Measurements on 3 - Cyanobenzyl 2 , 5 - bis ( 4 - / i - octyloxybenzoyl - oxy ) benzoate up to 250 MPa and 423
نویسنده
چکیده
P, Vm, T data have been measured for the nematic and isotropic phases of 3-cyanobenzyl 2,5-bis (4-n-octyloxybenzoyloxy)benzoate between 273 and 423 K and up to 250 MPa. The volume changes accompanying the crystal nematic and nematic isotropic transitions have been determined. The corresponding enthalpy changes have been calculated using the Clausius-Clapeyron equation. The p, Vm, T data enable also to estimate the volume entropy for the nematic-isotropic transition. It is found that the configurational part of the transition entropy amounts to 80%, this portion being distinctly larger than found in previous studies for conventional rod-like liquid crystals.
منابع مشابه
μ-1,4-Bis(pyridin-4-ylmethyl)piperazine-κ2 N:N′-bis[aquabis(3-bromo-5-carboxybenzoato-κO 1)copper(II)]
In the title compound, [Cu(2)(C(8)H(4)BrO(4))(4)(C(16)H(20)N(4))(H(2)O)(2)], slightly distorted square-planar-coordinated Cu(II) ions are bound by one aqua ligand and two monodentate 3-bromo-5-carb-oxy-benzoate anions, and linked into a centrosymmetric dinuclear mol-ecule by a bridging 1,4-bis-(pyridin-4-ylmeth-yl)piperazine (4-bpmp) ligand. In the crystal, mol-ecules are connected into a supra...
متن کاملBis(μ-2-hydroxybenozato)-κ3 O,O′:O′;κ3 O:O,O′-bis[(2-hydroxybenozato-κ2 O,O′)(1,10-phenanthroline-κ2 N,N′)cadmium(II)]
The dinuclear title compound, [Cd(2)(C(7)H(5)O(3))(4)(C(12)H(8)N(2))(2)], is located on a crystallographic rotation twofold axis. The two Cd(II) ions are connected by two tridentate bridging 2-hydroxy-benzoate anions. Each Cd(II) ion is seven-coordinated by five O atoms from three 2-hydroxy-benzoate ligands and two N atoms from 1,10-phenanthroline. The 2-hydroxy-benzoate mol-ecules adopt two ki...
متن کاملBis[tetraaqua(1,10-phenanthroline-κ2 N,N′)cobalt(II)] hexaaquacobalt(II) bis[3,5-bis(carboxylatomethoxy)benzoate] tetrahydrate
The title compound, [Co(C(12)H(8)N(2))(H(2)O)(4)](2)[Co(H(2)O)(6)](C(11)H(7)O(8))(2)·4H(2)O, was obtanied by the reaction of cobalt acetate with 3,5-bis-(carb-oxy-meth-oxy)benzoic acid and 1,10-phenanthroline. The asymmetric unit contains one tetra-aqua-(1,10-phenanthroline)cobalt(II) cation, one half of a hexa-aqua-cobalt(II) cation that is completed by inversion symmetry, one 3,5-bis-(carboxy...
متن کاملBis[4-amino-3,5-bis(pyridin-2-yl)-4H-1,2,4-triazole-κ2 N 2,N 3]bis(benzene-1,2-dicarboxylic acid-κO)copper(II) bis(2-carboxybenzoate)
In the complex cation of the title salt, [Cu(C(12)H(10)N(6))(2)(C(8)H(6)O(4))(2)](C(8)H(5)O(4))(2), the Cu(II) atom, lying on an inversion center, exhibits a distorted octa-hedral geometry defined by four N atoms from two 4-amino-3,5-bis-(pyridin-2-yl)-4H-1,2,4-triazole ligands in the equatorial plane and two axial O atoms from two benzene-1,2-dicarb-oxy-lic acid ligands. In the crystal, the co...
متن کاملThe role of temperature on the structure and dimensionality of MOFs: an illustrative study of the formation of manganese oxy-bis(benzoate) structures.
Three new manganese oxy-bis(benzoate) compounds, synthesized by increasing the reaction temperature, with increasing dimensionality and decreasing Mn-Mn distances, indicate a possible pathway through an entropy driven dehydration route.
متن کامل