title: Luminescent digold ethynyl thienothiophene and dithienothiophene complexes; their synthesis and structural characterisation.
abstract: A series of protected and terminal dialkynes with extended pi-conjugation through the fused oligothienyl linker unit in the backbone, 2,5-bis(trimethylsilylethynyl)thieno[3,2-b]thiophene 1a, 5,5'-bis(trimethylsilylethynyl)dithieno[3,2-b:2',3'-d]thiophene 1b, 2,5-bis(ethynyl)thieno[3,2-b]thiophene 2a, 5,5'-bis(ethynyl)dithieno[3,2-b:2',3'-d]thiophene 2b, has been synthesized and characterised. The digold alkynyl complexes [(Ph3P)Au(C[triple bond]C)(C6H2S2)(C[triple bond]C)Au(PPh3)] 3a and [(Ph3P)Au(C[triple bond]C)(C8H2S3)(C[triple bond]C)Au(PPh3)] 3b have then been prepared by the reaction of two equivalents of Ph3PAuCl and a methanolic KOH solution of 1a and 1b, respectively. The complexes have been characterised spectroscopically. The crystal structures show that the gold centres adopt a linear two-coordinate geometry appropriate for Au(i) complexes. Within the crystals adjacent molecules are linked by Au...S intermolecular interactions in the range 3.48-3.89 A, but there are no short Au...Au contacts. The absence of Au...Au interactions in solution is confirmed by UV/visible absorption and emission spectroscopy, the spectra being dominated by ligand-centred pi-pi* interactions.
authors.affiliation: Department of Chemistry, University of Cambridge, UK.
authors.forename: Peiyi
authors.initials: P
authors.lastname: Li
authors.forename: Birte
authors.initials: B
authors.lastname: Ahrens
authors.forename: Neil
authors.initials: N
authors.lastname: Feeder
authors.forename: Paul R
authors.initials: PR
authors.lastname: Raithby
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Teat
authors.forename: Muhammad S
authors.initials: MS
authors.lastname: Khan