The crystal and molecular structure of 7,7,8,8-tetracyanoquinodimethane

Long, Ran; Sparks, R. A.; Trueblood, K. N.

doi:10.1107/s0365110x65002256

Cited by 352 publications

(175 citation statements)

References 4 publications

(5 reference statements)

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“…Bond distances in the TCNQ molecule [Fig. 6,Table 4(b)] agree remarkably well with those found in the structure of TCNQ (Long, Sparks & Trueblood, 1965), and when compared to the compilation by Hoekstra, Spoelder & Vos (1972) they are indicative of a neutral ground state of the molecule. The quinonoid bond length is also very close to those found in the essentially neutral TCNQ compounds with phenazine and dibenzo-pdioxin (Goldberg & Shmueli, 1973a, b).…”

Section: Molecular Geometrysupporting

confidence: 68%

Structure and packing arrangement of molecular compounds. VII. 7,7,8,8-Tetracyanoquinodimethane–naphthalene (1:1)

Shaanan¹,

Shmueli²,

Rabinovich³

1976

Acta Crystallogr Sect B

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Crystals of the (1:1) 7,7,8,8-tetracyanoquinodimethane-naphthalene compound are triclinic, with one unit of the complex in a unit cell of dimensions a = 8.216 (1), b = 7.807 (1), c = 7.873 (1)/~ and 0c = 120.34 (1), fl= 92.22 (1), y = 96.63 (1) °. The structure was solved from three-dimensional precession diffractometer data, with Patterson methods, and was refined to a conventional R=0.062 and weighted r=0-038. TCNQ and naphthalene are alternately stacked along the [001] direction; however, their best planes deviate very significantly from the parallel arrangement so frequently observed in (1:1) compounds consisting of planar molecules and forming mixed stacks. The molecular geometries of TCNQ and naphthalene agree very well with those observed in the uncomplexed molecules. Both molecules are well ordered and the observed packing arrangement appears to be conditioned mainly by van der Waals and dipole-dipole interactions. Calculated energy profiles indicate that the observed librational motion of the molecules reflects usual packing restrictions.

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Section: Molecular Geometrysupporting

confidence: 68%

Structure and packing arrangement of molecular compounds. VII. 7,7,8,8-Tetracyanoquinodimethane–naphthalene (1:1)

Shaanan¹,

Shmueli²,

Rabinovich³

1976

Acta Crystallogr Sect B

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“…The broken symmetry is one of the most striking aspects of the patterns, as well as one of the principal mysteries connected with them. The mystery arises because-in contrast to the two cases mentioned above-in these experiments there is no microscopic symmetry breaking: TCNQ molecules are themselves inversion symmetric [17]. Furthermore, even though the 'seahorse' aggregates are polycrystalline [14], one can probably rule out symmetry breaking at the level of the unit cell, since TCNQ crystals are also achiral [17,18].…”

Section: Introductionmentioning

confidence: 99%

Chiral patterns arising from electrostatic growth models

et al. 1998

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Recently, unusual and strikingly beautiful seahorse-like growth patterns have been observed under conditions of quasitwo-dimensional growth. These 'S'-shaped patterns strongly break two-dimensional inversion symmetry; however such broken symmetry occurs only at the level of overall morphology, as the clusters are formed from achiral molecules with an achiral unit cell. Here we describe a mechanism which gives rise to chiral growth morphologies without invoking microscopic chirality. This mechanism involves trapped electrostatic charge on the growing cluster, and the enhancement of growth in regions of large electric field. We illustrate the mechanism with a tree growth model, with a continuum model for the motion of the one-dimensional boundary, and with microscopic Monte Carlo simulations. Our most dramatic results are found using the continuum model, which strongly exhibits spontaneous chiral symmetry breaking, and in particular finned 'S' shapes like those seen in the experiments.

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“…3 (b), (c), (e), (f). As compared to the diffraction profiles calculated from the structural parameters of F4-TCNQ 29 and TCNQ 30 , the (h 0 0) or (0 0 l) (h,l = 2n) indices could reasonably be assigned to the diffraction from F4-TCNQ or TCNQ films. Therefore, it is most plausible that crystalline organic thin films with typical orientations form on BSTS single crystal surface, and 9 this crystallographic information is consistent with the scenario of charge transfer depending on the E ea 's.…”

Section: Structures Of Organic Thin Films On Bsts Single Crystalsmentioning

confidence: 96%

Electron and Hole Injection via Charge Transfer at the Topological Insulator Bi_2–xSb_xTe_3–ySe_y–Organic Molecule Interface

et al. 2014

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As a methodology for controlling the carrier transport of topological insulators (TI's), a flexible tuning in carrier number on the surface states (SS's) of three dimensional TI's by surface modifications using organic molecules is described. The principle of the carrier tuning and its type conversion of TI's presented in this research are based on the charge transfer of holes or electrons at the TI/organic molecule interface. By employing 2, 3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) as an electron acceptor or tetracyanoquinodimethane (TCNQ) as a donor for n-and p-Bi 2-x Sb x Te 3-y Se y (BSTS) single crystals, successful carrier conversion from n to p and its reverse mode is demonstrated depending on the electron affinities of the molecules. The present method provides a nondestructive and efficient method for local tuning in carrier density of TI's, and is useful for future applications.

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The crystal and molecular structure of 7,7,8,8-tetracyanoquinodimethane

Cited by 352 publications

References 4 publications

Structure and packing arrangement of molecular compounds. VII. 7,7,8,8-Tetracyanoquinodimethane–naphthalene (1:1)

Structure and packing arrangement of molecular compounds. VII. 7,7,8,8-Tetracyanoquinodimethane–naphthalene (1:1)

Chiral patterns arising from electrostatic growth models

Electron and Hole Injection via Charge Transfer at the Topological Insulator Bi_2–xSb_xTe_3–ySe_y–Organic Molecule Interface

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The crystal and molecular structure of 7,7,8,8-tetracyanoquinodimethane

Cited by 352 publications

References 4 publications

Structure and packing arrangement of molecular compounds. VII. 7,7,8,8-Tetracyanoquinodimethane–naphthalene (1:1)

Structure and packing arrangement of molecular compounds. VII. 7,7,8,8-Tetracyanoquinodimethane–naphthalene (1:1)

Chiral patterns arising from electrostatic growth models

Electron and Hole Injection via Charge Transfer at the Topological Insulator Bi2–xSbxTe3–ySey–Organic Molecule Interface

Contact Info

Product

Resources

About

Electron and Hole Injection via Charge Transfer at the Topological Insulator Bi_2–xSb_xTe_3–ySe_y–Organic Molecule Interface