Noncovalent interactions have a constitutive role in the science of intermolecular relationships, particularly those involving aromatic rings such as p–p and cation–p. In recent years, anion–p contact has also been recognized as a noncovalent bonding interaction with important implications in chemical processes. Yet, its involvement in biological processes has been scarcely reported. Herein we ...

THE ASYMMETRIC UNIT OF THE TRICLINIC POLYMORPH OF THE TITLE COMPOUND (SYSTEMATIC NAME: 4-cyano-pyridinium 2,5-dichloro-4-hy-droxy-3,6-dioxocyclo-hexa-1,4-dien-1-olate), C(6)H(5)N(2) (+)·C(6)HCl(2)O(4) (-), consists of two crystallographically independent cation-anion units, in each of which the cation and the anion are linked by an N-H⋯O hydrogen bond. In the units, the dihedral angles between ...

The title complex, [Ni(C(10)H(10)N(6))(2)][Ni(CN)(4)]·2H(2)O, contains an octa-hedral nickel(II) cation and a square-planar nickel(II) anion. Both the cation and the anion reside on a crystallographic center of inversion. The Ni(II) center in the cation is coordinated by six pyrazol-1-yl rings of two chelating tripyrazol-1-ylmethane [HC(pz)(3)] ligands, with Ni-N distances that range between 2....

The structure of the title compound, [Ph(3)P=N=PPh(3)](+)[Ph(3)SnCl(2)](-) or (C(36)H(30)NP(2))[Sn(C(6)H(5))(3)Cl(2)], obtained as a by product of the reaction between Ph(3)SnCl and [Ph(3)P=N=PPh(3)](+)·HSeO(3) (-), consists of discrete essentially isolated ions. Both the cation and the anion lie on twofold axes which pass through the central N atom in the cation and through the Sn(IV) atom in ...

A 4-aza-1-azoniabicyclo-[2.2.2]octane cation, a 2-amino-benzoate anion and a neutral 2-amino-benzoic acid mol-ecule comprise the asymmetric unit of the title compound, C(6)H(13)N(2) (+)·C(7)H(6)NO(2) (-)·C(7)H(7)NO(2). An intra-molecular N-H⋯O hydrogen bond occurs in the anion and in the neutral 2-amino-benzoic acid mol-ecule. The cation provides a charge-assisted N-H⋯O hydrogen bond to the ani...

In the title salt, C26H40N3O2 (+)·ClO4 (-), the positive charge of the organic cation is delocalized between the two N atoms of the imidazole ring. The C N bond distances are 1.338 (2) and 1.327 (3) Å. The substituents on the benzene ring are rotated almost orthogonal with respect to this ring due to the presence of the bulky isopropyl substituents. The dihedral angle between the benzene and im...

A novel method was developed for the preparation of highly efficient anion- and cation-exchange microHPLC columns using an on-column polymerization of methacrylates having amine or sulfonic acid functional groups onto monolithic silica capillary columns modified with 3-methacryloxypropyltriethoxysilane as the anchor groups. The chromatographic evaluation of the columns using nucleic acids, nucl...

Tomato plants (Lycopersicon esculentum L. var. Ailsa Craig) were grown in water culture in nutrient solution in a series of 10 increasing levels of nitrate nutrition. Using whole plant data derived from analytical and yield data of individual plant parts, the fate of anion charge arising from increased NO(3) assimilation was followed in its distribution between organic anion accumulation in the...

The new complex of [H2en][Cu(pydc)2].2H2O (1) (where H2en and pydc are ethylenediammonium and 2,6-pyridinedicarboxylate, respectively) was synthesized by the reaction of a mixture of ethylenediamine (en) and 2,6-pyridinedicarboxylic acid (H2pydc) in a mixture of CH3OH/H2O as solvent. This complex was fully characterized by elemental analysis, IR, UV–Vis spectroscopy as well as single-crystal X-...

The title hydrated mol-ecular organic salt, C10H10N2 (2+)·C10H6O6S2 (2-)·2H2O, crystallized with half a bipyridinium cation, half a naphthalene-2,6-di-sulfonate anion and a water mol-ecule in the asymmetric unit. The whole cation and anion are generated by inversion symmetry, the inversion centers being at the center of the bridging C-C bond of the cation, and at the center of the fused C-C bon...