In the title mol-ecule, C(13)H(10)N(2)O(4), the dihedral angle between the mean planes of the benzene and phenolate rings is 21.6 (4)°. The nitro O atoms are twisted slightly out of the plane of the ring to which the nitro group is attached [dihedral angle 8.4 (3)°]. The amine group forms an intra-molecular hydrogen bond with both nearby O atoms. An extended π delocalization throughout the enti...

In the title compound, C(11)H(9)NO(2), the mean planes formed by the phenyl and acryl group are almost orthogonal to each other, with a dihedral angle of 88.61 (7)°. The carbonitrile side chain is almost linear, the C-C-N angle being 179.54 (16)°. In the crystal, mol-ecules are linked by inter-molecular O-H⋯O inter-actions into infinite chains running parallel to the b axis.

In the title compound, C(17)H(14)N(4)O(2)·1.5H(2)O, the mean planes of the pyridine ring and quinoline group make a dihedral angle of 21.0 (2)°. One water molecule lies on a twofold rotation axis. The organic mol-ecules and the three water mol-ecules are linked into infinite chains by N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds.

The structure of the title compound, C(9)H(10)O(2), is related to that of 4-methyl-phenyl 4-methyl-benzoate and ethyl-ene di-4-methyl-benzoate showing similar bond parameters. The mol-ecule is planar, the dihedral angle between the aromatic ring and the -COOMe group being 0.95 (6)°. The cystal structure exhibits inter-molecular C-H⋯O contacts that link mol-ecules into infinite chains extended i...

For any graded poset P, we define a new graded poset, E(P ), whose elements are the edges in the Hasse diagram of P. For any group, G, acting on the boolean algebra, Bn, we conjecture that E(Bn/G) is Peck. We prove that the conjecture holds for “common cover transitive” actions. We give some infinite families of common cover transitive actions and show that the common cover transitive actions a...