通过电子顺磁共振光谱法解析铬（I）1,3 - 双（二苯基膦），[Cr(CO)(dppp)]的光化学转变
Unravelling the Photochemical Transformations of Chromium(I) 1,3 Bis(diphenylphosphino), [Cr(CO)(dppp)], by EPR Spectroscopy.
作者信息
Luckham Stephen L J, Folli Andrea, Platts James A, Richards Emma, Murphy Damien M
机构信息
School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K.
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K.
出版信息
Organometallics. 2019 Jun 24;38(12):2523-2529. doi: 10.1021/acs.organomet.9b00226. Epub 2019 Jun 13.
UV-induced photochemical transformations of the paramagnetic [Cr(CO)(PhPCHCHCHPPh)] complex (abbreviated [Cr(CO)(dppp)]) in dichloromethane was investigated by CW EPR spectroscopy. Room-temperature UV irradiation results in the rapid transformation of [Cr(CO)(dppp)] into -[Cr(CO)(dppp)]. However, low-temperature (77-120 K) UV irradiation reveals the presence of an intermediate -[Cr(CO)(κ-dppp)(κ-dppp)] complex which photochemically transforms into -[Cr(CO)(dppp)]. The derived spin Hamiltonian parameters for these complexes were confirmed by DFT calculations. The photoinduced reaction is shown to be concentration-dependent, leading to a distribution of the three complexes ([Cr(CO)(dppp)], -[Cr(CO)(κ-dppp)(κ -dppp)], and -[Cr(CO)(dppp)]). A bimolecular photoinduced mechanism is proposed to account for the formation of -[Cr(CO)(κ-dppp)(κ-dppp)] and -[Cr(CO)(dppp)].
通过连续波电子顺磁共振光谱研究了顺磁性[Cr(CO)(PhPCHCHCHPPh)]配合物（缩写为[Cr(CO)(dppp)]）在二氯甲烷中紫外线诱导的光化学转变。室温紫外线照射导致[Cr(CO)(dppp)]迅速转变为-[Cr(CO)(dppp)]。然而，低温（77 - 120 K）紫外线照射揭示了中间体-[Cr(CO)(κ-dppp)(κ-dppp)]配合物的存在，该配合物通过光化学转变为-[Cr(CO)(dppp)]。这些配合物推导得到的自旋哈密顿参数通过密度泛函理论计算得到了证实。光诱导反应显示出浓度依赖性，导致三种配合物（[Cr(CO)(dppp)]、-[Cr(CO)(κ-dppp)(κ -dppp)]和-[Cr(CO)(dppp)]）的分布。提出了一种双分子光诱导机制来解释-[Cr(CO)(κ-dppp)(κ-dppp)]和-[Cr(CO)(dppp)]的形成。
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