Modification of Multi-Component Building Blocks for Assembling Giant Chiral Lanthanide-Titanium Molecular Rings.

Building blocks with multiple components are promising for the synthesis of complex molecular assemblies, but are rarely available. Herein, we report a modification procedure for a multi-component building block [Ln 3 Ti(HSA) 6 (SA) 4 (H 2 O)] - ({Ln 3 Ti-SA}, H 2 SA=salicylic acid, Ln=Eu/Gd) to form new building blocks {Ln 3 Ti x -MSA} (H 2 MSA=5-methoxysalicylic acid, x=1, 2, 3) by constructing [Ti(MSA) 3 ] 2- units. The obtained {Ln 3 Ti x -MSA} can further assemble into a chiral Ln 22 Ti 14 ring with the formulae [Eu 22 Ti 14 (MSA) 48 (HMSA) 22 (CH 3 COO) 4 (H 2 O) 10 (iPrOH)] and [Gd 22 Ti 14 (MSA) 46 (HMSA) 26 (CH 3 COO) 4 (H 2 O) 8 ]. Parallel experiments without Ti 4+ result in linear Ln chains. Detailed analysis shows that the [Ti(MSA) 4 ] 4- unit makes the originally variable Ln chains become available building blocks and the modified [Ti(MSA) 3 ] 2- further triggers interesting chiral-sorting behavior. Finally, the electronic adsorption and magneto-optic responses of these molecular rings are investigated.