CaCu_3Ti_(4+x)O_(12+2x)陶瓷的电学性能

采用传统的固相合成方法在1100℃,保温3 h制备了不同Ti含量的CaCu3Ti4+xO12+2x陶瓷(x=-0.5,-0.2,0,0.2,0.5)。通过XRD分析了CCTO的相组成;在-20~100℃温度范围内、500 Hz~1 MHz的频率范围测量了CaCu3Ti4+xO12+2x陶瓷的介电特性和阻抗特性。Ti的化学计量变化明显的影响了CCTO陶瓷的电学性能,系统对比发现Ti的含量偏离CaCu3Ti4O12的化学计量比,会显著的降低CCTO陶瓷的介电常数,同时增加介电损耗。     

Reaction of ethyl diazoacetate with Co3(CO)9(μ3-CCl): Isolation and X-ray structures of Co3(CO)9(μ3-CCO2Et), Co3(CO)9(μ3-CCH2CO2Et), and [Co3(CO)9(μ3-CCHCO2Et)]2

The reaction between the tricobalt cluster Co₃(CO)₉(₃-CCl) (1) and AlCl₃, followed by treatment with ethyl diazoacetate, N₂CHCO₂Et, affords a complex mixture of products in low yields. Column chromatography has allowed the isolation of the four cluster compounds Co₃(CO)₉(₃-CH) (2), Co₃(CO)₉(₃-CCO₂Et) (3), Co₃(CO)₉(₃-CCH₂CO₂Et) (4), and [Co₃(CO)₉(₃-CCHCO₂Et)]₂ (5). Clusters 4 and 5 are new and have been fully characterized in solution by IR and ¹H NMR spectroscopy. The molecular structures of clusters 3–5 have also been determined by single-crystal X-ray diffraction analysis. Co₃(CO)₉(₃-CCO₂Et) crystallizes in the triclinic space group P , a = 8.8393(5), b = 14.727(1), c = 15.272(1) Å, = 93.361(6), = 105.509(5)°, = 100.336(6)°, V = 1872.6(2) ų, Z = 4, and d _calc = 1.823 g/cm³. Co₃(CO)₉(₃-CCH₂CO₂Et) crystallizes in the monoclinic space group P2₁/n, a = 9.3806(7), b = 9.2617(8), c = 22.455(2) Å, = 94.483(7)°, V = 1944.9(3) ų, Z = 4, and d _calc = 1.803 g/cm³. [Co₃(CO)₉(₃-CCHCO₂Et)]₂ crystallizes in the monoclinic space group C2/c, a = 21.585(2), b = 8.7977(7), c = 20.784(1) Å, = 104.807(6)°, V = 3815.8(5) ų, Z = 4, and d _calc = 1.835 g/cm³. Plausible pathways leading to the formation of clusters 2, 4, and 5 are discussed.     

Crystal structure of triethylentetraammonium bis monohydrogen-monophosphate dihydrate β-NH3(CH2)2NH2(CH2)2NH2(CH2)2NH3(HPO4)2·2H2O

The salt triethylentetraammonium bis monohydrogen-monophosphate dihydrate is orthorhombic Pbca with unit cell dimensions a = 8.963(2), b = 10.326(2), c = 17.381(4)Å; Z = 4; D_m = 1.540 g cm^–3; D _x = 1.562 g cm^–3. The examination of the structure shows a layer arrangement parallel to the axis: planes of [HPO₄]^2– tetrahedra alternate with planes of [(NH₃(CH₂)₂NH₂CH₂)₂]⁴⁺. The [HPO₄]^2– tetrahedra are connected through O(W)s--H···O hydrogen bonds, so that infinite chains of the composition [HPO₄(H₂O)]_n ^2n– are formed in the structure parallel to the axis. The structure of this compound is built from [HPO₄]^2– anions, [(NH₃(CH₂)₂NH₂CH₂)₂]⁴⁺ cations and zeolitic water molecules connected by hydrogen bonds.     

