Crystal structure of 1,3-bis-(4-hexyl-5-iodo-thio-phen-2-yl)-4,5,6,7-tetra-hydro-2-benzo-thio-phene

In the crystal structure of the title compound, C28H36I2S3, a terthio-phene monomer, the central thio-phene unit is arranged anti-coplanar to the two outer thio-phene rings. There are two crystallographically independent mol-ecules in the asymmetric unit, which show different conformations. In one mol-ecule, the dihedral angles between the inner and the two outer thiophene rings are 15.7 (3) and 3.47 (3)°, whereas these values are 4.2 (3) and 11.3 (3)° for the second mol-ecule. Differences are also found in the arrangement of the hexyl chains: in one of the two molecules, both chains are nearly in plane to the central moiety, whereas in the second molecule, only one chain is in plane and the other one is nearly perpendicular to the central moiety. Some of the C atoms are disordered and were refined using a split model with occupancy ratios of 0.65:0.35 and 0.70:0.30 in the two mol-ecules.

Highly tin-selective stille coupling: synthesis of a polymer containing a stannole in the main chain

The incorporation of heavier Group 14 element heteroles into semiconducting polymers leads to unusual optoelectronic properties. However, polymers containing stannoles have not been accessible to date. We report a synthetic route to a well-defined, stannole-containing polymer, the first example of this class of π-conjugated polymers. This route was made possible by developing difunctionalized stannole monomers and highly tin-selective Stille coupling reactions that leave the tin in the stannole untouched. Compared to poly(3-n-hexylthiophene), the resulting polymer displays a remarkable bathochromic shift in its absorption.

Chemoselective cross-coupling reactions with differentiation between two nucleophilic sites on a single aromatic substrate

A new thiophene building block, containing both a stannyl group and a boronic ester, was prepared. From this starting material, a general, nucleophile-selective one-pot reaction was developed, exploiting the different reactivities of the Stille and Suzuki-Miyaura cross-coupling reactions. A series of aromatic electrophiles were used to demonstrate the high functional group tolerance.