An Efficient Procedure for the Synthesis of Polysubstituted Pyrroles in an Ionic Liquid

The ionic liquid 1-butyl-3-methyl-imidazolium hydrogen sulfate, [bmim]HSO 4 , was used as a catalyst and reaction medium for the pyrrole synthesis, and a wide range of aliphatic, aromatic, heteroaromatic and carboxylic 1,4-diketones easily underwent condensations with aniline and ethylenediamine to form polysubstituted pyrroles. Sequential decarboxylation/Paal-Knorr pyrrole condensation was observed, which provides a new and facile approach to monoester pyrroles from 1,4-diketo-2,3-dicarboxylic acid esters

Application of unsymmetrical bis-chalcone compounds in dye sensitized solar cell

A total of nine unsymmetrical bis-chalcone compounds have been synthesized and spectroscopically characterized. The unsymmetrical bis-chaclone compounds were substituted with either methoxy (OMe) or chloro (Cl) as the electron donor, and either difluoroboryl (BF2) or a ruthenium(II)-dimethylsulfoxide [Ru(II)-DMSO] complex as the electron acceptor. All these compounds were used as the dye sensitizer in dye sensitized solar cell (DSSC) by using fluorine doped tin oxide (FTO) glass coated with titanium(IV) oxide (TiO2) as the working electrode, and the indium tin oxide (ITO) glass coated with platinum as the counter electrode. The conversion efficiency of fabricated DSSCs were tested and the unsymmetrical bis-chalcone compound with OMe and BF2 substituents in the same molecule recorded the highest efficiency at 0.091%. In contrast, the unsymmetrical bis-chalcone with OMe and Ru(II)-DMSO complex has the lowest efficiency at 0.001%

A Way to Improve Luminescent Efficiency of Bis-Chalcone Derivatives

Chalcone related compounds have been reported as a poor luminescence molecule due to the quenching processes from the intramolecular torsional motions and cis-trans isomerization in th

A Way to Improve Luminescent Efficiency of Bis-Chalcone Derivatives

Chalcone related compounds have been reported as a poor luminescence molecule due to the quenching processes from the intramolecular torsional motions and cis-trans isomerization in the α,β-unsaturated ketone moiety. Despite this limitation, we found a way to improve the luminescent efficiency of our bis-chalcone derivative. In this project, two series of bis-chalcone compounds have been synthesized through Claisen-Schmidt condensation by reacting terephthaldehyde or 2,5-dimethoxyterephthaldehyde with the respective R-acetophenone [where R = H (1a and 2a) and ortho-hydroxy (1b and 2b)] in 1 : 2 mole ratio. The presence of a methoxy (OMe) substituent on the central phenyl ring of bis-chalcone has weakened the C=C bond at the α,β-unsaturated ketone moiety of 2a and 2b. Interestingly, the OMe group has improved the emission efficiency of the bis-chalcone; that is, the quantum yield of 1a in DCM solution was not able to be determined due to poor luminescence, but the quantum yield of 2a in DCM solution was improved to 0.57. In addition, compound 2a also shows solvatochromism effect where the λmax emission shifted from 499 nm in nonpolar solvents (benzene) to 523 nm in polar solvents (acetonitrile). This work provides another way to improve the emission efficiency of chalcone related compounds apart from using the complexation method which has been reported before