Deuterium Quadrupolar Parameters from and 2H NMR Spectra for Pyridine-d5, Benzonitrile-d5 and Chlorobenzene-d

Abstract

The quad ru p o la r coupling constants (D Q CC) and the asym m etry param eters (rj) for the ortho, meta and para deuterons in pyrid ine-d5, benzonitrile-d5 and chlorobenzene-d 5 were determ ined by N M R spectroscopy in oriented phases. The !H and 2H N M R spectra were recorded in the following solutions in liquid crystal solvents: pyridine + pyridine-ds in PCH, in ZLI 1167 and in EBBA; benzonitrile + benzonitrile-ds and chlorobenzene + chlorobenzene-d 5 in the sam e solvents. The o rder param eters o f the non-deuterated solutes in the various solutions were calculated using the d ipo lar couplings o f the proton spectra and the r* structures taken from the literature. The sam e order param eters were assum ed to describe also the o rientation o f the deu terated solute in the corresponding solutions. Each 2H spectrum yielded three quadrupolar splittings for the three different deuterated positions in the labelled solute. The splittings from the three different solutions o f the same solute, together with the order param eters and the r a structure, were used to determ ine D Q CC and rj o f the ortho, meta and para deuterons (Pyridine-ds: D Q C C ortho= 183(1) kHz, rionho = 0.030(5), D Q C C meta = 185(1) kHz, ^meta = o.030(10), DQCCPara = 188(6) kHz, ?/Para = 0.01(5). B enzonitrile-ds: D Q C C ortho = 171(12) kHz, >/ortho = 0.07(3), D Q C C meta = 175(12) kHz, nma* = 0.05(3), DQCCPara = 176(4) kHz, rj para = 0.10(7). C hlorobenzene-d 5: D Q C C ortho = 180(2) kHz, ^ ortho = 0.06(1), D Q C C meta = 174(2) kHz, //meta = 0.09(3), DQ CCPara= 182(4) kHz, //Para = 0.06(4)). The results are discussed, as well as the lim its and possibilities o f the m ethod used.

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Cite this paper

@inproceedings{Ambrosetti2012DeuteriumQP, title={Deuterium Quadrupolar Parameters from and 2H NMR Spectra for Pyridine-d5, Benzonitrile-d5 and Chlorobenzene-d}, author={Roberto Ambrosetti and Carlo Alberto Veracini}, year={2012} }