A series of pyrido[2,3-d]pyrimidines derivatives have been prepared by one-pot three-component reaction of 4(6)aminouracil, malononitrile and aromatic aldehydes. This efficient synthesis was done under microwave irradiation conditions (method A) and also using catalytic amount of diammonium hydrogen phosphate [(NH4)2HPO4] (DAHP) in aqueous media (method B). This procedure has the advantages of ...

The title compound, {(C(8)H(20)N(2))[PbCl(4)]}(n), crystallizes as an layered inorganic-organic hybrid perovskite-type structure. Corner-sharing PbCl(6) octa-hedra extend parallel to the ac plane. Adjacent layers are staggered relative to one another, with diammonium cations separating these layers. The cations exhibit symmetry and inter-act with the inorganic sheets via N-H⋯Cl hydrogen bonding...

In the dication of the title salt, C(6)H(16)N(2) (2+)·2C(6)H(4)NO(2) (-), the two ammonium groups are in the equatorial positions of the chair-shaped cyclo-hexyl ring. In the crystal, the cations and anions are linked by N-H⋯O and N-H⋯N hydrogen bonds, forming a layer network parallel to the ac plane. Weak π-π inter-actions between adjacent pyridine rings with a centroid-centroid distance of 3....

In the crystal structure of the title salt, C(2)H(10)N(2) (2+)·C(10)H(6)O(6)S(2) (2-), both the cation and anion lie on special positions of site symmetry. These are linked by N-H⋯O and N-H⋯(O,O) hydrogen bonds, forming a layer structure.

Calcium deficient nanohydroxyapatite (nanoHap) powders were synthesized by co-precipitation of calcium α-D-heptagluconate hydrate and diammonium hydrogen phosphate solutions. TEM and HRTEM images of powders after the drying of products showed that the reactant concentration affected the sizes and morphology of particles. Small changes were found in phase composition of nanoHap powders synthesiz...

Vibrational spectroscopy can give useful informa tian, both structural and dynamical, about phase transitions in molecular crystals. In particular, the data concerning the mechanism of the transformation at molecular level can be obtained. This is illustrated by examples of pure van der Waals crystals such as 3,5-dichloropyridine and 4-methylpyridine, hydrogen bonded malonic acid, inorganic fer...