A bowl-shaped circular trinuclear helicate generated from a TiO4 N2 motif by a multicomponent self-assembly approach

The synthesis of a bowl-shaped trinuclear circular titanium-based helicate is reported. The strategy allowing access to this neutral architecture is based on a multicomponent self-assembly approach in which the ligands involved in the process are a bis-biphenol strand and 2,2'- bipyrimidine. By reacting the bis-biphenol ligand and 2,2'-bipyrimidine with an equimolar amount [Ti(OiPr)4 ], a bowl-shaped architecture is obtained through the formation of 18 new coordination bonds. This aggregate built from three octahedral TiO4 N2 nodes displays an unusually high stability in solution compared to related species. In addition, by modifying the stoichiometry of the initial components, two assemblies incorporating two titanium centers bridged by a 2,2'-bipyrimidine ligand are obtained. The crystal structures of these species are reported.