The crystal structure of meso-tetrakis(2,4,6-trimethylphenyl)porphyrinatomanganese(III) 7,7,8,8-tetracyano-2,5-dimethyl-p-quinodimethanide, [MnTMesP][DMTCNQ]. 2p-C6H4Me2 provides the first example of a cis-1,2-mu-coordination motif having an infinite zigzag chain structure. [MnTMesP][DMTCNQ]. 2p-C6H4Me2 crystallizes in a triclinic <P(1)over bar> space group. The zigzag one-dimensional (1-D) chain is non-uniform and each acceptor does not lie on a centre of symmetry, although all acceptors are crystallographically equivalent. The ionic ground state of the complex was determined on the basis of X-ray photoelectron spectroscopy, crystallographic data, as well as the nu(CN) at 2184 and 2160 cm(-1). The susceptibility (chi) of the complex obeys the Curie-Weiss equation, chi = 1/(T - theta), where theta is -10 +/- 1 K (130 < T < 250 K), and +23 +/- 1 K (T > 250 K). A minimum of chi T(T) characteristic of 1-D antiferromagnetic coupling is observed at 115 K. Above 50 K, chi T(T) can be fitted by the Seiden model for non-interacting chains comprised of alternating g = 2, quantum S = 2 and classical S = 1/2 spins, with J/k(B) = -39 K for H = -2JS(i). S-j. The in-phase component, chi'(T), in a.c. susceptibility measurements shows a sharp maximum at 2.3 K associated with the ordering temperature, T-c, of the material.
