Effect of double bond on electronic and optical properties of coelenteramide: A time-dependent density functional theory investigation

Abstract

Coelenteramide has got attention for the great latent application in biologically inspired organic light-emitting devices. However, only blue light was emitted by coelenteramide. In order to obtain a wide distribution of light, the effect of double bond on electronic and optical properties of coelenteramide were studied by CAM-B3LYP/6-31+G(d) method. The results showed that the location of double bond was very important. For 1a, 2a, 2b and 3a, the double bond was inserted between amidopyrazine core and phenol group, which had strong π-conjugation effect, effectively improved the HOMO and LUMO energy levels, the capabilities of holes and electrons injection. The absorption and emission wavelengths generate a large bathochromic shift compared with native coelenteramide. In contrast, for 1b, 1c, 2c, double bond between amidopyrazine core and p-cresol, or between amidopyrazine core and benzyl group have little impact on HOMO and LUMO energy levels, energy gap, ionization potentials, electron affinities and absorption spectra.