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61.
Kizilel S Pérez-Luna VH Teymour F 《Langmuir : the ACS journal of surfaces and colloids》2004,20(20):8652-8658
We describe a new method that allows photopolymerization of hydrogels to occur on surfaces functionalized with eosin. In this work, glass and silicon surfaces were derivatized with eosin and photopolymerization was carried out using visible light (514 nm). This mild condition may have advantages over methods that use ultraviolet (UV) light (e.g., for encapsulation of cells and proteins, in drug screening, or in biosensing applications). The hydrogel formed on the modified surface is remarkably stable for an extended period of time. The resultant hydrogel was hydrated for more than 18 months without suffering delamination from the substrate surface. This strongly suggests covalent attachment of the hydrogel to the surface. Contact angle titration measurements and X-ray photoelectron spectroscopy analysis of eosin surfaces before and after irradiation in the presence of triethanolamine suggest that the eosin radical is responsible for the covalent attachment of the gel onto the substrate surface. This method allows for 2-D patterning of hydrogels, which is demonstrated here using the microcontact printing technique. However, noncontact photolithography could be used to form similar patterns by directing light through a mask. This method can be easily implemented to form arrays of fluorophores and proteins in situ. 相似文献
62.
Bentiss F Lagrenée M Mentré O Conflant P Vezin H Wignacourt JP Holt EM 《Inorganic chemistry》2004,43(6):1865-1873
Mu-chloro-mu-[2,5-bis(2-pyridyl)-1,3,4-thiadiazole] aqua chlorocopper(II) dichlorocopper(II) is the first characterized dimeric complex of a transition metal and this hetero ligand [C(12)H(10)Cl(4)Cu(2)N(4)OS; triclinic; space group P; a = 9.296(3) A, b = 9.933(3) A, c = 10.412(3) A; alpha = 79.054(5) degrees, beta = 82.478(6) degrees, gamma = 67.099(5) degrees; Z = 2 at room temperature]. The Cu(II) ions are bridged by the N-N thiadiazole bond and a chloride ion [Cu1-Cu2 = 3.7800(8) A]. Thermogravimetric analysis shows this structure to be stable at temperatures up to 348 K. At higher temperatures, the successive loss of a water molecule and one chloride of the dimeric unit is identified. From room temperature to 125 K, half of the Cu(2+) ions are progressively engaged in intermolecular dinuclear antiferromagnetic exchanges, while the other half remain paramagnetic. At lower temperatures, both susceptibility and electron paramagnetic resonance measurements show the paramagnetic-only couplings of this half of the Cu(2+) ions, involving a singlet ground state for interacting Cu(2+). This unusual behavior has been satisfactorily explained on the basis of intermolecular Cu-Cu interactions (J = -180 cm(-1)), involving the magnetic d(z)2 orbital perpendicular to the molecular plane, on which are seen the conjugate effects of the bridging chloride and the planar thiadiazole. It is noteworthy that the behavior of the title compound is original, compared to the systematic in-plane intramolecular antiferromagnetic coupling of other thiadiazole-containing binuclear complexes. 相似文献
63.
A 5 wt% Pd/SiO2 catalyst was synthesized by heating PdCl2-impregnated SiO2 in H2 at 300°C for 2 h. It was found that the metal particle dispersion is improved when the reduction step is preceded by calcination at 300°C for 2h. Thermogravimetry of the impregnated support in air, N2 and H2 atmospheres was used to monitor the interactions occurring during the various preparative steps (i.e. drying, calcination and reduction) of the catalyst. The solid prduct of each preparative step was characterized by X-ray diffractometry and UV/Vis diffuse reflectance spectroscopy. The results indicate that following the drying step (at 110°C in air) the palladium occurs in two detectable forms: PdCl2 particles and Si?O?Pdn+ surface species. The calcination appears to transform the PdCl2 particles into the latter surface species. The H2-reduction eventually converts the surface species into finely-dispersed Pd° metal particles (average size=8–14 nm). No other reduction products, such as PdySix, were detected. 相似文献
64.
Henri Arzoumanian Marcel Pierrot Fouad Ridouane Jose Sanchez 《Transition Metal Chemistry》1991,16(4):422-426
Summary Several penta-and tetracyanooxomolybdenum(IV) anions have been synthesized containing different numbers of H2O molecules, either coordinated or present as crystallisation molecules. The influence of these molecules on the reactivity of the complex, especially towards O2, is discussed. Three compounds were characterized by x-ray structure determination. [Mo(O)(CN)5(H2O)2(MeCN)2][PPh4]4Cl belongs to triclinic space group P-1 witha=13.146(3) Å,b=16.944(5) Å,c=21.761(6) Å, =84.72(2)°, =87.15(2)° and =85.25(2)°. The volume of the unit cell is 4678(6)Å3 withz=2. The structure was refined to R=6.5%. [Mo(O)(CN)4(H2O)·6H2O][PPh4]2 belongs to monoclinic space group P21/n witha=15.313(2)Å,b=19.983(3)Å,c=17.006(2)Å, =100.51(2)°. The volume of the unit cell is 5117(3)Å3 withz=4. The structure was refined to R=8.7%. [Mo(O)(CN)4(MeCN)](PH3)2N]2 belongs to triclinic space group P-1 witha=13.770(4)Å,b=16.292(5)Å,c=16.889(5)Å, =73.23(2)°, =72.02(2)° and =71.57(2)°. The volume of the unit cell is 3342(3)Å3 withz=2. The structure was refined to R=7.2%. 相似文献
65.
