The independent part of the unit cell with the atom numbering of (a) 4,4′-dimethyl-2,2′-bipyridyl with CLA complex and (b) 6,6′-dimethyl-2,2′-bipyridyl with CLA complex.
Crystal packing of (a) 4,4′-dimethyl-2,2′-bipyridyl with CLA complex (gray and black chain polarization vectors are different) and (b) 6,6′-dimethyl-2,2′-bipyridyl with CLA complex along the a -axis at 100 K.
Tunneling spectra (a) of 4,4′-dimethyl-2,2′-bipyridyl in the energy range ±14 μeV as well as (b) of its complex with chloranilic acid in the energy range ±4 μeV for several temperature between 3.5 and 40 K.
Arrhenius plot ln(ΔE) vs. 1/T for 4,4′-dimethyl-2,2′-bipyridyl with CLA.
Simultaneous DTA and TGA plots of the complex of 6,6′-dimethyl-2,2′-bipyridyl with CLA.
The results of the DSC calorimetric measurements for 6,6′-dimethyl-2,2′-bipyridyl with CLA during heating and cooling runs (20 K/min, m = 10 mg).
The temperature dependence of the linear thermal expansion, ΔL/L o , obtained along the a -, b -, and c -axis (notation for the monoclinic system – phase P21) for the 6,6′-dimethyl-2,2′-bipyridyl with CLA complex. (Thickness of the lines corresponds to the measurement error.)
The temperature dependence of the real part of the electric permittivity, along the b -axis for the selected frequencies.
The IR and Raman spectra between 3500 and 100 cm−1 of (a) 4,4′-, (b) 5,5′-, and (c) 6,6′-dimethyl-2,2′-bipyridyl complexes with CLA at 300 K.
(a) Infrared spectra for 4,4′-dimethyl-2,2′-bipyridyl with CLA between 850 and 950 cm−1 assigned to the CH3 deformation vibrations at the selected temperatures (10–300 K). (b) Temperature dependencies of the frequencies of some selected bands from the region between 2800 and 3200 cm−1 for 4,4′-dimethyl-2,2′-bipyridyl complex with CLA.
Crystal data and structure refinement.
Selected bond lengths (Å) and angles (°).
Hydrogen bonds for 4,4′-DMBP·CLA,a 5,5′-DMBP·CLA,b and 6,6′-DMBP·CLA.c
Tunneling energies (μeV) for the dimethyl-2,2′-bipyridyls and their 1:1 complexes with chloranilic acid at 3.5 K and corresponding energies of activation estimated according to Eqs. (4).
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