2-Aminopyridinium trifluoroacetate

Bis(2-aminopyridinium) tetra­chloridozincate(II)

In the title compound, (C(5)H(7)N(2))(2)[ZnCl(4)], the pyridine N atoms are protonated and the [ZnCl(4)](2-) anions adopt a slightly distorted tetra-hedral configuration. In the crystal, weak N-H⋯Cl hydrogen bonds link the mol-ecules into layers, while weak π-π inter-actions [centroid-centroid distance = 4.2758 (18) Å] also help to stabilize the packing.

2-aminopyridinium benzoate.

Cyclic eight-membered hydrogen-bonded rings exist in the title compound, C(5)H(7)N(2)(+).C(7)H(5)O(2)(-), involving the 2-aminopyridinium and benzoate ions. Each benzoate ion has two intramolecular hydrogen bonds. 2-Aminopyridinium benzoate ion pairs are linked by N-H...O hydrogen bonds, with an N...O distance of 2.8619 (14) A.

A second polymorph of 2-aminopyridinium dihydrogenphosphate.

In the title compound, beta-C5H7N2+.H2PO4-, the tetrahedral dihydrogenphosphate moieties are linked into double chains by O-H...O hydrogen bonds, and the organic species crosslink the chains into sheets by way of N-H...O bonds. The resulting structure is quite different from that of the previously described alpha polymorph of this stoichiometry [Czapla, Dacko & Waskowska (2003). J. Phys. Conden...

Ammonium Trifluoroacetate-Mediated Synthesis of 3,4-dihydropyrimidin-2(1H)-ones

A simple and economic synthesis of 3,4-dihydropyrimidin-2(1H)-ones using ammonium trifluoroacetate as catalyst and as solid support is accomplished. Easy workup procedure for the synthesis of title compounds is well arrived at and is well documented.

Synthesis, Growth and Characterization of Nonlinear Optical Bis(2-aminopyridinium) Sulfate Single Crystals