Facile Assembly of Chiral Metallosquares by Using Enantiopure Tribenzotriquinacene Corner Motifs.

A pair of enantiomerically pure metallosquares based on linear platinum-diacetylene edges and tribenzotriquinacene corner units was synthesized. Their structures were characterized by (1) H-, (13) C- and (31) P NMR spectroscopy as well as MALDI-TOF mass spectrometry and circular dichroism. Based on DFT calculation, the optimized geometry possesses a distorted square conformation in which the four edges are not sitting on the same plane. The molecular square further self-assembled in the solid state to afford microspheres with diameter of approximately 300 nm, as determined by scanning electron microscopy.