No abstract

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.

Key indicatorsSingle-crystal X-ray study T = 295 K Mean (C-C) = 0.002 Å R factor = 0.039 wR factor = 0.104 Data-to-parameter ratio = 10.8For details of how these key indicators were automatically derived from the article, see

Este artigo descreve a síntese e a caracterização espectroscópica e estrutural por difratometria de raios X em monocristal de dois novos complexos contendo o grupamento azo, cis-bis[4-nitro-2-(4-nitrofenilazo)-fenolato-κN 1 ]bis(piridino-κN)cádmio(II), 1, e cis-bis[2-(4-fenilazofenilimino)-2H-acenafteno-1-ona]dicloromercúrio(II), 2. Embora os ligantes e os metais sejam diferentes, observa-se para os dois complexos uma coordenação do tipo N,O-bidentada ao átomo central. Em 1, a coordenação é feita por um átomo de N do grupo azo e por um átomo de O do grupo fenolato, enquanto em 2 a coordenação ocorre exclusivamente via átomos de O e N da α-iminocetona. Ambos os complexos exibem interações intramoleculares do tipo π-π, que exercem um importante papel na determinação de suas estruturas moleculares, além de também exibirem arranjos supramoleculares governados por ligações de hidrogênio não-clássicas. Em adição, a estrutura de 2 é a primeira relatada na literatura com um novo tipo de ligante, a azo-iminocetona, e também a primeira contendo mercúrio complexado a uma α-iminocetona. This article describes the synthesis and the spectroscopic and structural characterization of two novel azo-containing complexes, cis-bis[4-nitro-2-(4-nitrophenylazo)-phenolate-κN 1 ] bis(piridino-κN)cadmium(II), 1, and cis-bis[2-(4-phenylazo-phenylimino)-2H-acenaphthylen-1-one]dichloromercury(II), 2. In spite of the different metal centres, both complexes show an N,Obidentate complexation to the metal. In 1 the metal coordinates to an azo N and to a phenolate O atom, whereas in 2 the metal binds to an O and an N atom of the α-iminoketone. Both complexes show intramolecular π-π interactions, which play an important role in their molecular structures. In addition they also present non-classical H-bonding, which is crucial to their supramolecular arrangements. Moreover, 2 is the first case in the literature of a complex with a new class of ligand, an azoiminoketone, as well as the first case of an α-iminoketone Hg complex.

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.