Photoinduced Charge Transfer in Short-Distance Ferrocenylsubphthalocyanine Dyads
Photoinduced Charge Transfer in Short-Distance Ferrocenylsubphthalocyanine Dyads
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DOI：
10.1021/ic3000608
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发表时间：
2012-06-18
影响因子：
4.6
通讯作者：
Nemykin, Victor N.
中科院分区：
文献类型：
--
作者：
Solntsev, Pavlo V.;Spurgin, Katelynn L.;Nemykin, Victor N.
制备了两种新的二茂铁基亚酞菁二偶体，其二茂铁甲氧基(2)和二茂铁羧酸酯(3)取代基通过轴向位置直接连接到亚酞菁配体上，并利用核磁共振、紫外-可见、磁性圆二色性（MCD）光谱和x射线晶体学对其进行了表征。采用循环伏安法（CV）研究了含二茂铁二偶体2和3的氧化还原性质，并与母体亚酞菁1进行了比较。CV数据显示，第一次可逆氧化以二茂铁为中心，而第二次氧化和第一次还原则定位在酞菁亚配体上。采用密度泛函理论极化连续统模型（DFT-PCM）和时间依赖（TD）DFT-PCM方法研究了所有目标化合物的紫外可见光谱和MCD光谱中观察到的光学带的电子结构和性质。在这两对中，HOMO-2的最高已占据分子轨道（HOMO）都是以二茂铁为中心的分子轨道，而HOMO-3以及最低未占据分子轨道（LUMO）和LUMO+1都定位在亚酞蓝配体上。配合物1-3的TDDFT-PCM数据与实验观察结果一致，表明在1-3的紫外可见光谱中pi-pi*跃迁占主导地位。利用时间相关单光子计数研究了二偶体2和三偶体的激发态动力学，结果表明二偶体3的荧光猝灭效率高于二偶体2。这些荧光寿命测量是在DFT-PCM计算的基础上解释的。
Two new ferrocenylsubphthalocyanine dyads with ferrocenylmethoxide (2) and ferrocenecarboxylate (3) substituents directly attached to the subphthalocyanine ligand via the axial position have been prepared and characterized using NMR, UV-vis, and magnetic circular dichroism (MCD) spectroscopies as well as X-ray crystallography. The redox properties of the ferrocenyl-containing dyads 2 and 3 were investigated using the cyclic voltammetry (CV) approach and compared to those of the parent subphthalocyanine 1. CV data reveal that the first reversible oxidation is ferrocene-centered, while the second oxidation and the first reduction are localized on the subphthalocyanine ligand. The electronic structures and nature of the optical bands observed in the UV-vis and MCD spectra of all target compounds were investigated by a density functional theory polarized continuum model (DFT-PCM) and time-dependent (TD)DFT-PCM approaches. It has been found that in both dyads the highest occupied molecular orbital (HOMO) to HOMO-2 are ferrocene-centered molecular orbitals, while HOMO-3 as well as lowest unoccupied molecular orbital (LUMO) and LUMO+1 are localized on the subphthalocyanine ligand. TDDFT-PCM data on complexes 1-3 are consistent with the experimental observations, which indicate the dominance of pi-pi* transitions in the UV-vis spectra of 1-3. The excited-state dynamics of the dyads 2 and 3 were investigated using time-correlated single photon counting, which indicates that fluorescence quenching is more efficient in dyad 3 compared to dyad 2. These fluorescence lifetime measurements were interpreted on the basis of DFT-PCM calculations.