空气中合成固溶体荧光粉Ba2(Zn, Mg)Si2O7:Ce3+,Eu2+,Eu3+及其发光特性

采用高温固相法在空气中合成了Ba_1.97-yZn_1-xMg_xSi₂O₇:0.03Eu,yCe³⁺系列荧光粉。分别采用X-射线衍射和荧光光谱对所合成荧光粉的物相和发光性质进行了表征。在紫外光330~360 nm激发下,固溶体荧光粉Ba_1.97-yZn_1-xMg_xSi₂O₇:0.03Eu的发射光谱在350~725 nm范围内呈现多谱峰发射,360和500 nm处有强的宽带发射属于Eu²⁺离子的4f⁶5d¹-4f⁷跃迁,590~725 nm红光区窄带谱源于Eu³⁺的⁵D₀-⁷F_J (J=1,2,3,4)跃迁,这表明,在空气气氛中,部分Eu³⁺在Ba_1.97-yZn_1-xMg_xSi₂O₇基质中被还原成了Eu²⁺;当x=0.1时,荧光粉Ba_1.97Zn_0.9Mg_0.1Si₂O₇:0.03Eu的绿色发光最强,表明Eu³⁺被还原成Eu²⁺离子的程度最大。当共掺入Ce³⁺离子后,形成Ba_1.97-yZn_0.9Mg_0.1Si₂O₇:0.03Eu,yCe³⁺荧光粉体系,其发光随着Ce³⁺离子浓度的增大由蓝绿区经白光区到达橙红区;发现名义组成为Ba_1.96Zn_0.9Mg_0.1Si₂O₇:0.01Ce³⁺,0.03Eu的荧光粉的色坐标为(0.323,0.311),接近理想白光,是一种有潜在应用价值的白光荧光粉。讨论了稀土离子在Ba₂Zn_0.9Mg_0.1Si₂O₇基质中的能量传递与发光机理。     

(NO)2+复合物阳离子的结构和性质研究

用B3LYP/6-311++G**方法对NO二聚体阳离子(NO)2+进行了研究.几何优化并结合振动分析表明,该复合物存在5种可能的稳定构型.能量最低的是N-N相连的反式异构体,具有C2h对称性.分析了各稳定构型的相对稳定性及成键特征.建立了态态相关并给出异构化过渡态,分析了各构型之间转化的途径.     

中位-四(对烷氧苯基 )卟啉 Co2+、Cu2+、Zn2+、Pb2+配合物的合成与表征

Synthesis of fourteen new complexes of meso-tetrakis(4-alkoxyphenyl) porphyrins with Co²⁺, Cu²⁺, Zn²⁺, Pb²⁺ were presented in this paper.Meso-tetrakis (4-alkoxyphenyl) porphyrins were prepared by condensation of 4-alkoxybenzaldehydes with pyrrole, then treated with corresponding metallic acetate to produce mentioned complexes, IR, UV, ¹H NMR, MS and elementary analysis were explored to confirm the structures of all theses new complexes.Characteristic spectrometric data of IR, UV, ¹H NMR related to these complexes have been systematically summarized.Ten of the fourteen complexes were found to exhibit liquid crystal properties.     

以[M(DETA)2)]n+(M=Cu2+, Ni2+, Co3+)为客体的MnPS3夹层化合物的合成、结构表征与磁性研究

将过渡金属配合物阳离子([M(DETA)₂]ⁿ⁺(M=Cu²⁺,Ni²⁺,Co³⁺;DETA=Diethylenetriamine,二乙烯三胺)作为客体插入层状MnPS₃层间得到了相应的3个夹层化合物。通过X-射线粉末衍射、元素分析和红外光谱对夹层化合物的结构进行了表征。结果表明,与主体MnPS₃ 0.65 nm的层间距相比较,夹层化合物(Mn_0.88PS₃[Cu(DETA)₂]_0.12)的层间距扩大了0.32 nm,由此推测客体[Cu(DETA)₂]²⁺在层间以平面四方的配位形式存在,而另2个夹层化合物(Mn_0.79PS₃[Ni(DETA)₂]_0.21和Mn_0.74PS₃[Co(DETA)₂]_0.17)的层间距扩大了0.48 nm,说明客体[(M(DETA)₂]ⁿ⁺,M=Co³⁺,Ni²⁺) 在主体层间以八面体配位形式存在。磁性测试结果表明过渡金属离子[(M(DETA)₂]ⁿ⁺(M=Cu²⁺,Co³⁺)的插入能引起主体MnPS₃的磁性在35~40 K发生由顺磁向亚铁磁性的转变并表现自发磁化,而客体[Ni(DETA)₂]²⁺却使夹层化合物的反铁磁相互作用增强,抑制了自发磁化的发生。     

