Iron Phosphate Nanozyme-Hydrogel with Multienzyme-like Activity for Efficient Bacterial Sterilization.

Pathogenic bacteria infections have posed a threat to human health worldwide. Nanomaterials with natural enzymatic activity provide an opportunity for the development of new antibacterial pathways. We successfully constructed iron phosphate nanozyme-hydrogel (FePO4-HG) with the traits of positive charge and macropores. Interestingly, FePO4-HG displayed not only peroxidase-like activity under acidic bacterial infectious microenvironment but also superoxide dismutase-catalase-like synergistic effects in neutral or weak alkaline conditions, thus protecting normal tissues from the peroxidase-like protocol with exogenous H2O2 damage. Furthermore, the positive charge and macropore structure of FePO4-HG could capture and restrict bacteria in the range of ROS destruction. Obviously, FePO4-HG exhibited excellent antibacterial ability against MRSA and AREC with the assistance of H2O2. Significantly, the FePO4-HG + H2O2 system could efficiently disrupt the bacterial biofilm formation and facilitate the glutathione oxidation process to rapid bacterial death with low cytotoxicity. Moreover, FePO4-HG was unsusceptible to bacterial resistance development in MRSA. Animal experiments showed that the FePO4-HG + H2O2 group could efficiently eliminate the MRSA infection and present excellent wound healing without inflammation and tissue adhesions. With further development and optimization, FePO4-HG has great potential as a new class of antibacterial agents to fight antibiotic-resistant pathogens.

Eight Zn(II) coordination networks based on flexible 1,4-di(1H-imidazol-1-yl)butane and different dicarboxylates: crystal structures, water clusters, and topologies.

Eight new Zn(II) coordination polymers based on flexible 1,4-di(1H-imidazol-1-yl)butane and different dicarboxylates, [Zn(dimb)(suc)·2DMF]n (1), [Zn(dimb)(mbda)·3H2O]n (2), [Zn(dimb)(adip)·DMF·2H2O]n (3), [Zn(dimb)(pma)·2.5H2O]n (4), [Zn2(dimb)(tha)2(H2O)]n (5), [Zn(dimb)(chda)·2H2O]n (6), [Zn(dimb)(obda)·DMF]n (7), [Zn(dimb)(tdga)·CH3OH]n (8) (dimb = 1,4-di(1H-imidazol-1-yl)butane, H2suc = succinic acid, H2mbda = m-benzenediacetic acid, H2adip = adipic acid, H2pma = pimelic acid, H2tha = thiophene-2,5-dicarboxylic acid, H2chda = 1,4-cyclohexanedicarboxylic acid, H2obda = o-benzenediacetic acid, H2tdga = thiodiglycolic acid; DMF = N,N'-dimethylformamide), have been synthesized and structurally characterized by single-crystal X-ray diffraction analyses, and further characterized by infrared spectra (IR), elemental analyses, powder X-ray diffractions (PXRD) and thermogravimetric analyses (TGA). Single-crystal X-ray diffraction analysis reveals that 1, 2, 4, 7 and 8 are 2D wavy 4(4)-sql networks with different dimensions of quadrilateral window units, depending on the conformation and length of dimb and dicarboxylates. Complex 3 is a 2D a 6(3)-hcb network incorporating a [Zn2(dimb)2] cyclic subunit. In complex 5, Zn(II) centers as 3-connected node are linked by dimb and tha to form a 3D 8-fold interpenetrating ThSi2 network. Complex 6 is a 4-connected noninterpenetrating cds network. Interestingly, an infinite T4(2)6(2) water tape and a D2h cyclic water tetramer are also found in complexes 2 and 3, respectively. In 1-8, all Zn(II) centers are located in a four-coordinated environment, and dimb and dicarboxylates are 2-connected linkers, but networks with diverse topologies are built, which indicates the linkage of central metal ion, the conformation of dimb and dicarboxylate have important influences on the resulting structures. Furthermore, the solid-state photoluminescence properties of the 1-8 were investigated at 298 and 77 K.

A novel two-dimensional CuSCN network templated by 2,2'-dimethyl-1,1'-(butane-1,4-diyl)bis(1H-imidazol-3-ium) cations.

The cation-templated self-assembly of 1,4-bis(2-methyl-1H-imidazol-1-yl)butane (bmimb) with CuSCN gives rise to a novel two-dimensional network, namely catena-poly[2,2'-dimethyl-1,1'-(butane-1,4-diyl)bis(1H-imidazol-3-ium) [tetra-µ2-thiocyanato-κ(4)S:S;κ(4)S:N-dicopper(I)]], {(C12H20N4)[Cu2(NCS)4]}n. The Cu(I) cation is four-coordinated by one N and three S atoms, giving a tetrahedral geometry. One of the two crystallographically independent SCN(-) anions acts as a µ2-S:S bridge, binding a pair of Cu(I) cations into a centrosymmetric [Cu2(NCS)2] subunit, which is further extended into a two-dimensional 4(4)-sql net by another kind of SCN(-) anion with an end-to-end µ2-S:N coordination mode. Interestingly, each H2bmimb dication, lying on an inversion centre, threads through one of the windows of the two-dimensional 4(4)-sql net, giving a pseudorotaxane-like structure. The two-dimensional 4(4)-sql networks are packed into the resultant three-dimensional supramolecular framework through bmimb-SCN N-H···N hydrogen bonds.

A two-dimensional silver-iodide organic network constructed from a unique [Ag6I6] hexagonal prism-based one-dimensional column motif.

A novel two-dimensional coordination polymer, poly[[µ2-1,3-bis(2-methyl-1H-imidazol-1-yl)propane]di-µ4-iodido-di-µ3-iodido-silver(I)], [Ag4I4(C11H16N4)]n, (I), has been synthesized by solvothermal reaction of AgNO3, KI and 1,3-bis(2-methyl-1H-imidazol-1-yl)propane (bmimp). In (I), the two unique Ag(I) cations have AgNI3 and AgI4 four-coordinated tetrahedral geometries. The bmimp ligand has imposed twofold symmetry. The Ag(I) cations and iodide anions form a unique one-dimensional polymeric column motif incorporating [Ag6I6] hexagonal prisms, which are then connected by bmimp ligands to form two-dimensional organic-inorganic layers. The layers are arranged in parallel in an ABAB fashion and are packed into the resultant three-dimensional supramolecular framework by van der Waals interactions.

A novel three-dimensional CdII metal-organic framework based on [Cd6(malonate)6] metallomacrocycles with zeolite SOD (sodalite) topology: poly[ammine-µ3-malonato-cadmium(II)].

A novel Cd(II) metal-organic framework, [Cd(C(3)H(2)O(4))(NH(3))](n), was synthesized by liquid diffusion conducted in the presence of ammonia. The Cd(II) atom has seven-coordinate O(6)N pentagonal-bipyramidal geometry. Six Cd(II) centers are joined by six malonate ligands to form an S(6)-symmetric [Cd(6)(malonate)(6)] metallomacrocycle, which is further extended through a side-on chelating malonate ligand to form a three-dimensional network. Topologically, each Cd(II) center is connected to four others to yield an infinite three-periodic four-coordinated SOD (sodalite) network with point symbol {4(2)·6(4)}. The overall network structure in the crystal is maintained and stabilized by the presence of N-H...O hydrogen bonds.