Chemek Mourad, Rhouma F I H, Chemek Marouane, Safi Zaki, Kadi Ammar, Naili Salem, Wazzan Nuha, Kamel Alimi
Laboratoire de Recherche: Synthèse asymétrique et ingénierie moléculaire de matériaux organiques pour l'électronique organique (LR18ES19), Faculté des Sciences de Monastir, 5000, Monastir, Tunisia.
Institut Supérieur des Sciences Appliquées et de Technologie de Sousse (ISSAT-Sousse), Université de Sousse-Tunisie, Sousse, Tunisia.
J Mol Model. 2024 Jul 17;30(8):271. doi: 10.1007/s00894-024-06062-4.
Density functional theory (DFT) calculations on the ground and the first excited state are performed on the modified and unmodified 4-(methoxyphenyl acetonitrile) monomer (referred to as MPA). The modified monomer named MFA is obtained by Knoevenagel condensation of MPA with dimethylformamide dimethyl acetal (DMF-DMA). DFT computations show that the chemical grafting of the dimethylamino group onto the MPA unit induces a great change in the geometric, electronic, and optical properties. Going from MPA to MFA monomer, a great change in the frontier orbitals of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the ground and the first excited state is observed. Consequently, a reduction in the energy gap HOMO-LUMO and an enhancement in the absorption and emission properties are observed under the chemical modification. The observed modifications in the electronics and optical properties are the result of the charge transfer appearing between the cyano (C≡N) acceptor group and the dimethylamino (DMF-DMA)-grafted group donor ring.
Quantum chemical calculations were performed in the ground and the first excited state using the density functional theory (DFT), and it extends the time-dependent density functional theory (TD-DFT), implemented in the Gaussian 09 software package. The ground state is obtained by optimization of the studied molecular geometries by employing the DFT/M062X/6-31G(d,p) level of theory. The first excited state is obtained by re-optimization of the ground state geometries using the TD-DFT/M062X/6-31G(d,p) level of theory. The contour plots of the frontier orbitals and the molecular electrostatic potential (MEP) maps are obtained from the ground and the first excited state, optimized geometries, and drawn using Gaussview software.
对改性和未改性的4-（甲氧基苯基乙腈）单体（称为MPA）进行了基态和第一激发态的密度泛函理论（DFT）计算。通过MPA与二甲基甲酰胺二甲基缩醛（DMF-DMA）的Knoevenagel缩合反应得到名为MFA的改性单体。DFT计算表明，二甲基氨基化学接枝到MPA单元上会引起几何、电子和光学性质的巨大变化。从MPA到MFA单体，在基态和第一激发态下，最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）的前沿轨道发生了巨大变化。因此，在化学改性下，观察到HOMO-LUMO能隙减小，吸收和发射性质增强。观察到的电子和光学性质的变化是氰基（C≡N）受体基团与二甲基氨基（DMF-DMA）接枝基团供体环之间出现电荷转移的结果。
使用密度泛函理论（DFT）在基态和第一激发态下进行量子化学计算，并扩展到在高斯09软件包中实现的含时密度泛函理论（TD-DFT）。通过采用DFT/M062X/6-31G(d,p)理论水平优化所研究分子的几何结构来获得基态。通过使用TD-DFT/M062X/6-31G(d,p)理论水平对基态几何结构进行重新优化来获得第一激发态。前沿轨道的等高线图和分子静电势（MEP）图是从基态和第一激发态、优化的几何结构中获得的，并使用Gaussview软件绘制。
