The recent development in oil and gas industry increases the production and consumption of oil. The enormous amount of oily wastewater produced is urged to be treated to prevent humanity and environment from being threatened. Membrane technology is an appealing alternative for oily wastewater treatment due to its design simplicity, energy efficiency and environmentally benign approach. In this ...

In the title compound, C10H19N3O4, the N- and C-termini are protonated and ionized, respectively, and the mol-ecule forms a zwitterion. The main chain is in a folded form. In the crystal, the N-terminal -NH3 (+) group hydrogen bonds to three C-terminal -COO groups and one carbonyl O atom, forming a three-dimensional network. In addition, an N-H⋯O hydrogen bond between the amide groups of the mi...

The title compound, C(16)H(15)NO(4), exists as a zwitterion in the solid state, with the carb-oxy-lic acid group being deprotonated and the imine N atom being protonated. The mol-ecule adopts an E configuration about the C=N double bond. The dihedral angle between the benzene rings is 46.34 (4)°. An intra-molecular N-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, adjacent mol-e...

A zwitterionic bis(guanidinium) ionophore bearing an anionic closo-borane cluster (1) and a dihydrochloride analogue (2) are investigated in polymeric membrane ion-selective electrodes (ISEs). Both compounds have been previously shown to complex and selectively extract oxoanions. By systematic variation of the kind and concentration of the ion-exchanger sites in the membrane, the optimal perfor...

The effective fragment potential (EFP) method is described and its capabilities illustrated using several applications. The original method, EFP1, was primarily developed to describe aqueous solvation, by representing Coulombic, induction and repulsive interactions via one-electron terms in the ab initio Hamiltonian. It is demonstrated, using water clusters, the Menshutkin reaction and the glyc...

In the title co-crystal, C(2)H(5)NO(2)·C(4)H(6)O(6), the gylcine mol-ecule is present in the zwitterion form. In the tartaric acid mol-ecule there is a short intra-molecular O-H⋯O contact. In the crystal, the tartaric acid mol-ecules are linked via pairs of O-H⋯O hydrogen bonds, forming inversion dimers. These dimers are linked via a number of O-H⋯O and N-H⋯O hydrogen bonds involving the two co...

The title compound, C(7)H(12)N(2)O(3)S, is a zwitterion precursor to a Brønsted acid ionic liquid with potential as an acid catalyst. The C-N-C-C torsion angle of 100.05 (8)° allows the positively charged imidazolium head group and the negatively charged sulfonate group to inter-act with neighboring zwitterions, forming a C-H⋯O hydrogen-bonding network; the shortest among these inter-actions is...

The title compound, C(12)H(14)N(2)O(4), crystallizes as a zwitterion. A negative charge is delocalized in the deprotonated carboxyl group attached to the pyridine ring. The piperidine N atom accepts a proton and the ring is transformed into a piperidinium cation. There is an intra-molecular N-H⋯O hydrogen bond between the protonated NH and a carboxyl-ate O atom. In the crystal, an O-H⋯O hydroge...