340734-69-2Relevant academic research and scientific papers
Reduction of oxygen catalyzed by nickel diphosphine complexes with positioned pendant amines
Yang, Jenny Y.,Bullock, R. Morris,Dougherty, William G.,Kassel, W. Scott,Twamley, Brendan,Dubois, Daniel L.,Rakowski Dubois
, p. 3001 - 3010 (2010/06/14)
Nickel(ii) bis(diphosphine) complexes that contain positioned bases in the second coordination sphere have been found to catalyze the reduction of O 2 with H2 to selectively form water. The complexes also serve as electrocatalysts for the reduction of O2 with the addition of a weak acid. In contrast, a closely related nickel diphosphine complex without the positioned bases is catalytically inactive for O2 reduction. These results indicate that pendant bases in synthetic catalysts for O2 reduction can play a similar role to proton relays in enzymes, and that such relays should be considered in the design of catalysts for multi-electron and multi-proton reactions.
Free-energy relationships between the proton and hydride donor abilities of [HNi(diphosphine)2]+ complexes and the half-wave potentials of their conjugate bases
Berning, Douglas E.,Miedaner, Alex,Curtis, Calvin J.,Noll, Bruce C.,Rakowski DuBois, Mary C.,DuBois, Daniel L.
, p. 1832 - 1839 (2008/10/08)
A linear free-energy relationship exists between the half-wave potentials of the (II/I) couples of Ni(diphosphine)2 complexes and the hydride donor ability (ΔG°H-) of the corresponding [HNi(diphosphine)2]+ complexes. A similar correlation is observed between the half-wave potentials of the (I/O) couples of Ni(diphosphine)2 complexes and the pKa values (or ΔG°H+) of the corresponding [HNi(diphosphine)2]+ complexes. As a result, it is possible to use the potentials of these two couples to predict the free energies of all three Ni-H bond cleavage reactions, ΔG°H+, ΔG°H·, and ΔG°H-, for this class of nickel complexes. The molecular structures of Ni(Et2PCH2CH2 PPh2)2 and Ni(Ph2PCHCHPPh2)2 were determined by single-crystal X-ray diffraction studies.
