Yayun Zhao

Biotemplated Syntheses of Macroporous Materials for Bone Tissue Engineering Scaffolds and Experiments in Vitro and Vivo

The macroporous materials were prepared from the transformation of cuttlebone as biotemplates under hydrothermal reactions and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric/differential thermal analyses (TG-DTA), and scanning electron microscopy (SEM). Cell experimental results showed that the prepared materials as bone tissue engineering scaffolds or fillers had fine biocompatibility suitable for adhesion and proliferation of the hMSCs (human marrow mesenchymal stem cells). Histological analyses were carried out by implanting the scaffolds into a rabbit femur, where the bioresorption, degradation, and biological activity of the scaffolds were observed in the animal body. The prepared scaffolds kept the original three-dimensional frameworks with the ordered porous structures, which made for blood circulation, nutrition supply, and the cells implantation. The biotemplated syntheses could provide a new effective approach to prepare the bone tissue engineering scaffold materials.

Pd- and Ni-Pyridyl Complexes Deposited as Films for Suzuki–Miyaura and Mizoroki–Heck Cross Coupling Reactions

Abstract A pyridyl fluorene ligand, 2,7-bis(4-pyridyl)-9,9-diethylfluorene (1), has been synthesized by a simple route. The ability of the two linearly terminal pyridyl nitrogen atoms of 1 to coordinate with the Pd(II) or Ni(II) ions has enabled the use of 1 as a linking ligand in the preparation of (PdCl2/1)n, (Ni(NO3)2/1)n films, PdCl2/1 and Ni(NO3)2/1 complex. The resulting films and complexes were characterized by UV–vis spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectrometer. The application of films and complexes as catalysts for Suzuki–Miyaura and Mizoroki–Heck reactions was carried out. (PdCl2/1)n films show high catalytic activity in the reactions with the Pd loading of ppm. (Ni(NO3)2/1)n multilayers as the active catalytic moieties for these reactions were investigated with very low Ni(II)-loading.Graphical AbstractThe (Pd or Ni/1)n multilayer films were used as high active catalysts for the C-C formation with extremely low M(II)-loading in ppm level.

Amplified spontaneous emission from 2,7-bis(4-pyridyl)fluorene-doped DNA- cetyltrimethyl ammonium complex films

Abstract. The 2,7-bis(4-pyridyl)fluorene (BPF) was synthesized via a Suzuki coupling reaction. The optical spectra properties of BPF and BPF-deoxyribonucleic acid (DNA)-cetyltrimethyl ammonium (CTMA) thin films composed of BPF, DNA, and CTMA were characterized by the measurements of UV/Vis absorption spectra and fluorescence spectra. The amplified spontaneous emission (ASE) of the BPF-DNA-CTMA films was researched experimentally by pumping of a pulse laser with a wavelength of 355 nm. The results show that the absorption peak and the fluorescence peak of BPF are located at 327 and 380 nm, respectively. The emission peak of BPF corresponds to the vibronic transitions from an excited state of S1 level to the ground state of S0 level. The ASE peak of the BPF-DNA-CTMA film is located at 384 nm, and the threshold of ASE excited energy density is 3.12  mJ·cm−2.

Synthesis, crystal structure and fluorescence spectrum of a cadmium(II) sulfaquinoxaline complex.

catena-Poly[[[4-amino-N-(quinoxalin-2-yl)benzenesulfonamidato]aquacadmium(II)]-μ-4-amino-N-(quinoxalin-2-yl)benzenesulfonamidato], [Cd(C14H11N4O2S)2(H2O)], has been synthesized hydrothermally and characterized by single-crystal X-ray diffraction, elemental analysis, fluorescence, IR and thermal analysis. Single-crystal X-ray analysis reveals that the complex is a one-dimensional zigzag chain structure, and the Cd(II) cation has a distorted octahedral coordination geometry formed by five N atoms from three different sulfaquinoxaline ligands and one O atom from a water molecule. The fluorescence spectrum reveals that the complex emits strong blue fluorescence and thermal analysis shows that the complex has high thermal stability.

Trace amount CuII (ppm) and mixture design of CuII/PdII catalyzed Suzuki cross-coupling reactions based on the cooperative interaction of metal with a conjugated pyridylspirobifluorene

Self-assembly of Cu/psf sheets and layer-by-layer (LbL) growth of PEI-(Cu/psf)n films were carried out and characterized (psf = 2,2′,7,7′-tetra(4-pyridyl)-9,9′-spirobifluorene). A mixture design was performed to evaluate the singular and combined catalytic effects of Cu(II), Pd(II) and psf ligands in the Suzuki cross-coupling reactions. The results showed that copper exhibited high catalytic activities in the presence of psf ligands. The (CuII/psf)n films were used as the reservoirs of catalysts capable of gradually discharging highly active catalytic moieties to promote the coupling reactions with ultra low Cu-loadings (as low as 1.4 × 10−5 mol%).

Electrochemical properties of a cobalt(II) complex with sulfadiazine and 1,3‐bis(pyridin‐4‐yl)propane

catena-Poly[[bis{4-[(pyrimidin-2-ylazanidyl)sulfonyl]aniline}cobalt(II)]-bis[μ-1,3-bis(pyridin-4-yl)propane]], [Co(C10H8N4O4S2)2(C13H14N2)]n or [Co(L)2(bpp)]n, crystallizes as a one-dimensional polymeric structure which is further stabilized by intermolecular hydrogen bonding. The refined Flack parameter, -0.001 (10), indicates that the model represents the correct absolute structure. Investigation of the thermal stability shows that the complex is stable up to 543 K. The structure is of interest with respect to its electrochemical properties in the reduction reaction of H2O2 to H2O.

Synthesis, Crystal Structure and Magnetic Properties of a Mn(II) Fluorenedicarboxylate Complex

A new Mn(II) metal-organic framework, [Mn(DFDC)(phen)]n (1) (where H2DFDC=9,9- diethylfluorene-2,7-dicarboxylic acid, phen=1,10-phenanthroline), was solvothermally synthesized and characterized by single-crystal and powder X-ray diffraction (PXRD), elemental and thermal analysis, IR, UV=Vis spectroscopy, fluorescence and magnetic measurements. Single-crystal X-ray analysis reveals that 1 exhibits a three-dimensional coordination polymer structure. The compound crystallizes in the orthorhombic space group Pnna with a=9.1215(9), b=26.436(3), c=10.2428(10) Å, V =2469.9(4) Å3, Z =4, final wR2=0.1323 for 2825 reflections. The Mn(II) ion is coordinated by four oxygen atoms from four different H2DFDC ligands and two nitrogen atoms from one phen ligand in an octahedral coordination geometry. The compound shows ferromagnetic coupling behavior and has high thermal stability up to 420 °C Graphical Abstract Synthesis, Crystal Structure and Magnetic Properties of a Mn(II) Fluorenedicarboxylate Complex