Infrared Spectroscopy of Ni+(C2H2)n Complexes: Evidence for Intracluster Cyclization Reactions
Infrared Spectroscopy of Ni+(C2H2)n Complexes: Evidence for Intracluster Cyclization Reactions
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Ni (C2H2)n 配合物的红外光谱：簇内环化反应的证据
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
M. Duncan
中科院分区：
文献类型：
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作者：
R. S. Walters;and T. D. Jaeger;M. Duncan
Ni+（C2 H2）n离子-分子复合物通过脉冲喷嘴源中的激光蒸发产生。这些离子的质量分析和大小选择与反射飞行时间光谱仪。用脉冲OPO/OPA激光器进行红外激发，诱导这些复合物的光解离，并通过C2 H2分子的连续损失来进行。在Ni+（C2 H2）n络合物（n = 3−6）的C-H伸缩区测量了IR共振增强光解离（IR-REPD）光谱。C-H伸缩振动的频率比自由乙炔的频率低，这与金属阳离子π-络合物的形成相一致。在n = 5和更大的簇尺寸，新的频带测量归因于表面乙炔分子。在n = 5及以上的额外的红移带被分配到簇内环化反应，形成π-键合的环丁二烯。
Ni+(C2H2)n ion−molecule complexes are produced by laser vaporization in a pulsed nozzle source. These ions are mass analyzed and size-selected with a reflectron time-of-flight spectrometer. Infrared excitation with a pulsed OPO/OPA laser induces photodissociation of these complexes that proceeds by sequential loss of C2H2 molecules. IR resonance-enhanced photodissociation (IR-REPD) spectra are measured in the C−H stretch region for Ni+(C2H2)n complexes (n = 3−6). The C−H stretch vibrations are shifted to lower frequencies than those in free acetylene, consistent with the formation of metal cation π-complexes. At the cluster sizes of n = 5 and larger, new bands are measured attributed to surface acetylene molecules. Additional red-shifted bands at n = 5 and beyond are assigned to an intracluster cyclization reaction, forming π-bonded cyclobutadiene.