Gas‐phase reactions of XH3+ (X = C,Si, Ge) with NF3: a comparative investigation on the detailed mechanistic aspects |
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Authors: | Paola Antoniotti Lorenza Operti Roberto Rabezzana Francesca Turco Cristina Zanzottera Maria Giordani Felice Grandinetti |
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Affiliation: | 1. Dipartimento di Chimica Generale e Chimica Organica and NIS Interdipartimental Centre of Excellence, Università degli Studi di Torino, C.so M. d' Azeglio, 48, 10125 Torino, Italy;2. Dipartimento di Scienze Ambientali, Università della Tuscia, L.go dell' Università, s.n.c., 01100 Viterbo, Italy |
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Abstract: | The gas‐phase reaction of CH3+ with NF3 was investigated by ion trap mass spectrometry (ITMS). The observed products include NF2+ and CH2F+. Under the same experimental conditions, SiH3+ reacts with NF3 and forms up to six ionic products, namely (in order of decreasing efficiency) NF2+, SiH2F+, SiHF2+, SiF+, SiHF+, and NHF+. The GeH3+ cation is instead totally unreactive toward NF3. The different reactivity of XH3+ (X = C, Si, Ge) toward NF3 has been rationalized by ab initio calculations performed at the MP2 and coupled cluster level of theory. In the reaction of both CH3+ and SiH3+, the kinetically relevant intermediate is the fluorine‐coordinated isomer H3X‐F‐NF2+ (X = C, Si). This species forms from the exoergic attack of XH3+ to one of the F atoms of NF3 and undergoes dissociation and isomerization processes which eventually result in the experimentally observed products. The nitrogen‐coordinated isomers H3X‐NF3+ (X = C, Si) were located as minimum‐energy structures but do not play an active role in the reaction mechanism. The inertness of GeH3+ toward NF3 is also explained by the endoergic character of the dissociation processes involving the H3Ge‐F‐NF2+ isomer. Copyright © 2009 John Wiley & Sons, Ltd. |
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Keywords: | germyl cation ion trap mass spectrometry methyl cation nitrogen trifluoride silyl cation theoretical calculations |
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