N,N′-Bis(2-aminophenyl)-3,4-diphenylthiophene-2,5-dicarboxamide acetonitrile solvate

In the title solvate, C30H24N4O2S·CH3CN, the substituted thiophene possesses approximate Cs(m) intrinsic symmetry, with the mirror plane passing through the S atom and the mid-point of the (Ph)C—C(Ph) bond. Despite the main backbone of the molecule being a long chain of conjugated bonds, it adopts a non-planar conformation due to the presence of various intra- and intermolecular hydrogen bonds. The hydrogen bonds result in twist configurations for both the amido and aminophenyl fragments relative to the central thiophene ring. There are two intramolecular Namine—H⋯O hydrogen bonds within the thiophene-2,5-dicarboxamide molecule that form seven-membered rings. In the crystal, the thiophene-2,5-dicarboxamide molecules form inversion dimers by four amide–amine N—H⋯N hydrogen bonds. The dimers are further linked into layers propagating in (100) both directly (via Namine—H⋯O hydrogen bonds) and through the acetonitrile solvate molecules (via amine–cyano N—H⋯N and CMe—H⋯O interactions).


Related literature
Data collection: SMART (Bruker, 1998); cell refinement: SAINT-Plus (Bruker, 1998); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL ; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL. and others have reported several approaches for the synthesis of such type of diamines (Picard et al., 2001;Sessler et al., 2005aSessler et al., , 2005bKatayev et al., 2007). In this work we present the synthesis and crystal structure of a diamine used by us recently to prepare anion selective receptors (Sessler et al., 2005a;Askerov et al., 2010).
The synthesis consists of the conversion of dicarboxylic acid into the corresponding chloride followed by coupling with 2-mercaptothiazoline ( Fig. 1). The activated acid was transformed into (I) by the reaction with 1,2-phenylenediamine.
Experimental 2,5-Bis((2-thio-1,3-thiazolidine-3-yl)carbonyl)-3,4-diphenylthiophene (II). 3,4-Diphenylthiophene-2,5-dicarboxylic acid (9 g, 27.7 mmol) was suspended in 35 ml freshly distilled SOCl 2 in the presence of several drops of DMF. The resulting mixture was heated at reflux for 1 hour. The excess SOCl 2 was removed under reduced pressure and the residue was further dried at 373 K under high vacuum. The thiophene diacid chloride obtained in this way was dissolved in 130 ml dry THF and added drop-wise during a 2 hour period to a solution containing 1,3-thiazolidine-2-thione (6.6 g, 55.4 mmol) and triethylamine (20 ml) in 330 ml dry THF. During this process carried out under continuous stirring the reaction temperature sup-2 was kept at 323 K. After the addition was complete the reaction mixture was maintained under the same conditions for an additional 2 hours and then for a further 16 h at room temperature with stirring. The reaction mixture was then filtered, and the resulting solid was washed with cold THF. The filtrate was reduced in volume to a dark paste using a rotary evaporator. This paste-like material was then taken up into 30 ml of ethyl acetate. After this mixing procedure, crude product was filtered off as a dark-yellow powder. Recrystallization from dichloroethane yielded 10.8 g (74%) of yellow crystals.  55.80, 127.90, 127.99, 129.60, 134.21, 136.08, 144.34, 164.16, 200.37 133.71, 136.90, 138.13, 139.58, 139.37, 141.32, 145.59, 147.12, 153.39, 153.48, 171.99

Refinement
The hydrogen atoms of the amino-groups as well as the solvate acetonitrile molecule were localized in the difference-Fourier map and included in the refinement with fixed positional (C-H = 0.98 Å) and isotropic displacement parameters [U iso (H) = 1.5U eq (C) for CH 3 -group and U iso (H) = 1.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.