N,7,7-Tricyanoquinomethanimine (TCQMI) Based Organic Magnetic Materials



The synthesis and characterization of a new family of magnetic materials based on the electron accepting cyanocarbon N,7,7-tricyanoquinomethanimine, TCQMI, its radical anion [TCQMI], and its σ-dimer, σ-[TCQMI]22−, are reported. [FeIIICp*2][TCQMI] (where Cp* is pentamethylcyclopentadienide) forms parallel chains of alternating [TCQMI]•− and [FeCp*2]•+ and magnetically orders at 3.4 K as a weak ferromagnet. M[TCQMI]2zCH2Cl2 (M = V, Fe) are amorphous solids with [TCQMI]•− coordinated to metal centers through the nitrile groups. The Fe compound magnetically orders as a weak ferromagnet at ≈4 K, whereas the V compound shows no evidence of magnetic ordering. {[MnIIITPP]+}2[TCQMI]22− (TPP = tetraphenylporphyrin) results from the reaction of TCQMI with MnIITPP(py) due to the formation of the [TCQMI]22− σ-dimer in situ, and is a weak ferromagnet below 3.7 K. The lack of magnetic ordering in V[TCQMI]2zCH2Cl2 is not currently understood, and is in strong contrast to V[TCNE]2zCH2Cl2, which magnetically orders above room temperature.