Pyridines steric aspects

The use of bulky ligands such as 2,6-di-tert-butyl-4-methylphenol allows isolation of the rare three- and four-coordinate forms of a variety of rare earths (Hitchcock et al., 1983). Theoretical aspects of the environment surrounding lanthanide complexes have been treated in calculations of steric interactions between NMR shift reagents and substituted pyridines (LaPlanche and Vanderkooi, 1983). This provided some insight into the steric factors that induce conformational alterations in these multifaceted species. 

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