Electronic Tuning Using Remote Substituents in Tetrakis(μ-N,N‘-diarylformamidinato)dinickel. Linear Free Energy Relationships in Dinuclear Compounds. 3

The series of tetrakis(μ-N,N‘-diarylformamidinato)dinickel(II), where the aryl is the phenyl modified with various substituent (X), is synthesized and thoroughly characterized. While both the coordination geometry and the UV−vis spectra remain essentially independent of X across the series, the one-electron oxidation potential, E1/2(Ni25+/Ni24+), correlates with the Hammett constant (σx) of substituents according to the equation: E1/2(X) − E1/2(H) = 114(8σx) (mV).