TY - JOUR
T1 - Nickel Bis-Diphosphine Complexes
T2 - Controlling the Binding and Heterolysis of H2
AU - Stolley, Ryan M.
AU - Darmon, Jonathan M.
AU - Das, Parthapratim
AU - Helm, Monte L.
N1 - Funding Information:
This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/9/12
Y1 - 2016/9/12
N2 - Two new Ni(II) complexes, the homoleptic [Ni(8PCy2NH)2]2+ complex (8PCy2NH = 3,7-cyclohexyl-1-amino-3,7-diphosphacyclooctane) containing two pendant amines on adjacent ligands, and the heteroleptic [Ni(8PCy2NH)(dppe)]2+ complex (dppe = bis(diphenylphosphino)ethane) containing only a single pendant amine, have been synthesized, and their electrochemical properties are reported. The [Ni(8PCy2NH)(dppe)]2+ complex is capable of heterolytically cleaving hydrogen, allowing for the first observation of an endo-protonated nickel hydride related to the [Ni(PR2NR′2)2]2+ family of complexes. The [Ni(8PCy2NH)(dppe)]2+ complex did not exhibit electrocatalytic H2 oxidation activity; however, [Ni(8PCy2NH)2]2+ is an active electrocatalyst for H2 oxidation with a maximum turnover frequency (kobs) of 18 s-1 under 1 atm H2 at Ecat/2 = -0.71 V versus the ferrocenium/ferrocene (Cp2Fe+/0) couple. In addition to an analysis of the effect of the number of pendant amines on the rates of electrocatalytic H2 oxidation of compounds related to the [Ni(PR2NR′2)2]2+ family, the effect of the secondary pendant amine on intermolecular deprotonation is discussed.
AB - Two new Ni(II) complexes, the homoleptic [Ni(8PCy2NH)2]2+ complex (8PCy2NH = 3,7-cyclohexyl-1-amino-3,7-diphosphacyclooctane) containing two pendant amines on adjacent ligands, and the heteroleptic [Ni(8PCy2NH)(dppe)]2+ complex (dppe = bis(diphenylphosphino)ethane) containing only a single pendant amine, have been synthesized, and their electrochemical properties are reported. The [Ni(8PCy2NH)(dppe)]2+ complex is capable of heterolytically cleaving hydrogen, allowing for the first observation of an endo-protonated nickel hydride related to the [Ni(PR2NR′2)2]2+ family of complexes. The [Ni(8PCy2NH)(dppe)]2+ complex did not exhibit electrocatalytic H2 oxidation activity; however, [Ni(8PCy2NH)2]2+ is an active electrocatalyst for H2 oxidation with a maximum turnover frequency (kobs) of 18 s-1 under 1 atm H2 at Ecat/2 = -0.71 V versus the ferrocenium/ferrocene (Cp2Fe+/0) couple. In addition to an analysis of the effect of the number of pendant amines on the rates of electrocatalytic H2 oxidation of compounds related to the [Ni(PR2NR′2)2]2+ family, the effect of the secondary pendant amine on intermolecular deprotonation is discussed.
UR - http://www.scopus.com/inward/record.url?scp=84986879748&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84986879748&partnerID=8YFLogxK
U2 - 10.1021/acs.organomet.6b00486
DO - 10.1021/acs.organomet.6b00486
M3 - Review article
AN - SCOPUS:84986879748
VL - 35
SP - 2965
EP - 2974
JO - Organometallics
JF - Organometallics
SN - 0276-7333
IS - 17
ER -