Crystal structures of functional building blocks derived from bis(benzo[b]thiophen-2-yl)methane.

The syntheses of three bis(benzo[b]thiophen-2-yl)methane derivatives, namely bis(benzo[b]thiophen-2-yl)methanone, C17H10OS2, (I), 1,1-bis(benzo[b]thiophen-2-yl)-3-(trimethylsilyl)prop-2-yn-1-ol, C22H20OS2Si, (II), and 1,1-bis(benzo[b]thiophen-2-yl)prop-2-yn-1-ol, C19H12OS2, (III), are described and their crystal structures discussed comparatively. The conformation of ketone (I) and the respective analogues are rather similar for most of the compounds compared. This is true for the interplanar angles, the Caryl-Cbridge-Caryl angles and the dihedral angles. The best resemblance is found for a bioisotere of (I), viz. 2,2'-dinaphthyl ketone, (VII). By way of interest, the crystal packings also reveal similarities between (I) and (VII). In (I), the edge-to-face interactions seen between two napthyl residues in (VII) are substituted by S...π contacts between the benzo[b]thiophen-2-yl units in (I). In the structures of the bis(benzo[b]thiophen-2-yl)methanols, i.e. (II) and (III), the interplanar angles are also quite similar compared with analogues and related active pharmaceutical ingredients (APIs) containing the dithiophen-2-ylmethane scaffold, though the dihedral angles show a larger variability and produce unsymmetrical molecules.

5,5'-(Ethyne-1,2-di-yl)diisophthalic acid dimethyl sulfoxide tetra-solvate.

In the title compound, C18H10O8·4C2H6OS, the mid-point of the triple bond of the main mol-ecule is located on a special position, i.e. about an inversion center. The carboxyl groups are twisted slightly out of the planes of the aromatic rings to which they are attached, making dihedral angles of 24.89 (1) and 7.40 (2)°. The cystal packing features strong O-H⋯O hydrogen bonds, weaker C-H⋯O inter-actions and O⋯S contacts [3.0981 (11) Å] and displays channel-like voids extending along the a-axis direction which contain the dimethyl sulfoxide solvent mol-ecules.

Redetermination of tetra-methyl tetra-thia-fulvalene-2,3,6,7-tetra-carboxyl-ate.

An improved crystal structure of the title compound, C(14)H(12)O(8)S(4), is reported. The structure, previously solved using the heavy-atom method (R = 7.1%), has now been solved using direct methods. Due to the improved quality of the data set an R value of 2.06% could be achieved. In the crystal, C-H⋯S and C-H⋯O contacts link the mol-ecules.

S,S'-(Pyridazine-3,6-di-yl)dithio-uronium dichloride methanol monosolvate.

In the title compound, C(6)H(10)N(6)S(2) (2+)·2Cl(-)·CH(3)OH, the pyrid-azine ring is almost planar, the greatest deviation from the mean plane being 0.025 (2) Šfor one of the ring N atoms. The two thiouronium substituents are tilted out of this plane by 60.87 (6) and 57.94 (7)°. The thiouronium cations and the chloride anions are linked by strong N-H⋯Cl hydrogen bonds. The methanol solvent mol-ecule inter-acts with both the chloride ion (through an O-H⋯Cl hydrogen bond) and the cation (through an N-H⋯O hydrogen bond), resulting in a three-dimensional supra-molecular arrangement.