Şener Sevil, Acar-Selçuki Nursel
Department of Chemical Technology Program, Aliaga Vocational School, Ege University, Izmir, Türkiye.
Department of Chemistry, Faculty of Science, Ege University, TR-35100, Bornova, Izmir, Türkiye.
J Mol Model. 2024 Dec 16;31(1):22. doi: 10.1007/s00894-024-06251-1.
Isatin-Schiff bases have wide applications in chemistry. The π conjugated electronic system and heterocylic structure of these materials make them valuable for use as photosensitized materials. The delocalization of π-electrons throughout the structure causes the UV-vis absorption spectra to shift to longer wavelengths. In this study, the isatin manganese carbonyl complex shifted the UV-vis absorption wavelength to a longer wavelength (vis. 400-700 nm) compared with our previous studies. The isatin derivatives (ISE (3[4-ethyl(phenyl)imino][indoline-2-one]), ISB (3[4-butly(phenyl)imino][indoline-2-one])) and their Mn carbonyl complexes MnISE ((ISE)Mn(CO)), and, MnISB ((ISB)Mn(CO)) were investigated via density functional theory (DFT) in different solvent media. The most stable complexes were found in medium polarity THF. The calculated HOMO-LUMO energy gap shows that the charge transfer occurs within the molecule. The HOMO-LUMO energy gap was increased with increasing solvent polarity for all investigated compounds. The smaller energy gap indicates that charge transfer occurs within the Mn(II) complex, in contrast to ISE and ISB, which exhibit larger energy gaps. As a result, the maximum absorption of Mn complexes shifts to the visible region. MnISB has the smallest HOMO-LUMO energy gap in THF. Additionally, the global reactivity parameters indicated that the MnISE complex has the highest electrophilicity index. DFT calculations have also been performed to investigate polarizability and first-order hyperpolarizability of these compounds. In water, the ISE had higher NLO values than the other structures did. These results indicate that all the studied molecules in different solvents could be good candidates for use in photosensitized and nonlinear optical materials.
Geometries were determined at the DFT level via the LANL2DZ basis set for Mn and cc-PVTZ for other atoms in the molecules with the B3LYP functional. The UV-vis absorption spectra and HOMO-LUMO energies of ISE, ISB, and their Mn complexes were calculated by Time-dependent DFT (TDDFT) with CAM-B3LYP using the same basis sets. The UV-vis absorption spectra of ISE were also measured in acetonitrile and compared with the calculated spectra, which were consistent with the experimental results. All calculations were repeated in different solvents with the polarizable continuum model (PCM).
异吲哚酮-席夫碱在化学领域有广泛应用。这些材料的π共轭电子体系和杂环结构使其作为光敏材料具有重要价值。π电子在整个结构中的离域导致紫外-可见吸收光谱向更长波长移动。在本研究中，与我们之前的研究相比，异吲哚酮羰基锰配合物使紫外-可见吸收波长移至更长波长（即400 - 700 nm）。通过密度泛函理论（DFT）在不同溶剂介质中研究了异吲哚酮衍生物（ISE（3[4-乙基（苯基）亚氨基][吲哚啉-2-酮]）、ISB（3[4-丁基（苯基）亚氨基][吲哚啉-2-酮]）及其锰羰基配合物MnISE（（ISE）Mn(CO)）和MnISB（（ISB）Mn(CO)）。发现最稳定的配合物存在于中等极性的四氢呋喃中。计算得到的最高占据分子轨道（HOMO）-最低未占据分子轨道（LUMO）能隙表明电荷在分子内发生转移。对于所有研究的化合物，HOMO-LUMO能隙随溶剂极性增加而增大。较小的能隙表明电荷在Mn(II)配合物内发生转移，这与ISE和ISB形成对比，它们表现出较大的能隙。结果，锰配合物的最大吸收移至可见光区域。MnISB在四氢呋喃中的HOMO-LUMO能隙最小。此外，全局反应性参数表明MnISE配合物具有最高的亲电指数。还进行了DFT计算以研究这些化合物的极化率和一阶超极化率。在水中，ISE的非线性光学（NLO）值高于其他结构。这些结果表明，所有研究的分子在不同溶剂中都可能是用于光敏和非线性光学材料的良好候选物。
使用B3LYP泛函，通过针对分子中Mn的LANL2DZ基组和针对其他原子的cc-PVTZ基组在DFT水平确定几何结构。ISE、ISB及其锰配合物的紫外-可见吸收光谱和HOMO-LUMO能量通过含时密度泛函理论（TDDFT）并使用CAM-B3LYP以相同基组进行计算。还在乙腈中测量了ISE的紫外-可见吸收光谱，并与计算光谱进行比较，计算光谱与实验结果一致。所有计算都使用极化连续介质模型（PCM）在不同溶剂中重复进行。
