Metal alkoxides: models for metal oxides. 7. Trinuclear and tetranuclear alkylidyne clusters of tungsten supported by alkoxide ligands
The ethylidyne capped triangulo compound W/sub 3/(..mu../sub 3/-CMe)(..mu../sub 2/-O-i-Pr)/sub 3/(O-i-Pr)/sub 6/ is formed in the reaction between W/sub 2/(O-i-Pr)/sub 6/(py)/sub 2/ and 1 equiv of MeC identical with CMe. Similarly, (t-BuO)/sub 3/ W identical with CMe and Mo/sub 2/(O-i-Pr)/sub 6/ react in hexane/i-PrOH to give Mo/sub 2/ W(CMe)(O-i-Pr)/sub 9/ which is isomorphous with the tritungsten compound. The W/sub 3/(CMe)(O-i-Pr)/sub 9/ molecule has virtual C/sub 3v/ symmetry. Variable-temperature /sup 1/H NMR studies on the W/sub 3/ and Mo/sub 2/W compounds indicate that a similar structure is maintained in solution and that site exchange between the terminal O-i-Pr ligands involves a pseudorotation mechanism. The reaction between (Me/sub 3/SiCH/sub 2/)/sub 4/ W/sub 2/(..mu..-CSiMe/sub 3/)/sub 2/ and excess EtOH in hexane yields W/sub 4/-(CSiMe/sub 3/)/sub 2/(OEt)/sub 14/ and Me/sub 4/Si. The molecule may be viewed as a dimer (W/sub 2/(..mu..-CSiMe/sub 3/)(OEt)/sub 7/)/sub 2/ with the two halves joined by a pair of alkoxy bridges. Each tungsten is in a distorted octahedral geometry, and the W/sub 4/C/sub 2/O/sub 14/ core represents the fusing together of two confacial bioctahedra along a common edge. The ..mu..-CSiMe/sub 3/ ligand occupies one site of the face shared by two tungsten atoms. These are the first trinuclear and tetranuclear alkylidyne clusters of tungsten supported exclusively by alkoxide ligands. 22 references, 5 figures, 7 tables.
- Research Organization:
- Indiana Univ., Bloomington
- OSTI ID:
- 5676582
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 107:5; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Metal alkoxides - models for metal oxides. 1. Preparations and structures of hexadecaalkoxytetatungsten compounds, W/sub 4/(OR)/sub 16/, where R = Me and Et, and octaoxotetraisopropoxytetrapyridinotetramolybdenum, Mo/sub 4/(O)/sub 4/(. mu. -O)/sub 2/(. mu. /sub 3/-O)/sub 2/(O-i-Pr)/sub 2/(. mu. -O-i-Pr)/sub 2/(py)/sub 4/
STUDIES ON ALKOXIDES AND ALKYLSILYLOXIDES OF URANIUM (thesis)
Related Subjects
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKOXIDES
ALKYL RADICALS
CHEMICAL PREPARATION
COHERENT SCATTERING
COMPLEXES
CRYSTAL STRUCTURE
DATA
DIFFRACTION
EXPERIMENTAL DATA
INFORMATION
LIGANDS
LOW TEMPERATURE
MOLYBDENUM COMPLEXES
NMR SPECTRA
NUMERICAL DATA
RADICALS
SCATTERING
SPECTRA
STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
TUNGSTEN COMPLEXES
X-RAY DIFFRACTION