N.M.R. study of acid-base equilibria of aminoalkylphosphonic acids, +NH3(CH2)nPO3H- (n = 1,2,3): Evidence for cyclization in solution

Abstract

The variations with pD of 31P, 13C and lH n.m.r. chemical shifts for D2O solution of MePO3H2 and NH2(CH2)nPO3H2 (n = 1, 2, 3) have been studied. In the aminoalkylphosphonic acids, δp is profoundly affected by amine deprotonation. 'Cyclic' conformations in which the amine group is close to the phosphonate group are proposed, with the strength of the amine-phosphonate interaction decreasing as n increases.

Aminoalkylbis(phosphonates): Their Complexation Properties in Solution and in the Solid State

“…Such behaviour can be explained by steric and/or electronic effects. The protonated amino group on the same carbon atoms can efficiently interact intramolecularly (electrostatically and/or through hydrogen bonds [20] ) with only one negatively charged phosphonate group. The [21] H 4 aca shows higher overall basicity due to the higher value of pK(H 3 L -).…”

Synthesis and spectroscopic study of mesoporous aluminum methylphosphonate foam templated by dibutyl methylphosphonate

“…5(b). Free MPA gives a sharp peak at 31 ppm [39], and free DBMP exhibits a peak at %34 ppm (this value was obtained from DBMP synthesized in our laboratory), while the as-synthesized DMM gives a predominant peak at 27 ppm and a very weak peak at 30 ppm (figures not shown). This result implies that a strong interaction, namely a hydrogen bond, exists between MPA and DBMP.…”

A New Tris(phosphonomethyl) Monoacetic Acid Cyclam Derivative: Synthesis, Acid‐Base and Metal Complexation Studies

“…The interpretation of the 31 P NMR spectroscopic chemical shift changes is still mostly empirical as different classes of phosphorus compounds show diverse behaviour. However, a significant amount of data has been published with respect to the aminoalkylphosphonate groups in acyclic [28][29][30][31] and macrocyclic [13,[20][21][22]25,26,[32][33][34][35] compounds. In the 31 P NMR spectroscopic titration of H 7 te3p1a, one of the resonances (δ a ) shows a different pH dependence from those of the other two signals (δ b and δ bЈ ).…”