Effects of Magnetic Fields on the Relaxation Processes of Photoexcited Oordination Compounds.

通过测量-(CH_2)_3-共价连接的卟啉二聚体的T-T瞬态吸收，检测了铜卟啉从激发态（三重三重态和三重三重态）到自由碱基最低激发态的能量转移。在受激单重态中具有自由碱的受激二聚体部分被铜对应物淬灭。另一方面，具有铜卟啉的激发二聚体在trip-multiplet态不仅被铜卟啉内部的基底电子弛豫所耗散，而且分子内的能量转移到自由碱基伴侣。用抗磁性金属terraphenylporphin在室温下观察了S_1和S_2延迟荧光。在外加磁场的作用下，延迟荧光的强度和衰减常数减小。在S_1和S_2延迟荧光上观察到相同的磁效应。这些结果表明，TT湮灭产生了高能量态（S_n, n< >或等于>），并引起了S_1和s_2态的重新分布。

Energy transfer from the excited triplet (trip-doublet and trip-quartet) state of copper porphyrin to the lowest excited triplet state of its free-base partner was detected by measurements of T-T transient absorption of a -(CH_2)_3- covalently linked porphyrin dimer. The excited dimer with free-base in the excited singlet is partly quenched by the copper counterpart. Oh the other p hand, the excited dimer with copper orphyrin in the trip-multiplet state is dissipated not only by the bast electronic relaxation within the copper porphyrin but also the intramolecular energy transfer to the free-base partner.The S_1 and S_2 delayed fluorescences were observed at om temperature with some diamagnetic metalloterraphenylporphins. The intensities and the decay-reat constants of the delayed fluorescences decreased in the presence of an external magnetic field. The same magnetic effects were observed on the S_1 and S_2 delayed fluorescences. These uesults indicate that highly energetic states (S_n, n<greater than or equal> is created by TT annihilation and give rise to the repopulation of S_1 and s_2 states.