Er~(3 ),Yb~(3 )∶YAl_3(BO_3)_4晶体的光谱性质研究

采用助熔剂法生长了Er3 ,Yb3 共掺的YAl3 (BO3 ) 4 晶体 ,测量了晶体的室温吸收谱。由此吸收谱 ,根据Judd Ofelt理论计算了Er3 在Er3 ,Yb3 ∶YAl3 (BO3 ) 4 晶体中的强度参数、自发辐射几率、积分发射截面等参数。强度参数为Ω2 =2 .4 4× 10 -2 0 cm2 、Ω4=2 .0 0× 10 -2 0 cm2 、Ω6=6 .10× 10 -2 0 cm2 。研究了晶体的荧光特性 ,并在 976nm激光泵浦下得到了上转换绿色荧光。     

Reaction of bis(dimethoxyphosphino)dimethylhydrazine (dmpdmh) with Ru3(CO)12: Evidence for facile ligand fragmentation in Ru3(CO)10(dmpdmh) to give Ru4(CO)12[μ-N(Me)N(Me)], Ru3(CO)11[P(OMe)3], and Ru3(CO)9[μ-P(OMe)3]

Thermolysis of the cluster Ru₃(CO)₁₂ with the bis(phosphanyl)hydrazine ligand (MeO)₂PN (Me)N(Me)P(OMe)₂ (dmpdmh) in toluene at 75°C furnishes the known clusters Ru₄(CO)₁₂ [-N(Me)N(Me)] (2) and Ru₃(CO)₁₁[P(OMe)₃] (3), in addition to the new cluster Ru₃ (CO)₁₀(dmpdmh) (1) and the phosphite-tethered cluster Ru₃(CO)₉[-P(OMe)₃] (4). The simple substitution product Ru₃(CO)₁₀(dmpdmh), a logical intermediate to clusters 2–4, was synthesized by treating Ru₃(CO)₁₂ with Me₃NO in CH₂Cl₂ at room temperature, and independent thermolysis reactions using cluster 1 was shown to yield clusters 2–4. The solid-state structure of clusters 2 and 4 were unequivocally established by X-ray diffraction analysis. Ru₄(CO)₁₂[-N(Me)N(Me)] crystallizes in the orthorhombic space group Pnna (#52), a = 12.913(1), b = 13.3238(6), c = 12.5690(8) Å, V = 2162.5(2) ų, Z = 4, and d _calc = 2.452 g/cm³. Ru₃(CO)₉[-P(OMe)₃] crystallizes in the triclinic space group P a = 9.586(1), b = 14.354(1), c = 14.997(2) Å, = 89.82(1)°, = 98.36(1)°, = 92.010(8)°, V = 2040.4(4) ų, Z = 4, and d _calc = 2.212 g/cm³. The coordination of the dimethylazo linkage to the four ruthenium atoms in 2 and the phosphorus atom and one of the oxygen atoms of the methoxy groups to the three ruthenium centers in 4 are confirmed by X-ray analysis.     

(K,Na)3La2(BO3)3固溶体系的晶体结构

本文合成了一系列的(K,Na)3La2(BO3)3硼酸盐,通过自发结晶得到了组分为K1.34,Na1.66La2(BO3)3的单晶.单晶X射线结构分析表明该晶体与Na3La2(BO3)3同构,并且当K+取代Na+的数量小于2/3时,晶体结构仍为Na3La2(BO3)3构型.该晶体的基本结构单元为孤立的(BO3)3-基团.一个单胞中含有6个BO3基团,其中两个沿c方向一致平行排列,而剩余的4个BO3基团的排列方向与c方向呈一定的角度,从而减小了BO3基团对非线性效应的贡献.粉末倍频测试该晶体的有效非线性系数约为KDP的2.4倍.此外,研究表明用适量的Rb+,Li+取代Na+时,固溶晶体结构也不发生改变.     

Na3La2(BO3)3的晶体结构

以Na2CO3-H3BO3-NaF为助熔剂,使用顶部籽晶法生长出Na3La2(BO3)3透明单晶.测定了Na3La2(BO3)3的晶体结构,该晶体属正交晶系,空间群:mm2(No.38),晶胞参数为a＝0.51580(10)nm,b=1.1350(2)nm,c=0.73230(15)nm,α＝β＝γ＝90°,V＝0.42871(15)nm3,密度:.053g/cm3.晶体结构中的硼氧基团是平面的BO3基团,BO3基团相互独立,且与Na(1)O6、Na(2)O8、Na(3)O6和La(1)O9配位多面体连结形成三维网络骨架结构.讨论了Na3La2(BO3)3的晶体结构与倍频效应的关系.     

