Jairo Bordinhão

Synthesis, structural and spectroscopic studies of novel azo-containing N,O-bonded complexes in the α-Iminoketone and Azophenolate forms

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-κN1]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,O-bidentate 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.

Crystal structures of 4-PhCOS-5-RS-1,2-dithiole-3-thione (R = Me and PhCH2), 4,5-(MeS)2-1,2-dithiole-3-thione and 3,4,5-(MeS)3-1,2-dithiolium iodide

Abstract The crystal structures of the neutral dmt compounds, 4,5-bis(methylthiolato)-1,2-dithiole-3-thione, (1), 4-benzoylthiolato-5-methylthiolato-1,2-dithiole-3-thione, (3) and 4-benzoylthiolato-5-benzylthiolato-1,2-dithiole-3-thione, (4), and the organic salt, 3,4,5-tris(methylthiolato)-1,2-dithiolium iodide (2) have been determined at 120 K. The packing of the molecules provides a variety of intermolecular, or interion, contacts. Notable features in 1 and 3 are the columns of overlapping dithiole rings. In both cases the columns are propagated in the direction of b and neighbouring rings are related to one another by the operation of crystallographic centres of symmetry. In 2 weak C–H · · · I (H · · · I = 3.0236 and 3.0166 Å) and C–H · · · S (H · · · S = 2.8660 Å) hydrogen-bonds, contacts with short I · · · S distances (3.433 and 3.370 Å) and a C–H · · · π contact, with the dithiole ring as acceptor (H · · · Cg = 2.946 Å), create zig-zag chains propagated in the direction of b which are further connected to form corrugated sheets parallel to (0 0 1) with methyl groups on their surfaces. Intermolecular O · · · Sthiole contacts much shorter than the sum of the contact radii (3.32 Å) of oxygen and sulphur are present in 3 and 4.The formation of 3 or 4 occurred regiospecifically from successive reactions of 4,5-bis(benzoylthiolato)-1,2-dithiole-3-thione with one equivalent of caesium hydroxide and RI (R = Me or PhCH2).

2,3-Bis[2-(trifluoromethyl)phenylimino]butane

The title compound, C18H14F6N2, crystallizes with the –N=C(CH3)—C(CH3)=N– diimino group around an inversion center in a trans configuration.

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

In the title compound, [Ni(C16H10N3O3)2(C5H5N)2], the NiII cation is in a distorted octahedral NiN4O2 coordination by two independent bidentate 1-[(4-nitrophenyl)diazenyl]-2-naphtholate anions and two pyridine ligands. C—H⋯O interactions between aromatic rings and the O atoms of the nitro substituents build up a two-dimensional supramolecular arrangement parallel to (100).

2-(2,6-Diisopropyl­phenyl­imino)-1-phenyl­propan-1-one

In the crystal structure of the title compound, C20H25NO, all bond lengths and angles show normal values. Non-classical hydrogen bonds are responsible for the deviation from a planar arrangement.