alkali and alkaline earth metals hydrogen sulfate catalyzed the one-pot three component condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1h)-ones in high yields at 80 °c. our results showed that biginelli reaction not only is ph dependent, but the cation of catalyst plays an important role.

Perfluoropolyether tetraol (PFPE tetraol) possesses a hydrophobic perfluoropolyether chain in the backbone and two hydroxyl groups at each chain terminal, which facilitates the formation of hydrogen bonds with water molecules resulting in the formation an extended physical network. About 3 wt% water was required for the formation of the microphase separated physical network of PFPE tetraol. The...

The cytochrome bo3 ubiquinol oxidase catalyzes the two-electron oxidation of ubiquinol in the cytoplasmic membrane of Escherichia coli, and reduces O2 to water. This enzyme has a high affinity quinone binding site (QH), and the quinone bound to this site acts as a cofactor, necessary for rapid electron transfer from substrate ubiquinol, which binds at a separate site (QL), to heme b. Previous p...

In the title salt, C(6)H(9)N(2) (+)·C(4)H(3)O(4) (-), the dihedral angle between the pyridine ring and the plane formed by the hydrogen fumarate anion is 85.67 (6)°. Excluding the amino and methyl groups, the atoms of the cation are coplanar, with a maximum deviation of 0.005 (1) Å. In the crystal structure, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the ca...

In spite of the key role of hydrogen bonding in the structural stabilization of the prototypic hybrid halide perovskite, CH3NH3PbI3 (MAPbI3), little progress has been made in our in-depth understanding of the hydrogen-bonding interaction between the MA(+)-ion and the iodide ions in the PbI6-octahedron network. Herein, we show that there exist two distinct types of the hydrogen-bonding interacti...

In the title compound, C(11)H(12)ClNO, intra-molecular N-H⋯O hydrogen bonding is present. The dihedral angle between the benzene ring and the pentenone unit is 46.52 (5)°. In the crystal, C-H⋯O inter-actions between hydrogen atoms of the aryl moiety and two separate oxygen atoms occur, leading to a three-dimensional network.

In the title compound, [Cd(H(2)O)(6)](C(13)H(10)NO(4)S)(2)·2H(2)O, the Cd atom (site symmetry ) adopts a regular octa-hedral coordination and the anion is stabilized by an intra-molecular O-H⋯N hydrogen bond. O-H⋯O hydrogen bonds involving the coordinated and uncoordinated water mol-ecules lead to a three-dimensional network.

In the redetermined structure [Koo (1965 ▶). Bull. Chem. Soc. Jpn, 38, 286] of the title compound, C(6)H(9)N(2) (+)·Cl(-), the H atoms have been located and the hydrogen-bonding scheme established. A series of N-H⋯Cl and N-H⋯N hydrogen bonds leads to a layered network parallel to the (010) plane.

In the crystal structure of the title compound, C(17)H(21)N(3)O(2)·2H(2)O, water mol-ecules are mutually O-H⋯O hydrogen bonded and form infinite chains propagating along the b axis. Neighboring chains are linked by the quinazoline mol-ecules by means of O-H⋯O=C hydrogen bonds, forming a two-dimensional network.