Na_(0.5)Bi_(0.5)TiO_3-K_(0.5)Na_(0.5)NbO_3无铅陶瓷介电性能研究

采用固相反应法制备了(1-x)Na0.5Bi0.5TiO3-K0.5Na0.5NbO3体系陶瓷,研究了KNN含量对Na0.5Bi0.5TiO3-xK0.5Na0.5NbO3陶瓷的晶体结构、显微结构和介电性能的影响。XRD分析结果表明,KNN进入NBT形成固溶体,该体系陶瓷均为钙钛矿结构。扫描电镜分析显示KNN的引入有利于细化晶粒,提高陶瓷致密度。测试了样品在不同频率(1 kHz,10 kHz,100 kHz,1 MHz)下的的介电温谱(室温~500℃),结果表明随着KNN含量的增加,介电峰逐渐变宽,弛豫性逐渐增强,铁电-反铁电相变温度Td和反铁电-顺电相变Tm都明显降低,当x≥0.25时,Td降至室温或更低;室温(1 kHz)下,KNN和NBT相对介电常数分别为675和575,而KNN和NBT形成的固溶体介电常数明显增大,当x=0.25时,达到最大值εr=1653。在NBT中掺入KNN得到了介电峰明显宽化、在较宽温度范围内具有低电容温度系数的致密弛豫铁电体。     

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.     

(1-x)Ba_(0.998)La_(0.002)TiO_3+xBi_4Ti_3O_(12)陶瓷电性能的研究

采用固相法制备了(1-x)Ba0.998La0.002TiO3+xBi4Ti3O12(0≤x≤0.03)陶瓷,研究了Bi4Ti3O12掺杂量以及烧结气氛对Ba0.998La0.002TiO3陶瓷显微结构、居里温度Tc及介电性能的影响。结果表明:Bi4Ti3O12在Ba0.998La0.002TiO3陶瓷中的掺杂抑制了陶瓷晶粒的生长,使居里温度提高到约150℃。在空气中烧结的陶瓷的介电常数随Bi4Ti3O12掺杂量的增加先减小后增大,当Bi4Ti3O12掺杂量为1.5 mol%时,陶瓷的介电常数最小(还原再氧化陶瓷的介电常数为6.0×103,空气中烧成的陶瓷的介电常数为9.0×102)。     

BaCo_(0.02)~IICo_(0.04)~IIIBi_(0.94)O_3/BaSb_(0.04)Sn_(0.96)O_3复合热敏厚膜电学性能研究

采用丝网印刷工艺制备了BaCoII0.02CoIII0.04Bi0.94O3/BaSb0.04Sn0.96O3复合热敏厚膜。借助X射线衍射仪、扫描电子显微镜和阻温测试仪对复合热敏厚膜的微结构、电学性能进行了表征分析。结果表明复合热敏厚膜主相仍为钙钛矿结构的BaCoII0.02CoIII0.04Bi0.94O3和BaSb0.04Sn0.96O3,厚膜表面随BaCoII0.02CoIII0.04Bi0.94O3含量增加趋于致密均匀。复合热敏厚膜的烧结温度、室温电阻率(ρ25)、热敏常数(β25/85)和活化能(E a)随BaCoII0.02CoIII0.04Bi0.94O3含量的增加呈现下降趋势,其烧结温度、ρ25、β25/85和E a分别处于870~1000℃、2.5 kΩ·cm~2.35 MΩ·cm、2764~4030 K和0.238~0.348 eV范围内。     

Regiospecific CO substitution in (μ-H)Ru3(μ3− η3-CHCHCMe)(CO)9 by 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione(bpcd). X-ray structure of (μ-H)Ru3(μ3−η3-CHCHCMe)(CO)7(bpcd)⋅MeOH

The triruthenium cluster ( -H)Ru₃( ₃–³-CHCHCMe)(CO)₉ reacts with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) in the presence of Me₃NO to afford ( -H)Ru₃( ₃– ³-CHCHCMe)(CO)₇(bpcd) in moderate yield. This new cluster has been isolated and characterized in solution by IR and NMR (¹H, ³¹P) spectroscopies, and the solid-state structure has been established by X-ray crystallography. ( -H)Ru₃( ₃– ³-CHCHCMe)(CO)₇(bpcd) MeOH crystallizes in the triclinic space group P , a = 11.2426(8) Å, b = 11.7141(8) Å, c = 16.195(1) Å, = 102.041(5)°, = 95.128(5)°, = 102.553(6)°, V = 2008.4(3) ų, Z = 2, d _calc. = 1.733 g/cm³; R = 0.0488, R _w = 0.0546 for 2212 observed reflections with I > 3 (I). The X-ray structure reveals that the bpcd ligand is bound exclusively to the Ru₃ core at the ruthenium center coordinated by the terminal CH unit of the -allylic ₃– ³-CHCHCMe moiety.     

