(±)-trans-6,7-Dimeth­oxy-1-oxo-3-(2-thien­yl)isochroman-4-carboxylic acid

The title compound, C16H14O6S, was synthesized by the reaction of 6,7-dimethoxy­homophthalic anhydride with thio­phene-2-carbaldehyde in the presence of 4-(dimethyl­amino)pyridine (DMAP) as a basic catalyst. The thio­phene ring of the title mol­ecule is disordered over two sites with occupancies of 0.877 (3) and 0.123 (3). The disorder corresponds to an approximate 180° rotation of the thio­phene ring with respect to the C—C bond linking it to the rest of the mol­ecule. The six-membered ring of the 3,4-dihydro­isochromanone ring system is not planar [puckering parameters Q T = 0.571 (2) Å, θ = 115.2 (2)° and ϕ = 99.1 (2)°]. The benzene ring of the 3,4-dihydro­isochromanone ring system makes dihedral angles of 75.0 (2) and 77.2 (5)° with the disordered thio­phene rings. Inter­molecular O—H⋯O and C—H⋯O hydrogen bonds, as well as C—H⋯π inter­actions, lead to the observed supra­molecular structure

Methyl trans-(±)-1-oxo-2-phenethyl-3-(thio­phen-2-yl)-1,2,3,4-tetra­hydro­isoquinoline-4-carboxyl­ate

In the title compound, C23H21NO3S, the piperidine ring of the tetra­hydro­isoquinolinone unit adopts a screw-boat conformation. The thio­phene ring is disordered in a 0.700 (3):0.300 (3) ratio by an approximate 180° rotation of the ring around the C—C bond linking the ring to the tetra­hydro­isoquinolinone unit. The benzene ring of the tetra­hydro­isoquinolinone unit makes dihedral angles of 83.1 (2) and 62.38 (11)° with the major occupancy thio­phene ring and the phenyl ring, respectively. The dihedral angle between the phenyl ring and the thio­phene ring is 71.0 (2)°. In the crystal structure, mol­ecules are linked together by inter­molecular C—H⋯O and C—H⋯π inter­actions

Phase transitions in higher-melting ionic liquids: Thermal storage materials or liquid crystals?

To assess the application potential of a material in thermal energy storage, the knowledge of their thermophysical properties is of key importance. Specifically, an efficient material has to show, among others, large enthalpies of phase change and a sufficiently large thermal conductivity. In this work, imidazolium-based ionic liquids (ILs) with long alkyl chain substituents 1-hexadecyl-3-methylimidazolium chloride and 1-hexadecyl-3-methylimidazolium saccharinate were studied in view of their possible use as phase-change materials. Differential scanning calorimetry (DSC) and the heat-leak modulus methods were used to determine the temperatures and the enthalpies of phase transitions in the studied ILs, enabling us to study the influence of the heating rates on the measured properties. Enthalpies of fusion near to or larger than 100 J·g-1 were found in the studied ionic liquids, making them promising candidates for thermal energy storage. Furthermore, peaks corresponding to possible liquid crystalline phases in the DSC traces of 1-hexadecyl-3-methylimidazolium saccharinate were observed. The measured properties are not only essential characteristics of a thermal storage material, temperatures and enthalpies of melting are necessary in thermodynamic description and modelling of solid-liquid phase behavior and thus in the possible utilization of the material in separation and crystallization processes. © Copyright 2018, AIDIC Servizi S.r.l

trans-rac-[1-Oxo-2-phenethyl-3-(2-thien­yl)-1,2,3,4-tetra­hydro­isoquinolin-4-yl]methyl 4-methyl­benzene­sulfonate

The title compound, C29H27NO4S2, was synthesized by reaction of trans-rac-4-(hydroxy­meth­yl)-2-phenethyl-3-(thio­phen-2-yl)-3,4-dihydro­isoquinolin-1(2H)-one and 4-methyl­benzene-1-sulfonyl chloride in the presence of Et3N in CH2Cl2. The relative orientations of the benzene ring (A) of the 3,4-dihydro­isoquinolinone ring system, the thio­phene ring (B), the benzene ring (C) of the methyl­benzene group and the phenyl ring (D) result in the following dihedral angles: A/B = 80.91 (16), A/C = 22.79 (18), A/D = 9.9 (2), B/C = 80.73 (19), B/D = 88.9 (2) and C/D = 29.9 (2)°. The crystal structure is stabilized by weak inter­molecular C—H⋯O hydrogen bonds and C—H⋯π inter­actions

Methyl trans-rac-2-hexyl-1-oxo-3-(2-pyrid­yl)-1,2,3,4-tetra­hydroisoquinoline-4-carboxyl­ate

The title compound, C22H26N2O3, was synthesized by esterification of trans-rac-2-hexyl-1-oxo-3-(2-pyrid­yl)-1,2,3,4-tetra­hydro­isoquinoline-4-carboxylic acid in the presence of H2SO4 in methanol. The dihedral angle between the benzene and pyridine rings is 84.46 (17)°. The piperidine ring adopts a screw-boat conformation. In the crystal, inversion dimers linked by two C—H⋯O bonds occur