Geometrically Restricted Intermediates in the Self‐Assembly of an M₁₂L₂₄Cuboctahedral Complex

Abstract

Abstract The self‐assembly of a cuboctahedral M 12 L 24 complex is traced by time‐dependent NMR spectroscopy and mass spectrometry. The metastable intermediate structures that exist during the self‐assembly process are not a chaotic mixture of numerous species, but instead are geometrically restricted. Short‐lived M 8 L 16 (D 4d ) and relatively long‐lived M 9 L 18 (D 3h ) are fully characterized as major intermediates. Employing a ligand with a smaller bend angle (112°) allows these two species to be kinetically trapped and more clearly observed by NMR spectroscopy. X‐ray crystallography shows that M 9 L 18 has the framework topology predicted by geometric discussion.