Nanoscale Tectonics:  Self-Assembly, Characterization, and Chemistry of a Novel Class of Organoplatinum Square Macrocycles

Six nanoscale molecular squares are reported. They are prepared in essentially quantitative yields via spontaneous self-assembly of preprogrammed 90° angular units with diverse bimetallic linear linkers. Characterization was accomplished with multinuclear NMR and, in two cases, via ESI-FTICR mass spectral data. The size of these novel metallomacrocycles range from 3.6 nm (diagonal) and 2.6 nm (side) for the smallest to 4.7 nm (diagonal) and 3.4 nm (side) for the largest as estimated by extensible systematic force field calculations. The molecular squares incorporating alkynyl units as corners are able to complex four Ag + ions via the π-tweezer effect.