An “S3N-ligand azo-dye” conjugate has been synthesised with a view to the development of a sensor for heavy metal ions. Complexation of this system with Ag(I), Hg(II) and Cu(II) salts has been investigated and an X-ray structure has been obtained for a Hg(II) complex. Complexation of the conjugated dye to these metals results in a bathochromic shift in the absorption maximum of the azo dye, an effect which is most pronounced for Cu(II).

The reaction between 3,6,9-trithia-1(2,6)-pyridinacyclodecaphane and representative group 10 and 11 metal salts [Cu(NO3)2, NiCl2 or Ag(CF3CO2)] afforded 1:1 complexes, which in the case of CuII and AgI were characterised by single-crystal X-ray crystallography. The catalytic activity of these complexes in A3-coupling reactions between aldehydes, terminal alkynes and amines was assessed in both protic (water) and aprotic (toluene) media. These A3-reactions prove to be more efficient, proceed with lower catalyst loadings and with faster reaction rates, when conducted in a focused microwave reactor as compared to the same reactions promoted by standard, thermal, modes of activation.

•Chiral Au(III) and Au(I) cyclometallated and NHC complexes is reported.•The use of chiral Au complexes in A3-reactions has been studied.•Chiral Au complexes do not effect the stereochemical outcome of A3-reactions.•The intervention of Au nanoparticles in A3-reactions is postulated.A series of cyclometallated and functionalised NHC gold(I) and gold(III) complexes, many of which feature chiral ligands, and their application to A3-coupling reactions is presented. Gold(III) complexes were found to be particularly effective catalysts for the coupling in a range of solvents, however no asymmetric induction was obtained when using chiral gold complexes and the rate of product formation was found to be similar even when using different ligand systems. In-situ NMR analysis of these reactions indicates that decomposition of the catalyst occurs during the course of the reaction while TEM studies revealed the presence of gold nanoparticles in crude reaction mixtures. Taken together these data suggest that the gold nanoparticles, rather than the intact gold complexes, could be the catalytically active species, and if so this may have significant implications for other gold-catalysed systems.Download high-res image (161KB)Download full-size image

The regioselective, orthogonal functionalisation of 4,10-dichlorochrysene enables the synthesis of a variety of 2,8,4,10-”A2B2”-tetrasubstituted chrysenes. Such compounds exhibit broadened UV-vis absorption spectra, decreased band gap and higher HOMO levels compared to the parent chrysene.

Treatment of (ortho-trimethysilyl)aryl phenylsulfonates with a soluble fluoride source initiates a Truce-Smiles rearrangement leading to the formation of functionalized bi-aryls. This new carbon–carbon bond-forming reaction proceeds without recourse to transition metal catalysis, under mild reaction conditions and with good functional group compatibility.

Gold-catalysed A3-reactions proceed efficiently when conducted in 2,2,2-trifluoroethanol as solvent. The rates of these reactions are accelerated considerably when conducted in a microwave reactor.Figure optionsDownload full-size imageDownload as PowerPoint slide

Treatment of (ortho-trimethysilyl)aryl phenylsulfonates with a soluble fluoride source initiates a Truce-Smiles rearrangement leading to the formation of functionalized bi-aryls. This new carbon–carbon bond-forming reaction proceeds without recourse to transition metal catalysis, under mild reaction conditions and with good functional group compatibility.

The regioselective, orthogonal functionalisation of 4,10-dichlorochrysene enables the synthesis of a variety of 2,8,4,10-”A2B2”-tetrasubstituted chrysenes. Such compounds exhibit broadened UV-vis absorption spectra, decreased band gap and higher HOMO levels compared to the parent chrysene.

An “S3N-ligand azo-dye” conjugate has been synthesised with a view to the development of a sensor for heavy metal ions. Complexation of this system with Ag(I), Hg(II) and Cu(II) salts has been investigated and an X-ray structure has been obtained for a Hg(II) complex. Complexation of the conjugated dye to these metals results in a bathochromic shift in the absorption maximum of the azo dye, an effect which is most pronounced for Cu(II).