NMR spectroscopy in coordination supramolecular chemistry: A unique and powerful methodology

作者：Pastor Aurelia^*; Martinez Viviente Eloisa

来源：Coordination Chemistry Reviews, 2008, 252(21-22): 2314-2345.

DOI：10.1016/j.ccr.2008.01.025

• Host-guest systems
• Molecular recognition
• NMR spectroscopy
• Supramolecular chemistry
• Self-assembly
• Structure elucidation

Metal-mediated self-assembly is emerging as a very important strategy for the synthesis of supramolecular species. Still, a major challenge in coordination supramolecular chemistry continues to be the characterization of the self-assembled complexes and the investigation of their dynamic behaviour in solution. In this context, NMR spectroscopy appears as a unique and powerful methodology. This practical-oriented review describes the rich variety of NMR techniques which are applied to the investigation of different aspects of the structure and behaviour of supramolecular complexes. "Classic" I D NMR spectra reflect characteristic chemical shifts due to metal-ligand interactions or encapsulation phenomena, as well as symmetry and chiral properties of host-guest assemblies. Mainstream (1)H, (13)C, (19)F and (31)P spectra are eventually complemented by the use of NMR-active metal nuclides. Homo- and heteronuclear 2D correlation experiments are ubiquitous in the literature, providing through-bond and through-space connectivities. Increasingly,diffusion measurements are also gaining popularity in this field, being used to gain in formation about molecular size, intermolecular interactions and even association constants of supramolecular complexes. Knowledge about the thermodynamic properties and the dynamic behaviour of coordination supramolecular assemblies is essential for the development of their practical applications. The most frequently used NMR methodologies for the calculation of association constants (simple signal integration, NMR titration and diffusion measurements) and for the investigation of dynamic supramolecular equilibria (lineshape analysis, selective inversion recovery experiments and 2D EXSY spectra) are described, together with the use of variable-temperature investigations for the determination of the thermodynamic and activation parameters of self-assembly and encapsulation processes.

• 出版日期2008-11