KNaCa2(PO4)2基质中Ce3+ →Tb3+的能量传递与发光特性

采用高温固相法合成了Ce3+,Tb3+激活的KNaCa2(PO4)2发光材料,并对其发光特性进行了研究.荧光光谱测试表明:Ce3+的加入显著增强了Tb3+的发射强度,观察到Ce3+对Tb3+的发光存在明显的敏化现象,且测得KNaCa2(PO4)2∶xCe3,yTb3+的最佳掺杂浓度为x=0.01,y=0.16.根据Forster-Dexter理论判定KNaCa2(PO4)2∶Ce3+,Tb3+中Ce3+对Tb3+的能量传递属于电偶极-电四极相互作用引起的共振能量传递.研究表明,KNaCa2(PO4)2∶Ce3+,Tb3+材料是一种优良的紫外-近紫外激发白光LED用高亮度绿色发光材料.     

Reaction of 1,2-bis(diphenylphosphino)cyclobutenedione (bpcbd) with fac-BrRe(CO)3(THF)2: X-ray diffraction structure of the dimeric complex [BrRe(CO)3]2(bpcbd) ⋅ CH2Cl2

Treatment of the diphosphine ligand 1,2-bis(diphenylphosphino)cyclobutenedione (bpcbd) with the THF adduct fac-BrRe(CO)₃(THF)₂ at room temperature furnishes the new dirhenium compound [BrRe(CO)₃]₂(bpcbd) instead of the expected mononuclear compound fac-BrRe(CO)₃(bpcbd). [BrRe(CO)₃]₂(bpcbd) was characterized in solution by IR spectroscopy, and the solid-state structure was solved by X-ray crystallography. [BrRe(CO)₃]₂(bpcbd), as the CH₂Cl₂ solvate, crystallizes in the space group P , a = 11.173(1), b = 13.362(1), c = 15.250(1) Å, = 108.973(7)°, = 99.477(8)°, = 110.466(7)°, V = 1915.0(3) ų, Z = 2, and d _calc = 2.143 g-cm^–3. The structure of [BrRe(CO)₃]₂(bpcbd) consists of two rhenium centers that are six-coordinate and possess nearly ideal octahedral geometry. The two Re(CO)₃ units are linked together by the bridging diphosphine ligand and two bridging bromide groups.     

Structural study of nitrovinylindoles: (I) 2-methyl-3-(2′-methyl-2′-nitrovinyl)indole and (II) 3-(2′-nitrovinyl)indole

Compound (I) is 2-methyl-3-(2-methyl-2-nitrovinyl)indole, C₁₂H₁₂N₂O₂,M _r=216.24, monoclinic,P2₁/n,a=16.710(1),b=7.627(1),c=17.646(1) Å,=104.8(1)°,V=2174.7(1) ų,Z=8.D _x=1.321 g cm^–3, MoK, =0.71073 Å,=0.858 cm^–1,F(OOO)=912, room temperature,R=0.061 for 1956 observed reflections. Compound (II) is 3-(2-nitrovinyl)indole, C₁₀H₈N₂O₂,M _r=188.18, monoclinic,P2₁/n,a=10.178(1),b=10.608(1),c=8.411(1) Å,=105.5(2)°,V=875.0(1) ų,Z=4,D _x=1.4284 g cm^–3, CuK, =1.5418 Å,=8.068 cm^–1,F(000)=392, room temperature,R=0.040 for 1330 observed reflections. Compounds (I) and (II) have a similar geometry, the only significant difference lying in the rotation of the nitrovinyl chain. This feature could be responsible for the difference in biological activity. In both compounds, the molecules are associated, forming charge-transfer complexes.     

