The title carbamate monohydrates, C13H12N2O2·H2O and C12H9BrN2O2·H2O, form isomorphous crystals that are isostructural in their primary hydrogen-bonding modes. In both carbamates, the primary hydrogen bonding and aggregation involves cyclic amide-water-pyridine moieties as (N-H⋯O-H⋯N)2 dimers about inversion centres [as R 4 (4)(14) rings], where the participation of strong hydrogen-bonding dono...

The effects of H-bonding on the redox potential and molecular vibrations of plastoquinone (PQ) that functions as a primary and a secondary quinone electron acceptor (QA and QB, respectively) in photosystem II (PSII) in plants and cyanobacteria were investigated using density functional theory calculations. Calculations were performed on the neutral and semiquinone anion forms of PQ and its H-bo...

background : composite resin restorations may have a short lifespan due to the degradation of resin–dentin interface. ethanol wet bonding technique may extend the longevity of resin–dentin bond. the purpose of this one year randomized clinical trial was to compare clinical performance of two adhesives with ethanol wet bonding technique. materials and methods: this randomized clinical trial was ...

Accurate computer simulation is important for understanding the role of irradiation-induced defects in zirconium alloys found nuclear reactors. Of particular interest distribution and trapping hydrogen, formation hydride. These simulations require an accurate representation Zr-H bonding order to predict behaviour H around atomic-scale defects, dislocation lines, loops. Here we explore Zr under ...

In the title compound, C(10)H(12)O(4)·H(2)O, the 2,4,5-trimeth-oxy-benzaldehyde mol-ecule is almost planar (rms deviation = 0.0183 Å). There is an R(1) (2)(5) ring motif due to O-H⋯O hydrogen bonding. In the crystal, the mol-ecules are stabilized in the form of one-dimensional polymeric chains extending along [010] due to O-H⋯O hydrogen bonding with adjacent water mol-ecules. The H atoms involv...

In the title compound, C(6)H(16)NO(3) (+)·C(7)H(4)NS(2) (-), the cations and anions are connected by O-H⋯N and O-H⋯S hydrogen bonding. Weak C-H⋯O hydrogen bonding between adjacent cations helps to stabilize the crystal structure.

Certain DNA polymerases (pols) were found to efficiently insert A opposite the hydrophobic T isostere 2,4-difluorotoluene (F) and vice versa, resulting in the widely held belief that some pols rely on shape rather than H-bonding for accurate replication. Using X-ray crystallography we have analyzed the geometry of F:A pairs in duplex DNA and observed a distance between fluorine and the exocycli...