Design and syntheses of two novel supermolecular frameworks through weak interactions

Two novel supermolecular frameworks constructed by 2,2′-biquinoline-4,4′-dicarboxylic acid (H2bqdc) were synthesized and their crystal structures were characterized by single crystal X-ray diffraction. Complex [Cu(C12H30N6)](NaOH)(bqdc)·2H2O (1) crystallizes in the triclinic space group P-1, with a=7.181(7), b=8.869(9), c=14.105(14) Å, α=101.315(8), β=100.487(6), γ=97.282(14)° and Z=1. It exhibits a 2-D framework constructed through hydrogen bonds. The macrocyclic-Cu(II) units decorate to the sheet also through H-bondings. Complex [Ni(en)2(H2O)2](bqdc)·2H2O (2) crystallizes in the triclinic space group P-1, with a=6.86030(10), b=7.2061(2), c=13.7801(4) Å, α=92.756(2), β=101.2050(10), γ=101.7210(10)° and Z=2. This complex exhibits a 3-D frameworks constructed also through weak interactions, especially H-bonding and π-π stacking. Interestingly, a hexa-oxygen ring was found in this structure formed by four water molecules and two carboxyl groups through hydrogen bonds. Thermography analyses of the two complexes were also tested.