2-{[3-Chloro-4-(4-chloro-phen-oxy)phen-yl]imino-meth-yl}-4-nitro-phenol.

In the title compound, C19H12Cl2N2O4, the imine bond length of 1.257 (6) Šis typical of a double bond. The dihedral angle between the para-nitro benzene ring and the central benzene ring is 12.06 (3)° and that between the central benzene and the para-chloro benzene ring is 73.81 (2)°. An intra-molecular O-H⋯N hydrogen bond generates an S(6) ring motif. In the crystal, mol-ecules are linked together by two pairs of C-H⋯O interactions (to the same O atom acceptor), forming inversion dimers. A short Cl⋯Cl contact [3.232 (4) Å] is observed.

1-Acetyl-5-ferrocenyl-3-phenyl-2-pyrazoline.

In the title compound, [Fe(C(5)H(5))(C(16)H(15)N(2)O)], the pyrazoline ring and the phenyl ring are nearly coplanar, making a dihedral angle of 6.54 (2)°, while the substituted cyclo-penta-dienyl ring is twisted out of the pyrazoline ring plane by 81.32 (1)°. The mol-ecules in the crystal structure are held together by weak C-H⋯O inter-molecular hydrogen bonds and two C-H⋯π inter-actions.

1-Acetyl-3-ferrocenyl-5-(2-nitro-phen-yl)-2-pyrazoline.

In the title compound, [Fe(C(5)H(5))(C(16)H(14)N(3)O(3))], the pyrazoline ring and the substituted cyclo-penta-dienyl ring are nearly coplanar, with a dihedral angle of 8.17 (2)°, while the nitro-substituted benzene ring is twisted out of the pyrazoline ring plane by 70.76 (1)°. The mol-ecules in the crystal structure are held together by three inter-molecular C-H⋯O hydrogen bonds. There is also an intra-molecular C-H⋯N hydrogen bond. The H atoms of the methyl group are disordered equally over two positions.

Bis(2,6-diamino-pyridinium)-adipate-adipic acid-water (2/1/1/2).

The crystal structure of the title compound, 2C(5)H(8)N(3) (+)·C(6)H(8)O(4) (2-)·C(6)H(10)O(4)·2H(2)O, consists of amino-pyridinium cations, adipate dianions, adipic acid mol-ecules and disordered solvent water mol-ecules [occupancies 0.50 (4) and 0.50 (4)]. Both the adipate and adipic acid are located across inversion centres. Eight-membered hydrogen-bonded rings exist involving amino-pyridinium and adipate ions. Adipic acid mol-ecules and adipate anions are linked into zigzag supra-molecular chains by O-H⋯O hydrogen bonds.

Crystal structure of 2-{[2-meth-oxy-5-(tri-fluoro-meth-yl)phen-yl]iminomethyl}-4-nitro-phenol.

In the title compound, C15H11F3N2O4, the N=C bond of the central imine group adopts an E conformation. The dihedral angle between two benzene rings is 6.2 (2)°. There is an intra-molecular bifurcated O-H⋯(N,O) hydrogen bond with S(6) and S(9) ring motifs. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds into a helical chain along the 31 screw axis parallel to c. The -CF3 group shows rotational disorder over two sites, with occupancies of 0.39 (2) and 0.61 (2).

Experimental and theoretical investigations of 4-chloro-N-(2-methoxyphenyl)benzamidoxime.

4-Chloro-N-(2-methoxyphenyl) benzamidoxime (CMB) has been synthesized and characterized by X-ray diffraction, (1)H NMR, (13)C NMR, FT-IR and FT-Raman spectra. The X-ray study showed that CMB has a Z configuration, due to the strong intramolecular N-H···O hydrogen bond and centrosymmetric dimer form due to intermolecular O-H···N' and O-H···O' hydrogen bonds. The 2-methoxyphenyl and 4-chlorophenyl rings are twisted from the mean plane of the hydroxyamidine group by 33.09 (1) and 44.89 (1)°, respectively. The optimized molecular structure and vibrational frequencies have been calculated with DFT (B3LYP) method by using a 6-311G(d,p) basis set. The (1)H and (13)C NMR chemical shifts were calculated by the gauge-including atomic orbital (GIAO) method with the B3LYP/6-311G (d,p) level. A comparison between experimental and calculated theoretical results indicate that the density functional B3LYP method provided satisfactory results for predicting IR, Raman, (1)H NMR and (13)C NMR spectra properties.

1,3-Bis(4-methylphenyl)triazene, 1-(4-chlorophenyl)-3-(4-fluorophenyl)triazene and 1-(4-fluorophenyl)-3-(4-methylphenyl)triazene.

The title 4,4'-disubstituted diphenyl-1,3-triazines, C14H15N3, (I), C12H9ClFN3, (II), and C13H12FN3, (III), each contain a triazene group (-N=N-NH-) having an extended conformation. The dihedral angles between the two benzene rings in (I), (II) and (III) are 4.3, 3.4 and 6.5 degrees , respectively. The molecules are almost entirely planar, with maximum deviations from the mean planes of 0.1087 (2), -0.1072 (7) and 0.1401 (3) A, respectively. In each compound, the molecules are linked by N-H...N hydrogen bonds to form chains and pack similarly in the crystal structures.

N,N'-bis[1-(pyrazin-2-yl)ethylidene]hydrazine.

Molecules of the title compound, C12H12N6, contain both a diimine linkage and an N-N bond, and assume a planar structure. The compound lies about an inversion centre and there are three intramolecular C-H...N hydrogen bonds.