Ferrimagnetic ordering of a methylthio-substituted planar porphyrin based electron transfer salt, octakis(2,3,7,8,12,13,17,18-methylthio)porphyrinatomanganese(III) tetracyanoethanide

The direct redox reaction between tetracyanoethylene (TCNE) and a planar porphyrinatomanganese(ii), octakis(2,3,7,8,12,13,17,18-methylthio)porphyrinatomanganese(II), (MnOMTP)-O-II, produced a polymeric electron transfer salt (ETS), that has been structurally and magnetically characterized. The ETS belongs to the orthorhombic Cmca space group. The ETS has an extended one-dimensional linear chain coordination polymer motif comprised of S = 2 [(MnOMTP)-O-III](+) and bridging S = 1/2 [TCNE](-.) with an Mn-N-TCNE distance of 2.330(5) Angstrom, and lacks solvent. The [TCNE](-.) is disordered over two orientations in a 1:1 ratio. The interchain Mn . . . Mn distance, 9.205 Angstrom, is shorter than the intrachain distance, 9.350 Angstrom (=a-axis). The 2 to 300 K temperature dependence of the magnetic susceptibility can be fit to a Curie-Weiss expression with an effective theta value of +40 K. Intrachain coupling was modelled to a Seiden expression (H = -2S(a).S-b) with a J(intra) of -125 K, and 10 Hz ac magnetic susceptibility indicates an ordering temperature, T-c, of 9.6 K. The frequency dependence of the ac susceptibility displays spin glass behaviour.