Association Complexes between Cationic Metallophthalocyanines and Anionic Metalloporphyrins II: Ultrafast Studies of Excited State Dynamics†
Association Complexes between Cationic Metallophthalocyanines and Anionic Metalloporphyrins II: Ultrafast Studies of Excited State Dynamics†
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阳离子金属酞菁和阴离子金属卟啉 II 之间的缔合配合物：激发态动力学的超快研究†
DOI：
10.1021/jp013502n
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发表时间：
2002
影响因子：
2.9
通讯作者：
M. Rodgers
中科院分区：
文献类型：
--
作者：
A. Gusev;E. Danilov;M. Rodgers
对带相反电荷的金属取代的 18-冠-6 四取代酞菁 (McrPc) 和金属取代的内消旋-(4-磺苯基)-卟啉 (MTPPS) 或内消旋-(4-羧基苯基)-卟啉 (MTPPC) 之间的自组装进行了飞秒瞬态吸收研究。激发可以在 400 nm（钛蓝宝石二次谐波）处进行，其填充卟啉局域 S 2 态或直接进入 CT 波段 (690)，并通过使用光学参量放大器改变泵浦脉冲波长来实现。每个复合物都显示出与激发波长无关的瞬态特征和动力学。 400 nm 激发后，所有配合物均显示出快速转变为低位电荷转移态。对 CuP/CuPc 复合物的研究表明，亚纳秒时间尺度上的瞬态没有显着衰减。然而，对含有不同过渡金属的配合物的研究表明，配合物激发态的失活是通过金属中心（d，d）态发生的。对于混合金属/游离碱配合物，无论是卟啉还是酞菁，激发态弛豫都是通过金属四吡咯组分发生的。在这些化合物中，电荷转移态在 2 ps 内失活形成金属中心 (d,d) 态，其寿命随金属中心的不同而有所不同。后一种状态重新填充了基态，寿命约为。 13 ps (NiP/NiPc)、200 ps (NiP/CuPc)、8 ps (CuP/NiPc) 和 7 ps (FbP/CoPc)。这些金属对基态速率与单体金属四吡咯的测量值相似。
Femtosecond transient absorption studies were conducted for self-assemblies between oppositely charged metal-substituted 18-crown-6 tetrasubstituted phthalocyanines (McrPc) and metal-substituted meso-(4-sulfophenyl)-porphine (MTPPS) or meso-(4-carboxylphenyl)-porphine (MTPPC). Excitation could be carried out at 400 nm (Ti-Sapphire second harmonic), which populates the porphyrin-localized S 2 state or directly into the CT band (690), and was achieved by changing the pump pulse wavelength with an optical parametric amplifier. Each complex showed the transient features and kinetics that were independent of the excitation wavelength. After 400 nm excitation, all complexes displayed rapid conversion to the low-lying charge-transfer state. Studies of the CuP/CuPc complex showed no significant decay of the transients on the subnanosecond time scale. However, investigations of the complexes containing different transition metals showed that deactivation of the complex excited state occurs through metal-centered (d,d) states. For the mixed metal/free-base complexes, the excited-state relaxation occurred through the metallotetrapyrrole component regardless of whether it was porphyrin or phthalocyanine. In these compounds, the charge transfer state deactivated to form the metal-centered (d,d) state within 2 ps, with lifetimes that varied somewhat with the metal center. This latter state repopulated the ground state with a lifetime of ca. 13 ps (NiP/NiPc), 200 ps (NiP/CuPc), 8 ps (CuP/NiPc), and 7 ps (FbP/CoPc). These metal-to-ground state rates were similar to those measured for the monomeric metallotetrapyrroles.