NMR Studies Of Supramolecules:assembled By Multi-topic Terpyridene Ligand And Fe²⁺

Metal supramolecules have diverse geometric configurations. Special functional groups can be introduced by small ligands, which lead to potential applications in the photoelectronic information, film, catalytic, nanomaterials and biomedical fields. The chemist?s purpose is to fulfill the functional role of supramolecules, by designing the structures of organic ligands, and by choosing different metal ions. However, the structures of self-assembled products are affected by many factors, such as the types of metal ions, anions, solvents, the ligand?s structures and the ratio of metal ions to ligands. A complete characterization method is needed for analysis of the product?s structure. In this paper, we use nuclear magnetic resonance(NMR) methods to study the structures and macroscopic sizes of superamolecules mainly including the following two parts:1. 2D NMR methods were applied to study the structures of supramolecules. Assignments of 1H and 13 C resonance were accomplished by 1D and 2D spectra, which then helped to identify the configurations of supramolecules. Through the comparative studies of ligands and supramolecules, the self-assembly process was confirmed.2. Molecular weight and molecular size of supramolecules were determined with the aid of PFG(Pulsed Gradient Field) NMR techniques. A series of Polystyrene(PS) samples with different molecular weights were used as standard samples to test the effective of this method. Diffusion coefficients D were obtained from DOSY(Diffusion Ordered Spectroscopy, using PFG technique) experiments. A standard fitting curve with good linearity was found for PS between their molecular weights M and D. This method was applied to the supramolecular system as well. The Stocks-Einstein equation was used to estimate the molecular size of different supramolecules. A relieable method for molecular weight and molecular size determination of supramolecules was established with PFG NMR.