1,1′-(p-Phenyl­enedimethyl­ene)dipyridinium bis­(hexa­fluoridophosphate)

The title salt, C18H18N2 2+·2PF6 −, exists as non-inter­acting cations and anions. In the cation, the pyridine and phenyl­ene rings are aligned at 62.9 (1)°; the pyridine ring lies on a special position of m site symmetry and the phenyl­ene ring on a special position of 2/m site symmetry. The angle at the methyl­ene C atom is 112.8 (1)°. The anion lies on a special position of m site symmetry; four F atoms lie on this mirror plane

Conductometric measurements of complexation study between 4-Isopropylcalix[4]arene and Cr3+ cation in THF–DMSO binary solvents

In the present work, the conductometric measurements for complexation process between Cr3+ cation and the macrocyclic ionophore, 4-Isopropylcalix[4]arene (IPC4) were studied in tetrahydrofuran–dimethylsulfoxide (THF–DMSO) binary non-aqueous medium at different temperatures. The results reveal that the stoichiometry of the IPC4–Cr3+ complex in all binary mixed solvents is 1:1. A non-linear behavior was observed for changes of logKf of this complex versus the composition of the binary mixed solvents, which was explained on the basis of changes occurring in the structure of the mixed solvents and also the preferential solvation of the cation, ionophore and the resulting complex in the solution. The thermodynamic parameters (DH�c and DS�c) for the formation of IPC4–Cr3+ complexes were obtained from the temperature dependence of the stability constant using the van’t Hoff plots. The results obtained in this study, show that the formed complex is enthalpy destabilized, but entropy stabilized and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents. The experimental data was tested by using artificial neural network (ANN) program and was in a good agreement with the estimated data

tert-Butyl 2-(1H-benzimidazol-1-yl)acetate

In the title compound, C13H16N2O2, the planes of the benzimidazole ring system and the acetate O—C=O fragment make a dihedral angle of 84.5 (3)°. In the crystal, mol­ecules are connected through C—H⋯N hydrogen bonds to form infinite chains in the [-110] direction

1,1′,2,2′-Tetra­methyl-3,3′-(p-phenyl­enedimethyl­ene)diimidazol-1-ium bis­(tetra­fluoridoborate)

The title imidazolium-based ionic-liquid salt, C18H24N4 2+·2BF4 −, has the cation lying about a center of inversion. The five-membered imidazole ring is approximately perpendicular to the six-membered phenyl­ene ring [dihedral angle = 86.9 (1)°]. The tetra­fluoro­borate anion is disordered over two sites in a 0.722 (3):0.278 (3) ratio

1,1′-{[1,4-Phenyl­enebis(methyl­ene)]bis­(­oxy)bis­(3,1-phenyl­ene)}diethanone

In the title compound, C24H22O4, the centroid of the central benzene ring lies on a special position of 2/m site symmetry, while the terminal aromatic rings are located on a mirror plane. The central and terminal benzene rings are perpendic­ular to each other. In the crystal, the mol­ecules are connected via C—H⋯O hydrogen bonds into a three-dimensional polymeric structure. The network is further consolidated by a C—H⋯π inter­action

1-Tosyl-2-[(1-tosyl-1H-benzimidazol-2-yl)methyl­sulfanyl]-1H-benzimidazole

In the title compound, C29H24N4O4S3, the two N-tosyl­benzimidazolyl unit are connected through a —S—CH2— fragment, the dihedral angle between the benzimidazole rings being 76.09 (5)°. The methyl­thio group is disordered with respect to exchange of the S and C atoms in a 0.547 (4):0.453 (4) ratio. In the crystal, C—H⋯O and C—H⋯π inter­actions connect adjacent mol­ecules into infinite layers parallel to the ab plane. The crystal packing is further stabilized by a π–π inter­action [centroid–centroid separation = 3.5187 (4) Å]

1,1′,2,2′-Tetra­methyl-3,3′-(p-phenyl­enedimethyl­ene)diimidazol-1-ium dibromide

The title imidazolium-based ionic-liquid salt, C18H24N4 2+·2Br−, has the cation lying about a center of inversion. The five-membered imidazole ring is disordered over two positions with the major component having a site occupancy of 0.712 (4); the N-bound methyl substituents are ordered. The imidazole ring is approximately perpendicular to the six-membered phenyl­ene ring [dihedral angle = 80.7 (5)° for the major disorder component and 89.8 (3)° for the other; the two components are off-set by 10.1 (6)°]

1,1′,2,2′-Tetra­methyl-3,3′-(p-phenyl­ene­dimethyl­ene)diimidazol-1-ium bis­[bis­(trifluoro­methyl­sulfon­yl)imide]

The cation of the imidazolium-based ionic-liquid title salt, C16H24N4 2+·2C2F6NO4S2 −, lies on a center of inversion; in the cation, the five-membered imidazolium ring is aligned at 84.4 (1)° with respect to the phenyl­ene ring; the angle at the methyl­ene C atom is 113.0 (2)°. In the anion, the negative charge formally resides on the two-coordinate N atom; the S—N—S angle at this atom is 125.2 (1)°

Production of glycerol 1,2-carbonate from glycerol with aid of ionic liquid as catalyst

The surplus formation of glycerol (glycerine or 1,2,3-propanetriol) during biodiesel production has led to a major concern. Glycerol price has dropped and it exerts a great impact on the refined glycerol market. This has triggered an extensive research focus to find an innovative way to revalorize glycerol and transform to value-added chemicals. Yet, it is undeniably a necessary move towards achieving greener and sustainable processes. For instance, glycerol 1,2-carbonate (4-hydroxymethyl-1, 3-dioxolan-2-one) is currently one of the most celebrated glycerol derivatives that captured arising scientific and industrial attentions due to its extensive potential applicability. This cyclic ester of glycerol with carbonic acid is reasonably reactive as it has reactive electrophilic and nucleophilic sites yet having low toxicity and good biodegradability. This important product has attracted numerous applications in chemical industry such as being the novel component of gas-separation membranes, non-volatile solvent for dyes, lacquers, detergents, adhesives and cosmetics, electrolyte ingredient of lithium-based batteries, surfactants and lubricating oils. Likewise, glycerol 1,2-carbonate is beneficial not only as a polar high boiling solvent or intermediate for the synthesis of polycarbonates, polyesters, polyamides and hyper branched polyethers, it also can be used as green substitution for petro-derivatives compounds (ethylene carbonate or propylene carbonate). The reactivity of glycerol 1,2-carbonate having both electrophilic and nucleophilic sites allows for the synthesis of new polymeric materials such as glycidol which is primarily being used in the production of a number of polymers. Please click Additional Files below to see the full abstract

1,1′,2,2′-Tetra­methyl-3,3′-(p-phenyl­enedimethyl­ene)diimidazol-1-ium bis­(trifluoro­methane­sulfonate)

In the solid form of the title imidazolium-based ionic liquid salt, C18H24N4 2+·2CF3SO3 −, the complete cation is generated by a crystallographic inversion centre. The five-membered imidazole ring is approximately perpendicular to the six-membered phenyl­ene ring [dihedral angle = 85.11 (11)°]. In the crystal, the components are linked by C—H⋯O interactions