The constituents of the title 1:1 co-crystal, C(7)H(6)O(2)·C(14)H(12)N(2), are connected into dimeric aggregates by a bifurcated O-H⋯N hydrogen bond; the hydroxyl-H atom is hydrogen bonded to the two N atoms of the 2,9-dimethyl-phenanthroline. The hydrogen-bonded residues are almost orthogonal to each other [dihedral angle = 78.56 (7) °]. In the crystal packing, the aggregates are assembled int...

The title bimolecular compound, C(4)H(5)N(3).C(21)H(18)O(2), constructed from 2-aminopyrimidine and 3,3,3-triphenylpropanoic acid, forms a tetramolecular hydrogen-bonded motif via O-H...N, N-H...O and N-H...N contacts. This aggregate organizes to give crystal-packing motifs with hydrophilic and hydrophobic regions.

The coproduction of 5-hydroxymethylfurfural (5-HMF) and furfural (FUR) via the direct hydrolysis holocellulose analogue composed cellulose hemicellulose was investigated. effects catalyst amount, solvent type reaction temperature time using sulfamic acid with dual active sites as were also studied. yields 5-HMF FUR at 37.2% 62.0% obtained volume ratio γ-valerolactone to water 25:1 180 °C for 3 ...

the silica boron sulfuric acid nanoparticles (sbsans) as an efficient heterogeneous solid acid catalyst with both brønsted and lewis acidic sites catalyzed the preparation of bis-4-hydroxycoumarin derivatives using reaction of aldehydes and 4-hydroxycoumarin under mild and solvent-free condition at room temperature. this new and efficient methodology has advantages in comparison with currently ...

A classification of the hydrogen fluoride H-F-bonded interactions comprising a large number of molecules has been proposed by Espinosa et al. [J. Chem. Phys. 117, 5529 (2002)] based on the ratio /Vr(c)/ / Gr(c) where /Vr(c)/ is the magnitude of the local potential-energy density and Gr(c) is the local kinetic-energy density, each evaluated at a bond critical point r(c). A calculation of the rat...

OBJECTIVES This study evaluated the effect of three different surface conditioning methods on the bond strength of a Bis-GMA based luting cement to six commercial dental ceramics. METHODS Six disc shaped ceramic specimens (glass ceramics, glass infiltrated alumina, glass infiltrated zirconium dioxide reinforced alumina) were used for each test group yielding a total number of 216 specimens. T...

The aim of the present study was undertaken to investigate the effects of several surface modi cation methods applied to lithium disilicate glass ceramics (LDCs) on their bonding durability with resin-based cement. The LDC specimens were sectioned using a low-speed diamond cutting machine, crystallized by heating in a furnace, and then subjected to several surface modi cation treatments such as...

The objective of this study was to test the effects of enamel deproteinization on bracket bonding with conventional and resin-modified glass ionomer cement (RMGIC). One hundred premolars, extracted for orthodontic reasons, were divided into five groups (n = 20). Group 1 (control): enamel was etched with 35 per cent phosphoric acid, a thin layer of adhesive was applied, and the brackets were bon...