Electrocatalytic Oxidation of Formate by [Ni(P R 2 N R' 2 ) 2 (CH 3 CN)] 2+ Complexes
New [Ni(PR2NR`2)2+(CH3CN)]2+ complexes with R = Ph, R` = 4-MeOPh; R = Cy, R` = Ph and a mixed ligand [Ni(PR2NR`2)(PR``2NR`2)]2+ with R = Cy, R` = Ph, R`` = Ph have been synthesized and characterized by single crystal X-ray crystallography. These complexes are shown to be electrocatalysts for the oxidation of formate in solution to produce CO2, protons, and electrons with rates which are first order in catalyst and in formate at formate concentrations below approximately 0.05 M. For the catalysts studied, maximum observed turnover frequencies vary from <1.1 s-1 to 12.5 s-1 at room temperature, which are the highest rates yet reported for formate oxidation by homogeneous catalysts. A mechanistic scheme is proposed which involves an initial nickel complex bound <1-OC(O)H followed by a rate limiting hydride transfer step. An acetate complex demonstrating the η1-OC(O)CH3 binding mode to nickel has also been synthesized and characterized by single crystal X-ray crystallography. The pendant amines have been demonstrated to be essential for this electrocatalytic activity as no activity toward formate was found for the similar [Ni(depe)2][BF4]2+ (depe = diethylphosphinoethane) complex. This work was supported by the US Department of Energy Basic Energy Sciences' Chemical Sciences, Geosciences & Biosciences Division. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1025062
- Report Number(s):
- PNNL-SA-77812; KC0302010; TRN: US1104824
- Journal Information:
- Journal of the American Chemical Society, Vol. 133, Issue 32; ISSN 0002-7863
- Publisher:
- American Chemical Society (ACS)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Reversible displacement of polyagostic interactions in 16e [Mn(CO)(R{sub 2}PC{sub 2}H{sub 4}PR{sub 2}){sub 2}]{sup +} by H{sub 2}, N{sub 2}, and SO{sub 2}. Binding and activation of {eta}{sup 2}-H{sub 2} trans to CO is nearly invariant to changes in charge and cis ligands
Thermodynamic Properties of the Ni-H Bond in Complexes of the Type [HNi(P2RN2R')2](BF4) and Evaluation of Factors that Control Catalytic Activity for Hydrogen Oxidation/Production