Benzocycloheptapyrimidines are an important class of compounds because of their pharmacological properties. We report here two new synthetic procedures for the preparation of 2,4-dialkylamino substituted benzocycloheptapyrimidines. One of these methods is based on the reaction of substituted cyanamides with the vinyl triflate of the 1-benzosuberone while the other preparation relies on the nucleophilic displacement of methylsulfonyl groups by secondary amines at the 2 and 4 positions of benzocycloheptapyrimidine intermediates. 相似文献
66.
R. Fouad 《应用有机金属化学》2020,34(4):e5497
The development of biocompatible fluorescent materials based on CdII (d10) systems for cytotoxic application and latent fingerprint detection under UV illumination has not yet been studied that thoroughly. In this sense, this work presents production of novel and dual nature pure Cd (II) phosphor complex based on ρ-dimethylaminobenzaldehyde thiosemicarbazone ligand (H-DMABTS). The structural characterization confirms that the ligand which acts as monoanionic bidentate through NS donor sites, forming mononuclear complex formulates as: [Cd (DMABTS)2(C2H5OH)2] where, DMABTS = anionic form of ρ-dimethylaminobenzaldehyde thiosemicarbazone. TEM analysis shows that Cd (II) complex has sheet like shape in micro scale. Moreover, the Cd (II) complex was dispersed into silica host. Photoluminescence emission and lifetime of H-DMABTS ligand, Cd (II) complex and Cd (II) complex dispersied into silica were measured. Cd (II) complex is intensive luminescent with impressive visual emission under UV excitation. All fluorescent materials were tested for their in vitro cytotoxicity against HepG-2 cell line. The Cd (II) phosphor complex shows higher activity (IC50 = 0.005 μM) than other prepared materials and different standard antitumor drugs. Furthermore, the Cd (II) phosphor complex has a lower toxicity value (LD50 = 130 mg/Kg) relative to the standard cis-platin (LD50 = 13.5 mg/Kg). Moreover, latent prints details, including their characteristic three levels, have been clearly identified from various forensic substrates (non-porous, semi-porous, porous) using Cd (II) phosphor complex. 相似文献
67.
68.
Luais Erwann Ghamouss Fouad Sakai Joe Defforge Thomas Gautier Gaël Tran-Van François 《Journal of Solid State Electrochemistry》2019,23(3):937-941
Journal of Solid State Electrochemistry - The present article describes the innovative combination of freestanding macroporous silicon layers on copper foil collectors and room temperature ionic,... 相似文献
69.
70.
Mesu JG Visser T Soulimani F van Faassen EE de Peinder P Beale AM Weckhuysen BM 《Inorganic chemistry》2006,45(5):1960-1971
Aqueous solutions of Cu2+/histidine (his) (1:2) have been analyzed in parallel with infrared, Raman, ultraviolet/visible/near-infrared, electron spin resonance, and X-ray absorption spectroscopy in the pH range from 0 to 10. Comprehensive interpretation of the data has been used to extract complementary structural information in order to determine the relative abundance of the different complexes. The formation of six different, partly coexisting species is proposed. Structural proposals from literature have been unambiguously confirmed, refined, or, in several cases, corrected. At highly acidic conditions, Cu2+ and his are present as free ions, but around pH = 2, coordination starts via the deprotonated carboxylic acid group. This results in the intermediate species Cu2+[H3his+(Oc)] and Cu2+[H3his+(Oc)]2. The coordination via Oc is attended with a drop in the pKa value of the other receptor groups resulting in a concomitant conversion to the bidentates Cu2+[H2his0(Oc,Nam)] and Cu2+[H2his0(Oc,Nam)]2, with the latter being dominant at pH = 3.5. Coordination of the imidazole ring begins around pH = 3 and leads to the formation of the mixed ligand complexes Cu2+[H2his0(Oc,Nam)][Hhis-(Oc,Nam,Nim)] and Cu2+[Hhis-(Nam,Nim)][Hhis-(Oc,Nam,Nim)] around pH = 5. It is demonstrated that coordination of the imidazole ring occurs predominantly via the N(pi) atom. At pH > 7, the double-tridentate ligand complex Cu2+[Hhis-(Oc,Nam,Nim)]2 is the major species with the N atoms in the equatorial plane and the O atoms in the axial position. This complex decomposes at pH > 10 into a copper oxide/hydroxide precipitate. The overall results provide a consistent picture of the mechanism that drives the coordination and complex formation of the Cu2+/his system. 相似文献