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1.
Two new organic-inorganic hybrid materials, 1-(2-fluorophenyl)piperazine-1,4-diium tetrachlorocuprate, (C10H15FN2)[CuCl4] (I) and 1-(2-fluorophenyl)piperazin-4-ium nitrate, (C10H14FN2)[NO3] (II), have been synthesized by an acid/base reaction at room temperature in the presence of 1-(2-fluorophenyl)piperazine as an organic-structure directing agent and their structures were determined by single crystal X-ray diffraction. Compound (I), (C10H15FN2)[CuCl4], crystallizes in the monoclinic system and P21/c space group with a = 7.5253 (2), b = 20.6070 (7), c = 9.7281 (3) Å, β = 103.6730 (17)°, V = 1465.82 (8) Å3 with Z = 4. Full-matrix least-squares refinement converged at R = 0.037 and wR(F2) = 0.088. Compound (II), (C10H14FN2)[NO3], belongs to the monoclinic system, space group P21/c with the following parameters: a = 10.8034 (2), b = 7.5775 (1), c = 14.4670 (3) Å, β = 111.761 (2)°, V = 1099.91 (4) Å3 and Z = 4. The structure was refined to R = 0.044, wR(F2) = 0.136.In the structures of (I) and (II), the anionic and cationic entities are interconnected by means of set of hydrogen bonding contacts forming three-dimensional networks. Intermolecular interactions were investigated by Hirshfeld surfaces and the contacts of the four different chloride atoms were notably compared. The results of the optimized molecular structure are presented and compared with the experimental one. The Molecular Electrostatic Potential (MEP) maps and the HOMO and LUMO energy gap of both compounds were computed. The vibrational absorption bands were identified by infrared spectroscopy. Theory (DFT) calculations of normal mode frequencies are compared with experimental ones. 相似文献
2.
Ioan Bica 《Journal of Industrial and Engineering Chemistry》2012,18(1):483-486
Two sets, each of five samples, of magnetorheological elastomers (MREs) based on silicone rubber and carbonyl iron were prepared. One set of samples was obtained by polymerization of the silicone rubber with additives in the absence of the magnetic field, while the other by polymerization of the silicone rubber with additives in the presence of the magnetic field (840 kA/m). The samples from each set differ by volume concentration of the magnetic phase. By means of an experimental setup described in the paper, the electrical resistance R of the samples was measured as a function of the force F applied on the surface of the samples, for fixed values of the transverse magnetic field strength H. From the as-measured dependence R = R(F)H, the dependence σ = σ(p)H of the electric conductivity σ on the applied pressure p was determined. The experimental results are discussed in view of possible applications like magneto-mechanical sensors working in hostile media. 相似文献
3.
《Journal of the European Ceramic Society》2017,37(4):1459-1466
Lead-free 0.94NBT-0.06BT-xLa ceramics at x = 0.0–1.0 (%) were synthesized by a conventional solid-state route. XRD shows that the compositions are at a morphotropic phase boundary where rhombohedral and tetragonal phases coexist. With increasing La3+ content pyroelectric coefficient (p) and figures of merits greatly increase; however, the depolarization temperature (Td) decreases. p is 7.24 × 10−4C m−2 °C−1 at RT at x = 0.5% and 105.4 × 10−4C.m−2 °C−1 at Td at x = 0.2%. Fi and Fv show improvements at RT from 1.12 (x = 0%) to 2.65 (x10 −10 m v−1) (x = 0.5%) and from 0.021 to 0.048 (m2.C−1) respectively. Fi and Fv show a huge increase to 37.6 × 10−10 m v−1 and 0.56 m2 C−1 respectively at Td at x = 0.2%. FC shows values of 2.10, 2.89, and 2.98 (x10−9C cm−2 °C−1) at RT at 33, 100 and 1000 (Hz) respectively. Giant pyroelectric properties make NBT-0.06BT-xLa at x = 0.2% and 0.5% promising materials for many pyroelectric applications. 相似文献
4.
