Calix[4]arenes substituted at their wide rim by four aryl urea residues (1) form hydrogen-bonded dimers in apolar solvents. Replacement of one urea residue by an acetamido moiety leads to calix[4]arene derivatives (5) which form hydrogen-bonded tetramers under the same conditions. Both self-assembly processes occur independently. Therefore, molecules have been prepared in which a tetra-urea cal...

In the title ylide, C(31)H(28)ClO(2)P [common name α-acetyl-α-p-chloro-benzoyl-methyl-enetri(p-tol-yl)phospho-rane], the dihedral angle between the 4-chloro-phenyl ring and that of the ylide moiety is 66.15 (10)°. The geometry around the P atom is slightly distorted tetra-hedral [angle range = 105.22 (8)-115.52 (9)°] and the carbonyl O atoms are syn-oriented with respect to the P atom. The ylid...

In the title compound, C(8)H(7)N(5)O(2), the dihedral angle between the benzene and tetra-zole rings is 63.13 (8)°. The crystal structure exhibits inter-molecular N-H⋯N hydrogen bonds which lead to the formation of one-dimensional chains along the [010] direction.

The title compound, C(9)H(7)N(5), is non-planar with a dihedral angle between the substituted benzene and tetra-zole rings of 71.13 (9)°. Molecules are connected in centrosymmetric dimers by weak C-H⋯N inter-actions [C⋯N is 3.548 (5) Å]; these are the only interactions of significance in the crystal structure.

The Sn(IV) atom in the centrosymmetric dinuclear title compound, [Sn(2)(C(4)H(9))(4)(C(7)H(3)NO(4))(2)(H(2)O)(2)], exists in a trans-C(2)SnNO(4) penta-gonal-bipyramidal geometry. There are two half-mol-ecules in the asymmetric unit that are completed by inversion symmetry. The crystal studied was a non-merohedral twin with a ratio of 47.3 (1)% for the minor twin component. Bond dimensions are s...

In the cation of the title compound, C(6)H(6)N(5) (+)·NO(3) (-), the dihedral angle between the pyridinium and tetra-zole rings is 8.2 (2)°. The constituent ions of the compound are linked via N-H⋯O hydrogen bonds, forming helical chains running along the b axis. C-H⋯N and C-H⋯O hydrogen bonds are also observed.

The five-membered ring in the title compound, C(6)H(13)O(3)P, exists in an envelope conformation with one of the ring C atoms at the flap position. The coordination geometry around the P atom is a distorted tetra-hedron. The crystal structure is stabilized by several weak C-H⋯O and P-H⋯O hydrogen bonds, forming a three-dimensional network.

In the title dye compound, C(19)H(14)BF(7)N(2), the boron-dipyrromethene core lies on a crystallographic mirror plane which bis-ects the BF(2) and penta-fluoro-phenyl groups. The dihedral angle between the penta-fluoro-phenyl ring and the tricyclic system is thus 90° by symmetry. The sp(3)-hybridized B atom has a slightly distorted tetra-hedral coordination.