Predictable Substituent Control of CoIII/II Redox Potential and Spin Crossover in Bis(dipyridylpyrrolide)cobalt Complexes
By McPherson, James N.; Hogue, Ross W.; Akogun, Folaranmi Sunday; Bond
Published in Inorganic Chemistry
2019
Abstract
A family of five easily prepared tridentate monoanionic 2,5-dipyridyl-3-(R1)-4-(R2)-pyrrolide anions (dppR1,R2)?, varying in the nature of the R1 and R2 substituents [R1, R2 = CN, Ph; CO2Et, CO2Et; CO2Me, 4-Py; CO2Me, Me; Me, Me], has been used to generate the analogous family of neutral [CoII(dppR1,R2)2] complexes, two of which are structurally characterized at both 100 and 298 K. Both the oxidation and spin states of these complexes can be switched in response to appropriate external stimuli. All complexes, except [CoII(dppMe,Me)2], exhibit gradual spin crossover (SCO) in the solid state, and SCO activity is observed for three complexes in CDCl3 solution. The cobalt(II) centers in the low spin (LS) complexes are Jahn