Vitor Rosa, Christophe Fliedel, Alessio Ghisolfi, Roberto Pattacini, Teresa Aviles, and Pierre Braunstein. "
{Influence of a thioether function in short-bite diphosphine ligands on the nature of their silver complexes: structure of a trinuclear complex and of a coordination polymer}."
{DALTON TRANSACTIONS}. {42} (2013): {12109-12119}.
Abstract{New cationic Ag(I) complexes were prepared by reaction of AgBF4 with two thioether-functionalized bis-(diphenylphosphino) amine ligands, Ph2PN(p-ArSMe)PPh2 (L1) and Ph2PN(n-PrSMe)PPh2 (L2), and compared with those obtained from the unfunctionalized ligands Ph2PN(Ph)PPh2 (L3) and Ph2PN(n-Bu)PPh2 (L4), respectively. The complex {[}Ag-3(mu(3)-Cl)(2)(mu(2)-L1-P, P)(3)](BF4) (1 center dot BF4) contains a triangular array of Ag centres supported by three bridging L1 ligands and two triply-bridging chlorides. In contrast, ligand L2 led to the coordination polymer {[}\{Ag-2(mu(3)-L2,-P,P,S)(2)(MeCN)(2)\}\{Ag-2(mu(2)-L2-P,P)(2)(MeCN)(2) \}(BF4)(4)](n) (2) in which the tethered thioether group connects intermolecularly a Ag2 unit to the diphosphine bridging the other Ag2 unit. With L3 and L4, two similar complexes were obtained, {[}Ag-2(mu(2)-L3)(BF4)(2)] (3) and {[}Ag-2(mu(2)-L4)(BF4)(2)] (4), respectively, with bridging diphosphine ligands and a BF4 anion completing the coordination sphere of the metal. Complexes 1 center dot BF4 center dot CH2Cl2, 2 center dot THF, 3 center dot 3CH(2)Cl(2) and 4 have been fully characterized, including by single crystal X-ray diffraction.}
AS, Pedrosa, Borges JPMR, Neagu E, Marat-Mendes JN, and Lança MCH Electrical characterization of biphasic ceramics used in hard tissue replacement. Coimbra Portugal, 2013.
AbstractHydroxyapatite [Hap; Ca10(PO4)6(OH)2) and b-tricalcium phosphate [b-TCP; Ca3(PO4)2] are biocompatible calcium phosphates used in skeletal surgery. The natural HAp is one of the main components of bone and, as a synthetic material, has been widely used for bone replacement presenting good bioactivity. Nevertheless synthetic HAp presents a slow in vivo degradation rate which is disadvantageous for bone’s reparative process. b-TCP has also good osteogenic characteristics presenting the ability to form strong bonds with the bone however, its degradation rate is too fast [1]. Therefore, a composite combining these two ceramics is valuable as it exhibits a suitable degradation rate. Because of the piezoelectric properties of bone it is known that electrical polarization of calcium phosphates can enhance the bioactivity and biointegration of implants [2]. Previous studies have already showed that HAp/b-TCP ceramics can be electrically polarized and that electrical polarization enhances osteogenesis in the early stage of the implantation process. However further studies are required to understand, optimize and improve the polarization technique [1]. In this work a commercial biphasic ceramic powders were pressed in a mold at 200 MPa to produce disc shaped samples. Afterwards, the samples were sintered at temperatures from 950ºC to 1150ºC and the influence of the heat treatment in the electrical polarization and subsequent bioactivity was investigated. The samples were polarized under a high DC electric field at relatively lower temperature (200oC) compared to previous studies and the stability of polarization was tested using TSDC (thermally depolarization currents) measurements. It was studied the influence of the water, initially present in the material, in the total charge deposited during polarization, its stability and its relation with heat treatment after pressing. The influence of the addition of b-TCP on sample’s stored charge was also evaluated. Finally bioactivity tests in a simulated body fluid solution were made taking into account the signal of the charge in each surface of the disc samples so that the results could be compared to previous ones.