IN THE TITLE COMPOUND [SYSTEMATIC NAME: bis-(4-meth-oxy-3,4-di-hydro-quinazolin-1-ium) 2,5-di-chloro-3,6-dioxo-cyclo-hexa-1,4-diene-1,4-diolate], 2C9H11N2O(+)·C6Cl2O4 (2-), the chloranil-ate anion lies about an inversion center. The 4-meth-oxy-3,4-di-hydro-quinazolin-1-ium cations are linked on both sides of the anion via bifurcated N-H⋯(O,O) and weak C-H⋯O hydrogen bonds, giving a centrosymmet...

In the title compound, C25H20N6O2·0.15H2O, the dihedral angles between the least-squares planes of the indole and pyrrolidine rings and between the oxindole and imidazole rings are 77.66 (7) and 45.31 (7)°, respectively. The pyrrolidine ring and the fused five-membered pyrrolidine ring of the oxindole moiety exhibit twisted conformations. The amide N atom is involved in both intra- and inter-mo...

bonds [either N–H···O (keto-amine tautomer) or N···H–O (phenol-imine tautomer)] can exist. It is claimed that the hydrogen-bond type depends neither on the stereochemistry of the molecule nor on the sort of substituent bonded to the N imino atom, but on the kind of aldehyde used.1 In the solid state, it is also claimed that only an intramolecular N–H···O type hydrogen bond is present in naphtha...

In the title salt, C(12)H(11)N(2)O(2) (+)·C(7)H(5)O(6)S(-), the dihedral angle between the benzene and pyridine rings in the 4-(4-nitro-benz-yl)pyridinium cation is 82.7 (2)°. Within the anion there is an intramolecular hydroxy-O-H⋯O(carboxylic acid) bond. In the crystal, the cation forms a single N(+)-H⋯O(sulfonate) hydrogen bond with the anion. These cation-anion pairs inter-act through duple...

Crystal structures of Schiff bases containing pyridoxal (PL), N-(pyridoxylidene)-tolylamine, C(15)H(16)N(2)O(2) (I), N-(pyridoxylidene)-methylamine, C(9)H(12)N(2)O(2) (III), and their 1:1 adduct with 2-nitrobenzoic acid, (I)(+) C(7)H(4)NO_4;- (II), and 4-nitrobenzoic acid, (III)(+) C(7)H(4)NO_4;- (IV), serve as models for the coenzyme pyridoxal-5'-phosphate (PLP) in its PLP-dependent enzymes. T...

In the structure of the title salt, C(12)H(10)N(3)O(4) (+)·C(7)H(3)N(2)O(7) (-), the cations and the anions are linked by a single N(+)-H⋯O(carbox-yl) hydrogen bond, the discrete cation-anion unit having no inter-molecular associations other than weak cation-anion aromatic ring π-π inter-actions [ring centroid separation = 3.7320 (14) Å] and a number of weak inter-unit aromatic C-H⋯O contacts. ...

In mol-ecule of the title compound, C(16)H(14)N(2)O(2), the two aromatic rings form a dihedral angle of 6.93 (3)° and an intramolecular N-H⋯O hydrogen bond occurs. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into zigzag chains running in the [10] direction.

The title compound, C(7)H(4)Cl(2)O(2), exhibits a layer crystal structure; mol-ecules within each layer are linked by weak C-H⋯O inter-molecular hydrogen bonds. There is also an intramolecular O-H⋯O hydrogen bond.

The title compound, C(20)H(21)NO(7), is asymmetric with a chiral centre located in the pyran ring and crystallizes as a racemate. The mol-ecular framework is somewhat bent; the coumarin moiety and the pyran ring are inclined by 7.85 (5)°. The mol-ecular structure is characterized by an intra-molecular N-H⋯O hydrogen bond, which generates an S(6) ring motif, and the crystal packing is stabilized...