The title compound, C(14)H(11)Br(2)NO, was prepared by the condensation of benzyl-amine and 3,5-dibromo-2-hydroxy-benzaldehyde. The crystal structure is stabilized by aromatic π-π stacking inter-actions between the phenol rings of neighbouring mol-ecules [centroid-centroid distance = 3.530 (5) Å]. In addition, the stacked mol-ecules exhibit inter-molecular C-H⋯π and intra-molecular O-H⋯N inter-...

The title compound, C(18)H(12)N(2), adopts an E conformation with the benzyl-idenemalononitrile and phenyl groups located on opposite sides of the C=C bond. The two phenyl rings are oriented at a dihedral angle of 62.49 (7)°.

In the title compound, C(13)H(10)N(2)S, the dihedral angle between the imidazole and thio-phene rings is 16.89 (19)°, and the double bond adopts an E configuration. In the crystal structure, N-H⋯N hydrogen bonds link the mol-ecules into rows along b. There is also evidence of weak C-H⋯S inter-actions.

The title compound, C(8)H(10)N(2)O(2)S, was prepared by the reaction of 2-cyano-3,3-bis-(methyl-sulfan-yl)acrylate and 2-amino-ethanethiol at 350 K. The mol-ecular structure and packing are stabilized by N-H⋯O hydrogen-bond inter-actions. All the non-H atoms are nearly in the same plane with the maximum deviation being 0.08 Å.

The title compound, C(19)H(14)N(2)O(4), crystallizes with two molecules with very similar conformations in the asymmetric unit; the angles between the two ring systems are 8.7 (1) and 4.2 (1)°. In the crystal, inter-molecular π-π inter-actions [centroid-centroid distance 3.973 (1) Å] lead to a three-dimensional network.

In the title compound, C(17)H(13)NO(2), the dihedral angle between the benzene and the phenyl ring is 65.92 (7)°. The carbonitrile side chain is almost linear, the C-C-N angle being 175.55 (14)°. The crystal structure is stabilized by inter-molecular C-H⋯O inter-actions.

The equivalence of mass and energy is indelibly linked with relativity, both by scientists and in the popular mind. Here I prove that E = mc 2 by demanding momentum conservation of an object that emits two equal electromagnetic wave packets in opposite directions in its own frame. In contrast to Einstein's derivation of this equation, which applies energy conservation to a similar thought exper...

In the title compound, C(12)H(11)N(5)O(2), the mol-ecule adopts an E configuration, with the benzene and pyrazine rings located on opposite sides of the N=C double bond. The face-to-face separations of 3.413 (14) and 3.430 (8) Å, respectively between parallel benzene rings and between pyrazine rings indicate the existence of π-π stacking between adjacent mol-ecules. The crystal structure also c...

The title compound, C(11)H(16)O(4), crystallizes with three molecules in the asymmetric unit. The cyclo-hexane ring adopts a chair conformation. Inter-molecular O-H⋯O hydrogen bonds are observed and these help to establish the crystal packing.

The mol-ecule of the title compound, C(14)H(10)N(2)O(2), adopts the phenol-imine tautomeric form. The dihedral angle between the planes of the two benzene rings is 13.84 (13)°. A strong intra-molecular O-H⋯N hydrogen-bonding inter-action stabilizes the mol-ecular conformation. In the crystal structure, centrosymmetrically related mol-ecules are linked into dimers by inter-molecular C-H⋯O and O-...