Crystal structure of (3-aminopropionato)bis(ethylenediamine)cobalt(III) catena-di(μ-chloro)dichloroplumbate(II) monohydrate

Crystals of [Co(C₂H₈N₂)₂(C₃H₆NO₂)]PbCl₄ · H₂O [a = 7.627(1) Å, b = 11.238(1) Å, c = 11.444(1) Å, α = 99.125(1)°, β = 103.80(1)°, γ = 94.739(1)°, V = 933.09(1) ų, Z = 2, and space group $P\bar 1$ ] contain the octahedral PbCl₆ groups that share edges to form infinite [Cl₂Pb(μ-Cl)₂] _n ²ⁿ chains, in which the terminal Cl atoms occupy the cis positions. The Pb-Cl bond lengths are 2.763(1)–3.180(3) Å. In the discrete cationic complexes, the Co atom is coordinated by two ethylenediamine molecules and the 3-aminopropionate anion. In the enantiomeric complex with the Δ absolute configuration, the ethylenediamine rings have the λ and δ configurations and the aminopropionate ring has the λ configuration.     

新型稀土发光材料Sr_(3-x)MgSi_3O_(10)∶Tb_x~(3+)的合成及性质

采用凝胶-燃烧法,在活性炭弱还原气氛下合成了新型荧光粉Sr3-xMgSi3O10∶Tb3x+,通过热分析仪、红外光谱、X射线粉末衍射、X射线能量色散谱仪及荧光分光光度计等对产物的形成过程、结构、组成及发光性质进行了分析和表征。结果表明:干凝胶起火燃烧得前驱物,经900℃还原热处理即可得目标产物,其晶体结构与Sr2MgSi2O7相似,同属四方晶系。Sr3-xMgSi3O10∶Tb3x+的激发光谱为一位于200～300nm的宽带,主激发峰在249nm左右;发射光谱由491nm,544nm,586nm,624nm等一系列窄带发射峰组成,归属于Tb3+的5D4到7FJ(J=6,5,4,3)的跃迁。主发射峰位于544nm,对应于Tb3+的5D4→7F5的能级跃迁,导致一种黄绿光发射。研究发现:还原温度及Tb3+掺杂浓度对发光强度有着重要的影响,并对浓度猝灭机制进行了探讨。     

Crystal structure and spectroscopy of the high-spin compound: Tris-(2,2′-bipyridine-1,1′-dioxide)Iron(III) tris(perchlorate) bis(acetonitrile), [Fe(bpdo)3](ClO4)3(CH3CN)2

The first high-spin iron(III) compound with the ligand 2,2-bipyridine-1,1-dioxide (abbreviated as bpdo) is reported. The compound [Fe(bpdo)₃](ClO₄)₃(CH₃CN)₂ crystallizes in the space group P , with a = 11.767(3), b = 13.166(4), c = 15.951(4) Å, = 104.62(3), = 101.66(3), = 112.14(3)°, and Z = 2. The Fe(III) atom is octahedrally surrounded by six oxygen atoms of three bpdo ligands. In the far-infrared region the Fe—O vibration is observed at 411 cm^–1. The magnetic susceptibility reveals a of 6.04 ± 0.04 BM in the 10–280 K region, typical of high-spin Fe(III).     

Pb(Zn,Nb)O3-(Pb(Zn,Ti)O3)1-x(LaySr1-y MnO3)x 固溶体系磁电特性研究

采用常规陶瓷制备工艺制备了xLaySr(1-y)MnO3+(1-x) [0.2PbZn0.5Yb0.5O3-0.8Pb0.33Zr0.67TiO3](x=0.025、0.05、0.075、0.1、0.15、0.2,y=0.7、0.9)三元体系陶瓷,系统研究了不同成分LSMO掺杂对FZN-PZT磁学及电学性能影响.结果表明,掺入不同比例的LSMO均溶解入PZN-FZT晶格,导致PZN-PZT峰位偏移;随着LSMO掺杂量的提高,陶瓷的矫顽场E及剩余极化强度Pr降低;原本分别呈现铁磁性和反铁磁性的LyS(1-y) MO3(y=0.7、0.9)磁性消失;随着LMSO掺杂量的提高,晶粒尺寸变大.     

Na3La9O3(BO3)8的晶体结构

以Na2CO3-H3BO3为助熔剂,用顶部籽晶法生长出Na3La9O3(BO3)8单晶.测定了Na3La9O3(BO3)8晶体结构,结果表明:该晶体属六方晶系,空间群:P62m,晶胞参数为a=b=0.89229(13)nm,c=O.87366(17)nm,α=β=90°,γ=120°,Z=1,V=0.60240(17)nm3,密度为5.066g/cm3.晶体结构中的硼氧基团是平面的BO3基团,BO3基团相互独立,通过与Na(1)O6、La(1)O9和La(2)O8的配位多面体连结形成层状结构,所有层平行于(001)面.描述了Na3La9O3(BO3)8晶体在非线性光学材料领域的应用前景.     