过渡金属氧化物(M2O5)+m=1,2(M=V, Nb, Ta)与C2H4气相反应机理的密度泛函研究

采用密度泛函理论研究了过渡金属钒族氧化物阳离子团簇(M2O5)+m=1,2(M=V, Nb, Ta)与C2H4气相反应机理. 反应为(M2O5)m++C2H4→(M2O5)m-1M2O4++C2H4O, 反应物先化合生成C—O键相连的化合物, 经过过渡态后M—O键断裂, 从而发生氧原子转移到碳氢化合物上的反应. 对于V2O5+与C2H4的反应, 存在经顺式和反式两种过渡态结构路径, 从能量上看, 经反式过渡态结构的路径更有利. 计算结果表明, 发生反应时C2H4与钒氧化物阳离子反应大量放热, 而与铌、钽氧化物阳离子反应却放热较少甚至不放热, 这与实验结果一致. 钒、铌、钽氧化物阳离子团簇发生氧转移反应活性不同的原因是金属-氧键的强弱不同所致.     

[M(dipicH2)(H2O)3], M = Ni,Cu, Zn (dipicH2 = dipicolinic acid) – A combined crystallographic,spectroscopic and computational study

Cationic metal complexes of dipicolinic acid (dipicH₂) are stabilized by [Ce(dipic)₃]²⁻ ions in the three isomorphous crystals [M(dipicH₂)(OH₂)₃][Ce(dipic)₃] · 3H₂O (M = Ni, 1; Cu, 2; Zn, 3). Magnetic dilution provided by the bulky anions leads to well-resolved EPR spectra in polycrystalline samples of 2. The cations have 4+2 coordination, the carbonyl atom of the carboxylic acid groups coordinating weakly from trans positions. In the case of 2 this steric distortion is augmented by Jahn–Teller distortion. All the three structures are satisfactorily modelled by calculations based on density functional theory (DFT). The switch of the Jahn–Teller axis upon deprotonation of the complex, leading to the neutral species Cu(dipic)(H₂O)₃, is also reproduced by DFT. Electronic transition energies as well as the g-tensor component of the d⁹ complex obtained are in good agreement with experiment. However, the calculated hyperfine coupling constants are in error. DFT also fails to satisfactorily account for the electronic transition in the d⁸ ion in 1.     

UO22＋•nH2O和PuO22＋•nH2O (n＝2, 4, 5, 6)密度泛函理论研究

首先用密度泛函理论(DFT)方法研究了铀酰和钚酰离子的几何与电子结构, 计算结果与实验基本符合, 表明DFT方法也能用于含铀和钚重原子的化合物计算. 然后对铀酰和钚酰水合离子的几何构型、Mulliken集居数分布以及铀酰(钚酰)与配体水分子的结合能进行计算, 计算结果表明UO₂^2＋•5H₂O和PuO₂^2＋•5H₂O分别为铀酰和钚酰系列水合离子中最稳定的配合物.     

Tetraphenylantimony(V) hexachloroplatinate, tetrachloroaurate, and hexachlorostannate [Ph4Sb] 2+ [PtCl6]2?, [Ph4Sb]+[AuCl4]?, and [Ph4Sb] 2+ [SnCl6]2?: Synthesis and crystal structures

The reactions of tetraphenylantimony with hexachloroplatinic and chloroauric acids in benzene afford bis(tetraphenylantimony) hexachloroplatinate (I) and tetraphenylantimony tetrachloroaurate (II), respectively. Compound II is also synthesized from tetraphenylantimony chloride and chloroauric acid in acetone. Bis(tetraphenylantimony) hexachlorostannate (III) is synthesized from tin dichloride and tetraphenylantimony chloride in acetone or from tin tetrachloride and tetraphenylantimony chloride in benzene. The crystal structures of compounds I–III are determined by X-ray diffraction analysis. The antimony atoms in the [Ph₄Sb]⁺ cations have a distorted tetrahedral coordination (CSbC bond angles range from 105.7(1)° to 118.5(1)° (I), from 106.2(3)° to 114.4(3)° (II), and from 106.0(1)° to 117.1(1)° (III)). The Sb-C bond lengths vary in intervals of 2.094(2)–2.098(2), 2.087(7)–2.111(7), and 2.093–2.100(3) ?, respectively. The coordination of the Pt and Sn atoms in complexes I and III is close to an ideal octahedral coordination with ClPtCl and ClSnCl bond angles of 88.68(2)°–91.32(3)° and 88.84(3)°–91.16(3)°, respectively. The square coordination of the Au atom in complex II is slightly distorted: the Au-Cl bond lengths are 2.266(2)–2.277(2) ?, the ClAuCl bond angles are equal to 89.7(1)°–90.5(1)°, the root-mean-square deviation of the atoms from the coordination plane being 0.004 ?. Original Russian Text ? V.V. Sharutin, V.S. Senchurin, O.A. Fastovets, A.P. Pakusina, O.K. Sharutina, 2008, published in Koordinatsionnaya Khimiya, 2008, Vol. 34, No. 5, pp. 373–379.