Crystal Engineering and Self‐Assembled Nanoring Formation with Purine‐CdII/HgII Supramolecular Frameworks

We report three complexes of CdII and HgII with two purine rare tautomers, N9‐(pyridin‐2‐ylmethyl)‐N6‐methoxyadenine, L1 and N7‐(pyridin‐2‐ylmethyl)‐N6‐methoxyadenine, L2, highlighting diverse crystallographic signatures exhibited by them. Influence of substituents, binding sites, steric effects and metal salts on the different modes of binding enabled an insight into metal‐nucleobase interactions. L1 interacted with two and three equivalents of Cd(NO3)2.4H2O and HgCl2, respectively, while L2 interacted with two equivalents of HgCl2, altogether leading to three different complexes (1 [C48H48Cd6N34O50], 2 [C12H12Cl4Hg2N6O] and 3 [C12H12Cl2HgN6O]) possessing varied dimensionality and stabilising interactions. The photoluminescent properties of these coordination frameworks have also been probed. Notably, nanoring‐like structures were obtained, as a result of self‐assembly of 3 when investigated by transmission electron microscopy, additionally supported by molecular dynamics simulations. A comparative crystallographic study of Cd(II)/Hg(II) complexes of isomeric purine rare tautomers and subsequent nanoring formation investigated by molecular dynamics simulations and transmission electron microscopy.