The title compound, C(11)H(8)Br(2)N(4), is a Schiff base obtained from 6-bromo-picolinaldehyde and 5-bromo-pyridine-3,4-diamine. The mol-ecule has an E configuration about the C=N bond and the dihedral angle between the two pyridine rings is 14.02 (1)°. The observed conformation is stabilised by an intramolecular N-H⋯N hydrogen bond. In the crystal, mol-ecules are stacked along the b axis and a...

In the title compound, C(17)H(14)ClF(2)NO(2), the amino-acrylo-yloxy group makes dihedral angles of 47.55 (11)° with the 4-chloro-phenyl group and 8.74 (12)° with the difluoro-phenyl group; the dihedral angle between the rings is 52.32 (11)°. The structure of the title compound reveals a Z configuration with respect to the C=C double bond in the amino-acrylate fragment. A bifurcated intramolecu...

A novel Gemini amphiphile, N,N′-bis-(4-decyloxy-2-hydroxybenzylidene)-ethane-1,2-diamine, was synthesized and characterized. This amphiphile is capable of forming stable monolayer at air–water interface. The limiting area has a minimum when the pH value of subphase is 12. The unique behavior is attributed to the formation of intramolecular hydrogen bond between hydroxyl groups. The existence of...

Cooperativity in hydrogen bonding has been repeatedly invoked in the literature. Very often a distinction is made between the association constant for the “dimer” formation and the corresponding constant for the formation of association complexes beyond dimer. This work examines this cooperativity hypothesis and proposes a straightforward manner of integrating it in the framework of the lattice...

Buried solvent molecules are common in the core of globular proteins and contribute to structural stability. Folding necessitates the burial of polar backbone atoms in the protein core, whose hydrogen-bonding capacities should be satisfied on average. Whereas the residues in alpha-helices and beta-sheets form systematic main-chain hydrogen bonds, the residues in turns, coils and loops often con...

The title compound, C(13)H(10)ClNO(2), exists in a trans configuration about the central C=N bond. The two benzene rings are almost coplanar, making a dihedral angle of 2.48 (10)°. An intra-molecular O-H⋯N hydrogen bond generates an S(6) ring motif. In the crystal structure, O-H⋯O hydrogen bonds link the mol-ecules into chains along [101]. Short C⋯Cl contacts [3.584 (2)-3.646 (2) Å] are observe...

In the title compound, [Fe(C(5)H(5))(C(13)H(9)N(2))], the dihedral angle between the substituted cyclo-penta-dienyl plane and the plane of the pyridine ring is 8.43 (14)°. The double bond adopts a Z configuration. In the crystal structure, weak C-H⋯N inter-actions link the molecules into a zigzag chain. A weak intramolecular C-H⋯N hydrogen bond is also present.

Ciprofloxacin belongs to a family of quinolone antibacterial agents. The crystal structure of ciprofloxacin hydrochloride 1,34-hydrate was determined. Most of the bond lengths and angles of the ciprofloxacin cation are very similar to those of ciprofloxacin hexahydrate, which appears in the zwitterionic form. The exceptions are the carbon-oxygen bond distances in the carboxylic group, since in ...

The title Schiff base compound, C(22)H(28)N(2)O(4), lies across a crystallographic inversion centre and adopts an E configuration with respect to the C=N bond. Pairs of weak inter-molecular C-H⋯O inter-actions link neighbouring mol-ecules into dimers with an R(2) (2)(28) ring motif. The crystal structure is stabilized by inter-molecular C-H⋯π inter-actions. An intramolecular O-H⋯N hydrogen bond...

The replacement of oxygenated functionality (hydroxy and alkoxy) with a fluorine atom is commonly used bioisosteric in medicinal chemistry. In this paper, we use molecular matched-pair analysis to better understand the effects on lipophilicity. It seems that reduced log P compound normally dominant determining size difference. We observe presence additional electron-donating groups an aromatic ...