A Way to Improve Luminescent Efficiency of Bis-Chalcone Derivatives

Abstract

Chalcone related compounds have been reported as a poor luminescence molecule due to the quenching processes from the intramolecular torsional motions andcis-transisomerization in theα,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 (1aand2a) andortho-hydroxy (1band2b)] 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 theα,β-unsaturated ketone moiety of2aand2b. Interestingly, the OMe group has improved the emission efficiency of the bis-chalcone; that is, the quantum yield of1ain DCM solution was not able to be determined due to poor luminescence, but the quantum yield of2ain DCM solution was improved to 0.57. In addition, compound2aalso shows solvatochromism effect where theλmaxemission 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.

Theoretical Assessments, Optical and Electrochemical Properties of the Alkoxylated Bischalcone as Emissive Material in Single Layer OLED

“…The medium intensity at 2933.73 cm − 1 and 2864.29 cm − 1 were assigned as stretching vibrations of v(C-H alkanes). The keto-enol group attributed by v(C = O), v(C = C alkene) were observed at 1656.85 cm − 1 and 1494.83 cm − 1 with sharp IR band observed respectively in the range spectrum as found by previous researchers [19]. The effect of delocalization of π-electrons between α and β carbon decreases the C = O order thus increasing the bond order of carbonyl carbon and α-carbon [20].…”

“…The CSAB revealed an oxidation peak at (E ox = 2.40 V). For this alkoxylated bischalcone system, the oxidation peak occurs at anodic peak due to the absorption of chalcone and/or oxidation of the product occurred on the electrode surface [19]. For electrochemical reduction, cyclic voltammogram of CSAB reveals in the range of -…”

The Synthesis and Spectral Properties of Benzofuran Derivative Bis-Chalcone

“…The chemical structure of purified product was characterized by spectroscopic data (FT-IR, , respectively) because of the conjugation effect of C=C-C=O moiety. Also the presence of electron donor groups at ortho-positions of benzofuran rings shifted the IR frequencies of C=O and C=C bands to a lower values [16]. Moreover, the spectrum shows several weak bands in the region of 2835-3137 cm -1 corresponding to aliphatic and aromatic C-H stretching vibration frequencies.…”

“…Signals due to aromatic ring, α, and β-carbon atoms were appeared in the range of 128.09-144.30 ppm. Relatively high chemical shift values for phenolic protons and carbonyl carbons (12.68 and 194.52 ppm, respectively) might be due to the formation of intramolecular hydrogen bonding between the carbonyl oxygens with phenolic hydroxyl protons (Scheme 3) [16].…”

A Quantum Chemical Screening of Two Imidazole-Chalcone Hybrid Ligands and Their Pd, Pt and Zn Complexes for Charge Transport and Nonlinear Optical (NLO) Properties: A DFT Study

“…Although the biological uses of chalcones have been investigated widely in recent times, the use of chalcones as potential optoelectronic materials is still a topic of great research interest [4]. Often, in a bid to get around the reported poor luminescence properties of chalcone-based organic molecules, partly due to the quenching pro-cesses from the intramolecular torsional motions and cis-trans isomerization in the α, β-unsaturated ketone moiety, the complexation method is often a way out towards improving their optical properties [3] [13]. Fortunately, organometallic and coordination complexes have found a place of choice for the production of NLO materials due to their tunable metal centers and their inherent chargetranfer transitions [14].…”