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The combination of a [zinc(II)-4,4 0 -bpy] coordination moiety with, respectively, formato, acetato and propionato ligands leads to the formation of the compounds {[Zn 3 (4,4 0 -bpy 3). The molecular structures determined by singlecrystal X-ray diffraction data reveal significant changes, which are apparently due to the sole different steric hindrance between a H atom (formato, compound 1), a methyl group (acetato, compound 2) and an ethyl group (propionato, compound 3). The three coordination materials have been fully characterized and their thermal decomposition behavior has been investigated. The 3D (1), 1D (2) and 2D (3) networks exhibit voids that contain the counter-ions and guest molecules as well, namely water for compounds 1 and 2, and water/4,4 0 -bpy for compound 3.

Three porous crystalline coordination polymers, i.e. the three-dimensional framework {[Zn(3)(4,4'-bpy)(3.5)(mu-O(2)CH)(4)(H(2)O)(2)](ClO(4))(2)(H(2)O)(2)}(n) (1), the one-dimensional three-leg ladder {[Zn(3)(4,4'-bpy)(3)(mu-O(2)CCH(3))(4)(H(2)O)(2)](PF(6))(2)(H(2)O)(2)}(n) (2), and the two-dimensional layered network {[Zn(3)(4,4'-bpy)(4)(mu-O(2)CCH(2)CH(3))(4)](ClO(4))(2)(4,4'-bpy)(2)(H(2)O)(4)}(n) (3), have been investigated. All networks exhibit voids that contain the counter-ions and guest molecules, namely water for compounds 1 and 2, and water/4,4'-bpy for compound 3. In addition, compounds 2 and 3 are further stabilized by hydrogen bonds and pi-pi stacking interactions to form intricate supramolecular frameworks. The removal and reintroduction of guest water molecules for compounds 2 and 3 have been explored for their dynamic structural transformation. Interestingly, all Zn(II) compounds are active heterogeneous catalysts for the high-yield cyanosilylation of acetaldehydes in dichloromethane.

No abstract

Functionalities of 3D printing filaments have gained much attention owing to their properties for various applications in the last few years. Innovative biocomposite 3D printing filaments based on polylactic acid (PLA) composited with ZnO nanoflowers at varying contents were successfully fabricated via a single-screw extrusion technique. The effects of the varying ZnO nanoflower contents on their chemical, thermal, mechanical, and antibacterial properties were investigated using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and tensile testing, as well as qualitative and quantitative antibacterial tests, respectively. It was found that the ZnO nanoflowers did not express any chemical reactions with the PLA chains. The degrees of the crystallinity of the PLA/ZnO biocomposite filaments increased when compared with those of the neat PLA, and their properties slightly decreased when increasing the ZnO nanoflower contents. Additionally, the tensile strength of the PLA/ZnO biocomposite filaments gradually decreased when increasing the ZnO nanoflower contents. The antibacterial activity especially increased when increasing the ZnO nanoflower contents. Additionally, these 3D printing filaments performed better against Gram-positive (S. aureus) than Gram-negative (E. coli). This is probably due to the difference in the cell walls of the bacterial strains. The results indicated that these 3D printing filaments could be utilized for 3D printing and applied to medical fields.