Structure and magnetic properties of meso-tetrakis(2,4,6-trimethylphenyl)porphyrinatomanganese(III) 7,7,8,8-tetracyano-2,5-dimethyl-p-quinodimethanide with a 2.3 K Tc. The first example of cis coordination of a tetracyano-p-quinodimethanide

Ken-ichi Sugiura; Shinji Mikami; Mitchell T. Johnson; Joel S. Miller; Kentaro Iwasaki; Kazunori Umishita; Shojun Hino; Yoshiteru Sakata

doi:10.1039/A907241A

Ken-ichi Sugiura,^a Shinji Mikami,^a Mitchell T. Johnson,^b Joel S. Miller,*^b Kentaro Iwasaki,^c Kazunori Umishita,^c Shojun Hino^c and Yoshiteru Sakata*^a

Author affiliations

* Corresponding authors

^a The Institute of Scientific and Industrial Research (ISIR), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, Japan
E-mail: sakata@sanken.osaka-u.ac.jp

^b Department of Chemistry, 315 S. 1400 E. RM Dock, University of Utah, Salt Lake City, USA
E-mail: jsmiller@chemistry.chem.utah.edu

^c Faculty of Engineering, Chiba University, Inage-ku, Chiba, Japan

Abstract

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-μ-coordination motif having an infinite zigzag chain structure. [MnTMesP][DMTCNQ]·2p-C₆H₄Me₂ crystallizes in a triclinic Image ID:a907241a-t1.gif 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 ν_CN at 2184 and 2160 cm⁻¹. The susceptibility (χ) of the complex obeys the Curie–Weiss equation, χ = 1/(T − θ), where θ is −10 ± 1 K (130 < T < 250 K), and +23 ± 1 K (T > 250 K). A minimum of χT(T) characteristic of 1-D antiferromagnetic coupling is observed at 115 K. Above 50 K, χT(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, χ′(T), in a.c. susceptibility measurements shows a sharp maximum at 2.3 K associated with the ordering temperature, T_c, of the material.

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Article information

DOI: https://doi.org/10.1039/A907241A
Article type: Paper
Submitted: 07 Sep 1999
Accepted: 21 Jan 2000
First published: 08 Mar 2000

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J. Mater. Chem., 2000,10, 959-964

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