COMMENTS ON THE MICROWAVE SPECTRA OF METHYLCHLORO-DIAZIRINE, TRIMETHYLAMINE AND ETHYLENE EPISULFOXIDE.

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1969

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Ohio State University

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Abstract

Ground state rotational spectra of $CH_{3}^{25}CICN_{2}$ and $CH_{3}^{37}CICN_{2}$ have been assigned, and the derived $r_{0}$ structural parameters are: $r(NN)= 1.241 \pm 0.005{\AA}, r(CCl) = 1.743 \pm 0.01{\AA}, r(CC) = 1.498 \pm 0.01{\AA}, \sphericalangle CC-C-Cl = 116.7^{\circ} \pm 1.0^{\circ}, \sphericalangle CCN_{2} = 124.5^{\circ} \pm 1.0^{\circ}$, and $\sphericalangle NCN = 50.2^{\circ} \pm 0.5^{\circ}$. The internal rotation splittings for $CH_{3}^{35}CICN_{2}$ yield a barrier to internal rotation of $1689 \pm 10$ calories mole$^{-1}$. The Cl quadrupole coupling constants (MHz) for $CH_{3}^{35}ClCN_{2}$ are $\chi_{aa} = -66.51, \chi_{bb}=32.91, \chi_{cc}=33.60$ and for $CH_{3}^{37}ClCN_{2}$ are $\chi_{aa}=- 53.07, \chi_{bb} = 26.40, \chi_{cc} = -66.51, \chi_{bb} = 32.91, \chi_{cc} = 33.60$ and for $CH_{3}^{37}ClCN_{2}$ are $\chi_{aa} -53.07, \chi_{bb} = 26.40, \chi_{cc} = 26.67$. The nitrogen quadrupole splitting were generally unresolved. The ground state rotational spectra of $(CH_{2}D) (CH_{3})_{2}N, (CH_{3})_{3}^{15}N$, and $(^{13}CH_{3}) (CH_{3})_{2}N$ have been assigned yielding the effective moments of inertia. This information has been combined with that for $(CH_{3})_{3}N$ to give the following structural parameters: $\begin{array}{l}r(CN) = 1.451 \pm 0.003 {\AA}, r(CH_{8}) = 1.109 \pm 0.008{\AA},\\ r(CH_{a}) = 1.088 \pm 0.008{\AA}, \sphericalangle CNC = 110.9^{\circ} \pm 0.6^{\circ},\\ \sphericalangle NCH_{a} = 111.7^{\circ} \pm 0.4^{\circ}, \sphericalangle NCH_{a} = 110.1^{\circ} \pm 0.5^{\circ},\\ \sphericalangle H_{a}CH_{a} = 108.1^{\circ} \pm 0.7^{\circ}, and \sphericalangle H_{a}CH_{a} = 108.6^{\circ} \pm 0.8^{\circ},\end{array}$ where $H_{2}$ lies in a symmetry plane. $A C_{3v}$ equilibrium conformation has been established and the methyl groups appear to be tilted by $1.3^{\circ}$ toward the unshared electron pair. A mild Coriolis interaction has been observed between the lowest two vibrational states of ethylene episulfoxide.

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LeRoy H. Scharpen is co-author of methylchlorodiazirine work. Victor W. Laurie is co-author of trimethylamine work William F. White is co-author of ethylene episulfoxide work.
Author Institution: McDonnell Douglas Corporation

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