Perovskite-structured Pb0.6Bi0.4(Ti0.75Zn0.15Fe0.1)O3 ceramics was reported with high Curie temperature TC of 705 °C and tetragonality of c/a = 1.10, promising for high temperature applications with large piezoelectric anisotropy. In this paper, it was experimentally demonstrated to ease poling processing and enhance piezoelectricity through substituting lead with calcium of Pb0.6?xCaxBi0.4(Ti0.75Zn0.15Fe0.1)O3. For the x = 0.18 sample, electromechanical coupling factor ratio of kt/kp → ∞, dielectric constant of 380, piezoelectric coefficient d33 of 80 pC/N, mechanical quality factor Qm of 50 and Curie point TC of 237 °C were obtained, which exhibits better piezoelectric performance than the (Pb0.76Ca0.24)(Ti0.96(Co0.5W0.5)0.04)O3. The enhanced piezoelectric response was analyzed with relation to the reduction of tetragonality and Curie temperature. 相似文献
5.
The new anion [Cr2(CO(NH2)2)2(C6H4O7)2]2 − has been isolated in the complex [Cr(CO(NH2)2)6]2[Cr2(CO(NH2)2)2(C6H4O7)2]3. The crystals of this complex were obtained by a one-pot synthetic method using 1:1 molar ratio of hexaureachromium(III) chloride and trisodium citrate in aqueous medium. It was characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction analysis. The compound crystallizes in space group R‾3 of the trigonal system with three formula units in a cell of dimensions a = b = 24.7461(4) Å, c = 13.7204(3) Å and γ = 120°. The crystal structure comprises the columns consisting of [Cr(CO(NH2)2)6]3 + cations surrounded by a cylinder of complex anions, [Cr2(CO(NH2)2)2(C6H4O7)2]2 − which are packed in a honeycomb-like manner. This supramolecular architecture is formed and stabilized by inter- and intramolecular NH⋯O hydrogen bonds. 相似文献
6.
Dependence of electrical properties on the structural characteristics of Li0.04(K0.5Na0.5)0.96(Nb1?ySby)O3 (LKNNS (x = 0, 0.00 ≤ y ≤ 0.10)) and [Li0.04(K0.5Na0.5)0.96?xAgx](Nb0.925Sb0.075)O3 (LKNANS (0.01 ≤ x ≤ 0.05, y = 0.075)) were investigated. The oxygen octahedral distortion was dependent on Ag+ and/or Sb5+ content which affected to the phase transition temperature of LKNNS and LKNANS ceramics. The orthorhombic–tetragonal and tetragonal–cubic phase transition temperatures (TO–T, TC) of the specimens were decreased with increasing of average octahedral distortion. With increasing of Sb5+ content, the electromechanical coupling factor (kp), piezoelectric constant (d33) and dielectric constant (?r) of the sintered specimens were increased up to y = 0.075, and then decreased. These results could be attributed to the shift of TO–T to near room temperature for Li0.04(K0.5Na0.5)0.96(Nb0.0925Sb0.075)O3. 相似文献
7.
Lead free Ba1?x(Bi0.5Na0.5)xTiO3 (x=0, 0.02, 0.04, 0.06, 0.08, 0.1) ferroelectric ceramics were synthesized by conventional solid state reaction technique. Sintering was done at 1200 °C for 2 h in air atmosphere. The final products have tetragonal symmetry with decreasing c/a ratio confirmed by X-ray diffraction analysis. The grain size varies between 300 nm to 1000 nm for x=0 to 0.1. With increase in Bi0.5Na0.5TiO3 [BNT] content, the room temperature permittivity decreases whereas the Curie temperature (Tc) increases and its highest value was found to be 155 °C for 10 mol% of BNT addition. The ceramics show stable and low dielectric loss characteristics. The remnant polarization (Pr) and the coercive field (Ec) increases monotonously with increase in BNT content. The highest value of 2Pr (=17 μC/cm2) and 2Ec (=22 Kv/cm) was obtained for x=10 mol% BNT addition. 相似文献
8.
