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Studies in the chemistry of the nitrogen-halogen bond

Cowan, N. D. (1977) Studies in the chemistry of the nitrogen-halogen bond. Doctoral thesis, Durham University.



The reactions of diraethylchloramine with a variety of different substrates has been studied. With basic substrates such as hydrazine and the alkyl substituted hydrazines, dimethylchloramine acts as an oxidising agent, but with ammonia and the methylamines contrast was found with the corresponding NH(_2)Cl reactions. Simple nucleophillic attack of the amine on the diraethylchloramine nitrogen explains the products found in the reactions with CH(_3)NH(_2) and NH(_3), whilst dehydrohalegonation reaction accounts for the observed products. With dimethylamine a complex reaction occurs which is most probably intimately associated with the decomposition of (CH(_3))(_2)NCl itself. Dimethylchloramine reacts in two different ways with methyl esters of certain acids. On the one hand, esters typified by CH(_3)0S0(_2)F, and including CH(_3)0Cl0(_3), yielding a cationic species identified as (CH(_3))(_3)(^+)NCl. In this cation, the nitrogen chlorine bond possesses a slight dipole, the positive end of which is directed towards the chlorine atom, in accord with the (^36)Cl NQR absorption frequency of 56.09 MHz, found in the Cl0(^-)(_4), (CH(_3))(_3)(^+)3NCl Cl0(^-)(_4), being in excess of that found for Cl2 . The application of standard approximate methods to the observed coupling constants for the CIO4 and BP4 indicate that the bonding between the nitrogen and chlorine atoms in the cation involves an almost pure chlorine p orbital. The ion, (CH(_3))(_3)(^+)NCl, is precipitable from aqueous solutions of the chlorine trimethylaraine complex, (CH(_3))(_3)NCl(_2), by Cl0(^-)(_4) and BF(^-)(_4) ions. With the methyl halides, dimethylchloramme reacts to yield, with methyl bromide, the addition complex of trimethylaraine, (CH3)3NBrCl, the infra red spectrum of which fits well with the trends observed for other (CH3)3N (Halogen)2 addition complexes, whilst with methyl iodide, a novel tetramethylammonium pseudopolyhalide, (CH(_3))(_4)(^+)N[(CH(_3))(_2)N(ICl)(_2)](^-), forms. Dimethyl bromamine, (CH(_3))(_2)NBr, reacts in a similar way to (CH(_3))(_2)NCl, with alkylating agents, the unstable (CH(_3))(_3)(^+)NBr 0S02(_)F(^-) forms with CH(_3)0S0(_2)F and (CH(_3))(_2)NBr Cl0(^-)(_4) can be precipitated from aqueous solutions of the fluorosulphate by Cl0(^-)(_4) ions. With CH(_3)I, (CH(_3))(_2)NBr yields, in a similar way to (CH(_3))(_2)NCl, (CH(_3))(_4)(^4)N[(CH(_3))(_2)N(IBr(_2))](^-).

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Thesis Date:1977
Copyright:Copyright of this thesis is held by the author
Deposited On:18 Sep 2013 15:55

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