H/D isotope effects on 1H-NMR chemical shifts in cyclic heterodimers and heterotrimers of phosphinic and phosphoric acids

Valeriia V. Mulloyarova, Daria O. Ustimchuk, Aleksander Filarowski, Peter M. Tolstoy

Результат исследований: Научные публикации в периодических изданияхстатья

1 Цитирования (Scopus)

Аннотация

Hydrogen-bonded heterocomplexes formed by POOH-containing acids (diphenylphosphoric 1, dimethylphosphoric 2, diphenylphosphinic 3, and dimethylphosphinic 4) are studied by the low-temperature (100 K) 1H-NMR and 31P-NMR using liquefied gases CDF3/CDF2Cl as a solvent. Formation of cyclic dimers and cyclic trimers consisting of molecules of two different acids is confirmed by the analysis of vicinal H/D isotope effects (changes in the bridging proton chemical shift, δH, after the deuteration of a neighboring H-bond). Acids 1 and 4 (or 1 and 3) form heterotrimers with very strong (short) H-bonds (δH ca. 17 ppm). While in the case of all heterotrimers the H-bonds are cyclically arranged head-to-tail, ···O=P–O–H···O=P–O–H···, and thus their cooperative coupling is expected, the signs of vicinal H/D isotope effects indicate an effective anticooperativity, presumably due to steric factors: when one of the H-bonds is elongated upon deuteration, the structure of the heterotrimer adjusts by shortening the neighboring hydrogen bonds. We also demonstrate the formation of cyclic tetramers: in the case of acids 1 and 4 the structure has alternating molecules of 1 and 4 in the cycle, while in case of acids 1 and 3 the cycle has two molecules of 1 followed by two molecules of 3.

Язык оригиналаанглийский
Номер статьи25081907
ЖурналMolecules
Том25
Номер выпуска8
DOI
СостояниеОпубликовано - апр 2020

Предметные области Scopus

  • Аналитическая химия
  • Химия (разное)
  • Молекулярная медицина
  • Фармация
  • Поиск новых лекарств
  • Физическая и теоретическая химия
  • Органическая химия

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