Han-Gung Chen Yih-Hsing Lo Feng-Ling Wu Han-Ying Wang Li-Sheng Hsu Pei-I Hsiao Yao-Ren Liang Ting-Shen Kuo Chiung-Cheng Huang 《Inorganic chemistry communications》2010,13(8):956-958
Treatment of benzophenone imine complex [Tp(PPh3)(NH═CPh2)Ru–Cl] (1) {Tp═HB(pz)3, pz = pyrazolyl} with 4-Ethynyltoluene in the presence of H2O in distilled ethanol afforded the chelate alkenyl ketone complex [Tp(PPh3)RuCCH2(p-MeC6H4)═CHC(O)(p-MeC6H4)] (2). On the other hand, reaction of 1 with HC≡C(O)OR1 in R2OH produced the chelate vinyl ether complexes [Tp(PPh3)Ru–C(OR2)═CHC(O)OR1] (3a, R1 = Me, R2 = Me; 3b, R1 = Et, R2 = Me; 3c, R1 = Et, R2 = Et; 3d, R1 = Me, R2 = Et), respectively. Preliminary results on the catalytic activity of 1 are also presented. Intriguingly, complex 1 is found to catalyze the dimerization of terminal alkynes HC≡CR (R = p-MeC6H4, C(O)OCH3) in the presence of Et3N to give eynes. The structures of 3c and 3d have been determined by X-ray diffraction analysis. 相似文献
9.
《Journal of the European Ceramic Society》2014,34(15):3675-3683
The microstructure, electric-field-induced strain, polarization, and dielectric permittivity in (Bi0.5Na0.5)0.945−x(Bi0.2Sr0.7□0.1)xBa0.055TiO3 (BNBT–xBST) (0 ≤ x ≤ 0.08) electroceramics are investigated. An irreversible transition from rhombohedral and monoclinic coexistence phase to single rhombohedral phase is indicated with the remnant strain Sr = 0.330% at x = 0. As the BST content increases, the ferroelectric order is disrupted resulting in a degradation of the remnant polarization, coercive field, and the ferroelectric-to-relaxor transition temperature (TF–R). The coexistence of ferroelectric relaxor and ferroelectric phase is observed for the optimum composition x = 0.02 at ambient temperature with a large strain of 0.428% at 60 kV/cm (normalized strain Smax/Emax = 713 pm/V). The large strain is contributed by both ferroelectric domain reorientation behavior and the reversible relaxor to ferroelectric phase transition. 相似文献
10.
Dongfang Qiu Yuquan Feng Hongwei Wang Xiaoyu Bao Yingchen Guo Yanxiang Cheng Lixiang Wang 《Inorganic chemistry communications》2010,13(5):613-617
A novel Pt(II) complex [(L)PtCl] (HL = 4-{p-[N-(4-(9-carbazole))butyl-N-phenyl] aniline}-6-phenyl-2,2′-bipyridine) has been synthesized and verified by 1H NMR, elemental analysis and X-ray crystallography. The crystal (C44H35N4ClPt, Mr = 850.30) belongs to monoclinic system, space group P2(1)/c, with a = 21.864(6), b = 9.306(3), c = 17.240(5) Å, β = 96.483(6)°, Z = 4, V = 3485.3(16) Å3, DC = 1.620 g/cm3, μ(Mo-Kα) = 4.141 mm? 1, F(000) = 1688, R1 = 0.0591, wR2 = 0.0976. The coordinate geometry of the Pt atom is a distorted square planar configuration. The complex molecules are stacked by a weak π–π interaction in a head-to-tail fashion along the b axis to form 1D chain and the alternating 1D chains are packed to form the 2D lamellar system. The complex shows an intense metal-to-ligand charge transfer (1MLCT) (dπ(Pt) → π*(L)) transitions (ε ~ 2 × 104 dm3 mol? 1 cm? 1) at 448 nm in the UV–Vis absorption spectrum and a strong phosphorescence at 592 nm in CH2Cl2 solution at room temperature. An intramolecular energy transfer process from the carbazole unit to the arylamine-modified [(C^N^N)PtCl] emissive center exists in the complex. 相似文献
11.
