Alkylation reactions of the CCO ligand in triruthenium carbonyl clusters. Synthesis and x-ray crystal structure of Ru/sub 3/(CO)/sub 9/(. mu. /sub 3/-CO)(. mu. /sub 3/-C=C(OCH/sub 3/)CH/sub 3/)
Alkylation reactions of the series of ruthenium ketenylidenes (Ru/sub 3/(CO)/sub 6/(..mu..-CO)/sub 3/(..mu../sub 3/-CCO))/sup 2 -/ (1), (HRu/sub 3/(CO)/sub 9/(..mu../sub 3/-CCO))/sup -/ (2), and H/sub 2/Ru/sub 3/(CO)/sub 9/(..mu../sub 3/-CCO) (3) were studied. The dinegative cluster 1 is attacked by the electrophile CH/sub 3/I to produce the acetyl cluster (Ru/sub 3/(C()/sub 10/(..mu../sub 3/-CC(O)CH/sub 3/))/sup -/ (4). /sup 13/C-labeling experiments show that the acyl CO in 4 is derived from a metal-bound carbonyl ligand on 1, instead of from the CO of the CCO ligand. An alkylation mechanism consistent with the observations is proposed. The product of the reaction of 1 with CH/sub 3/I reacts further with the strong alkylating reagent CH/sub 3/OSO/sub 2/CF/sub 3/ to produce the vinylidene cluster Ru/sub 3/(CO)/sub 9/(..mu../sub 3/-CO)(..mu../sub 3/-C=C(OCH/sub 3/)CH/sub 3/) (5) which has been characterized by a single-crystal X-ray structure determination. Compound 5 readily reacts with H/sub 2/ with concomitant CO loss to produce H/sub 2/Ru/sub 3/(CO)/sub 9/(..mu../sub 3/-C=C(OCH/sub 3/)CH/sub 3/) (6). In contrast to the nucleophilicity of dianion 1, the mononegative and neutral clusters (HRu/sub 3/(CO)/sub 9/(..mu../sub 3/-CCO))/sup -/ (2) and H/sub 2/Ru/sub 3/(CO)/sub 9/(..mu../sub 3/-CCO) (3) are electrophilic, as demonstrated by their reaction with the nucleophile LiCH/sub 3/. In either case, attack by LiCH/sub 3/ occurs at the ..beta..-carbon of the CCO ligand. Extended Hueckel molecular orbital calculations suggest that the observed reactions of 2 and 3 with nucleophiles are orbital-controlled reactions. The /sup 13/C NMR data reported for the compounds include carbon-carbon coupling constants for the capping ligands. Crystals of 5 are monoclinic of space group P2/sub 1//n with a = 8.3993 (17) A, b = 15.9259 (16) A, c = 14.1140 (13) A, ..beta.. = 90.95 (1)/sup 0/, V = 1887.73 A, and d/sub calcd/ = 2.296 g/cm/sup 3/ for Z = 4.
- Research Organization:
- Northwestern Univ., Evanston, IL
- OSTI ID:
- 6043622
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 109:20; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ALKYLATION
CARBON 13
CARBON ISOTOPES
CARBONYLS
CHEMICAL PREPARATION
CHEMICAL REACTIONS
COHERENT SCATTERING
COMPLEXES
COUPLING CONSTANTS
CRYSTAL STRUCTURE
DATA
DIFFRACTION
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
INFORMATION
ISOTOPES
LABELLING
LIGANDS
LIGHT NUCLEI
MAGNETIC RESONANCE
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
RESONANCE
RUTHENIUM COMPLEXES
SCATTERING
SPACE GROUPS
SPECTRA
STABLE ISOTOPES
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
X-RAY DIFFRACTION