硅离子（苯）n 团簇和硅离子（苯）（n）氩团簇的紫外及红外光解离

Ultraviolet and infrared photodissociation of Si(+)(C6H6)n and Si(+)(C6H6)(n)Ar clusters.

作者信息

Jaeger J B, Pillai E D, Jaeger T D, Duncan M A

机构信息

Department of Chemistry, University of Georgia, Athens, Georgia 30602-2556, USA.

出版信息

J Phys Chem A. 2005 Mar 31;109(12):2801-8. doi: 10.1021/jp044798a.

DOI:10.1021/jp044798a

PMID:16833593

Abstract

Ion-molecule complexes of the form Si(+)(C6H6)n and Si(+)(C6H6)(n)Ar are produced by laser vaporization in a pulsed nozzle cluster source. These clusters are mass-selected and studied with ultraviolet (355 nm) photodissociation and resonance-enhanced infrared photodissociation spectroscopy in the C-H stretch region of benzene. In the UV, Si(+)(C6H6)n clusters (n = 1-5) fragment to produce the Si(+)(C6H6)n mono-ligand species, suggesting that this ion has enhanced relative stability. IR photodissociation of Si(+)(C6H6)n complexes occurs by the elimination of benzene, while Si(+)(C6H6)(n)Ar complexes lose Ar. Resonances reveal C-H vibrational bands in the 2900-3300 cm(-1) region characteristic of the benzene ligand with shifts caused by the silicon cation bonding. The IR spectra confirm that the major component of the Si(+)(C6H6)n ions studied have the pi-complex structure rather than the isomeric insertion products suggested previously.

摘要

通过脉冲喷嘴团簇源中的激光汽化产生形式为Si(+)(C6H6)n和Si(+)(C6H6)(n)Ar的离子 - 分子复合物。这些团簇经过质量选择，并在苯的C - H伸缩区域用紫外（355 nm）光解离和共振增强红外光解离光谱进行研究。在紫外光下，Si(+)(C6H6)n团簇（n = 1 - 5）发生碎片化，生成Si(+)(C6H6)n单配体物种，这表明该离子具有增强的相对稳定性。Si(+)(C6H6)n复合物的红外光解离是通过苯的消除发生的，而Si(+)(C6H6)(n)Ar复合物则失去Ar。共振揭示了在2900 - 3300 cm(-1)区域内苯配体的C - H振动带，这些振动带因硅阳离子键合而发生位移。红外光谱证实，所研究的Si(+)(C6H6)n离子的主要成分具有π - 络合物结构，而非先前提出的异构插入产物结构。