304852-58-2Relevant academic research and scientific papers
Acid-base equilibria in nonpolar media. 2. Self-consistent basicity scale in THF solution ranging from 2-methoxypyridine to EtP1(pyrr) phosphazene
Rodima, Toomas,Kaljurand, Ivari,Pihl, Aino,Maeemets, Vahur,Leito, Ivo,Koppel, Ilmar A.
, p. 1873 - 1881 (2002)
Relative ion-pair basicities ΔpKip of 25 substituted aryl and alkyl iminophosphoranes (phosphazenes) and 20 other N-bases (various pyridines, amines, amidines) have been measured in THF medium using the UV-Vis and/or 13C NMR methods. The ΔpKip values were corrected for ion pairing using the Fuoss equation to obtain relative ionic basicities ΔpKα. Based on the measurements, a basicity scale ranging from 2-methoxypyridine to EtP1(pyrr) and having a total span over 18 pK units has been created. The scale has been anchored to the pKα value of triethylamine (pKα = 12.5). The results are compared to pKa values in various other solvents and in the gas phase. The pKα values give better correlations than the pKip values, thus indirectly validating the procedure of correction for ion pairing. The predictability of the basicity together with suitable spectral properties in the UV range make the phenylphosphazenes convenient neutral indicators in the high basicity range where the choice of neutral indicators is very limited.
Synthesis of N-aryl-substituted iminophosphoranes and NMR spectroscopic investigation of their acid-base properties in acetonitrile
Rodima, Toomas,Maeemets, Vahur,Koppel, Ilmar
, p. 2637 - 2644 (2007/10/03)
A series of RN=P(Pyrr)3 iminophosphoranes (P1 phosphazenes), where R is amino-, a-naphthyl- or substituted phenyl group, is prepared by the Kirsanov reaction and characterized by FT NMR and other properties. The ΔpKa-value
