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A flurry of research activity has emerged in recent years resulting in reliable strategies for the formation of spectacular self-assembled metal-ligand clusters and capsules. Main group ions have not shared in this burst of activity. In fact, ions in this part of the periodic table have largely been overlooked for use as directing elements in self-assembly reactions, despite the need for improved chelators for main group ions for a variety of applications. This review surveys our approach to developing design strategies to prepare self-assembled nanoscale supramolecular complexes containing main group ions, with a particular emphasis on supramolecular arsenic(III) coordination chemistry.

The synthesis and crystal structures of two new macrocyclic compounds, As2(L2,5)2Cl2 and As2(L2,3)2Cl2, are described, where L2,3 and L2,5 are dithiolate ligands. For each compound, several diastereomeric isomers are possible (anti-“aligned”, syn-“aligned”, anti-“unaligned”, syn-“unaligned”), as shown by density functional theory (DFT) calculations, but only one is crystallized out of solution. For As2(L2,5)2Cl2, only the anti-aligned isomer crystallizes, as expected based on steric arguments and backed up by DFT calculations. Surprisingly, for As2(L2,3)2Cl2, an anti isomer crystallizes in which one As−Cl unit has folded into the macrocyclic cavity. While this goes against steric arguments and DFT calculations, this conformation best fills the space within the cavity, avoiding the entropic cost of a large void.

Three discrete supramolecular self-assembled arsenic(iii) complexes including an unusual S(4)-symmetric tetranuclear [As(4)L(2)Cl(4)] metallacyclophane and two diastereomeric cis/trans-[As(2)LCl(2)] metallacycle intermediates co-crystallize within a single crystal lattice.

A flurry of research activity has emerged in recent years resulting in reliable strategies for the formation of spectacular self-assembled metal-ligand clusters and capsules. Main group ions have not shared in this burst of activity. In fact, ions in this part of the periodic table have largely been overlooked for use as directing elements in self-assembly reactions, despite the need for improved chelators for main group ions for a variety of applications. This review surveys our approach to developing design strategies to prepare self-assembled nanoscale supramolecular complexes containing main group ions, with a particular emphasis on supramolecular arsenic(III) coordination chemistry.