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Synthesis, Electronic Structure, and Reactivity of a Planar Four-Coordinate, Cobalt-Imido Complex
Yoonsu Park1, Scott P Semproni1, Hongyu Zhong1
1Department of Chemistry, Princeton University, Frick Laboratory 292, Princeton, NJ, 08544, USA.
Abstract:
A four-coordinate cobalt-imido complex, (tBu mPNP)Co=NMes (tBu mPNP=modified PNP pincer ligand) has been synthesized from addition of 2,4,6-trimethylphenylazide (Mes-N3 ) to the corresponding dinitrogen complex. The solid-state structure determined by X-ray diffraction established a rare, idealized planar geometry with a Co=N bond distance of 1.716(2) Å. Magnetic measurements revealed an S=1 ground state with CAS-SCF calculations supporting radical character on the imide nitrogen. Thermolysis of the cobalt-imido compound induced selective insertion of the imido group into a Co-P bond and yielded a three-coordinate cobalt complex with a distorted T-shaped geometry. Transition state analysis conducted with DFT calculations established the thermodynamic stability of the P-N coupled product and provided insight into the exclusive selectivity.
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