Remarkably Large ¹⁵N, ¹³C and ¹⁸O Isotope NMR Shifts of the Mono-coordinate Phosphorus Atoms in the Compounds (Me₃ Si)ⁱPrNCP, K⁺[ⁱPrNCP]-and KOCP · 2 DME (DME = 1,2-Dimethoxyethane)

Abstract

Aminomethylidynephosphane, Phosphantriylmethylamide, Isotope Shifts The 31P and 13C NMR spectra of the heteroatom-substituted A3-phosphaalkynes (Me^Si)-'PrNCP (1), K+ ['PrNCPl-(2) and KOCP • 2 DME (3) are described (Me = methyl; 'Pr = isopropyl). In addition,1 N NMR data of 1 and 2 as well as further NMR results o f all accessible nuclei of 1 to 3 are reported. The absolute values of the coupling constants 'y(31P13C) of 1, 2 and 3, 18.2, 45.7 and 57.2 Hz, respectively, are considerably different; the geminal coupling constants 2/ ( 31Pl5N) of the first two compounds show a decrease in the reverse order, 15.1 and 3.3 Hz. I3C, 29Si,15N, and lsO isotope effects on the nuclear shielding of the 31P nucleus in the non isotope-enriched compounds 1, 2 or 3 are presented and discussed. The [mono-13C]isotopomers of 1, 2 and 3 exhibit extremely negative 31P13C one-bond isotope shifts varying from -211 to -2 2 3 ppb. Remarkably, for 1 and 2 large two-bond 3IP15N isotope shifts of -3 2 and -8 4 ppb, respectively, are observed. An unexpectedly large two-bond 31P 80 isotope effect of -1 2 4 ppb was assigned to the [mono-l80]isotopomer of compound 3. A three-bond 31P13C isotope shift of -2 7 ppb was found in 2.

[(CF3)3BCP]− and [(CF3)3BCAs]−: Thermally Stable Phosphaethynyl and Arsaethynyl Complexes

“…(1)] and in addition the relatively high stability is due to the negative charge, which makes polymerization to highly charged anionic products more difficult. The interaction of the lone pair(s) at the heteroatom with the p system of the CÀP triple bond is clearly shown by ab initio calculations, [11] NMR spectroscopy, [10] and structural studies.…”

“…[6] By using transition-metal catalysts tetramerizations are possible, which yield cubane analogous compounds. [6,7] The anionic derivatives [OCP] À , [8] [SCP] À , [9] and [iPrNCP] À [10] are resonance stabilized [Eq. (1)] and in addition the relatively high stability is due to the negative charge, which makes polymerization to highly charged anionic products more difficult.…”

Simultaneous determination of five tetracycline and macrolide antibiotics in feeds using HPCE

“…Anionische Derivate wie OCP − ,8 SCP − 9 und i PrNCP − 10 sind entsprechend Gleichung (1) resonanzstabilisiert. Ihre relativ hohe Stabilität kann ferner durch die negative Ladung erklärt werden, da die Polymerisation zu hochgeladenen anionischen Produkten erschwert ist.…”

[(CF3)3BCP]− und [(CF3)3BCAs]− –thermisch stabile Phosphaethinyl‐ und Arsaethinyl‐Komplexe

“…[2] Ansonsten polymerisieren die instabilen C-P-Dreifachbindungen, [6] oder es entstehen durch übergangsmetallkatalysierte Tetramerisierungen Cuban-analoge Verbindungen. [6,7] Anionische Derivate wie OCP À , [8] SCP À [9] und iPrNCP À [10] sind entsprechend Gleichung (1) resonanzstabilisiert. Ihre relativ hohe Stabilität kann ferner durch die negative Ladung erklärt werden, da die Polymerisation zu hochgeladenen anionischen Produkten erschwert ist.…”

“…Ihre relativ hohe Stabilität kann ferner durch die negative Ladung erklärt werden, da die Polymerisation zu hochgeladenen anionischen Produkten erschwert ist. Die Wechselwirkung von freien Elektronenpaaren am Heteroatom mit dem p-System der C-P-Dreifachbindung wird durch Ab-initio-Rechnungen, [11] NMR-spektroskopische Untersuchungen [10] und Strukturanalysen [9] deutlich.…”