In the title mol-ecule, C19H20O6, the conformation about the C=C bond of the central enone group is E. The dihedral angle formed by the benzene rings is 11.6 (2)°. The hy-droxy group is involved in an intra-molecular O-H⋯O hydrogen bond. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into chains along [010].

The conformation of the N-H bond in the title compound, C(10)H(10)Cl(3)NO, is anti to the C=O bond. The amide H atom exhibits both intra-molecular N-H⋯Cl and inter-molecular N-H⋯O hydrogen bonding. The latter inter-actions link the mol-ecules into infinite chains.

The N-H bond in the title compound, C(13)H(19)NO, is anti to the C=O bond and is also anti to both the 2- and 3-methyl substituents in the aromatic ring. In the crystal, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into chains propagating along the c axis.

In the title molecular salt, C36H30NP2(+)·C24BF20(-), the P-N bond lengths in the cation are equal [1.573 (2) and 1.572 (2) Å], indicating a resonance structure and the P-N-P bond angle is 144.79 (12)°. In the crystal, weak C-H⋯F interactions link the cations and the anions.

Classical interatomic bond-order potentials (BOPs) have previously been obtained by coarse-graining the quantum-mechanical electronic structure within the chemically intuitive reduced tight-binding (TB) framework. This paper generalizes the reduced tight-binding approximation to the case of multicomponent sp-valent systems, thereby allowing a rigorous derivation of expressions for the and bond ...

The six-coordinate Sn(IV) atom in the title compound, [Sn(C(8)H(9))Cl(3)(C(3)H(4)N(2))(2)], shows an octa-hedral coordination. The N atoms of the N-heterocycle are cis to each other. The Sn-N bond that is trans to the Sn-C bond is shorter than the Sn-N bond trans to the Sn-Cl bond. Weak N-H⋯Cl hydrogen bonds link adjacent mol-ecules, generating a double chain running along the c axis.

In the title compound, C(12)H(10)N(2)O(4)S, the conformation of the N-H bond in the -SO(2)-NH- fragment is syn to the ortho-nitro group in the sulfonyl-benzene ring. The mol-ecule is twisted at the S-N bond, the C-N-S-C torsion angle being -72.83 (15)°. The dihedral angle between the benzene rings is 59.55 (7)°. The amide H atom and the nitro group O atom form an intra-molecular hydrogen bond, ...

The conformation of the N-H bond in the structure of the title compound, C(10)H(13)NO, is syn to both the 2- and 3-methyl substituents on the aromatic ring, and is anti to the C=O bond. N-H⋯O hydrogen bonds link the mol-ecules into supra-molecular chains.

The mol-ecule of the title compound, C(27)H(24)N(4)O(5), exists in the keto-enamine tautomeric form, stabilized by an intra-molecular N-H⋯O hydrogen bond. An intra-molecular C-H⋯·O hydrogen bond also occurs. In the crystal, C-H⋯O hydrogen bonds link the mol-ecules into chains.