1,5-Bis(2-formyl-phen-oxy)-3-oxapenta-ne.

In the title mol-ecule, C(18)H(18)O(5), the two aromatic rings are connected by a flexible 3-oxapentane chain. The mol-ecule has a crystallographic twofold rotation axis (C(2)) passing through the central O atom. An intra-molecular C-H⋯O hydrogen bond is observed in the solid state.

cis-Bis{1-[(4-nitro-phen-yl)diazen-yl]-2-naphtholato}dipyridine-nickel(II).

In the title compound, [Ni(C(16)H(10)N(3)O(3))(2)(C(5)H(5)N)(2)], the Ni(II) cation is in a distorted octa-hedral NiN(4)O(2) coordination by two independent bidentate 1-[(4-nitro-phen-yl)diazen-yl]-2-naph-thol-ate anions and two pyridine ligands. C-H⋯O inter-actions between aromatic rings and the O atoms of the nitro substituents build up a two-dimensional supra-molecular arrangement parallel to (100).

trans-Bis[1-methyl-3-(p-nitrophenyl)triazenido 1-oxide-kappa2N3,O]dipyridinenickel(II).

In the centrosymmetric title complex, [Ni(C(7)H(7)N(4)O(3))(2)(C(5)H(5)N)(2)], the coordination geometry about the Ni(2+) ion is octahedral, with two deprotonated 1-methyl-3-(p-nitrophenyl)triazenide 1-oxide ions, viz. [O(2)NC(6)H(4)NNN(O)CH(3)](-), acting as bidentate ligands (four-electron donors). Two neutral pyridine (py) molecules complete the coordination sphere in positions trans to each other. The triazenide 1-oxide ligand is almost planar, the largest interplanar angle of 8.80 (12) degrees being between the phenyl ring of the p-nitrophenyl group and the plane defined by the N(3)O moiety. The Ni-N(triazenide), Ni-O and Ni-N(py) distances are 2.0794 (16), 2.0427 (13) and 2.1652 (18) A, respectively.

cis-Bis[1,3-bis(2-fluorophenyl)triazenido-kappa2N1,N3]bis(pyridine-kappaN)cadmium(II).

In the title compound, [Cd(C12H8F2N3)2(C5H5N)2], the Cd atom lies on a crystallographic twofold axis in space group Iba2. The coordination geometry about the Cd(II) ion corresponds to a rhombically distorted octahedron, with two deprotonated 1,3-bis(2-fluorophenyl)triazenide ions, viz. FC6H4NNNC6H4F-, acting as bidentate ligands (four-electron donors). Two neutral pyridine (py) molecules complete the coordination sphere in positions cis with respect to one another. The triazenide ligand is not planar (r.m.s. deviation = 0.204 A), the dihedral angle between the phenyl rings of the terminal 2-fluorophenyl substituents being 24.6 (1) degrees. The triazenide and pyridine Cd-N distances are 2.3757 (18)/2.3800 (19) and 2.3461 (19) A, respectively. Intermolecular C-H.F interactions generate sheets of molecules in the (010) plane.

3-(4-Acetylphenyl)-1-(4-nitrophenyl)triazene.

The crystal structure of the title compound, C(14)H(12)N(4)O(3), shows that the stereochemistry about the N=N double bond of the N=N-N(H) moiety is trans. The whole molecule is almost planar (r.m.s. deviation = 0.0654 A), the interplanar angle between the phenyl rings being 0.7 (1) degrees and the largest interplanar angle being that between the phenyl ring and the nitro group of the 4-nitrophenyl substituent [11.5 (2) degrees ]. Intermolecular N-H.O interactions between molecules related by translation give rise to chains along the [110] and [1-10] directions, and these chains are held together by N.O pi-pi interactions. An unequal distribution of the double-bond character among the N atoms suggests a delocalization of pi electrons over the diazoamine group and the adjacent aryl substituents.

1,3-Bis(2,4-dibromophenyl)triazene.

The crystal structure of the title compound, C(12)H(7)Br(4)N(3), shows that the stereochemistry about the N[double bond]N double bond of the N[double bond]N-N(H) moiety is trans. The whole molecule deviates slightly from planarity (r.m.s. deviation 0.164 A). While one of the aryl substituents is almost coplanar with the triazene chain, weak intermolecular Br...C contacts cause the second aryl substituent to deviate by an angle of 9.1 (8) from the plane defined by the N[double bond]N-N group. Weak intermolecular N-H...Br interactions between molecules related by the diagonal glide plane give rise to chains, which are stacked along the [100] crystallographic direction. An unequal distribution of double-bond character between the N atoms suggests a delocalization of pi electrons over the diazoamino group and the adjacent aryl groups.

1,3-Bis(4-nitrophenyl)triazene.

The structure of the title compound, C(12)H(9)N(5)O(4), reveals an almost planar molecule (r.m.s. deviation = 0.061 A), in which the interplanar angle between the phenyl rings is 5.7 (1) degrees and the largest interplanar angle is that between the phenyl ring and the nitro group of one of the 4-nitrophenyl substituents [8.8 (3) degrees ]. The observed molecular conformation suggests a delocalization of pi-electrons extended over the diazoamine group and the terminal aryl substituents. Intermolecular N-H.O interactions between the twofold screw-related molecules give rise to helical chains along the [010] direction. Intermolecular C-H.O interactions then generate sheets of molecules in the (10-1) plane, and these sheets are held together by N.C and O.O pi-pi interactions.

trans-Bis[3-(2-fluorophenyl)-1-(4-nitrophenyl)triazenido-kappaN3]bis(pyridine-kappaN)palladium(II).

In the title complex, [Pd(C(12)H(8)FN(4)O(2))(2)(C(5)H(5)N)(2)] or trans-[Pd(FC(6)H(4)N=N-NC(6)H(4)NO(2))(C(5)H(5)N)(2)], the Pd atom lies on a centre of inversion in space group P-1. The coordination geometry about the Pd(2+) ion is square planar, with two deprotonated 3-(2-fluorophenyl)-1-(4-nitrophenyl)triazenide ions, FC(6)H(4)N=N-NC(6)H(4)NO(2)(-), acting as monodentate ligands (two-electron donors), while two neutral pyridine molecules complete the metal coordination sphere. The whole triazenide ligand is not planar, with the largest interplanar angle being 16.8 (5) degrees between the phenyl ring of the 2-fluorophenyl group and the plane defined by the N=N-N moiety. The Pd-N(triazenide) and Pd-N(pyridine) distances are 2.021 (3) and 2.039 (3) A, respectively.