Antiradical Properties of trans-2-(4-substituted-styryl)-thiophene.

2-substituted thiophene compounds with electron donating and electron withdrawing p-phenyl substitution were synthesized and studied their radical scavenging properties using DPPH assay and DFT method. It is shown that p-hydroxy and p-amino phenyl substituted compound exhibit radical scavenging activity. From DFT and radical scavenging studies, a correlation between IC with the bond dissociation enthalpy, proton affinity, ground state dipole moment and optical band gap of compound is found.

Tuning of optical properties of p-phenyl ethenyl-E-furans: A Solvatochromism and Density functional theory.

p-Phenyl ethenyl-E-furans (1-6) with varied electron donor and acceptor substituent (NO, CN, Cl, H, OCH, NH) were synthesized and studied the substituent induced optical properties (dipole moment, transition dipole moment, oscillator strength, optical band gap, hyperpolarizability) using Solvatochromism and Density functional theory. It is shown that furan acts as a weak electron donor in presence of an electron withdrawing p‑phenyl substituent (NO, CN, Cl), whereas furan acts as a weak electron acceptor in presence of an electron donating p‑phenyl substituent (OCH, NH). In comparison to ethenylfuran 4, the HOMO-LUMO energy band gap is decreased upon increasing the electron donating or electron withdrawing nature of the phenyl ring.

Substituent Dependent Optical Properties of p-phenyl Substituted ethenyl-E-thiophenes.

Various electron donor and acceptor substituted (NO, CN, Cl, H, OCH, NH) p-phenyl ethenyl-E- thiophenes (1-6) were synthesized and substituent dependent optical properties (dipole moment, transition dipole moment, oscillator strength, optical band gap, hyperpolarizability) were studied using Solvatochromism and Density functional theory. It is shown that thiophene acts as a weak electron donor in presence of an electron withdrawing p-phenyl substituent (NO, CN, Cl), whereas thiophene acts as a weak electron acceptor in presence of an electron donating p-phenyl substituent (OCH, NH). In comparison to ethenyl thiophene 4, the HOMO-LUMO energy band gap is decreased upon increasing the electron donating or electron withdrawing capacity of p-phenyl substituent.