Nickel-Dithiolene Ion-Pair Compounds Showing Thermotropic Liquid Crystal Behaviors and Alkyl Chain Length Dependent Electrochemical Properties

Abstract

Nine ion-pair compounds [C n -Apy] 2 [Ni(mnt) 2 ] (C n -Apy + = 1-alkyl-4-aminopyridinium, n = 2-10, corresponding to compounds 1-9; mnt 2-= maleonitriledithiolate) were synthesized and characterized structurally. The hydrocarbon chain in the countercation adopts all trans-plane conformation when n < 7; otherwise, it adopts the mixed trans and gauche conformation. 1, 2, 8, and 9 show the layered packing structure of alternating anions and cations, whereas 3-6 display the mixed stacking structure of anions (A) and cations (C) in a . . . ACCA . . . manner. 3-9 exhibit the thermotropic liquid crystal behaviors. The redox couple of [Ni(mnt) 2 ] − /[Ni(mnt) 2 ] 2in the solid state depend on the hydrocarbon chain length in the cation.

Phase Transition, Dielectrics, Single-Ion Conductance, and Thermochromic Luminescence of a Inorganic–Organic Hybrid of [Triethylpropylammonium][PbI3]

“…As displayed in Figure 2b, the endothermic and exothermic events occur in two sequential thermal cycles in the range of 400−480 K; it is worth noting that the exothermic peaks almost coincide with each other in two sequential heating and cooling runs, while the endothermic peak shifts slightly toward the hightemperature side in the second heating run with respect to that in the first thermal process. The analogous thermal behavior is normally observed in the ion-liquid crystals 42,43 and related to the fact that the thermal motion of the alkyl chains cannot follow the temperature change during the heating−cooling cycle. In the first heating process, the onset and peak temperatures of the endothermic event locate at 440 and 445 K, respectively.…”

Significant Role of Supramolecular Interactions on Conformational Modulation of Flexible Organic Cation Receptors in a Metal-Bis(dithiolate) Coordination Complex Matrix

“…The present electrochemical data can be explained on the basis of Scheme , proposed by McCleverty, Hoyer, and others. , According to this scheme, the oxidative responses for compounds 1a – 1c and 2a – 2c are ascribed due to the couple [M III (mnt) 2 ] −1 /[M II (mnt) 2 ] −2 (M = Cu, Ni). All these oxidative response values of ion-pair dithiolene complexes are in accord with the reported electrochemical data of relevant compounds; − , from this, we can say that there is no change in oxidative response by changing the different substituents of countercation in ion-pair dithiolene complexes. Cyclic voltammetry data for compounds 1b , 1c and 2b , 2c are presented in section 6 in Supporting Information (Figure S11).…”

Crystal structure of bis(1-hexyl-N,N-dimethylpyridinium) bis(maleonitriledithiolato)nickelate(II)

“…The complex dianion possesses an approximately planar geometry with Ni-S bond lengths of the bidentate ligands of 2.1791 (9) and 2.1810 (8) Å and an1 S-Ni-S2 bite angle of ISSN 2056-9890 91.93 (3) . These values are in good agreement with those found in various [Ni(mnt) 2 ] 2À compounds (Duan et al, 2014a).…”