{"title":"Structure of molecular and ionic H-bonded complexes of Hexamethylphosphortriamide by low temperature NMR in freon solution","authors":"N.S. Golubev, S.F. Bureiko, G.S. Denisov","doi":"10.1016/0378-4487(82)80055-1","DOIUrl":null,"url":null,"abstract":"<div><p>The <sup>1</sup>H NMR spectra have been obtained for a number of H-bonded complexes formed by the interaction of OH-acids of increasing strength and [(CH<sub>3</sub>)<sub>2</sub>N]<sub>3</sub>PO (HMPT) in a freon mixture (CDF<sub>2</sub>Cl + CDFCl<sub>2</sub>) at 100 K.The signals of the complexes with moderately strong acids (pK<sub>a</sub>> −2) are singlets,which proves that they have a molecular structure,AH…B.With stronger acids,a doublet spin-spin coupling of the bridge proton with <sup>31</sup>P nucleus occurs (J<sub>PH</sub>=cca 20 Cps) indicating a complete proton transfer,A<sup>−</sup>…HB<sup>+</sup>.The conclusion has been drawn that a sharp change in structure is caused by gradual change in the interaction energy as measured by ΔpK<sub>a</sub>.The spectra of a number of conjugated complexes,[BHB]A<sup>−</sup>,have been taken.If B=B,the homoconjugated cation with a centrosymmetric H-bond is formed,followed by a strong decrease in J<sub>PH</sub>.</p></div>","PeriodicalId":100049,"journal":{"name":"Advances in Molecular Relaxation and Interaction Processes","volume":"24 4","pages":"Pages 225-231"},"PeriodicalIF":0.0000,"publicationDate":"1982-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0378-4487(82)80055-1","citationCount":"5","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Advances in Molecular Relaxation and Interaction Processes","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/0378448782800551","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 5
Abstract
The 1H NMR spectra have been obtained for a number of H-bonded complexes formed by the interaction of OH-acids of increasing strength and [(CH3)2N]3PO (HMPT) in a freon mixture (CDF2Cl + CDFCl2) at 100 K.The signals of the complexes with moderately strong acids (pKa> −2) are singlets,which proves that they have a molecular structure,AH…B.With stronger acids,a doublet spin-spin coupling of the bridge proton with 31P nucleus occurs (JPH=cca 20 Cps) indicating a complete proton transfer,A−…HB+.The conclusion has been drawn that a sharp change in structure is caused by gradual change in the interaction energy as measured by ΔpKa.The spectra of a number of conjugated complexes,[BHB]A−,have been taken.If B=B,the homoconjugated cation with a centrosymmetric H-bond is formed,followed by a strong decrease in JPH.