Constructing novel Cd(II) metal-organic frameworks based on different highly connected secondary building units via alteration of reaction conditions

摘要

Upon solvothermal reactions between Cd(II) salt and 5-pyridyl-tetrazolate (4-Ptz) under different reaction conditions, three new Cd(II) metal-organic frameworks (MOFs), namely [Cd-3(4-Ptz)(5)(H2O)(2)(mu(3)-OH)center dot 3DMA center dot 5H(2)O center dot CH3OH](n) (1), [Cd-5(4-Ptz)(8)(CH3OH)(2)(mu(3)-OH)(2)center dot 2DMA center dot 4H(2)O center dot 3CH(3)OH](n) (2) and [{Cd-9(4-Ptz)(14)(AC)(2)(mu(3)-OH)(2)(H2O)(4)}center dot 8DMA center dot H2O center dot 3CH(3)OH](n) (3), were synthesized based on different highly connected secondary building units (SBUs). In the presence of triethylamine, 1 was constructed based on an 8-connected triangular trinuclear Cd-3 SBU and exhibits a three-dimensional framework, while 2 was generated upon the addition of HCl, assembled through a close packing of the octahedron cages consisting of unprecedented 12-connected 4-Ptz bridged Cd-5 SBUs and thus showing high thermal and chemical stability. For generating 3, two different kinds of Cd-3 SBUs, including an 8-connected triangular SBU and a 10-connected linear SBU, were constructed and further integrated into a distorted octahedron-based net under the addition of both triethylamine and NaCl. In addition to the structural analysis, we also focused on the investigation of gas adsorption and solid-state fluorescence properties of 2.