Electronic Control of the Rotational Barrier in η 2 ‐Alkyne‐1‐thio Complexes

Autor: Beatriz López Sánchez, Wolfram W. Seidel, Matthias J. Meel, Tania Pape, Alexander Hepp
Rok vydání: 2007
Předmět:
Zdroj: European Journal of Inorganic Chemistry. 2007:936-943
ISSN: 1099-0682
1434-1948
DOI: 10.1002/ejic.200600619
Popis: A family of thio-alkyne complexes [Tp′Mo(CO)(L)(BnSC2S)] {Bn = benzyl, Tp′ = hydrotris(3,5-dimethylpyrazolyl)borate, L = carbonyl (2), 2,6-dimethylphenyl isocyanide (7), tert-butyl isocyanide (8), 4-(dimethylamino)pyridine (9)} was prepared by reductive removal of a benzyl group in the corresponding bis(benzylthio)acetylene complexes [Tp′Mo(CO)(L)(BnSC2SBn)](PF6) (1-PF6, 4-PF6, 5-PF6 and 6-PF6). All complexes were characterized by IR, 1H, 13C spectroscopy and cyclic voltammetry. X-ray diffraction studies of 5-PF6, 8 and 9 were carried out. The alkyne ligand is bound symmetrically to molybdenum in 5-PF6 and unsymmetrically in 8 and 9. The trend in the π-acidity of ligand L is reflected in the spectroscopic and electrochemical data as well as in the molecular structures. Variable temperature 1H NMR investigations with 7, 8 and 9 disclosed that the barrier of the alkyne rotation at molybdenum decreases in the order of rising electron density at the metal center while the steric demand increases. Therefore, electronic control of the barrier by the specific character of the ligand L is evident.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Databáze: OpenAIRE
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