《Inorganic chemistry communications》2005,8(5):479-482
Two novel one-dimensional (1D) coordination polymers of stoichiometry [{Si(CH2SR)4}HgBr2]n (R = Me, 2a; R = Ph, 2b) have been prepared by treatment of HgBr2 with the functionalized silanes Si(CH2SR)4 (R = Me, 1a; R = Ph, 1b) acting as tetradentate thioether ligands. The extended structures result from intermolecular Hg–S interactions linking the monomeric {Si(CH2SR)4}HgBr2 units, as established for 2a, b using single-crystal X-ray diffraction. The effective coordination around the Hg atoms in both compounds is best described as distorted octahedral. 相似文献
12.
Dielectric properties of (Zn1/3Nb(2?x)/3Tax/3)0.5(Ti0.8Sn0.1Ge0.1)0.5O2 (x = 0, 1, 2) and/or (Zn1/3Nb1/3Tal/3)0.5(Ti0.8Sn0.2(l?y)Ge0.2y)0.5O2 (y = 0, 0.5, 1) were investigated at the microwave frequencies. For the compositions with single phase of rutile structure, the dielectric constant (K) of specimens was not only dependent on the dielectric polarizabilities, but also on the bond length ratio of apical bond (dapical) to equatorial bond (dequatorial) of oxygen octahedron in the unit cell. Temperature coefficients of the resonant frequencies (TCF) of the specimens with B = Nb5+ and/or M = Sn4+ was larger than those with B = Ta5+ and/or M = Ge4+. These results could be attributed to the changes of the degree of oxygen octahedral distortion. Quality factors (Qf) of the specimens with B = Ta5+ and/or M = Sn4+ were larger than those with B = Nb5+ and/or M = Ge4+. 相似文献
13.
《Diamond and Related Materials》2007,16(10):1799-1805
The dynamics of hopping transport in amorphous carbon nitride is investigated in both Ohmic and non-linear regimes. Dc current and ac admittance were measured in a wide range of temperatures (90 K < T < 300 K), electric fields (F < 2 × 105 V cm− 1) and frequencies (102 < f < 106 Hz).The dc Ohmic conductivity is described by a Mott law, i.e. a linear ln(σOHMIC) vs T− 1/4 dependence. The scaling of field-enhanced conductivity as ln(σ / σOHMIC) = ϕ[FS / T] with S ≈ 2/3, observed for F > 3 × 104 V cm− 1 over 5 decades in σ(T,F), is explained by band tail hopping transport; the filling rate, ΓF(EDL), of empty states at the transport energy is obtained with a “filling rate” method which incorporates an exponential distribution of localized states, with a non-equilibrium band tail occupation probability f(E) parametrized by an electronic temperature TEFF (F).As the ac frequency and temperature increase, the increase in conductance G is accurately described by Dyre's model for hopping transport within a random spatial distribution of energy barriers. This model predicts a universal dependence of the complex ac conductivity of the form σac = σ(0)[iωτ / ln(1 + iωτ)], where σ(0) is the zero frequency ac conductivity and τ(T,F) is a characteristic relaxation time. We find that the inverse characteristic time 1 / τ can also be described by a Mott law. It is compatible with the filling rate ΓF(EDL) at the transport energy, which governs the dc conductivity; this rate increases with increasing dc field, as more empty states become available in the band tail for hopping transitions. This “universal” scaling law for the ac conductance provides a scaling parameter K(T,F) = τ(T,F) σ(T,F,ω = 0) / ɛ which is found to decrease with increasing electric field from 5 to 0.5, depending weakly on temperature. Our band tail hopping model predicts a high-field value of K(T,F) smaller than the Ohmic value, under the condition (eFγ− 1 / E°) ≤ (kT / E°)1/4, where γ− 1 is the localization radius and E° the disorder energy of the band tail distribution. 相似文献
14.
