Structures and Mixed-valence State in Ni(mnt) 2 Salts of Biferrocenes

Ni(mnt) 2 salts of 1′, 1′′′-diisopropyl-1,1′′-biferrocene ( 1 ) and 1′,l′′′-dibenzyl-1 ,1′′-biferrocene ( 2 ) have been prepared. Both complexes show segregated-stack crystal structure, consisting of a mixed-valent biferrocenium monocation and a Ni(mnt) 2 monoanion. The D-A ratio is 1:1 in both compounds. The trapped-valence state is demonstrated for 2 at room temperature.