溶胶-凝胶法制备Zn_3Ga_2Ge_2O_(10)∶Cr_(0.01)~(3+),Pr_(0.03)~(3+),Yb_(0.3)~(3+)纳米长余辉材料及其表面修饰的研究

以Ga(NO_3)_3·8H_2O、Zn(NO_3)_2·6H_2O、Pr(NO_3)_2·6H_2O、GeO_2、Yb(NO_3)_3·5H_2O、Cr(NO_3)_2·9H_2O为原料,采用溶胶-凝胶法合成了Cr~(3+),Pr~(3+),Yb~(3+)共掺杂的Zn_3Ga_2Ge_2O_(10)长余辉纳米材料(PLNPs)。利用XRD,SEM,激发发射图谱,余辉曲线测试确定1000℃煅烧,保温3 h时,基质Zn_3Ga_2Ge_2O_(10)已形成。Yb~(3+)掺杂百分比为0.3时,样品的发光性能最好。Zn_3Ga_2Ge_2O_(10)∶Cr_(0.01)~(3+),Pr_(0.03)~(3+),Yb_(0.3)~(3+)纳米长余辉材料在波长为267 nm的紫外线激发下发射出中心波长为745 nm的深樱桃红色光,此时晶粒粒径约为150 nm;随着Yb3+掺杂百分比的增加,晶粒粒径逐渐变小。通过FT-IR,Zeta电势,激光粒度测试,TEM及悬浮实验测试表明,PEG修饰PLNPs后,可观察到明显的核壳结构,水合粒径约为155 nm;水溶性大大增加,0.3 mg/m L的浓度下其悬浮时间超过48 h,这表明PEG包裹PLNPs成功。     

Na3La2(BO3)3晶体生长及光谱特性

本文以起始摩尔比为1:1的Na2CO3:H3BO3,并添加5;质量分数的NaF为助熔剂,用顶部籽晶法生长出φ35mm×5mm的透明Na3La2(BO3)3单晶.该晶体属正交晶系,空间群:Amm2,晶胞参数为a=0.51580(10)nm,b=1.1350(2)nm,c=0.73230(15)nm,α=β=γ=90°.测量了Na3La2(BO3)3晶体在室温下的透过光谱,紫外截止波长约为200nm.该晶体常温下稳定,不吸潮,但却易溶于稀酸.     

合成方式对(1-x)Ba_(0.998)La_(0.002)TiO_3-xBi_4Ti_3O_(12)陶瓷性能影响的研究

采用固相法制备了Bi4Ti3O12(BIT)与La2O3共掺杂的(1-x)Ba0.998La0.002TiO3-xBi4Ti3O12(0.001≤x≤0.03)系统陶瓷,研究了不同合成工艺(一步合成法:BIT与La2O3直接掺杂到BaTiO3陶瓷中;两步合成法:先将La2O3和BaTiO3预合成Ba0.998La0.002TiO3陶瓷,再将BIT掺杂到Ba0.998La0.002TiO3陶瓷中)对(1-x)Ba0.998La0.002TiO3-xBi4Ti3O12陶瓷显微结构、居里温度Tc及电性能的影响。结果表明:BIT对两种方式合成的(1-x)Ba0.998La0.002TiO3-xBi4Ti3O12陶瓷的晶粒长大均有抑制作用,而随着BIT加入量的增加晶粒又逐渐长大;一步合成法制备的(1-x)Ba0.998La0.002TiO3-xBi4Ti3O12陶瓷存在晶粒异常长大,而两步合成法制备的BLIT陶瓷晶粒较小;一步合成法对(1-x)Ba0.998La0.002TiO3-xBi4Ti3O12陶瓷的居里温度没有影响,而两步合成法制备的(1-x)Ba0.998La0.002TiO3-xBi4Ti3O12陶瓷居里温度提高到约150℃。     

CaYO(BO3)3晶体坩埚下降法生长

本文首次报道了Ca4YO(BO3)3(YCOB)晶体的坩埚下降法生长.在1600～1650℃炉温下,固液界面处的纵向温度梯度为40～60℃/cm,以0.2～0.6mm/h的生长速率,在近封闭的Pt坩埚中生长出了直径达25mm、长度超过50mm的完整透明YCOB晶体.介绍了生长工艺和原料制备,观察发现晶体中的主要宏观缺陷是包裹体.分析了包裹体生成的原因.     

紫外低吸收YAl3(BO3)4晶体生长

本文对用于紫外低吸收YAB晶体生长的助熔剂体系进行了筛选,测定了YAB-Li2B4O7-AlBO3体系的结晶关系.采用顶部籽晶熔盐法生长紫外低吸收YAl3(BO3)4晶体,测定了晶体的真空紫外透过截止波长,结果表明其真空紫外吸收边达到165 nm.