Molecular motion in pyridazinium/crown ether supramolecular cation salts of a nickel dithiolene complex

Abstract

anions were observed in salt 2, whose magnetic behaviour followed the Bonner-Fisher model.

Evaluation of the Magnetic Interactions in Salts Containing [Ni(dmit)2]− Radical Anions

“…The system can be considered as an alternating AF−F 1D chain, with α = J inter /|J intra | = 0.04 or even better as composed by magnetically isolated dimers. The χ(T) curve, however, is also compatible with an alternating AF−F chain with α = J inter /|J intra | = 0.52 as the model used by Liu et al 17 Our results put in evidence the difficulties of inferring interaction spin models based only on the quality of the fittings and promote the use of accurate calculations to get a wider knowledge of the physical factors governing the macroscopic properties at the molecular level. A deeper and rational understanding of the magnetic behavior of these systems has significant consequences on the design of functional materials based on the Ni(dmit) 2 anion radicals, and the control and enhancement of their properties by external stimuli.…”

“…22,23 In compound D, however, the slippage occurs along the y axis, and in such extension that there is no net π−π overlap between the [Ni(dmit) 2 ] − ions, but they interact via lateral sulfur−sulfur contacts (Scheme 3), forming a one-dimensional chain with weak dimers stabilized through side-by-side interactions. 17 In the two latter, the χ(T) behavior has been explained by means of the alternating antiferromagnetic Heisenberg chain model.…”

“…A good quality fitting has been reported 18 with J intra = −21.96 cm −1 , g = 2.0, and α = 0.58, i.e., J inter = −12.74 cm −1 , in concordance with the Huckel estimates of the transfer integrals (t intra = −35.5 meV, t inter = 19.0 meV). Compound D. In the (pyridazinium)(DCH [18]-crown-6)[Ni(dmit) 2 ] salt (D) the crown ether and the pyradizinium cation alternate along the a axis, forming one-dimensional columns 17 (Figure 4). The [Ni(dmit) 2 ] molecules are arranged in the same direction through lateral S•••S contacts in onedimensional chains.…”

“…The χ(T) plot has been fitted assuming an alternating chain model, with two fitting parameters, the intradimer coupling J intra = −34.4 K and the interdimer coupling constant J inter = 18 K. Notice that although referred by the authors as an alternating antiferromagnetic chain model, the values provided correspond to an alternating antiferromagnetic−ferromagnetic chain. 17 3. COMPUTATIONAL DETAILS Different computational models have been employed to determine the electronic structure of the systems and evaluate the intradimer J intra , interdimer J inter , and interchain J chain coupling constants.…”

Phase transition and switchable dielectric behaviours in an organic–inorganic hybrid compound: (3-nitroanilinium) 2 (18-crown-6) 2 (H 2 PO 4 ) 2 (H 3 PO 4 ) 3 (H 2 O)

“…phase transition, giving rise to phase transition materials with potential applications in energy storage, temperature controlling, data communications and phase shifters [10][11][12][13][14][15][16][17][18][19]. Molecular switchable dielectrics typically have dielectric constants that vary between high and low states upon temperature change.…”