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181.
Aurel Pui Theodor MalutanLucia Tataru Corina MalutanDoina Humelnicu Gabriela Carja 《Polyhedron》2011,30(12):2127-2131
Some new Schiff bases derivates from 2-furaldehyde and phenylenediamines (L1-3) and their complexes with lanthanum (La), samarium (Sm), gadolinium (Gd) and erbium (Er) have been synthesized. These complexes with general formula [Ln(L1-3)2(NO3)2]NO3·nH2O (Ln = La, Sm, Gd, Er) were characterized by elemental analysis, UV-Vis, FT-IR and fluorescence spectroscopy, molar conductivity and thermal analysis. The metallic ions were found to be eight coordinated. The emission spectra of these complexes indicate the typical luminescence characteristics of the Sm(III), La(III), Er(III) and Gd(III) ions. 相似文献
182.
Tăbăcaru A Pettinari C Masciocchi N Galli S Marchetti F Angjellari M 《Inorganic chemistry》2011,50(22):11506-11513
Solvothermal reactions of the flexible, pyrazole-based 1,4-bis((3,5-dimethyl-1H-pyrazol-4-yl)methyl)benzene ligand (H(2)BDMPX) with late transition metal ions allowed the isolation of the four coordination compounds M(x)(BDMPX) (x = 1 for M = Zn, 1; Co, 2; Cd, 3; x = 2 for M = Cu, 4). The investigation of the thermal behavior assessed the high thermal robustness of these materials, which are stable in air at least up to 300 °C, with the Cd(II) derivative starting to decompose only around 500 °C. As retrieved by ab initio X-ray powder diffraction, the isomorphous compounds 1-3 possess a dense 3-D network featuring rhombic motifs hinged about rigid and parallel chains of tetrahedral MN(4) chromophores. As demonstrated by thermodiffractometric measurements, temperature increase triggers framework flexibility. The latter is at work also when N(2) adsorption is assayed at 77 K: 1 and 2 show permanent porosity, with BET and Langmuir specific surface areas of 515, 667 m(2)/g and 209, 384 m(2)/g, respectively. 1 and 2 thus represent an intriguing example of "porosity without pores", their pro-porous nature being explained in terms of the flexibility of the rhombic motifs, stimulated by the gas probe and facilitated by the nature of the ligand. 相似文献
183.
Mangiapia G Coppola C Vitiello G D'Errico G De Napoli L Radulescu A Montesarchio D Paduano L 《Journal of colloid and interface science》2011,354(2):718-724
Ionophores are an important class of synthetic molecules which mimic natural ion channels or carriers. Here we report the aggregation behavior in pseudo-physiological environment of three Cyclic Phosphate-Linked Oligosaccharides (CyPLOS) derivatives, synthetic ion transporters based on cyclic, phosphate-linked disaccharide skeleton differing for the nature of the tails (tetraethylene-TEG glycol and/or n-undecyl chains) attached to the C-2 and C-3 of the constitutive monosaccharides. Their aggregation behavior has been studied by a combined use of dynamic light scattering (DLS), electron paramagnetic resonance spectroscopy (EPR) and Small Angle Neutron Scattering (SANS). DLS measurements were performed to reveal the formation and size distribution of the CyPLOS aggregates. EPR measurements, by using 5-doxyl stearic acid (5-DSA) as spin-probe, showed that the aggregates are mainly due to the formation of double layers and allowed to analyze the local fluidity. Finally, SANS measurements allowed estimating the layer thickness of the double layers. Our results indicate that the three CyPLOS analogs show self-aggregation properties that depend on the different nature of the inserted tails. 相似文献
184.
Kais Elghniji Constantin Virlan Elimame Elaloui Aurel Pui 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):806-821
AbstractTunisian industrial phosphoric acid H3PO4 was supported on silica gel SiO2 (SIPA) to catalyze the hydrolysis reaction of aqueous alkaline sodium borohydride (NaBH4). The SiO2 was produced from purified quartz sand using alkali fusion-acidification chemical process. The BET surface area results indicate that the prepared silica gel could reach a specific surface area up to 585 m2/g. The addition of PO3H2 functional groups resulted in an increase of surface acidity of SiO2 catalyst as shown by FT-IR and DTA-DTG spectra. The total acidity of SIPA catalyst was determined by titration to be 2.8?mmol H+/g. SEM/EDS maps reveal the distribution of heavy metals on the silica surface. The effect of supported PO3H2 functional groups and heavy metals on the NaBH4 hydrolysis reaction was studied for different ratios of SIPA catalyst to NaBH4. The sample 12SIPA/NaBH4 leads to a very high hydrogen generation rate (up to 90%). The activation energy of hydrogen generation by NaBH4 hydrolysis was 25.7?kJ mol?1. 相似文献
185.
Pettinari C Tăbăcaru A Boldog I Domasevitch KV Galli S Masciocchi N 《Inorganic chemistry》2012,51(9):5235-5245
The reaction of the rigid spacer 4,4'-bipyrazole (H(2)BPZ) with late transition metals, either following conventional routes or under solvothermal conditions, afforded the coordination polymers [M(BPZ)]·Solv (M = Zn, 1; Co, 2; Cd, 3; Hg, 4; Cu, 5; Ni, 6; Pd, 7; Solv = DMF, 3; MeCN, 5 and 6; H(2)O, 7), [Cu(H(2)BPZ)(2)(NO(3))(2)] (8), and [Cd(H(2)BPZ)(CH(3)COO)(2)] (9). State-of-the-art laboratory powder diffraction methods allowed to disclose the isomorphous character of 1 and 2, as well as of 5 and 6, which feature 3D porous networks containing 1D channels of square and rhombic shape, respectively. 3, crystallizing in the relatively rare P6(1)22 space group, consists of homochiral helices of octahedral Cd(II) ions, packing in bundles mutually linked by "radial", nonplanar BPZ ligands. Finally, the dense species 8 and 9 contain parallel 2D layers of square and rectangular meshes, respectively. Thermogravimetric analyses witnessed the relevant thermal robustness of all the [M(BPZ)] materials [except the mercury(II) derivative], which are stable in air at least up to 300 °C, with the zinc(II) derivative decomposing only around 450 °C. Variable-temperature powder diffraction experiments highlighted the permanent porosity of 1-3, 5, and 6, retained along consecutive temperature cycles in all cases but 3. When probed with N(2) at 77 K, 1-3 and 5-7 showed Brunauer-Emmett-Teller and Langmuir specific surface areas in the ranges 314(2)-993(11) and 509(16)-1105(1) m(2)/g, respectively. 相似文献