Photophysical and Quantum Chemical Insights into Coumarin Derivatives for Optoelectronics Applications

In this study, we presented the photophysical characteristics of coumarin derivatives, specifically 1-((4-(((2-chloroquinolin-3-yl)methoxy)methyl)-1H-1,2,3-triazol-1-yl)methyl)-3H-benzo[f]chromen-3-one (CCQC-BN) and 4-((4-(((2-chloroquinolin-3-yl) methoxy) methyl)-1H-1,2,3-triazol-1-yl)methyl)-6-methyl-2H-chromen-2-one (CCQC-6-ome). We measured the absorption and emission spectra of CCQC-BN and CCQC-6-ome molecule dissolved in different solvents being at room temperature results suggest that changes in shape, position and intensity. A ground state dipole moment was calculated using Density Functional Theory (DFT) theoretically and experimentally using solvatochromic shift method. Our findings indicate that the excited state dipole moments of both compounds exceed their dipole moments than in the state of ground, suggesting significant red distribution of π electron density upon excitation. When the state is excited, the dipole moment is more polarized as compared to the ground state. Furthermore, we calculated molecular orbitals with the highest occupancy (HOMO) and lowest unoccupied (LUMO) and also energy gap using DFT and compared these findings with those obtained experimentally through cyclic voltammetry. Additionally, we evaluated global reactivity's parameters by using LUMO and HOMO. Energy gap of both CCQC-BN and CCQC-6-ome were determined to be 3.59 eV and 3.72 eV respectively. The MESP or molecular electrostatic potential is useful in context of photochemical applications. As a result quantum chemical calculations and also spectroscopic characteristics on the molecule can provide further information about applications in optoelectronic devices.