1,4-Bis(2-nitro-phen-oxy)butane.

The asymmetric unit of the title compound, C(16)H(16)N(2)O(6), contains one-half mol-ecule, the mid-point of the central C-C bond being located on a crystallographic inversion center. The crystal structure shows weak inter-actions between the O atoms of the nitro groups and two different C-H groups of the benzene rings. The extended weak hydrogen-bond formation, involving the NO(2) groups, generates an infinite three-dimensional network.

Acyclic Schiff base salts derived from 1,3-diaminopropane and 1,3-diamino-2-hydroxypropane.

Two salts of acyclic Schiff base cationic ligands, namely N,N'-bis(2-nitrobenzyl)propane-1,3-diammonium dichloride monohydrate, C(17)H(22)N(4)O(4)(2+).2Cl(-).H(2)O, (I), and 2-hydroxy-N,N'-bis(2-nitrobenzyl)propane-1,3-diammonium dichloride, C(17)H(22)N(4)O(5)(2+).

4-(4-bromophenyl)-2-methyl-1,3-thiazole.

In the structure of the title compound, C(10)H(8)BrNS, the dihedral angles between the planes of the thiazole and aryl rings, viz. 4.2 (6) and 7.

Flat versus twisted rotamers of 2,4-disubstituted thiazoles: the effect of intermolecular hydrogen bonds.

In the title compounds, 2-amino-4-(2-chloro-4,5-dimethoxyphenyl)-1,3-thiazole, C(11)H(11)ClN(2)O(2)S, (I), and 4-(2-chloro-4,5-dimethoxyphenyl)-2-methyl-1,3-thiazole, C(12)H(12)ClNO(2)S, (II), the dihedral angles between the thiazole moiety and the chloroaryl group are 51.61 (10) and 8.44 (14), respectively.