An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The synthesis and electropolymerisation of a new terthiophene, 1,3-di-2-thienylthieno[3′,4′:5,6][1,4]dithiino[2,3-b]quinoxaline, is reported. The compound bears a quinoxaline unit fused to the central thiophene ring via a 1,4-dithiin ring; the latter unit ensures a non-planar structure for the molecule. The corresponding polymer, prepared electrochemically, has been characterized by cyclic voltammetry and UV-vis-NIR spectroelectrochemistry. The material is oxidised within the conjugated chain, but the reduction processes are complex and arise from both the polythiophene and the independent quinoxaline units. The polymer has two distinct colour states—orange in the neutral form and green–blue in the oxidised state. Electrochromic studies on poly(1,3-di-2-thienylthieno[3′,4′:5,6][1,4]dithiino[2,3-b]quinoxaline) reveal fast switching speeds that are superior to those of poly(3,4-ethylenedioxythiophene) (PEDOT) and a colouration efficiency of 381 cm2 C−1 at 650 nm.

The title compound has been reacted with I-2, IBr and ICl to afford the charge-transfer adducts 4.2I(2), 4.IBr and 4.ICl.I-2, respectively. The products have been characterised by Raman and IR spectroscopy and X-ray crystallography. The adducts contain linear S...I-X (X=I, Br or Cl) units (174-178degrees) in which the S...I contacts range from 2.534-2.597 AAngstrom. In 4.2I(2) and 4.ICl.I-2, the materials contain additional 'free' diiodine units which are held within a matrix of intermolecular contacts, predominantly through non-covalent halogen halogen and sulfur-halogen interactions. Although the functional groups in the parent molecule (4) are inert at the supramolecular level, the bromomethyl groups in the adducts contribute strong interactions through Br...Br, Br...I, Br...S and Br...H close contacts. The structures of the complexes are polymeric in nature, providing interactions in two and three dimensions.

Three new, highly crystalline 2,5-dibromothiophene compounds polymerise on standing in the absence of solvent and catalyst; X-ray crystallography shows that the molecules are held in close proximity by several short intermolecular contacts, facilitating the coupling of monomers.

Three new, highly crystalline 2,5-dibromothiophene compounds polymerise on standing in the absence of solvent and catalyst; X-ray crystallography shows that the molecules are held in close proximity by several short intermolecular contacts, facilitating the coupling of monomers.

A new approach to the one-step synthesis of cadmium selenide (CdSe) quantum dots is reported using the air stable complex cadmium imino-bis(diisopropylphosphine selenide); the ligand is readily prepared from elemental selenium and the precursor, quantum dots of comparable quality to those prepared by conventional methods are obtained.