Two-photon absorption properties of self-assemblies of butadiyne-linked bis(imidazolylporphyrin)
Two-photon absorption properties of self-assemblies of butadiyne-linked bis(imidazolylporphyrin)
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DOI：
10.1021/jp054444z
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发表时间：
2005-11-24
影响因子：
3.3
通讯作者：
Ohta, K
中科院分区：
文献类型：
--
作者：
Ogawa, K;Ohashi, A;Ohta, K
通过咪唑与锌的互补配位，由丁二炔连接的双（咪唑基卟啉）制备了超分子卟啉自组装体，并使用开孔 Z 扫描方法在飞秒时间尺度上研究了它们的双光子吸收（2PA）和高阶非线性吸收特性。共轭单锌双卟啉 7D 的自组装卟啉二聚体在 887 边缘处具有较大的 2PA 横截面（7.6 x 10(3) GM，其中 I GM = 10(-50) cm(4) s 分子(-1) 光子(-1)）。通过将该结果与没有丁二炔连接的内消旋-内消旋连接的卟啉阵列（3.7 x 10(2) GM at 964 urn）的结果进行比较，证明横截面显着增强的主要因素是卟啉-卟啉π共轭的扩展。自配位和单锌金属化也被发现是促成因素。此外，由平均分子量M-n = 1.5 x 10(5) Da的双锌络合物组成的新型自组装卟啉聚合物8P显示出非常大的双光子吸收截面（873 nm处的4.4 x 10(5) GM）。还对 7D 和 8P 进行了纳秒 Z 扫描实验，测量了大有效 2PA 截面，包括激发态吸收（7D 分别为 2.1 X 10(5) GM，8P 分别为 2.2 x 10(7) GM）。最后，通过飞秒Z扫描实验在1188 nm（7.1 X 10(-89) m(6) s(2)）和1282 nm（1.8 x 10(-89) m(6) s(2)）处观察到三光子吸收，这是卟啉化学中的首次观察。
Supramolecular porphyrin self-assemblies have been prepared from butadiyne-linked bis(imidazolylporphyrin) by complementary coordination of imidazole to zinc, and their two-photon absorption (2PA) and higher-order nonlinear absorption properties were investigated over femtosecond time scales using an open-aperture Z-scan method. The self-assembled porphyrin dimer of the conjugated monozinc bisporphyrin 7D was shown to have a large 2PA cross section (7.6 x 10(3) GM, where I GM = 10(-50) cm(4) s molecule(-1) photon(-1)) at 887 rim. By comparison of this result with that for a meso-meso-linked porphyrin array without the butadiyne connection (3.7 x 10(2) GM at 964 urn), it was demonstrated that the predominant factor in this significant enhancement of the cross section was the expansion of porphyrin-porphyrin pi-conjugation. Self-coordination and monozinc metalation were also found to be contributing factors. Furthermore, a novel self-assembled porphyrin polymer 8P consisting of a biszinc complex with a mean molecular weight Of M-n = 1.5 x 10(5) Da was shown to exhibit an extraordinarily large two-photon absorption cross section (4.4 x 10(5) GM at 873 nm). Nanosecond Z-scan experiments for 7D and 8P were also undertaken and resulted in the measurement of large effective 2PA cross sections, including the excited-state absorption (2.1 X 10(5) GM for 7D and 2.2 x 10(7) GM for 8P, respectively). Finally, three-photon absorption was observed by femtosecond Z-scan experiments at 1188 nm (7.1 X 10(-89) m(6) s(2)) and 1282 nm (1.8 x 10(-89) m(6) s(2)), an observation which is the first of its kind in porphyrin chemistry.