Holzer Noah, Sharma Jatan K, Peterson Steven, Bayard Brandon J, Nesterov Vladimir N, Karr Paul A, D'Souza Francis, Poddutoori Prashanth K
Department of Chemistry & Biochemistry, University of Minnesota Duluth, 1038 University Drive, Duluth, Minnesota 55812, USA.
Department of Chemistry, University of North Texas, 1155 Union Circle, # 305070, Denton, Texas 76203-5017, USA.
Dalton Trans. 2022 Apr 12;51(15):5890-5903. doi: 10.1039/d2dt00675h.
The +5 oxidation state of antimony induced push-pull style intramolecular charge transfer in an elegantly designed axial dimethoxyantimony(V) porphyrin series: SbP(OMe)·PF, SbMP(OMe)·PF, SbDMP(OMe)·PF, SbTMP(OMe)·PF with phenyl (P), 4-methoxyphenyl (MP), 3,5-dimethoxyphenyl (DMP), and 3,4,5-trimethoxyphenyl (TMP) units, respectively, in its positions. The Sb(+5) made the porphyrin ring electron-poor, whereas the methoxy groups on the phenyl unit produced electron-rich sites within the molecule. The presence of electron-poor and electron-rich parts in the same molecule resulted in a push-pull type intramolecular charge transfer (ICT). However, the ICT is strongly dependent on the position of the methoxy groups on the phenyl ring. The charge transfer character is more pronounced in -methoxy substituted antimony(V) derivatives (SbDMP(OMe)·PF, SbTMP(OMe)·PF) than the -methoxy or no-methoxy substituted antimony(V) derivatives (SbP(OMe)·PF, SbMP(OMe)·PF). Steady-state and transient spectroscopic techniques, as well as solvatochromism techniques, were employed to establish the tunable ICT. Additionally, time-dependant density functional theory (TD-DFT) calculations were used to complement the experimental results. The systematic study of antimony(V) porphyrins, especially the tunable push-pull nature could play an important role in instigating high yield charge-separated states in multi-modular donor-acceptor systems for solar energy conversion and molecular electronic and photonic applications.
在精心设计的轴向二甲氧基锑（V）卟啉系列：分别在其 位带有苯基（P）、4 - 甲氧基苯基（MP）、3,5 - 二甲氧基苯基（DMP）和 3,4,5 - 三甲氧基苯基（TMP）单元的 SbP(OMe)·PF、SbMP(OMe)·PF、SbDMP(OMe)·PF、SbTMP(OMe)·PF 中，锑的 +5 氧化态引发了推 - 拉式分子内电荷转移。Sb(+5) 使卟啉环缺电子，而苯基单元上的甲氧基在分子内产生富电子位点。同一分子中存在缺电子和富电子部分导致了推 - 拉型分子内电荷转移（ICT）。然而，ICT 强烈依赖于苯环上甲氧基的位置。与 α - 甲氧基或无甲氧基取代的锑（V）衍生物（SbP(OMe)·PF、SbMP(OMe)·PF）相比，β - 甲氧基取代的锑（V）衍生物（SbDMP(OMe)·PF、SbTMP(OMe)·PF）中的电荷转移特性更为显著。采用稳态和瞬态光谱技术以及溶剂化显色技术来确定可调谐的 ICT。此外，使用含时密度泛函理论（TD - DFT）计算来补充实验结果。对锑（V）卟啉的系统研究，特别是其可调谐的推 - 拉性质，在激发用于太阳能转换以及分子电子和光子应用的多模块供体 - 受体系统中的高产率电荷分离态方面可能发挥重要作用。
