PtII Diimine Chromophores with Perfluorinated Thiolate Ligands: Nature and Dynamics of the Charge-Transfer-to-Diimine Lowest Excited State
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- 作者：Julia A. Weinstein ; Alexander J. Blake ; E. Stephen Davies ; Adrienne L. Davis ; Michael W. George ; David C. Grills ; Igor V. Lileev ; Alexander M. Maksimov ; Pavel Matousek ; Mikhail Ya. Mel'nikov ; Anthony
- 刊名：Inorganic Chemistry
- 出版年：2003
- 出版时间：November 3, 2003
- 年：2003
- 卷：42
- 期：22
- 页码：7077 - 7085
- 全文大小：155K
- 年卷期：v.42,no.22(November 3, 2003)
- ISSN：1520-510X
文摘
The synthesis of new PtII diimine complexes bearing perfluorinated thiolate ligands, PtII(NN)(4-X-C6F4-S)2, whereNN = 2,2'-bipyridine or 1,10-phenanthroline and X = F or CN, is reported, together with an investigation of thenature and dynamics of their lowest excited states. A combined UV-vis, (spectro)electrochemical, resonance Raman,and time-resolved infrared (TRIR) study has suggested that the HOMO is mainly composed of thiolate(
)/S(p)/Pt(d) orbitals and that the LUMO is largely localized on the * (diimine) orbital, thus revealing the {charge-transfer-to-diimine} nature of the lowest excited state. An enhancement of the thiolate ring vibrations, C-F vibrations, andthe vibration of the CN-substituent on the thiolate moiety was observed in the resonance Raman spectra, whereasno such enhancement was seen for the nonfluorinated analogues. Thus, the introduction of fluorine substituents onthe thiolate moiety probably leads to a more pronounced contribution of the intrathiolate modes to the HOMOcompared to the analogous complexes with nonfluorinated thiolates. Furthermore, the introduction of the p-CNgroup into the thiolate moiety has allowed the dynamics of the lowest excited state of Pt(bpy)(4-CN-C6F4-S)2 tobe monitored by picosecond TRIR spectroscopy. The dynamics of the lowest {charge-transfer-to-diimine} excitedstate are governed by ca. 2-ps vibrational cooling and 35-ps back electron transfer.
)/S(p)/Pt(d) orbitals and that the LUMO is largely localized on the * (diimine) orbital, thus revealing the {charge-transfer-to-diimine} nature of the lowest excited state. An enhancement of the thiolate ring vibrations, C-F vibrations, andthe vibration of the CN-substituent on the thiolate moiety was observed in the resonance Raman spectra, whereasno such enhancement was seen for the nonfluorinated analogues. Thus, the introduction of fluorine substituents onthe thiolate moiety probably leads to a more pronounced contribution of the intrathiolate modes to the HOMOcompared to the analogous complexes with nonfluorinated thiolates. Furthermore, the introduction of the p-CNgroup into the thiolate moiety has allowed the dynamics of the lowest excited state of Pt(bpy)(4-CN-C6F4-S)2 tobe monitored by picosecond TRIR spectroscopy. The dynamics of the lowest {charge-transfer-to-diimine} excitedstate are governed by ca. 2-ps vibrational cooling and 35-ps back electron transfer.