Na3La2(BO3)3:Tb3+的合成及其光谱特性

采用固相反应法合成了一系列掺Tb3+的Na3La2(BO3)3多晶粉末,Tb3+的最大掺杂浓度约为30mo1;.在室温下测试了Na3La2(BO3)3:Tb3多晶粉末的红外光谱、发射光谱、激发光谱和荧光寿命.结果表明:在253 nm紫外光的激发下,Tb3+在487 nm、545 nm、583 nm和621 nm处有一组发射峰,分别对应于Tb3的5D4→7FJ(J=6,5,4,3)的跃迁.研究了荧光发射强度与Tb3+浓度之间的关系,掺杂浓度小于30mo1;时,荧光发光强度随Tb3+掺杂浓度的增加而增强.     

Na3La2(BO3)3:Nd3+的合成及其光谱特性

本文采用固相反应法合成了一系列掺Nd3+的Na3La2(BO3)3(Na3La2(BO3)3:Nd3+)多晶粉末,X-ray粉末衍射分析表明,它们属于正交晶系,Amm2空间群.测试了Na3La2(BO3)3:Nd3+的红外光谱、反射光谱和荧光光谱,观察到试样在590 nm、740 nm和800 nm附近存在显著吸收,以及在878 nm、1067 nm、1326 nm三个发射带.研究了发光强度与Nd3+离子浓度之间的关系,确定了Nd3+离子在Na3La2(BO3)3基质中发光的适宜浓度为10 ;摩尔分数.     

Structure of [La(NO3)3(OH2)2(OHMe)(bipy)]·15-crown-5

[La(NO₃)₃(OH₂)₂(OHMe)(bipy)·15-crown-5 is monoclinic,P2_t/n, witha=11.239(6),b=19.302(7),c=14.458(8) , =92.47(5)°, andD _calc=1.63 g cm^–3 forZ=4. In the complex, two nitrogen atoms (from bipy) and nine oxygen atoms (six from three bidentate nitrate anions, two from water molecules, and one from a methanol molecule) coordinate to the La(III) ion forming a coordination polyhedron which approximates a skewed trigonal prism with an interpenetrating pentagon. The coordinated methanol and water molecules donate hydrogen bonds to the oxygen atoms of the crown ether forming polymeric hydrogen bonded chains which propagate along theac diagonal in the unit cell.     

Synthesis and structure of (NH4)3[UO2(C3H2O4)2(NCS)] · 2H2O

Malonate-thiocyanate complex (NH₄)₃[UO₂(C₃H₂O₄)₂(NCS)] · 2H₂O is synthesized and studied by X-ray diffraction. The compound crystallizes in the monoclinic system: a = 13.9983(4) Å, b = 8.1947(2) Å, c = 16.4678(4) Å, β = 100.846(1)°, space group Cc, Z = 4, and R = 0.0158. The main structural units of the crystal are mononuclear [UO₂(C₃H₂O₄)₂(NCS)]^3? groups belonging to the AB ₂ ⁰¹ M ₁ crystal chemical group of uranyl complexes (A = UO ₂ ²⁺ , B ⁰¹ = C₃H₂O ₄ ^2? , M ¹ = NCS^?). Discrete uranium-containing groups are connected by electrostatic interactions with ammonium ions and by hydrogen bonds. Some specific structural features of crystals containing [UO₂(L)₂(NCS)]^3? complexes, where L is the oxalate or malonate ion, are discussed.     

Synthesis and crystal structure of [Y(NO3)3(OH2)3]·(Me2-16-crown-5)·H2O

The complex [Y(NO₃)₃(OH₂)₃]·(Me₂-16-crown-5)·H₂O has been prepared and its crystal and molecular structure determined using single crystal X-ray diffraction. The colorless crystals belong to the monoclinic space group P2₁/n with Z = 4. Lattice parameters are a = 10.420(1), b = 17.257(3), c = 14.646(2) Å, = 96.79(1)°, V = 2615.1(6) ų. The yttrium(III) ion is nine-coordinate, bonded to three bidentate nitrate groups and three water molecules. The average Y–O(nitrate) and Y–O(water) distances are 2.42(3) and 2.33(1) Å, respectively. The average HO–H···O hydrogen bonded separation is 2.767Å.     

