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1.
梁敬魁  张预民 《化学学报》1986,44(2):117-124
本文用X射线衍射(高温、室温)和热分析(DTA、DSC、TGA)等方法测定了Li~2SO~4-MgSO~4和Li~2SO~4-Li~4SO~4体系相图,并研究了化合物的性能和晶体结构。Mg~4Li~2(SO~4)~5在840℃由包晶反应形成,它在105℃分解为Li~2SO~4为基的固溶体和MgSO~4.在105℃反应时,形成每摩尔的Mg~4Li~2(SO~4)~5吸热2.57kJ,反应激活能为173.5kJ/mol. Mg~4Li~2(SO~4)~5属正交晶系,在180℃的点阵常数α=8.577A,b=8.741A, c=11.918A, 可能的空间群为P222或Pmmm,Z=2。Li~8-2x(SiO~4)~2-x(SO~4)~x是在953℃由包晶反应形成的新相.随着温度的降低,相区扩大,在室湿x=0.96-0.58.该相属正交晶系,空间群为Pmmn,Z=2.晶体的点阵常数在x=0.8时有一定最大值,a=5.002A,b=6.173A, c=10.608A.Li~g-2x(SiO~4)~2-x(SO~4)~x在空气中能吸收7.6wt%的水蒸汽和其他气体,脱水温度高于350℃,水份的吸脱不改变晶体结构,与沸石分子筛具有相似性质,脱水激活能为171.5kJ/mol.熔化后的Li~2SO~4-MgSO~4和Li~2SO~4-Li~4SiO~4试样以10℃/min速率降温,分别形成亚稳态共晶体系。  相似文献   

2.
4-Amino-4-deoxy-4′-demethylepipodophyllotoxin has beendirectly synthesized from 4′-demethylepipodophyllotoxin and HN_3in the presence of BF3·Et_2O,followed by hydrogenation withpalladium on charcoal as catalyst.  相似文献   

3.
本文用X射线衍射(高温、室温)相热分析(DTA、DSC、TGA)等方法测定了Li_2SO_4-MgSO_4和Li_2SO_4-Li_4SiO_4体系相图,并研究了化合物的性能和晶体结构. Mg_4Li_2(SO_4)_5在840℃由包晶反应形成,它在105℃分解为Li_2SO_4为基的固溶体和MgSO_4.在105℃反应时,形成每摩尔的Mg_4Li_2(SO_4)_5吸热2.57kJ,反应激活能为173.5kJ/mol.Mg_4Li_2(SO_4)_5属正交晶系,在180℃的点阵常数α=8.577A,b=8.741A,c=11.918A,可能的空间群为.P222或Pmmm,Z=2. Li_(8-2x)(SiO_4)_(2-x)(SO_4)_x是在953℃由包晶反应形成的新相.随着温度的降低,相区扩大.在室温x=0.96—0.58.该相属正交晶系,空间群为.Pmmm,Z=2.晶体的点阵常数在x=0.8时有一最大值,α=5.002A,b=6.173A,c=10.608A.Li_(8-2x)(SiO_4)_(2-x)(SO_4)_x在空气中能吸收7.6wt%的水蒸气和其他气体.脱水温度高于350℃,水份的吸脱不改变晶体结构,与沸石分子筛具有相似性质,脱水激活能为171.5kJ/mol. 熔化后的Li_2SO_4-MgSO_4和Li_2SO_4-Li_4SiO_4试样以10℃/min速率降温,分别形成亚稳态共晶体系.  相似文献   

4.
本文通过球半径比的优化选择,给出了七个含氢正四面等价电子分子的SCF-X。方法非重叠近似方案的计算结果.就中性分子CH_4,SiH_4及GeH_4而言,总能量和结合能计算值有了显著改进,使SiH_4和GeH_4的成键稳定性得到了合理说明.对离子计算,同时给出了Watson球存在和不存在的计算结果,通过对比,说明自由离子是一种更不稳定的状态,而Watson球确是稳定离子的环境的合理模拟.对离子的结合能也作了讨论,并联系了有关晶体化合物的热稳定性作出了解释.与此同时,还发现优化球半径比与中央原子的电负性存在线性关系,且符合于Virial定理的要求。  相似文献   

