Structures of 1,1′,3,3′-tetra(2-methyl-2-nonyl)ferrocenium(1+) salts of CB11H12−, B12F122−, BF4−, PF6−, and ClO3−

The interdigitated and layered structures of the tetraalkylferrocenium salts [DEC][CB11H12], [DEC]2[B12F12], [DEC][BF4], [DEC][PF6], and [DEC][ClO3] were determined by single-crystal X-ray diffraction (DEC+ = 1,1′,3,3′-tetrakis(2-methyl-2-nonyl)ferrocenium(1+)). The structures of the salts of the two smaller anions were similar to the previously published oxoanion structures of [DEC][XOn−] (XOn− = NO3−, ClO4−, and ReO4−), with layers of trigonal-pyramidal ClO3− or tetrahedral BF4− anions stuffed between layers of interdigitated ferrocenium ions. The DEC+ cations in structures with the more highly charged and/or larger anions B12F122−, CB11H12−, and PF6− are also layered but the interdigitation is not as regular and not as complete as in the structures with relatively small 1− anions. Other differences and similarities of the eight [DEC]n[X] structures (n = 1, 2) are discussed.