1352832-63-3Relevant academic research and scientific papers
Stabilization of nickel complexes with Ni0H-N bonding interactions using sterically demanding cyclic diphosphine ligands
Wiedner, Eric S.,Yang, Jenny Y.,Chen, Shentan,Raugei, Simone,Dougherty, William G.,Kassel, W. Scott,Helm, Monte L.,Bullock, R. Morris,DuBois, M. Rakowski,DuBois, Daniel L.
, p. 144 - 156 (2012/04/10)
The series of complexes Ni(PtBu2NR 2)2, [Ni(PtBu2NR 2)2]BF4, [HNi(PtBu2N R2)2]BF4, and [Co(P tBu2NPh2)2]BF 4(PtBu2NR 2 = 1,5-dialkyl-3,7-tert-butyl-1,5-diaza-3,7-diphosphacyclooctane; alkyl = phenyl, benzyl) have been synthesized and characterized. Spectroscopic, electrochemical, and X-ray diffraction studies indicate these complexes are stable as a result of the tetrahedral arrangement of the two diphosphine ligands. Electrochemical oxidation of [HNi(PtBu2NPh2) 2]BF4 results in rapid proton transfer from nickel at a rate faster than can be observed on the CV time scale. Double protonation of Ni(PtBu2NBn2)2forms the endo-endo, endo-exo, and exo-exo isomers of [Ni(PtBu 2NBnHNBn)2](BF4) 2, which were found to be more stable toward loss of H2 than previously observed for similar complexes. The presence of Ni0HN hydrogen bonds at the endo protonation sites of [Ni(PtBu 2NBnHNBn)2](BF4) 2 results in significant differences in the Ni(I/0) oxidation potentials of each of the isomers. The differences in E1/2(I/0) values correspond to bond free energies of 7.4 and 3.7 kcal/mol for the first and second Ni0HN hydrogen bonds of the endo-exo and endo-endo isomers, respectively. Computational studies give bond dissociation energies of the Ni0HN bonds that are within 1-2 kcal/mol of the experimentally determined values.
