Reduction of carbon monoxide by binuclear tantalum hydride complexes

Journal Article · Wed May 04 00:00:00 EDT 1983 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00347a022· OSTI ID:5655008

Belmonte, P A; Cloke, F G; Schrock, R R

(TaCp'Cl/sub 2/H)/sub 2/ (Cp' = n/sup 5/-C/sub 5/Me/sub 4/Et) reacts with CO to give yellow, crystalline Ta/sub 2/Cp'/sub 2/Cl/sub 4/(H)(CHO); the hydride bridges the two metals as does the side-on bonded formyl fragment. When PMe=3 is added to Ta/sub 2/Cp'/sub 2/Cl/sub 4/(H)(CHO) the formyl C-O bond is broken to give Ta/sub 2/Cp'/sub 2/Cl/sub 4/(H)(O)(CHPMe/sub 3/). The reaction of a mixture of (TaCP'Cl/sub 2/H)/sub 2/ and (TaCp'Cl/sub 2/D)/sub 2/ with CO followed by PMe/sub 3/ to give only a mixtue of Ta/sub 2/Cp'/sub 2/Cl/sub 4/(H)(O)(CHPMe/sub 3/) and Ta/sub 2/Cp'/sub 2/Cl/sub 4/(D)(O)(CDPMe/sub 3/) suggests that the dimer does not fragment when it reacts with CO. This was confirmed by a crossover experiment involving (TaCp'Cl/sub 2/H)/sub 2/ and (TaCp/sup s/Cl/sub 2/H)/sub 2/ (Cp/sup s/ = n/sup 5/-1,3-C/sub 5/H/sub 3/(SiMe/sub 3/)/sub 2/). (TaCp'Cl/sub 2/H/sub 2/ forms a green, diamagnetic pyridine adduct that contains two inequivalent hydride ligands. (TaCp'Cl/sub 2/H)/sub 2/ forms an unstable, purple CO adduct that shows a terminally bound CO band (v/sub CO/ = 1939 cm/sup -1/) and two different hydride bands (v/sub MH/ = 1560 and 1599 cm/sup -1/) in the IR spectrum of a thin film at -78/sup 0/C, and a singlet ascribed to the carbonyl carbon atom at 238 ppm in the /sup 13/C NMR spectrum. (TaCp'Cl/sub 2/H)/sub 2/(CO) decomposes rapidly in solution or in the solid state at -30/sup 0/C to give Ta/sub 2/Cp'/sub 2/Cl/sub 4/(H)(CHO) quantitatively. Methane is formed in approx.70% yield when Ta/sub 2/Cp'/sub 2/Cl/sub 4/(H)(CHO) is treated with AlCl/sub 3/ under molecular hydrogen. Methanol is formed in high yield when Ta/sub 2/Cp'/sub 2/Cl/sub 4/(H)(CHO) is hydrolyzed with aqueous HCl.

• Research Organization: Massachusetts Institute of Technology, Cambridge
• OSTI ID: 5655008
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 105:9
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON MONOXIDE
REDUCTION
TANTALUM COMPLEXES
CATALYTIC EFFECTS
CHEMICAL BONDS
DIMERS
LIGANDS
TANTALUM HYDRIDES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
COMPLEXES
HYDRIDES
HYDROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
TANTALUM COMPOUNDS
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties