Structure and magnetism of N N NN′-tetramethyl-p-phenylenediamine -pentacyanocyclopentadienide (TMPD-PCCp)

Abstract
TMPD‐PCCp crystallizes in the triclinic space group P1̄ with cell parameters a=6.814(2), b=10.595(3), c=14.540(3) Å, α=74.65(2), β=81.93(2), γ=79.04(2)°, V=989.3 Å3, Z=2, and w R=0.064. The complex exhibits novel mixed stacking of TMPD+ ion radicals and diamagnetic PCCp ions and is weakly antiferromagnetic, with a Weiss constant of 2.6 K. An empirical model for ferromagnetic superexchange is presented for properly oriented ion radicals forming mixed stacks with symmetric diamagnetic spacers.