Reaction of o-phenylenediamine with diacetyl monoxime: characterisation of the product by solid-state 13C and 15N MAS NMR.
2,3-dimethylquinoxaline (DMQ) and dimethylglyoxime (DMGH2) form a 1:1 hydrogen-bonded complex in the solid state, which is completely dissociated in methanol solution. There are small differences in solid-state 13C shifts between the separated components DMQ and DMGH2 and the complex. The changes in 15N solid-state chemical shifts are more significant: the hydrogen bond imparting a low frequency shift of ca 19 ppm. The effect of direct protonation on the DMQ solid-state 15N shifts was measured, and the experimental 15N data correlated with those from GIAO molecular orbital (MO) calculations.
Radhakrishnan
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Department of Chemistry, University of Zululand, Private Bag X1001, Kwadlangezwa 3886, Kwa Zulu Natal, Republic of South Africa.
Sreekumari Nair
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Kolawole
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Revaprasadu
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Hawkes
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Motevalli
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Bento
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O'Brien
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