The pyridine N atom of the cation in the title hydrated salt, C(13)H(11)N(2) (+)·NO(3) (-)·H(2)O, is protonated; the N atom of the NH(2) group shows a planar conformation. The former N atom is hydrogen bonded to a water mol-ecule. The amino group is involved in three N-H⋯O hydrogen bonds with two neighboring nitrate anions. The water mol-ecule is hydrogen bonded to two adjacent nitrate anions. ...

The title half-sandwich rhodium(III) complex, [Rh(C10H15)(C7H7O3S)2(H2O)]·H2O, consists of a π-bonded penta-methyl-cyclo-penta-dienyl group, two σ-bonded tosyl-ate groups and an aqua ligand. The structure displays both inter- and intra-molecular O-H⋯O hydrogen bonding. The inter-molecular hydrogen bonding results in an extended helical chain along a 21 screw axis parallel to c, due to hydrogen ...

The asymmetric unit of a second polymorph of the title compound, C(9)H(4)F(6)O(2), contains five independent mol-ecules, which form hydrogen-bonded O-H⋯O dimers about inversion centers. The most significant structural difference between this structure and that of the first polymorph [Tobin & Masuda (2009 ▶). Acta Cryst. E65, o1217] is the hydrogen-bonded, dimeric orientation of the carb-oxy-lic...

Hybrid density functional calculations are used to directly calculate the principal hyperfine tensor values for H, C and O in two models of the tyrosyl radical, p-methylphenoxyl and p-ethylphenoxyl. Both hydrogen bonded and non-hydrogen bonded phenoxyl radicals are studied. A comparison is made between calculated values and those obtained from experimental EPR and ENDOR studies. Outstanding agr...

3-Fluoro-salicylaldoxime, C(7)H(6)FNO(2), unlike many salicylaldoxime derivatives, forms a crystal structure containing hydrogen-bonded chains rather than centrosymmetric hydrogen-bonded ring motifs. Each chain inter-acts with two chains above and two chains below via π-π stacking contacts [shortest centroid-centroid distance = 3.295 (1) Å]. This structure at 6.5 GPa represents the final point ...

The hydrogen-bond-acceptor (HBA) templates 2,3-bis(4-methylenethiopyridyl)naphthalene (2,3-nap) and 1,8-bis(4-pyridyl)naphthalene (1,8-dpn) are used to assemble (E,E)-2,5-dimethylmuconic acid (dmma) in the solid state for an intermolecular [2 + 2] photocycloaddition. Co-crystallisation of 2,3-nap with dmma affords an 1D hydrogen-bonded polymer that is photostable while 1,8-nap affords a 0D hydr...

The spectral complexity in the NH stretching mode of hydrogen-bonded pyrazoles is traced back to an extensive Fermi resonance system involving combinations and overtones of at least four aromatic ring modes with significant in plane hydride bending character. The couplings are shown to be inherent in the monomer, but hydrogen bonding is required to bring them into resonance with the NH stretchi...