Chemistry in nanodroplets: Studies of protonation sites of substituted anilines in water clusters using FT-ICR

Journal of the American Chemical Society

Volumn 122, Issue 38, 2000, Pages 9201-9205

  Lee, Sang Won ^a,b   Cox, Heather ^a   Goddard III, William A ^a   Beauchamp, J L ^a  

^a CALIFORNIA INSTITUTE OF TECHNOLOGY   (United States)

^b PACIFIC NORTHWEST NATIONAL LABORATORY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ANILINE DERIVATIVE; WATER;

ARTICLE; ENERGY; EVAPORATION; FOURIER ANALYSIS; GAS; HYDRATION; MASS SPECTROMETRY; MOLECULAR STABILITY; PHASE TRANSITION; PROTON TRANSPORT;

EID: 0034721431     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja0009875     Document Type: Article

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17. To avoid the complication in calculations from the different orientation of the ethyl group in ethylanilines, proton affinities of m-/p-oluidine were calculated in this study instead of m-/p-ethylaniline. It is expected that the substituent effects of methyl and ethyl groups are similar. Calculation results from m-/p-oluidine are accordingly used to explain and compare with experimental results of m-/p-ethylaniline.
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24. We were not able to measure water clusters of p-thiomethylaniline, since the mass spectrum of p-thomethylaniline contains a strong impurity peak, which is not assigned, and overlaps with water cluster peaks of protonated p-thiomethylaniline, affecting the relative abundance of cluster peaks.
25. There is a slight indication of a magic number at n = 20 for m-anisidine (the average intensity ratio for m-anisidine is 1.01 with a standard deviation of 0.15, and the intensity ratio at n = 20 is 1.26). However, the intensity ratio at n = 20 for p-anisidine is 2.02 (average = 1.02, standard deviation = 0.26). It is unclear whether the slight increase in intensity ratio at n = 20 for m-ansidine is due to a small sub-population of amine-protonated species, a stable isomer at n = 20 which does hot resemble the clathrate structures proposed here, or whether it simply occurs as a statistical fluctuation in the data.