Dual Fluorescence from an Isonido ReIII Rhenacarborane Phosphine Complex, [7,10--H-7-CO-7,7-(PPh3)2<
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- 作者：Steven W. Buckner ; Matthew J. Fischer ; Paul A. Jelliss ; Rensheng Luo ; Shelley D. Minteer ; Nigam P. Rath ; Aleksander Siemiarczuk
- 刊名：Inorganic Chemistry
- 出版年：2006
- 出版时间：September 4, 2006
- 年：2006
- 卷：45
- 期：18
- 页码：7339 - 7347
- 全文大小：341K
- 年卷期：v.45,no.18(September 4, 2006)
- ISSN：1520-510X
文摘
The complex [7,10-
-H-7-CO-7,7-(PPh3)2-isonido-7,8,9-ReC2B7H9] has been synthesized by treatment of the complexsalt [NHMe3][3,3-Cl2-3,3-(CO)2-closo-3,1,2-ReC2B9H11] with PPh3 in refluxing THF (tetrahydrofuran) and isolated asintensely colored orange-red microcrystals. Spectroscopic NMR and IR data have suggested that the product hasa highly asymmetric structure with two inequivalent PPh3 ligands and a single CO ligand. Measurement of 11BNMR spectra in particular have indicated seven distinct boron vertexes, although the resulting cage degradation byremoval of two BH vertexes was confirmed only following X-ray crystallographic analysis, which revealed thepentadecahedral isonido-7,8,9-ReC2B7 architecture. The 11B NMR resonances span an enormous chemical shiftrange (
= 113), and this appears to be a direct consequence of the deshielding of the boron vertex directlyopposite the quadrilateral ReCC B
em = 442 nm, 
= 0.012). Fluorescence spectroscopymeasurements in MeTHF (2-methyltetrahydrofuran) glass at 77 K have indicated that the likely cause of such abroad emission is dual fluorescence (em = 404, 505 nm), with both emissions displaying vibronic structure. Followingexcited-state lifetime decay analysis, the emissive behavior has been accredited to metal-perturbed 1IL states, withthe lower energy emission arising from a slight geometric distortion of the initially excited complex.
-H-7-CO-7,7-(PPh3)2-isonido-7,8,9-ReC2B7H9] has been synthesized by treatment of the complexsalt [NHMe3][3,3-Cl2-3,3-(CO)2-closo-3,1,2-ReC2B9H11] with PPh3 in refluxing THF (tetrahydrofuran) and isolated asintensely colored orange-red microcrystals. Spectroscopic NMR and IR data have suggested that the product hasa highly asymmetric structure with two inequivalent PPh3 ligands and a single CO ligand. Measurement of 11BNMR spectra in particular have indicated seven distinct boron vertexes, although the resulting cage degradation byremoval of two BH vertexes was confirmed only following X-ray crystallographic analysis, which revealed thepentadecahedral isonido-7,8,9-ReC2B7 architecture. The 11B NMR resonances span an enormous chemical shiftrange ( = 113), and this appears to be a direct consequence of the deshielding of the boron vertex directlyopposite the quadrilateral em = 442 nm, = 0.012). Fluorescence spectroscopymeasurements in MeTHF (2-methyltetrahydrofuran) glass at 77 K have indicated that the likely cause of such abroad emission is dual fluorescence (em = 404, 505 nm), with both emissions displaying vibronic structure. Followingexcited-state lifetime decay analysis, the emissive behavior has been accredited to metal-perturbed 1IL states, withthe lower energy emission arising from a slight geometric distortion of the initially excited complex.