Preparation, NMR Spectroscopic, and ab Initio/DFT/GIAO-MP2 Studies of Halomethyl Cations1

A series of halomethyl cations was prepared and studied by 13C NMR spectroscopy. Their structures and 13C NMR chemical shifts were also calculated by ab initio/DFT/GIAO-MP2 methods. The δ13C of trihalomethyl cations CX3 + (X = Cl, Br, I) and dimethylhalocarbenium ions Me2CX+ (X = F, Cl, Br) correlat...

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Published inJournal of the American Chemical Society Vol. 118; no. 15; pp. 3580 - 3583
Main Authors Olah, George A, Rasul, Golam, Heiliger, Ludger, Prakash, G. K. Surya
Format Journal Article
LanguageEnglish
Japanese
Published American Chemical Society 17.04.1996
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Summary:A series of halomethyl cations was prepared and studied by 13C NMR spectroscopy. Their structures and 13C NMR chemical shifts were also calculated by ab initio/DFT/GIAO-MP2 methods. The δ13C of trihalomethyl cations CX3 + (X = Cl, Br, I) and dimethylhalocarbenium ions Me2CX+ (X = F, Cl, Br) correlate well with the Pauling electronegativities of the halogen atoms and δ11B of the isostructural and isoelectronic boron halides as well as with the calculated charge of carbon atoms. The CF3 + cation was not observed, but a chemical shift of δ13C 150 is indicated by comparison with other experimentally observed trihalomethyl cations. GIAO-MP2 chemical shift calculations gave δ13C 169.2 for the CF3 + cation.
Bibliography:ark:/67375/TPS-WDBK267P-Z
istex:12EABCBDA85055B2B702B6E08CBA9C2C6C029DEA
Abstract published in Advance ACS Abstracts, April 1, 1996.
ISSN:0002-7863
1520-5126
DOI:10.1021/ja9538905