Grain size control of lead-free Li0.06(Na0.5K0.5)0.94NbO3 piezoelectric ceramics by Ba and Ti doping
Ken-ichi Kakimoto Kiyotaka Ando Hitoshi Ohsato 《Journal of the European Ceramic Society》2010,30(2):295-299
In this study, Ba- and Ti-doped Li0.06(Na0.5K0.5)0.94NbO3 [(1 ? x)Li0.06(Na0.5K0.5)0.94NbO3–xBaTiO3 (x = 0–0.07)] ceramics were prepared by using conventional solid state reaction method, and the microstructure and electric properties of these samples were investigated. The grain size distribution of non-doped Li0.06(Na0.5K0.5)0.94NbO3 ceramics was relatively wide. The microstructure was composed of grains ranging 1.1–5.0 μm in size. However, with increasing Ba and Ti content, the grain size distribution became narrow and the average grain size decreased from 2.0 to 0.9 μm in size. In particular, the microstructure of x = 0.07 sample was composed of grains ranging 0.5–2.2 μm in size. As a result, the frequency dispersion of dielectric constant for the (1 ? x)Li0.06(Na0.5K0.5)0.94NbO3–xBaTiO3 (x = 0–0.07) ceramics was reduced and the mechanical quality factor Qm was enhanced with increasing Ba and Ti content. 相似文献
15.
T. Wojewoda P. Achatz L. Ortéga F. Omnès C. Marcenat E. Bourgeois X. Blase F. Jomard E. Bustarret 《Diamond and Related Materials》2008,17(7-10):1302-1306
As a result of the larger covalent radius of boron (rB = 0.88 Å) when compared to that of carbon (rC = 0.77 Å), the introduction of substitutional boron into diamond leads to an expansion δa/a of the lattice parameter. This has been found previously to follow a linear interpolation (Vegard law) as long as the boron content is lower than about 0.5 at.% in MPCVD epilayers or 1.5 at.% in HPHT bulk crystals.Above those concentrations, the expansion is less pronounced than predicted by Vegard. In order to explain this effect, we have performed ab initio calculations on C:B substitutional alloys. The results show that the presence of interstitial boron and of boron clusters is not necessary to explain the experimental data available in the literature. Moreover, quantitative estimates are proposed for the deformation potential of the valence band maximum and for the steric effect associated to boron pairing. We then apply these conclusions to discuss the different variations of δa/a vs boron contents observed by high resolution XRD experiments performed on “insulating” and metallic (and superconducting) p++ diamond epilayers grown by MPCVD on (100)- and (111)-oriented type Ib substrates, for which boron concentration profiles have been determined by Secondary Ion Mass Spectroscopy. 相似文献
16.
《Journal of the European Ceramic Society》2006,26(6):875-882
Solid solutions of (x)Re(Co1/2Ti1/2)O3–(1 − x)CaTiO3 (Re = La and Nd, abbreviated to xLCT and xNCT, respectively) where x = 0, 0.25, 0.5, 0.75 and 1 have been fabricated using solid state synthesis. Samples have been examined using X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM) and their dielectric properties measured at microwave (MW) frequencies. Formation of single phase solid solutions were confirmed by XRD and the measured lattice parameters varied linearly from LCT (a = 5.66 Å, b = 7.867 Å and c = 5.494 Å) and NCT (a = 5.636 Å, b = 7.914 Å and c = 5.461 Å) to CT (a = 5.596 Å, b = 7.731 Å and c = 5.424 Å). XRD and TEM confirmed both in-phase and antiphase rotations of O-octahedra consistent with an a−a−c+ tilt system across the entire solid solution series. Electron diffraction revealed that LCT and NCT have reflections associated with B-site cation ordering which is absent for x ≤ 0.75. MW dielectric measurements showed that LCT and NCT were highly insulating with microwave quality factor (Qf0) values of 39,000 and 34,000, respectively. Compositions anticipated to have a zero temperature coefficient of resonant frequency (τf) are 0.48LCT-CT and 0.52NCT-CT with ɛr = 45 and Qf0 ∼ 5000 and ɛr = 43 and Qf0 ∼ 4000, respectively. 相似文献
17.
