ChemInform Abstract: Synthesis and 31P and 13C NMR Studies of Pyrophosphonic Acids.

Abstract

Synthesis and 31P and 13C NMR Studies of Pyrophosphonic Acids. -A variety of pyrophosphonic acids, e.g. (III) and (V), are prepared by dehydration of phosphonic acids via their ammonium salts or by partial hydrolysis of phosphonic acid dichlorides and characterized by NMR spectra. -(OHMS, G.; GROSSMANN, G.; SCHWAB, B.; SCHIEFER, H.; Phosphorus, Sulfur Silicon Relat. Elem. 68 (1992) 1-4, 77-89; Inst. Anal. Chem., TU Dresden, O-8027 Dresden, Fed. Rep. Ger.; EN)

Interfacing Quantum Dots and Graphitic Surfaces with Chlorine Atomic Ligands

“…Three of such signals (29.3, 22.4, and 21.7 ppm) can also be found in the solid 31 P{ 1 H} NMR spectrum of pure ODPA (see inset). The dominating contribution at 30.4 ppm is similar to the value reported for solution ODPA 31 P NMR. , The signals observed in Figure c at ∼22 ppm and 18.3 ppm can be assigned to ODPA species directly bound to Cd in the form of octadecylphosphonates (double deprotonated ODPA 2– ) and anhydrides of phosphonic acids, respectively. ,,, The presence of ODPA (neutral molecule) could be related with the hydrolysis of anhydrides and hydrogen bonding between ODPA molecules might be the origin of the peaks at 22.4 and 21.7 ppm, according to previous work . Finally, we attribute the small signal at 34 ppm to a small contribution of Se-TOP.…”

“…Figure c shows the solid 31 P { 1 H} NMR spectra for rodlike CdSe NCs (upper line) and dihexagonal pyramids (lower line), respectively (not supported on the C-sp 2 surface, see Methods for further details). Previously reported solution 31 P NMR spectra of ODPA-capped CdSe NCs consisted of two broad signals centered at 20 and 30 ppm. , The solid spectra shown in Figure c show distinct sets of well-defined signals both for rodlike and pyramidal NCs. Comparison between them reveals that the transformation from rod to pyramids involves a shift and/or broadening of the signals.…”