)4WCC6H5 (3).The monocarbonyl substituted analogue of 3, Br(CO)(t-BuNC)3WCC6H5 (4), is observed by IR spectroscopy as an intermediate of this reaction.Its preparation is achieved by the CoCl2 catalyzed decarbonylation of 2 in the presence of one equivalent of t-BuNC. trans-Br(t-BuNC)4WCC6H5 (3) and the analogous iodocompound trans-I(t-BuNC)4WCC6H5 (5) react with HX (X = Br, I) to give respectively, Br2(t-BuNC)3WC-C6H5> (6) and I2(t-BuNC)3WC-C6H5> (7) in high yield.Complexes 6 and 7 contain a 4e-donor acetylene ligand resulting from the proton induced coupling of one tert-butylisonitrile with the phenylcarbyne ligand at the tungsten center.The reaction of complex 4 wih HBr leads also to the coupling product Br2(CO)(t-BuNC)2WC-C6H5> (8), the carbonyl containing analogue of 6, in low yield.With one equivalent of t-BuNC and TlPF6 compounds 6 and 7 are converted to the cationic complexes C-C6H5>>(+)PF6(-) (9) and C-C6H5>>(+)PF6(-) (10) respectively.The analogous chloro compound C-C6H5>>(+)PF6(-) (11) is obtained by halogen exchange from 10 and PPN(+)Cl(-).The composition and structure of the new complexes 3, 4, and 6-11 have been determined by elemental analyses, IR, 1H NMR, 13C NMR and mass spectra. - Keywords: trans-Bromo(tetra-tert-butylisonitrile)(phenylcarbyne)tungsten, Dibromo(tri-tert-butylisonitrile)(tert-butylamino)phenylacetylene)tungsten, Diiodo(tri-tert-butylisonitrile)(tert-butylamino)phenylacetylene)tungsten, trans-Bromo(tetra-tert-butylisonitrile)(tert-butylamino)phenylacetylene)tungsten Hexafluorophosphate, trans-Iodo(tetra-tert-butylisonitrile)(tert-butylamino)phenylacetylene)tungsten Hexafluorophosphate
