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Title: Carbon dioxide chemistry and electrochemistry of a binuclear cradle complex of Ni(0), Ni/sub 2/(. mu. -CNMe)(CNMe)/sub 2/(PPh/sub 2/CH/sub 2/PPh/sub 2/)/sub 2/

Conference · · J. Am. Chem. Soc.; (United States)
OSTI ID:6868572

The binuclear Ni(0) complex, Ni/sub 2/(..mu..-CNMe)/sub 2/(CNMe)(dppm)/sub 2/, (1) undergoes two one-electron oxidations (E/sub 1/2/ = -0.51 and -0.83 V vs Ag/AgCl) to form the complex, Ni/sub 2/(..mu..-CNMe)(CNMe)/sub 2/(dppm)/sub 2//sup 2 +/, (2) the crystal structure of 2 as the PF/sub 6//sup -/ salt has been determined. Complex 2 crystallized in the space group P2/sub 1/ with a = 13.659 (3) A, b = 14.852 (4) A, c = 17.970 (3) A, ..beta.. = 101.44 (1)/sup 0/, V = 3573.0 (2) A/sup 3/, and Z = 2. The structure was refined to convergence (R = 0.056, R/sub w/ = 0.073) for 4036 unique data over the range 4/sup 0/ less than or equal to 2 theta less than or equal to 45/sup 0/ by using Mo K..cap alpha.. radiation. Complex 2 exhibits an unusual trans,cis-diphosphine configuration at the Ni centers and contains a semibridging isocyanide. The electrochemical behavior of 2 in the presence of CO/sub 2/ has been examined. Complex 2 reacts with CO/sub 2/ by an EC electrochemical mechanism to afford the CO/sub 2/ complex Ni/sub 2/(..mu..-CNMeCO/sub 2/)(CNMe)/sub 2/(dppm)/sub 2/, (3) complex 3 also has been prepared by reaction of 1 with CO/sub 2/(1). Prolonged reaction of 1 with CO/sub 2/(l) leads to complete carbonylation and Ni/sub 2/(..mu..-CO)(CO)/sub 2/(dppm)/sub 2/, (4) the results of labeling experiments using /sup 13/CO/sub 2/ and 99% /sup 13/C-enriched Ni/sub 2/(..mu..-/sup 13/CNMe)(/sup 13/CNMe)/sub 2/(dppm)/sub 2/ are interpreted in terms of a reaction pathway involving O-atom transfer from CO/sub 2/ to the carbon atom of the bridging isocyanide of 1.

Research Organization:
Purdue Univ., West Lafayette, IN
DOE Contract Number:
FG22-84PC70791
OSTI ID:
6868572
Journal Information:
J. Am. Chem. Soc.; (United States), Vol. 109:3
Country of Publication:
United States
Language:
English