LAUSR

Solvothermal coordination polymerization of a semi-rigid tritopic ligand, namely, 1,3,5-tris(2,6-dimethyl-4-(α-carboxy)methoxyphenyl)benzene (H3BTA), with Zn(NO3)2 in DEF-EtOH-H2O (4:2:1, v/v/v) mixture leads to the formation of three compositionally distinct coordination polymers (CPs) with different morphologies, i.e., rods (Zn-R), needles (Zn-N) and blocks (Zn-B), in the same pot at different concentrations and temperatures; in fact, two sets of compositionally distinct CPs are formed concomitantly at two different concentrations, with one of them being common to the two sets. Attempts to intercovert the three CPs at different temperatures using the same solvent show that the acentric crystals of Zn-N and Zn-R convert to the chiral crystals of Zn-B irreversibly, while the latter remain intact. The crystal packing analysis reveals that the three CPs have different Zn2+ coordination geometries and secondary buliding units (SBUs), framework structures and solvent-accessible volumes, indicating the interplay of kinetic and thermodynamic factors in determining the energetics of metal-mediated self assembly. The occurrence of two sets of concomitant compositionally distinct CPs at different concentrations in the same pot, and conversion of achiral crystals to the chiral ones are reconciled from coordination preferences of the metal ions and structural flexibility of the semi-rigid linker with the solvent system playing a pivotal role.