Properties of the short-lived triplet states of pyridazine and 3,6-dichloropyridazine studied by a time-resolved EPR method
Properties of the short-lived triplet states of pyridazine and 3,6-dichloropyridazine studied by a time-resolved EPR method
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通过时间分辨 EPR 方法研究哒嗪和 3,6-二氯哒嗪短寿命三重态的性质
DOI：
10.1063/1.450207
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发表时间：
1986
影响因子：
4.4
通讯作者：
N. Hirota
中科院分区：
文献类型：
--
作者：
M. Terazima;S. Yamauchi;N. Hirota
用激光激发下的时间分辨EPR方法研究了哒嗪和3，6-二氯吡嗪(DCP)的短寿命三重态(T1)的磁性和衰变性质。对二溴苯(DBB)中DCP的零点为X=0.094 cm−1，Y=−0.164 cm−1，Z=0.070 cm−1，氮基Hfcc为Ax=27 G，Ay=18 G，Az=25 G，证实了T1态的nπ*性质。在其他环境中，DCP和Dazazine也获得了类似的零点荧光。通过对3.0K下测量的瞬时EPR信号的分析，确定了次能级衰变速率常数和相对填充速率，其中自旋晶格驰豫的影响可以忽略。在这两个系统中都发现Ky远大于简单的群论预测的kx，kz。结果表明，对苯二酚的KY约为10~6 S−1，比嘧啶的KY大1~4个∼。文中还对Ky偏大的原因进行了讨论，特别是从位置扭曲的角度进行了讨论。
The magnetic and decay properties of the short‐lived triplet (T1) states of pyridazine and 3,6‐dichloropyridazine (DCP) were studied by means of time‐resolved EPR with laser excitation. The zfs of DCP in the p‐dibromobenzene (DBB) host are X=0.094 cm−1, Y=−0.164 cm−1, and Z=0.070 cm−1, and the nitrogen hfcc are Ax=27 G, Ay=18 G, and Az=25 G, which confirms the nπ* character of the T1 state. Similar zfs were obtained for DCP and pyridazine in other environments. The sublevel decay rate constants and the relative populating rates were determined from the analysis of the transient EPR signals measured at 3.0 K where the effect of the spin lattice relaxation can be neglected. It was found in both systems that ky is much greater than kx, kz as predicted by a simple group theoretical consideration. ky of DCP and pyridazine were determined to be on the order of 106 s−1, being larger than that of pyrimidine by a factor of ∼104. The reasons for the large ky are discussed, particularly, in terms of the distorted po...