Metallosupramolecular Architectures of Ambivergent Bis(Amino Acid) Biphenyldiimides

The metallosupramolecular chemistry of two enantiopure dicarboxylate ligands has been explored for their potential to form discrete or polymeric interlocked motifs. Consequently, both discrete and polymeric supramolecular complexes have been synthesised, yielding M₂L₂ metallomacrocycles (1 and 2), a heteroleptic M₂L₃ metallomacrobicycle (3), a non-interpenetrated coordination polymer (4), and highly unusual chiral M₈L₈ squares (5 and 6). There appears to be a preference for the ligands to form M₂L₂-type metallomacrocyclic structural units (which feature in 1–4), although these do not engage in any mechanical interlocking, which is perhaps a combined function of the ligand flexibility and relatively small pi-surface contrasted to previous analogues. Using copper paddlewheel SBUs, chiral double-walled squares (5 and 6) are formed with large internal cavities yet poor stabilities, unexpectedly featuring the paddlewheel motifs at the vertices of the polygonal complex.