Saccharide-functionalized organoplatinum(II) metallacycles

Coordination-driven self-assembly can be used to construct metallacycles decorated with saccharide functionalities by combining organoplatinum acceptor building blocks with glycosylated dipyridyl donors. We describe here the synthesis of a suite of donors encoded with 120° directionality. The 1,3-bis(pyridin-4-ylethynyl)benzene cores contain one of four pendant saccharide groups, resulting in a glucose-, galactose-, mannose-, and lactose-variant. The angularity of these donors makes them suitable for the self-assembly of [2 + 2] rhomboids and [3 + 3] hexagons containing two and three saccharide groups on combination with a 60 or 120° acceptor, respectively. The synthesis and characterization of eight such metallacycles are described, supported by multinuclear NMR and electrospray mass spectrometry data that confirm clean, highly symmetric products with the expected stoichiometries of formation. This work illustrates the use of coordination-driven self-assembly to obtain nanoscopic metallacycles with biologically relevant functionalities in high yields and facile synthetic methods.