Tuning the Framework Formation of Ni(II) Complexes by Controlling the Hydrolysis of 2,2‘,3,3‘-Thiodiphthalic Dianhydride: Syntheses, Crystal Structures, and Physical Properties

Three novel coordination polymers, namely, {[Ni(2,2‘,3,3‘-H2tdpa)(H2O)2]·(H2O)2}n (1), [Ni3(2,2‘,3,3‘-Htdpa)2(H2O)12]n
(2), and {[Ni4(2,2‘,3,3‘-tdpa)2(bpy)4(H2O)4]·(H2O)10}n (3), were prepared under hydrothermal conditions through rational control of
the hydrolysis of a new flexible ligand of 2,2‘,3,3‘-tdpda (2,2‘,3,3‘-tdpda = 2,2‘,3,3‘-thiodiphthalic dianhydride; 2,2‘,3,3‘-H4tdpa =
2,2‘,3,3‘-thiodiphthalic acid) and characterized by elemental analyses, IR spectra, thermogravimetric analysis, and single-crystal
X-ray diffraction analysis. In 1, two neighboring nickel ions are first bridged together through 3-COO- in bidentate fashion and
μ2-H2O to form a one-dimensional (1D) Ni chain. These 1D chains are further locked with each other by 2‘-COO- in monodentate
fashion to form a two-dimensional (2D) alternate square tubule sheet. For 2, Ni1 atoms are coordinated by 2,2‘-COO- in monodentate
fashion to form alternate left- and right-helices, which are further bridged together by the coordination interactions between Ni2
atoms and 3-COO- to give a 2D helical coordination polymer. 3 has a three-dimensional (3D) chiral open framework with homochiral
sheets and 4,4‘-bpy pillars. Thermogravimetric analysis and powder X-ray diffraction analysis show that the porous framework of
3 is stable after removal of both solvent and coordination water molecules. Both 1 and 2 show paramagnetic behaviors, while 3
displays a metamagnetic behavior.