The crystal structure of L-serine has been determined at room temperature at pressures between 0.3 and 4.8 GPa. The structure of this phase (hereafter termed L-serine-I), which consists of the molecules in their zwitterionic tautomer, is orthorhombic, space group P212121. The least compressible cell dimension (c), corresponds to chains of head-to-tail NH...carboxylate hydrogen bonds. The most c...

It is shown that the mutagen base analogue 2-aminopurine is hydrogen-bonded at its 1-ring position when annealed with cytosine in DNA. The presence of stably hydrogen-bonded regions proximal to the 2-aminopurine-cytosine base mispair is a prerequisite for the occurrence of two hydrogen bonds coupling the bases at their 1-3- and 2-2-positions. We consider the possibility that, in the resulting h...

The title ionic compound, C(2)H(10)N(2) (2+)·2Cl(-), crystallizes with a center of symmetry within the cation. Each of the positively charged ammonium ends of the mol-ecule is trigonally hydrogen bonded to three different chloride counter-ions, while each of the chloride ions is trigonally hydrogen bonded to three different ethyl-enediammonium cations. The hydrogen-bonding network leads to stab...

Hydrogen-Bonded Frameworks. A hydrogen-bonded framework that was predicted to have 3-D porosity has been discovered experimentally by Anna G. Slater, John W. Ward, Marc A. Little, Andrew I. Cooper et al. in their Research Article (e202303167). It is one of the most porous frameworks synthesized date.

A redetermination of the crystal structure of the title compound, C(6)H(16)N(2) (2+)·2Cl(-), was undertaken. All atomic coordinates including those of the H atoms were refined freely. The cation is located on a centre of symmetry. Important for the crystal structure are wavy hydrogen-bonded layers that are formed by ammonium groups and chloride anions, giving hydrogen-bonded rings.

This contribution reports solution-phase structural studies of oligomers of a family of peptides derived from the β-amyloid peptide (Aβ). We had previously reported the X-ray crystallographic structures of the oligomers and oligomer assemblies formed in the solid state by a macrocyclic β-sheet peptide containing the Aβ(15-23) nonapeptide. In the current study, we set out to determine its assemb...

MP2/6-311++G(d,p) calculations have been carried out to investigate the conformation, protonation and the hydrogen bonding interactions with water of several halogenated ethers (CH(3)OCH(2)Cl, CH(2)ClOCH(2)Cl, CH(3)OCHCl(2), CHFClOCHF(2)). The optimized geometries, ν(CH) harmonic vibrational frequencies and the SAPT decomposition of the interaction energies are studied. The interaction with one...

The formation of hydrogen bonded complexes between nucleic acid bases and acetamide has been studied by nuclear magnetic resonance in CDC13 at different temperatures. Pairs of hydrogen bonds are formed when acetamide binds to nucleic acid bases. Thermodynamic parameters have been computed and compared to those obtained for the association of carboxylic acids with nucleic acid bases. The role of...

The liquid crystals (LC), due to their naturally high bulk ordering, strong birefringence and easy electrooptical driving, serve as matrix in the nanocomposites doped with non-mesogenic or mesogenic nanoparticles. The nanocomposite’s structural units exhibit very complex molecular form indicating the strength and the intermolecular interaction between the matrix and dopant’s molecules. Hydrogen...

The structures and interaction energies of guanine and uracil quartets have been determined by B3LYP hybrid density functional calculations. The total interaction energy ∆E T of the C 4h-symmetric guanine quartet consisting of Hoogsteen type base pairs with two hydrogen bonds between two neighbor bases is-66.07 kcal/mol at the highest level. The uracil quartet with C6-H6...O4 interactions betwe...