The ruthenium complex with bridging H3O2− ligand was obtained and the crystal structure was determined. The compound cis-[{RuNO(NH3)2Cl2}2(μ2-H3O2)]Cl crystallizes in the monoclinic space group P21/n with cell parameters a = 15.0651(5), b = 6.3624(2), c = 15.3813(6) Å, β = 94.9690(10)°, Z = 4 and R = 0.0185. The hydroxide hydrate anion is coordinated to the ruthenium atoms of the identical cis-{RuNO(NH3)2Cl2} fragments. The protonation of the starting cis-[RuNO(NH3)2(NO2)2OH] complex leads to the required coordinated aqua/hydroxide ratio if the specific amount of hydrochloric acid is used. The DFT calculations confirm the formation of the dimer structure in the gas phase. However, the presence of water molecules dramatically reduces the dimerization efficiency. 相似文献
18.
Tolulope O. Salami Stephanie N. Patterson Victoria D. Jones Antonio Masello Khalil A. Abboud 《Inorganic chemistry communications》2009,12(11):1150-1153
A rare two-dimensional layered inorganic–organic hybrid material, strontium sulfonate Sr[C2H4(SO3)2] was synthesized by hydrothermal reaction of strontium chloride hexahydrate and ethane disulfonic acid at 160 °C. Single-crystal X-ray diffraction was utilized for structural determination. Data showed that the compound, crystallized in the monoclinic system and space group of C2/c. With cell parameters a = 8.3183(7) Å, b = 5.4416(5) Å and c = 14.9784(13) Å. The new material was extensively studied by DRIFT-infrared spectroscopy, thermogravimetric analysis, SEM and powder X-ray diffraction. Results show that the compound is thermally stable. 相似文献
19.
《Journal of the European Ceramic Society》2007,27(8-9):3099-3104
The Mg3(VO4)2–xBa3(VO4)2 ceramics have been investigated to obtain a low-temperature co-fired ceramic (LTCC). The highest quality factor (Qf) of approximately 114,000 GHz was obtained when the ceramic with x = 0.2 was sintered at 950 °C for 5 h in air. The temperature coefficient of resonant frequency (τf) of the ceramics sintered at 1025 °C varied from −90 to 60 ppm/°C as the amount of xBa3(VO4)2 increased, and was a near zero value in the sample obtained at x = 0.5 where the dielectric constant (ɛr) and the Qf values were approximately 12 and 55,000 GHz, respectively. In order to reduce the sintering temperatures of Mg3(VO4)2–xBa3(VO4)2 ceramics, the effects of Li2CO3 addition as a sintering aid on the microwave dielectric properties of Mg3(VO4)2–0.5Ba3(VO4)2 ceramics were also characterized in this study. The Li2CO3 addition was effective in reducing the sintering temperature without detrimental effects on the Qf values of the ceramics. One result: the microwave dielectric properties of Mg3(VO4)2–0.5Ba3(VO4)2 with 0.0625 wt%-doped Li2CO3 ceramic, which was sintered at 950 °C for 5 h in air, has a ɛr value of 13, a Qf value of 74,000 GHz, and a τf value of −6 ppm/°C. 相似文献
20.
Wenjuan Wu Dingquan Xiao Jiagang Wu Jing Li Jianguo Zhu Bin Zhang 《Ceramics International》2012,38(3):2277-2282
In order to solve the low temperature stability of electrical properties in KNN-based ceramics, (1 ? x)[(K0.5Na0.5)0.95Li0.05](Nb0.95Sb0.05)O3–xBaTiO3 [(1 ? x)KNLNS–xBT] lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method. The introduction of BT stabilizes the tetragonal phase of KNLNS ceramics at room temperature, results in a typical ferroelectric relaxor behavior, and shifts the polymorphic phase transition to below room temperature. Moreover, there is a strong BaTiO3 concentration dependence of relaxor behavior and electrical properties, and the ceramic with x = 0.005 exhibits optimum electrical properties and typical relaxor behavior (d33 = 269 pC/N, kp = 0.50, ?r = 1371, tan δ = 0.03, TC ~ 349 °C and γ = 1.88024). These results indicate that the BT is an effective way to improve the temperature stability as well as the electrical properties of KNN-based ceramics. 相似文献