Lalasangi Dayanand, Hanagodimath S M, Khanadal Tairabi, Padmashali Basavaraj, Jadhav Mangesh S
Department of Physics, Gulbarga University, Kalaburagi, Karnataka, India.
Department of Chemistry, Rani Channamma University, Belagavi, Karnataka, India.
J Fluoresc. 2025 May;35(5):3109-3117. doi: 10.1007/s10895-024-03732-7. Epub 2024 May 9.
The effects of solvent on the absorption and emission spectra and dipole moments of the 5ABBM have been extensively studied in a series of solvents. The dipole moments in the excited state are observed to be greater than those in the ground-state in all the solvents studied for the chosen molecule. The dipole moment increase in the excited singlet state ranges from 2.42 to 24.14 D. The experimentally calculated ground state and excited state dipole moments were determined using the solvatochromatic shifts in the absorption and emission spectra as a function of dielectric constant (ɛ) and refractive index (n). These data are used to estimate the excited-state dipole moment using the experimentally determined ground-state dipole moment. A series of fifteen different organic solvents (toluene, methanol, n-butyl alcohol, ethyl acetate, DMS, acetonitrile, benzene, isopropyl alcohol, water, DMF, DCM, DIO, THF, ethanol, and octanol) were investigated at constant dye concentrations. Small changes in the fluorescence spectrum were observed for the different solvents; the highest fluorescence intensity was observed for DMS, and the lowest was observed for water. The Stokes shift in different solvents was studied for the 5ABBM molecule. This results in molecule being more polar in the excited state than in the ground state for the solvents used. The ground state dipole moments, HOMO-LUMO, and molecular electrostatic potential maps were also computed via ab initio calculations and evaluated via Gaussian 09 W software.
在一系列溶剂中，已对溶剂对5ABBM的吸收光谱、发射光谱和偶极矩的影响展开了广泛研究。在所研究的所有溶剂中，对于选定的分子，观察到其激发态的偶极矩大于基态的偶极矩。激发单重态的偶极矩增加范围为2.42至24.14德拜。利用吸收光谱和发射光谱中作为介电常数（ɛ）和折射率（n）函数的溶剂化显色位移，确定了实验计算的基态和激发态偶极矩。这些数据用于根据实验测定的基态偶极矩估算激发态偶极矩。在染料浓度恒定的情况下，研究了十五种不同的有机溶剂（甲苯、甲醇、正丁醇、乙酸乙酯、二甲基亚砜、乙腈、苯、异丙醇、水、二甲基甲酰胺、二氯甲烷、二氧六环、四氢呋喃、乙醇和辛醇）。观察到不同溶剂的荧光光谱有微小变化；二甲基亚砜的荧光强度最高，水的荧光强度最低。研究了5ABBM分子在不同溶剂中的斯托克斯位移。这导致在所使用的溶剂中，分子在激发态比在基态更具极性。还通过从头计算法计算了基态偶极矩、最高已占分子轨道-最低未占分子轨道以及分子静电势图，并使用高斯09 W软件进行了评估。