Crystal structure of NH3(CH2)2NH3BiCl5·2H2O

The ethylenediammonium pentachlorobismuthate(III) dihydrate salt is monoclinic with the following unit cell dimensions: a = 10.902(8)Å, b = 7.926(6)Å, c = 15.199(6)Å, = 96.40(1)°, space group P2₁/n with Z = 4. The structure shows a layer arrangement parallel to the axis: planes of the [Bi₂Cl₁₀]^4– bioctahedra alternate with planes of [NH₃(CH₂)₂NH₃]²⁺ dications. The [Bi₂Cl₁₀]^4– bioctahedra are connected through O(W)–H··· Cl hydrogen bonds, so that infinite unidimensional chains of composition [Bi₂Cl₁₀(H₂O)₂] _n ^4n– are formed in the structure parallel to the axis. These chains are themselves interconnected by means of the N–H···Cl bonds originating from the [NH₃(CH₂)₂NH₃]²⁺ entities, forming a three-dimensional network.     

Synthesis and structure analysis of 2-(2′-propanonylthio)-3-(o-methyl phenyl) quinazol-4(3H)-one

The three-dimensional molecular and crystal structure of 2-(2'-propanonylthio)3-(o-methyl phenyl)quinazol-4(3H)-one has been determined by X-ray crystallographic methods. This compound crystallizes in the orthorhombic space group P_bca with unit cell parameters: a=9.649(5), b=30.102(10), c=11.403(9)Å. It has been solved by direct methods and refined to a residual index of 0.054. The magnitude of torsion along C16— C11— N3— C4 bond is 93.5(4)°. The dihedral angle between the plane comprising all the ring atoms of quinazoline moiety and the atoms of the methyl substituted phenyl ring is 94.12(1)°. The crystal structure is stabilized by one intramolecular C— HsO interaction and three intermolecular C— HsN contacts.     

Eu3+掺杂对Ba2Mg(BO3)2∶Eu3+荧光粉基质晶格及发光性质的影响

系统研究了Ba2Mg(BO3)2∶Eu3荧光粉的高温固相法制备工艺条件,发现在900 ℃C下保温3h制得的样品的发光性能最好.研究了Eu3掺杂浓度对基质晶格环境和发光性质的影响,当Eu3+浓度较低时,荧光粉在594 nm的发射峰强度最大,随着Eu3掺杂浓度的增加,Eu3+偏离对称中心的程度越来越大,当Eu3浓度超过3at;时,荧光粉在613 nm的发射峰强度开始急剧增强,浓度达到3.5at;时,613 nm的发射开始占主导,这是由于晶体结构的扭曲程度导致晶格对称性发生了较大的改变,释放了更多禁戒的5 D0 →7F2电偶极跃迁.制备的橙色荧光粉可以被近紫外InGaN芯片有效激发,应用于白光LED.     

Synthesis and crystal structure of (CN3H6)2[UO2(OH)2(NCS)]NO3 and β-Cs3[UO2(NCS)5]

Compounds (CN₃H₆)₂[UO₂(OH)₂(NCS)]NO₃ (I) and β-Cs₃[UO₂(NCS)₅] (II) are synthesized and studied by IR spectroscopy and single-crystal X-ray diffraction. I and II crystallize in the orthorhombic system. For I, a = 12.2015(13) Å, b = 7.3295(8) Å, c = 16.310(2) Å, space group Pnma, Z = 4, and R = 0.0327; for II, a = 21.7891(6) Å, b = 13.5120(3) Å, c = 6.8522(2) Å, space group Pnma, Z = 4, and R = 0.0268. In structure I, complex groups form infinite chains [UO₂(OH)₂(NCS)] _n ^n? belonging to the AM ₂ ² M ¹ crystal chemical group of uranyl complexes (A = UO ₂ ²⁺ , M ² = OH^?, and M ¹ = NCS^?). The main structural elements of crystals II are mononuclear [UO₂(NCS)₅]^3? groups belonging to the AM ₅ ¹ group of uranyl complexes (A = UO ₂ ²⁺ and M ¹ = NCS^?). In I and II, uranium-containing complexes are connected with outer-sphere cations by electrostatic interactions, and in I a system of hydrogen bonds also contributes to their binding. Specific features of the packing of complex [UO₂(NCS)₅]^3? groups in the structures of two modifications of Cs₃[UO₂(NCS)₅] are discussed.     

