<b>Substituted Quinodimethans. III. Displacement Reactions of 7,7,8,8-Tetracyanoquinodimethan</b>

Hertler, W. R.; Hartzler, H. D.; Acker, D. S.; Benson, R. E.

doi:10.1021/ja00876a030

Cited by 134 publications

(90 citation statements)

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“…[11,12,18,19] Consistent with a brief early report, [18] we have found recently that aromatic amines can also replace cyano groups to give rise to highly conjugated molecules. [13,14] Even though monosubstitution can be achieved with specific amines such as pyrrolidine, taken in less than equivalent amounts, [12,18] bis-substituted products are the most common in these reactions. Surprisingly, we have observed now that, when TCNQ is treated with five equivalents of 2-methyl-4-chloroaniline in acetonitrile in the presence of pyridine, three well-defined products with distinct optical properties are obtained in a one-pot, single-step reaction (Scheme 1).…”

Section: Resultssupporting

confidence: 79%

Molecular Materials with Contrasting Optical Responses from a Single‐Pot Reaction and Fluorescence Switching in a Carbon Acid

Patra

Radhakrishnan

2009

Chemistry A European J

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A wide variety of amines are known to react with 7,7,8,8-tetracyanoquinodimethane (TCNQ) to yield push-pull diaminodicyanoquinodimethanes with a strongly zwitterionic structure and significant optical and nonlinear optical properties. A novel course of reaction is observed now with the amine 2-methyl-4-chloroaniline, which leads to three well-defined products, A-C, in a single pot. A and B are formed through the replacement of one cyano group in TCNQ by the amine; A is a carbon acid and B is its corresponding salt. C is the conventional product in which two cyano groups in TCNQ are replaced by the amine. The products are characterized structurally and spectroscopic studies reveal contrasting optical responses. A is nonfluorescent, whereas B and C show red and green emission, respectively, in the solution and solid states. The acid/conjugate-base pair A and B can be interconverted through facile, reversible, and repeated deprotonation/protonation cycles, which are accompanied by instantaneous switching of the fluorescence. The current study illustrates an interesting case of a single-pot reaction yielding different optical materials with attributes that can be switched through simple approaches such as protonation or tuned through modification of the push-pull characteristics.

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Section: Resultssupporting

confidence: 79%

Molecular Materials with Contrasting Optical Responses from a Single‐Pot Reaction and Fluorescence Switching in a Carbon Acid

Patra

Radhakrishnan

2009

Chemistry A European J

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“…4). [7] This spectrum was similar to that of the oligomerization of TCNQ with 1-methoxycyclohexene through the zwitterionic intermediate reported by Kondo and Iwatsuki. [8] Further, an ESR spectrocopic study of the reaction mixture was attempted in the early stage of the copolymerization (Fig.…”

Section: Entrysupporting

confidence: 84%

Spontaneous alternating copolymerization of methoxyallene with 7,7,8,8-tetracyanoquinodimethane through a zwitterionic intermediate

Yamamoto

Sanda

Endo³

2000

Macromol. Chem. Phys.

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“…Synthesis DED-TCNQ was prepared by the reaction of TCNQ with N, N diethylamine in THF by methods analogous to those described by Hertler and co-workers. 16 Single-crystals were grown from acetonitrile solution.…”

Section: Methodsmentioning

confidence: 99%

Charge-density study of the nonlinear optical precursor DED-TCNQ at 20 K

et al. 2002

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. A charge-density study of the nonlinear-optical ͑NLO͒ precursor ͕4-͓bis͑diethylamino͒-methylium͔ phenyl͖dicyanomethanide ͑DED-TCNQ͒, space group P2 1 /c, aϭ11.174(2) Å; bϭ12.859(2) Å; c ϭ12.486(2) Å; ␤ϭ112.00(1)°, is presented. The results derive from a suitable combination of complementary 20 K x-ray and neutron diffraction data, the latter being important for locating the hydrogen atoms precisely. The compound is one in a series of TCNQ derivatives that exhibit varying degrees of quinoidal and zwitterionic character, these two electronic states being very close energetically. Bond-length-alternation type calculations show that the molecule at 20 K exists in a mixture of the two states, the zwitterionic ground state being dominant ͑63:37% zwitterionic: quinoidal͒. A topological analysis of the bonding density within the benzenoid ring provides for a more direct, alternative method to calculate this ratio which utilizes ellipticity values derived from the charge-density study. Results are identical thus corroborating the validity of the ''strength-length'' relationship implicitly assumed in bond-length-alternation type calculations. The ratio determined corresponds well to the electronic configuration needed to meet the requirements of the general rule for obtaining a maximum value of ␤ ͑a measure of the NLO response on the molecular scale͒ as a function of bond-length alternation. The promise of this class of compounds for nonlinear optics also lies partly in their high molecular dipole moments and so the pseudoatomic charges derived from this study were used to evaluate the nature of the molecular charge transfer in detail and the solid-state dipolar vector moment . Such measurements of are otherwise difficult in the solid state. A value of ͉͉ϭ91ϫ10 Ϫ30 Cm was deduced which compares with liquid and gas phase theoretical calculations of ϭ66.71ϫ10 Ϫ30 Cm and ϭ33.36 ϫ10 Ϫ30 Cm, respectively. This comparison, combined with an analysis of the sense of this vector, show that local crystal-field effects are highly influential in the solid state.

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Substituted Quinodimethans. III. Displacement Reactions of 7,7,8,8-Tetracyanoquinodimethan

Cited by 134 publications

References 0 publications

Molecular Materials with Contrasting Optical Responses from a Single‐Pot Reaction and Fluorescence Switching in a Carbon Acid

Molecular Materials with Contrasting Optical Responses from a Single‐Pot Reaction and Fluorescence Switching in a Carbon Acid

Spontaneous alternating copolymerization of methoxyallene with 7,7,8,8-tetracyanoquinodimethane through a zwitterionic intermediate

Charge-density study of the nonlinear optical precursor DED-TCNQ at 20 K

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