Crystal spectrum of bis-trimethylbenzylammoniumtetrachlorocuprate (II)

Structures of bis(4-aminopyridinium) tetrachlorocuprate(II) monohydrate, [C5H7N2]2[CuCl4].H2O and bis(2-amino-3-hydroxypyridinium) tetrachlorocuprate(II), [C5H7N2O]2[CuCl4]: correlation of CuCl4 2− geometry with hydrogen bonding and electronic structure

“…, (b) Antolini et al (1980), (c) Noren et al (1989), (d) , (e) Ferguson (1964), (/) Willett et al (1967), (g) Dyrek et al (1987), (h) Harlow et al (1974), (0 Antolini et al (1981), (j) Furlani et al (1967), (k) Doadrio & Gutierrez Rios (1979), (/) Battaglia et al (1982), (m) Gaura et al (1982), ( The gallate head groups are hydrogen bonded with the water molecules to form a strong system of intraand intermolecular hydrogen bonds consisting of finite and infinite chains. The crystals undergo crystal-to-crystal phase transitions at 365 K on heating and at 333 K on cooling, but despite the molecular packing which is analogous to that of the mesogenic alkyl glycosides, there is no thermotropic liquid crystal phase prior to the formation of the isotropic liquid phases at 376 K. Similary, no lyotropic liquid crystal phases are observed at room temperature in contact with a mixture of water and propanediol in which the crystals are soluble.…”

Structural, spectroscopic, and electron paramagnetic resonance studies on two solid phases of bis-dipropylammonium tetrachlorocuprate(II) (DPACC)

“…The dearth of optically resolved spectra for CuCI4" ions at large distortion angles (but not the square-planar limit) makes definitive assignment of the states difficult. That is, there exist only a few studies of C U C I~~-using either polarized or cryogenic spectroscopic methods (17,19 Table 5. (32) and an extensive spectroscopic investigation including the thermal dependence and vibrational fine structure of the d-d transitions have been undertaken (33). In the distorted tetrahedral case, however, the energy level ordering is not as well understood.…”

“…In the distorted tetrahedral case, however, the energy level ordering is not as well understood. The early spectroscopic work of Ferguson on Cs2CuC14 (17) and Furlani et al (19) on [(C6H5)-CH2N(CH3)3]CuC14 has shown that the ordering of the term energies (ignoring spin-orbit coupling) in these systems is 'B2(xy) << 'E(xz, yz) < 'Bl(x2 -y2) < 'A1(z2), corresponding to a 'B2(xy) ground state. In the DZd point group, the 'B2 + ' E and 'B2 + 'A, transitions are dipole allowed and have been assigned as the lowest and highest-energy d-d bands, respectively, in these systems, while the forbidden 'B2 + 'B1 was assigned as a weak band in the Cs2CuC14 case only, assuming contribution from spin-orbit coupling effects and site group symmetry lowering.…”

Crystal and molecular structure of bis[(+)-N,.alpha.-dimethylphenethylammonium] tetrachlorocuprate(II). Relation between the electronic spectrum and the distortion of the tetrachlorocuprate chromophore from tetrahedral symmetry

“…The least-squares refinement of the Bragg angles (Cu , 1.54050 Á) for 18 high-angle reflections (85°< 2 < 104°) produced the following unit cell parameters: a = 12.115 (3) Á, b = 12.968 (2) k, c = 8.741 (2) A, a = 106.64 (1)°, ß = 100. 25 (2)°, 7 = 98.88…”