Shape-Persistent Polyphenylene Dendrimers—Restricted Molecular Dynamics from Advanced Solid-State Nuclear Magnetic Resonance Techniques

The molecular dynamics of polyphenylene dendrimers(e.g., the second generation dendrimer shown in the Figure) is investigated here using advanced solid-state NMR techniques. It is found that well-localized, restricted reorientation of single terminal phenyl substituents occurs around fixed axes only, clearly demonstrating the shape persistence of these dendrimers. The synthetic approach to these polyaromatic dendrimers is also described.