Hydrido methylidene, hydrido vinylidene, hydrido oxo, and hydrido formaldehyde derivatives of bis(pentamethylcyclopentadienyl)tantalum

Journal Article · Wed Aug 20 00:00:00 EDT 1986 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00277a051· OSTI ID:5458769

van Asselt, A; Burger, B J; Gibson, V C; Bercaw, J E

Transition-metal complexes of the general class L/sub n/M(H)(=X) (X = CH/sub 2/; C = CH/sub 2/, O) are of interest as models for reactive intermediates in a variety of catalytic processes. Hydrido alkylidene complexes, generated by a 1,2-hydrogen shift from metal alkyls, have been postulated to play an important role in the metathesis and polymerization of olefins, while surface-bound vinyldene species have been detected and recently proposed to account for linear/branched hydrocarbon distributions in Fischer-Tropsch synthesis. The third member of the class described here, L/sub n/M(H)(=O), is of fundamental importance in reactions involving H/sub 2/O, O/sub 2/, or peroxides. Although an example of an oxo hydride has not previously been reported, several oxo alkyl species have been characterized recently. The authors have described the preparation of a number of permethyltantalocene derivatives and commented on the remarkable stability conferred by two pentamethylcyclopentadienyl ligands. This important facet and a general reluctance for permethyl-metallocene derivatives to undergo oligomerization processes have allowed us to prepare and investigate the reaction chemistry of a number of monomeric hydrido derivatives of general formula Cp*/sub 2/ Ta(H)(=X) (Cp* = eta/sup 5/-C/sub 5/Me/sub 5/; X = CH/sub 2/ (1), C = CH/sub 2/. We have also isolated an eta/sup 2/-formaldehyde adduct CP*/sub 2/Ta(H)(eta/sup 2/-CH/sub 2/O). Such species continue to attract interest as models for possible intermediates in CO hydrogenation, and they describe herein a novel C-O bond cleavage reaction at elevated temperatures to afford the oxo alkyl derivative, Cp*/sub 2/ Ta(CH/sub 3/)(=O).

• Research Organization: California Institute of Technology, Pasadena
• DOE Contract Number: FG03-85ER13431
• OSTI ID: 5458769
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 108:17
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
10 SYNTHETIC FUELS
01 COAL, LIGNITE, AND PEAT
IODINE COMPLEXES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
ORGANIC COMPOUNDS
ADDUCTS
DERIVATIZATION
EXPERIMENTAL DATA
LIGANDS
COMPLEXES
DATA
INFORMATION
NUMERICAL DATA
SYNTHESIS
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)
090121 - Hydrocarbon Fuels- Chemical Synthesis- (1976-1989)
010403 - Coal & Coal Products- Hydrogenation- (-1987)