NQPI Seminar 9/17/2026 - Michael Jensen

The Nanoscale and Quantum Phenomena Institute (NQPI) Seminar Series is pleased to welcome Michael P. Jensen, Associate Professor, Department of Chemistry & Biochemistry, Ohio University, as our featured speaker on Thursday, September 17 at 4:10 p.m. All seminars take place in Walter 145 and are also accessible virtually via Teams. Title: Heteroleptic Sandwich Complexes [(Tp3R,5R)M(Bp3R′,5R′)]: Semi-"agostic" B-H Coordination, Spin Crossover and Catalysis Abstract: We have prepared and characterizwed thirteen heteroleptic scorpionate sandwich complexes [(Tp3R,5R)M(Bp3R′,5R′)]: 3R = 5R = Me, 3R′ = 5R′ = H, M = Co, Ni (1M); 3R = 5R = 3R′ = 5R′ = Me, M = Mn-Ni (2M); 3R = Ph, 5R = 3R′ = 5R′ = Me, M = Mn-Ni (3M); and 3R = 3R′ = Ph, 5R = 5R′ = Me M = Fe-Ni (4M). The systematic variation of ligand substituents across these tetragonal complexes results in constraint of the hemilabile endohedral borohydride on the Bp3R′,5R′ coligand at specific distances from the metal. Short M•••HB′ distances consistent with a three-center, three-electron (i.e., semi-"agostic") bond were observed in crystal structures of 4M, essentially nonbonding distances were found in 1M and in 3M, and intermediate pre-"agostic" dispositions were obtained in 2M. DFT modeling correlated these distances to chemical shifts of the borohydride resonances observed in 1H NMR spectra, and to frequencies of (B-H) modes in FTIR spectra. DFT calculations are also consistent with spin crossover in the cobalt complexes