Photochemistry of Trimethyltin Iodide in Polar Media: Orbital Parentage and Observed Reactivity
详细信息 查看全文
- 作者：Jinquan Dong ; P. Sujatha Devi ; D. Sunil ; Edgar Mendoza ; and Harry D. Gafney
- 刊名：Inorganic Chemistry
- 出版年：2002
- 出版时间：January 14, 2002
- 年：2002
- 卷：41
- 期：1
- 页码：11 - 18
- 全文大小：110K
- 年卷期：v.41,no.1(January 14, 2002)
- ISSN：1520-510X
文摘
(CH3)3SnI exists as individual tetrahedral molecules in hexane but reacts with the silanol moieties present on thesurface of porous glass and with the hydroxyl group of ethanol and hexanol to form five-coordinate adducts. Withthe exception of slight shifts to higher energy, formation of the adduct has little effect on the electronic spectrumof the complex, and the wavelength and O2 dependencies of the quantum yield of (CH3)3SnI disappearance indicatethat the photochemistry of the complex initiates from the ligand-to-metal charge-transfer (LMCT) state populatedon absorption in each medium. Nevertheless, 254 nm excitation in hexane leads to I2 and ((CH3)3Sn)2, whereasexcitation of the five-coordinate adduct on the glass surface leads to I2, I3-, ((CH3)3Sn)2, and (CH3)3Sn-OSi
(OSi represents a surface siloxyl), while in ethanol, I3- is the only detectable product. Regardless of the medium,the ground state is polarized and population of the LMCT state creates a more uniform charge distribution fromwhich homolytic cleavage of the (CH3)3Sn-I bond is the dominant reaction pathway in each medium. In hexane,the (CH3)3Sn
and I radicals couple to form ((CH3)3Sn)2 and I2, whereas adsorbed onto the glass, a fraction of theradical pairs thermalize via electron transfer to form I3- and a surface-bound (CH3)3Sn-OSi species. In ethanol,excitation of the solvent adduct (CH3)3Sn-OHC2H5 leads to homolytic cleavage and I2 formation, which reactsthermally with (CH3)3Sn-OHC2H5 to form an [(CH3)3Sn+, I3-] ion pair.
(OSi represents a surface siloxyl), while in ethanol, I3- is the only detectable product. Regardless of the medium,the ground state is polarized and population of the LMCT state creates a more uniform charge distribution fromwhich homolytic cleavage of the (CH3)3Sn-I bond is the dominant reaction pathway in each medium. In hexane,the (CH3)3Sn and I radicals couple to form ((CH3)3Sn)2 and I2, whereas adsorbed onto the glass, a fraction of theradical pairs thermalize via electron transfer to form I3- and a surface-bound (CH3)3Sn-OSi species. In ethanol,excitation of the solvent adduct (CH3)3Sn-OHC2H5 leads to homolytic cleavage and I2 formation, which reactsthermally with (CH3)3Sn-OHC2H5 to form an [(CH3)3Sn+, I3-] ion pair.