Modular metallotecton for engineering permanently porous frameworks: supernumerary role of ancillary ion.

Abstract

The formation of robust supramolecular frameworks built from hetero-polytopic metal complexes and interacting with different ancillary ions remains a long-standing and underexplored desire. Herein, the secondary sphere interaction chemistry of [Ru(5-oxido-6-hydroxy-1,10-phenanthroline)a(5,6-dihydroxy-1,10-phenanthroline)(3-a)]-(a-2) (1) (a = 1, 3) coordination ion is reported, where the π-conjugated phenanthroline ligands are functionalized with catecholate groups used as H-bond donors and ligands. The deprotonation of the catechols is found to control the overall charge stoichiometry in 1, acting as a metallotecton to interact with anions of different basicity (Cl- in 1.Cl and Br- in 1.Br) as well as with Li+ cations (in 1.Li+). These interactions lead to the formation of 2D porous honeycomb networks without any significant alteration in the molecular packing. This implies that the self-assembly process is controlled by complementary intermolecular non-covalent interactions making the choice of the ancillary ion insignificant. The robust porous structure of the frameworks is established by uptake of D2O and I2 molecules within the microporous channels. This work demonstrates that supramolecular frameworks appear as flexible candidates for applications in gas sorption, separation and chemical sensing.