Structural characterization of the neutral-ionic phase transition in tetrathiafulvalene-chloranil: evidence for C-H.cntdot..cntdot..cntdot.O hydrogen bonding

Crystallographic study of the 1,5-diazabicyclo[3.3.0]octadienedione (9,10-dioxabimane) system. Crystal structures and molecular conformations of 2,8-dimethyl-1,5-diazabicyclo[3.3.0]octa-2,7-diene-4,6-dione [syn-(CH3,H)-9,10-dioxabimane], 2,6-dimethyl-1,5-diazabicyclo [3.3.0]octa-2,6-diene-4,8-dione [anti-(CH3,H)-9,10-dioxabimane] and 2,6-dimethyl-3,5-dioxo-4,11-diazatricyclo[5.3.1.04,11]undeca-1,6-diene-9,9-dicarbonitrile {μ-[C(CN)2]-syn-(CH<

“…Experimental evidence for C-H...O bonding with methyl, methylene and ~C-H groups as H donors has repeatedly been described in recent literature (e.g., Bernstein, Cohen & Leiserowitz, 1974;Goldberg, 1975;Schomberg, 1980;Batail, LaPlaca, Mayerle & Torrance, 1981). We tentatively conclude, therefore, that such bonding also provides a structure-determining contribution in the crystals of the bimane species referred to above.…”

Directing the Structures and Collective Electronic Properties of Organic Conductors: The Interplay of π-Overlap Interactions and Hydrogen Bonds

“…Two NÀH´´´O and C-H´´´O hydrogen bonds are identified between molecules A and B, and between molecules B and C, both of which involve the oxygen atom of the amidic group as the hydrogen-bond acceptor (Figure 2). The occurrence of such CÀH´´´O bonds [19,20] demonstrates a significant activation of the hydrogen atom, whose origin is to be found in both its position ortho to the amidic group and the cationic state of the EDT-TTF core. This ortho effect has already been observed in the structures of a,b-unsaturated acids [21] and quinones, [22] while the C À H activation upon oxidation of the TTF core was revealed some years ago in the analysis of the structural transition accompanying the neutralto-ionic transition in TTF´Chloranil.…”

“…This ortho effect has already been observed in the structures of a,b-unsaturated acids [21] and quinones, [22] while the C À H activation upon oxidation of the TTF core was revealed some years ago in the analysis of the structural transition accompanying the neutralto-ionic transition in TTF´Chloranil. [19] The chelating ability of this amide bearing an ortho-hydrogen atom gives rise to a cyclic motif, denoted R 2 1 (7) in Etters notation.…”

Dramatically Different Conductivity Properties of Metal–Organic Framework Polymorphs of Tl(TCNQ): An Unexpected Room‐Temperature Crystal‐to‐Crystal Phase Transition

“…[2] Materials that respond to the application of an electric field or changes in light, pressure, or temperature are being sought for incorporation into electronic devices with ultrafast operating speeds. [3,4] Examples of molecule-based materials that exhibit fascinating properties are the spin-crossover complex [Fe(picolylamine) 3 Cl 2 (C 2 H 5 OH)], [5,6] the neutralionic transition system TTF-chloranil (TTF = tetrathiafulvalene), [7][8][9] the metallo-organic conductor Cu(DM-DCNQI) 2 , [10][11][12][13][14][15][16] (DM-DCNQI = dimethyl-N,N'-dicyanoquinonediimine) and the salt (EDO-TTF) 2 PF 6 , [17,18] (EDO-TTF = ethylenedioxytetrathiafulvalene). These materials provide compelling evidence for the contention that molecular solids may eventually be useful in device applications.…”

“…[3,4] Examples of molecule-based materials that exhibit fascinating properties are the spin-crossover complex [Fe(picolylamine) 3 Cl 2 (C 2 H 5 OH)], [5,6] the neutralionic transition system TTF-chloranil (TTF = tetrathiafulvalene), [7][8][9] the metallo-organic conductor Cu(DM-DCNQI) 2 , [10][11][12][13][14][15][16] (DM-DCNQI = dimethyl-N,N'-dicyanoquinonediimine) and the salt (EDO-TTF) 2 PF 6 , [17,18] (EDO-TTF = ethylenedioxytetrathiafulvalene). These materials provide compelling evidence for the contention that molecular solids may eventually be useful in device applications.In terms of electric-field-induced behavior, the most extensively studied examples are the organocyanide-based materials Cu(TCNQ) (TCNQ = 7,7,8,, which exhibits reversible switching from a highresistance state to a conducting state promoted by the application of an electric field or upon irradiation, [19][20][21] and the current-driven conductor K(TCNQ) salt.[22] The latter material is a key member of the binary series of alkali-metal salts of TCNQ that behave as so-called "Mott insulators" at high temperatures, in which the fully reduced radical anions are arranged in columns with evenly spaced TCNQ units. At lower temperatures, these "soft" materials undergo a phase transition in which the TCNQ units are brought into close proximity as a result of p dimerization.…”