Electronic Structure and Absorption Properties of Strongly Coupled Porphyrin-Perylene Arrays.
Electronic Structure and Absorption Properties of Strongly Coupled Porphyrin-Perylene Arrays.
复制标题
强耦合卟啉-苝阵列的电子结构和吸收特性。
DOI：
10.1021/acs.jpca.5b05600
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Jakubikova,Elena
中科院分区：
文献类型：
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作者：
High,JudahS;Virgil,KyleA;Jakubikova,Elena
Porphyrin–perylene arrays are ideal candidates for light-harvesting systems capable of panchromatic absorption. In this work, we employ density functional theory (DFT) and time-dependent DFT to investigate the unique UV–vis absorption properties exhibited by a series of ethynyl-linked porphyrin–perylene arrays that were previously synthesized and characterized spectroscopically [Chem. Commun. 2014, 50, 14512−5]. We find that the ethynyl linker is responsible for strong electronic coupling of porphyrin and perylene subunits in these systems. Additionally, these arrays exhibit a low barrier to rotation around the ethynyl linker (<1.4 kcal/mol per one perylene substituent), which results in a wide range of molecular conformations characterized by different porphyrin–perylene dihedral angles being accessible at room temperature. The best match between the calculated and experimental UV–vis spectra is obtained by averaging the calculated UV–vis spectra over the range of conformations defined by the porphyrin−perylene dihedral angles. Finally, our calculations suggest that the transitions in the lower energy region (550–750 nm) can be assigned to the excitations originating from the porphyrin subunit; the mid-energy region transitions (450–550 nm) are assigned to the perylene-centered excitations, while the high-energy transitions (350–450 nm) involve contributions from both porphyrin and perylene subunits.
