1:2 Dimethyl-substituted tetracyanoquinodimethane.

Sugimoto, Toyonari; Ueda, Kazuyuki; Endo, Satoshi; Toyota, Naoki; Tada, Toshiji; Nishimura, Kei Ichiro; Kohama, Masakado; Shiwaku, Kaoru; Yamamoto, Kōji; Yamaguchi, Toshiyuki; Suenaga, Yusaka; Munakata, Megumu

doi:10.1016/s0009-2614(98)00343-1

Cited by 12 publications

(2 citation statements)

References 21 publications

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“…A possible approach for dimerization of TCNQ .À molecules to be suppressed is to introduce sterically bulky substitutents on TCNQ .À such as methyl groups and halogen atoms. In fact, for a tetramethyl-phosphonium (PMe 4 + ) salt of 2,5-dimethyl-substituted TCNQ radical anion (Me 2 TCNQ .À ) and a tetramethylarsonium (AsMe 4 + ) salt of Cl 2 TCNQ .À the Me 2 TCNQ .À and Cl 2 TCNQ .À molecules form a uniform stacking structure at room temperature (Sugimoto et al, 1998;Ueda et al, 2001). In this paper, the structure of the title compound, NMP + ÁCl 2 TCNQ .À , (I), is reported.…”

Section: Commentmentioning

confidence: 99%

N-Methylphenazinium 2,5-dichloro-7,7′,8,8′-tetracyanoquinodimethanide

2001

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In the title compound, C13H11N2+·C12H2Cl2N4.−, the N‐methylphenazinium cations have a dimerized structure with an interplanar distance of 3.42 (9) Å without effective overlap between the dimers. On the other hand, the 2,5‐dichloro‐7,7′,8,8′‐tetracyanoquinodimethanide radical anions form a one‐dimensional columnar structure along the a axis. In the column, there are two different kinds of modes in the overlap of the molecules: one mode has a slipped structure along a longer molecular axis of the molecules, whose six‐membered rings are shifted by 2.14 (8) Å, and in the other mode, the C(CN)2 groups are only overlapped with each other. The modes have interplanar distances of 3.11 (4) and 3.19 (2) Å, respectively.

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Section: Commentmentioning

confidence: 99%

N-Methylphenazinium 2,5-dichloro-7,7′,8,8′-tetracyanoquinodimethanide

2001

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“…As exemplified by TTF-TCNQ and Na, K, Rb-TCNQ, 1) those compounds exhibit striking structural, electric and/or magnetic properties depending on the degree of the charge transfer from cations to TCNQ and on the dimensionality of the resultant electronic states. The compound (NMe 4 ) 2 TCNQ 3 , which is examined in this Letter, is one of the neutral-radical mixed compounds that have been synthesized recently by Sugimoto and his coworkers, [2][3][4] where NMe 4 denotes tetramethylammonium N(CH 3 ) 4 . Similar to Cs 2 TCNQ 3 , 5) the compounds contain neutral and radical TCNQ molecules in a molar ratio of 1 : 2.…”

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Structural Phase Transition in (NMe₄)₂TCNQ₃

et al. 1999

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The structural properties of a neutral/radical 1 : 2 mixed compound, (NMe 4 ) 2 TCNQ 3 , have been studied by the X-ray diffraction method in a temperature range between 25 and 150 °C. The experimental data show that a second order phase transition takes place at around 60 °C and that the high-temperature phase has a monoclinic C2/m structure. The molecular planes of dimerized TCNQ -⋅ radicals, being slipped against each other in the low temperature phase, are expected from the C2/m symmetry to be totally eclipsed in the high-temperature phase. A good fit of the power law (1 − T / T c ) α to the temperature variation of the intensity of the Bragg reflection arising from the slipped TCNQ -⋅ radicals is obtained with T c = 330.7± 0.8 K and α = 0.66± 0.05 for T ≤ T c .Influences of this novel phase transition on the electronic properties are discussed.

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Molecular magnetism via resonating valence bonds for conjugated radicals and selected transition metal complexes

Klein

March

2001

Int J of Quantum Chemistry

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ABSTRACT:Currently there is considerable interest in the nature of exchange interactions leading to unpaired electrons in molecular and cluster magnets. Here, the focus is largely at a qualitative level, via a novel "mean-field" resonance-theoretic view, to deal with exchange couplings, so as to allow unpaired electrons in either (or both of) the π-and σ -parts of a (largely organic) bipartite (or alternate) molecular network. The (quantitative) number and (qualitative) location of unpaired spins are dealt with by this simple approach, which also offers some (qualitative) information on the occurrence of low-lying higher-spin states. To illustrate the approach it is applied to a variety of systems where the spin sources are conjugated π-network molecules and polymers, carbenes, variously defected graphites, and a few species involving transition metals, especially Cu. The discussion deals not only with traditional conjugated organics compounds but also with selected inorganic species.

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1:2 Dimethyl-substituted tetracyanoquinodimethane.

Cited by 12 publications

References 21 publications

N-Methylphenazinium 2,5-dichloro-7,7′,8,8′-tetracyanoquinodimethanide

N-Methylphenazinium 2,5-dichloro-7,7′,8,8′-tetracyanoquinodimethanide

Structural Phase Transition in (NMe₄)₂TCNQ₃

Molecular magnetism via resonating valence bonds for conjugated radicals and selected transition metal complexes

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1:2 Dimethyl-substituted tetracyanoquinodimethane.

Cited by 12 publications

References 21 publications

N-Methylphenazinium 2,5-dichloro-7,7′,8,8′-tetracyanoquinodimethanide

N-Methylphenazinium 2,5-dichloro-7,7′,8,8′-tetracyanoquinodimethanide

Structural Phase Transition in (NMe4)2TCNQ3

Molecular magnetism via resonating valence bonds for conjugated radicals and selected transition metal complexes

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Structural Phase Transition in (NMe₄)₂TCNQ₃