Faculty of Science, Agriculture & Engineering

Solid-State NMR (SSNMR)

Prof William McFarlane

  • Emeritus Professor

An initial attraction to organometallic chemistry was fostered by Prof William McFarlane's Ph.D. supervisor, Professor Sir Geoffrey Wilkinson, and this led to an enduring interest in nuclear magnetic resonance (NMR) spectroscopy and its applications throughout the periodic table. Early research was on the dependence of coupling constants and chemical shifts for many different nuclei on structural and electronic molecular features.

Current work embraces the use of ROESY and other n.O.e - based two-dimensional NMR experiments to determine the solution structures, absolute configurations, and conformations of (catalytically important) organometallic and coordination compounds; the synthesis, structural characterisation and molecular dynamics of novel polyhosphines and their complexes; and the study of structure/reactivity relationships of metallo-proteins.


Organometallic and coordination compounds play vital roles in modern chemistry as catalysts and sources of new materials with important electrical, optical or other special properties. They are also of considerable relevance to biological chemistry. Sophisticated n.m.r. methods are being used to investigate the behaviour in solution of such substances with a view to elucidating their modes of action and and as an aid to the synthesis of new materials.

At present work is underway on the conformations of chiral ligands and their complexes, using the technique of two-dimensional rotating frame nuclear Overhauser effect spectroscopy (ROESY). This permits the measurement of the relative distances through space between the hydrogen atoms in a molecule and hence leads to a determination of its detailed molecular structure in solution. The attainable precision is comparable with that obtained in X-ray diffraction studies, although this latter technique is restricted to studies of solids and depends upon the availability of suitable crystals. Recently we have developed a ROESY-based method for the unambiguous assignment of the absolute configurations of chiral ligands and have applied it to complexes such as 1 and 2 below. It has considerable potential in many areas of chemistry.

Many of the molecules studied contain polydentate amine or phosphine ligands coordinated to transition metals and multinuclear studies are undertaken of such nuclei as P-31, Se-77, Mo-95, Rh-103, Sn -119, W-183 and Pt-195, together with the proton and C-13 on a routine basis. Allied to special 2D n.m.r. techniques such as COSY, NOESY, ROESY, and EXSY and the use of multiple quantum experiments these provide remarkable detail on the structures, solution dynamics and electron exchange behaviour of species as diverse as crown ether analogues for the sequestration of heavy metals, catalysts for asymmetric synthesis, and metallo-proteins with important electron transfer functions.