二苯甲酮 - N - 甲基邻苯二甲酰亚胺二元体系中的可逆分子内三重态 - 三重态能量转移

Reversible intramolecular triplet-triplet energy transfer in benzophenone-N-methylphthalimide dyad.

作者信息

Sakamoto Masanori, Kim Sung Sik, Fujitsuka Mamoru, Majima Tetsuro

机构信息

The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.

出版信息

J Phys Chem A. 2008 Feb 21;112(7):1403-7. doi: 10.1021/jp075885g. Epub 2008 Jan 30.

DOI:10.1021/jp075885g

PMID:18229897

Abstract

In the present paper, we synthesized a series of benzophenone (BP)-N-methylphthalimide (MePI) dyads (Cn, n = 3, 6, and 9, where n denotes the number of methylene in the linker) and investigated the photochemical properties and intramolecular triplet-triplet energy transfer from BP(T1) to MePI. Formation of two different intramolecular complexes was found, that is, a ground-state complex and a singlet exciplex. The formation of the triplet-equilibrium between MeBP and MePI was observed. The triplet-equilibrium constant (1.0 and 1.1 for C6 and C9, respectively) and forward ((3.8 +/- 1.3) x 107 and (3.9 +/- 1.2) x 107 s-1 for C6 and C9, respectively) and back ((3.8 +/- 1.3) x 107 and (3.6 +/- 1.2) x 107 s-1 for C6 and C9, respectively) energy transfer rates were estimated from the result of transient absorption measurements. From the van't Hoff plots, enthalpy and entropy change for the equilibrium formation were estimated.

摘要

在本论文中，我们合成了一系列二苯甲酮（BP）-N-甲基邻苯二甲酰亚胺（MePI）二元化合物（Cn，n = 3、6和9，其中n表示连接基中甲基ene的数量），并研究了其光化学性质以及从BP（T1）到MePI的分子内三重态-三重态能量转移。发现形成了两种不同的分子内络合物，即基态络合物和单线态激基复合物。观察到MeBP和MePI之间三重态平衡的形成。从瞬态吸收测量结果估计了三重态平衡常数（C6和C9分别为1.0和1.1）以及正向（C6和C9分别为(3.8 ± 1.3) x 107和(3.9 ± 1.2) x 107 s-¹）和反向（C6和C9分别为(3.8 ± 1.3) x 107和(3.6 ± 1.2) x 107 s-¹）能量转移速率。从范特霍夫图估计了平衡形成的焓变和熵变。