A 31P{1H} NMR Spectroscopic Study of Phosphorus-Donor Ligands and Their Transition Metal Complexes

EthanC. Cagle, Timothy R. Totsch, Mitzy A. Erdmann, Gary M. Gray

Index: 10.1021/acs.jchemed.7b00673

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Abstract

31P{1H} nuclear magnetic resonance spectroscopy is a particularly useful tool for studying the reactions of P-donor ligands such as phosphines and phosphites with transition metals and other Lewis bases because the reactions take place on the nonbonding pair of electrons on the phosphorus. In addition, 31P has a 100% natural abundance and a high gyromagnetic ratio resulting in a high sensitivity that allows the spectra to be recorded using small amounts of sample. An activity that combines air-sensitive synthesis of transition metal complexes of P-donor ligands and the characterization of these complexes with 31P{1H} NMR spectroscopy has been developed for an upper-division, laboratory-based inorganic course. This laboratory familiarizes students with this useful nucleus for NMR spectroscopy and allows them to study the factors that affect the 31P{1H} NMR chemical shifts of phosphorus-donor ligands and their transition metal complexes. Details of the activity, including procedure and pretest, are provided. Alternative methods and presentations are also proposed.