Reported herein is elucidation of a novel Co-based oxygen evolution catalyst generated in situ from cobalt phosphide (CoP) nanoparticles. The present CoP nanoparticles, efficient alkaline hydrogen-evolving materials at the cathode, are revealed to experience unique metamorphosis upon anodic potential cycling in an alkaline electrolyte, engendering efficient and robust catalytic environments toward the oxygen evolution reaction (OER). Our extensive ex situ characterization shows that the transformed catalyst bears porous and nanoweb-like dispersed morphologies along with unique microscopic environments mainly consisting of discrete cobalt-oxo/hydroxo molecular units within a phosphate-enriched amorphous network. Outstanding OER efficiency is achievable with the activated catalyst, which is favorably comparable to even a precious iridium catalyst. A more remarkable feature is its outstanding long-term stability, superior to iridium and conventional cobalt oxide-based materials. Twelve-hour bulk electrolysis continuously operating at high current density is completely tolerable with the present catalyst.

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Manganese tricarbonyl complexes of fluorinated tris(pyrazolyl)borate ligands [HB(3,5-(CF3)2Pz)3]- and [HB(3-(CF3)Pz)3]- (where Pz = pyrazolyl) were synthesized by treating BrMn(CO)5 with [HB(3,5-(CF3)2Pz)3]Ag(THF) or [HB(3-(CF3)Pz)3]Na(THF). The reaction of [HB(3-(CF3)Pz)3]Na(THF) with copper(I) trifluoromethanesulfonate under CO afforded [HB(3-(CF3)Pz)3]CuCO. Compounds [HB(3,5-(CF3)2Pz)3]Mn(CO)3 (5), [HB(3-(CF3)Pz)3]Mn(CO)3 (6), and [HB(3-(CF3)Pz)3]CuCO (7) were characterized by 1H NMR, 19F NMR, and IR spectroscopy and by X-ray crystallography. They have relatively high C−O stretching frequencies. However, the νCO values are much lower than that in free CO and the relative lowering is higher for manganese adducts. The CF3 substitution on the 5-position has a significant effect on the metal center. This is readily apparent from the infrared spectroscopic data. Theoretical calculations of the geometries of [tris(pyrazolyl)borato]manganese(I) and -copper(I) carbonyls are in excellent agreement with the experimental results. Increasing the degree of fluorination lengthens the metal−C and metal−N bonds and shortens the C−O distance. The metal−Pz bonding is essentially a pure σ-interaction. Cyclic voltammetry data for the copper complexes show high oxidation potentials for the fluorinated analogs. IR spectroscopic data of the [tris(pyrazolyl)borato]manganese and -copper carbonyls have also been compared to those of cyclopentadienyl analogs.

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