Building Large Structures with Curved Aromatic Surfaces by Complexing Metals with Phosphangulene.

Phosphangulene (1) is a hexacyclic triarylphosphine with a distinctive conical shape and an electron-rich aromatic surface that is geometrically and electronically complementary to fullerenes such as C60 and C70. As a result, suitable derivatives of phosphangulene can cocrystallize with fullerenes or even bind them in solution. Surprisingly, previous work has largely overlooked the potential of phosphangulene to form complexes with metals, which offers a simple way to create large molecular structures with curved aromatic surfaces. To explore this approach, we have prepared and characterized a series of complexes of phosphangulene with Ag+ and Cu+. Our results show that Phang ligands are exceptional for many reasons. In particular, they can yield metal complexes with unique coordination, and the metal centers hold the concave aromatic surfaces of multiple ligands in various divergent arrays. Moreover, the rigid conical structure of phosphangulene gives the complexes an awkward shape that cannot be packed efficiently without complementary partners. As a result, metal complexes of phosphangulene are predisposed to cocrystallize with fullerenes, thereby yielding materials in which metals and fullerenes are brought together in ordered arrangements.