Synthesis and Characterization of Two Isomeric, Self-Assembled Arsenic−Thiolate Macrocycles

The use of labile As−S bond formation in the self-assembly of discrete supramolecular structures is extended.
Macrocyclic structures of chemical formula As2L2Cl2 (H2L = α,α‘-dimercapto-p-xylene) were prepared and
characterized. Diastereomeric syn and anti isomers of these macrocycles were selectively crystallized and
characterized in the solid state using single-crystal X-ray diffraction. Both the syn and anti macrocycles show close
contacts between the arsenic(III) ions and the aromatic carbons, consistent with intramolecular arsenic−π interactions.
The dynamic behavior of the isomers in solution is also investigated. anti-As2L2Cl2·AsCl3 crystallizes in monoclinic
space group P21/c (No. 14) with a = 10.6194(5) Å, b = 16.7780(9) Å, c = 8.5725(4) Å, β = 100.6830(10)°, and
Z = 2. syn-As2L2Cl2 crystallizes in orthorhombic space group Pnma (No. 62) with a = 10.8881(8) Å, b = 19.3511(14) Å, c = 9.9524(7) Å, and Z = 4.