Crystal and molecular structures of the 4-(1H)-pyridone (=L) lanthanide complexes {[GdL(NO3)3(H2O)]·CH3OH}2 and [DyL4(NO3)2](NO3) and of L2HNO3

The crystal structures of the title compounds have been determined by single crystal diffraction methods. Crystals of the dysprosium compound are monoclinic, space groupP2₁/c witha=14.133(4),b=13.438(5),c=14.401 (4)Å,=103.98(2)°,V=2654(1)ų,Z=4,D _c =1.82 g cm^–3, finalR=0.035. The Dy atom is eight-coordinate with a distorted dodecahedral coordination geometry involving two bidentate nitrate groups and four pyridone oxygen atoms. An erbium complex with analogous stoichiometry was also prepared but not structurally characterized. Crystals of the Gd compound are monoclinic, space groupP2₁/n, witha=11.226(2),b=9.075(2),c=16.737(3)Å,=93.88(3)°,V=1701(1)ų,Z=2,D _c =1.91 g cm^–3, finalR=0.042. Each Gd atom is bonded to one pyridone oxygen atom, a water molecule and three bidentate nitrate groups. An oxygen atom of one of the bidentate nitrates additionally serves to bridge pairs of Gd atoms so as to form a dinuclear complex in which each Gd atom is nine-coordinate with a tricapped trigonal prismatic geometry. Crystals of L₂HNO₃ are monoclinic, space groupI2/a witha=12.479(4),b=6.535(2),c=14.297(6)Å,=96.07(3)°,V=1159(1)ų,Z=4,D _c =1.45 g cm^–3, finalR=0.057. The pyridones are linked in pairs by very short (2.44 Å) symmetrical OHO hydrogen bonds. Each pair is further linked via a nitrate ion by means of N-HO(nitrate)H-N hydrogen bonds, so as to form an extended chevron-like pyridone-pyridone-nitrate-pyridone-pyridone array. Adjacent chains are linked via weak C-HO(NO₃) interactions.     

Mercury(II) complex with terpyridine: structure of the 2∶1 solvate of [Hg(terpy)2](CF3SO3)2 with acetone

[Hg(terpy)₂](CF₃SO₃)₂·0.5(CH₃)₂CO crystallizes in the triclinic space group witha=14.631(6),b=15.258(4),c=18.785(7) Å, =69.66(2), =70.72(1), =88.55(1)°. The crystal structure consists of two independent [Hg(terpy)₂]²⁺ cations, four trifluoromethanesulfonate anions and an acetone molecule in the asymmetric unit. Each mercury atom is coordinated by two tridentate terpyridine ligands forming an irregular six-coordination polyhedron. The Hg–N bond lengths range from 2.27(2) to 2.53(2) Å.     

Crystal structure of triethylentetraammonium bis monohydrogenmonophosphate dihydrate, [NH3(CH2)2NH2(CH2)2NH2(CH2)2NH3](HPO4)2 · 2H2O

The salt triethylentetraammonium bis monohydrogenmonophosphate dihydrate is monoclinic with the following unit cell dimensions: a = 8.462(1), b = 10.500(1), c = 9.520 Å, = 99.297(1)°, space group P2₁/n with Z = 2. The structure was solved by the Patterson method and refined to final R value of 0.043 for 1590 independent reflections. The structure consists of infinite parallel two-dimensional [ 01] planes built of mutually connected ions and water molecules by strong O—H···O and N—H···O hydrogen bonding.