5.
Through the optimization of sphere radii ratios, seven tetrahedral hydrides species withequal valence electrons are investigated by means of SCF-X_αSW method in muffin-tin ap-proximation scheme. In comparison with those published results, the calculated total statis-tical energies and the corresponding binding energies of neutral molecules concerned have beenmuch better improved, which offers reasonable interpretation of their bonding stabilities, no-tably for SiH_4 and GeH_4. For ionic species, attention is focused on the role of Watson sphere,thus two kinds of calculation with and withcut Watson sphere are simultaneously given for com-parison. It reveals that free ions always behave more unstably and Watson sphere seems tobe a suitable model for describing the environment of a stabilized ion. The calculated bind-ing energies of ions have been utilized to correlate the thermostability trend for a few crystalcompounds. Also, an empirical linear relationship between optimized sphere radii ratios andelee  相似文献   

6.
用高效液相色谱法(HPLC)对4,4'-二氯二苯砜(双氯),4,4'二羟基二苯砜(双酚)及4-氯-4'-羧基二苯砜(单酚)进行了完全的分离,研究双氯部分水解制单酚发现,NaOH用量越大、反应温度越高,水解速度越快,极值产率却越低;副产物双酚的含量随着反应时间增加,超过极值单酚产率后,由于副产物的增加,产率相对降低。最佳水解条件为水解温度135~140℃,NaOH/双氯(摩尔比)为3.25∶1,水解时间2.5~3小时,产率90%以上。另外,还对水解过程中的缩聚现象及产物的纯化条件进行了讨论。  相似文献   

7.
4氨基4′氰基联苯,不仅是制备烷氧基联苯的原料,而且可以制备高正介电各向异性液晶及系列酯类液晶材料.但通常要经过酰化、氧化、酰氯化、氨解、脱水、硝化和还原[1]等多步反应,步骤长、收率低,本文用联苯为原料,经过硝化、碘代、氰代和还原反应合成4氨基4′氰基联苯.反应步骤及时间比原路线减少近一半,而且反应条件温和,收率高.联苯(CP,上海化学试剂一厂);N,N二甲基甲酰胺(AR,临平化工试剂厂);氯仿(AR,沈阳试剂一厂);亚硫酸氢钠(AR,大连辽南化学品厂);碘酸(AR,北京化工厂)…  相似文献   

8.
Sincethediscoveryoftristableswitching'andthesubsequentidentificationofmesomorphicphasesinMHPOBC2'3I,thesynthesisofnewliquidcrystalshaveattractedmuchattention.Theliquidcrystals,incorporatingtheSatom,suchasthioester4,sulfoxides5andsulfone',havebeenstudied.PrelindnarydatasuggestedthatthisstrUcturalchangefavoredtheformationofsmecticphases.WefirstintroducedsuIfonateintoliquidcrystalsandplannedthesynthesisofthiscategoryinordertostudyitsproperties.Wepresentherethesynthesisandcharacterizationsbase…  相似文献   

9.
Podophy1lotoxinl,isolatedfromPodoPhyllumpeIatumL.orPodoPhyllumemodiL.,showshighantitUmoractivity.But,itcatmotbeusedasantitUmoragentclinicallybecauseofitsseriousside-effect.Itssemisyntheticderivatives,EtoPoside2andTeniposide3,arewide-usedasboortantanticancerdrugs'.Howevef,theyhaveseverallimitationssuchaspoorwatersolubilitymetabolicinachvahonanddevelopmentofdrugresistance.Toovercometheselindtations,manyderivahvesofpodophyllotoxinhavebeensynthesizedinmanylaboratories2~5.Ithasbeenrecognisedt…  相似文献   

10.
11.
Mononuclear copper( Ⅰ ) complex [Cu(PPh3)2(BH4)] has been synthesized by ligand replacement reaction in methanol and characterized by elemental analyses, molecular weight determination, IR spectra and X-ray single crystal analysis,its conductivity has also been measured. The crystal is monoclinic, space group C2/c, a =24.776(4), b=9.173(7), c=15.564(2)A; β=116.10(1)°, V=3176.73 A3, Z =4, F(000)=1256, μ(MoKα)=8.11 cm-1, Dc=1. 26 g/cm3, M=602.79, R=0. 039, Rw= 0. 050. The results show that PPh3 coordinates as monodentate ligand to the Cu ( Ⅰ ) atoms, and BH4 behaves as a bidentate ligand in the prepared complex.The central copper atom belongs to tetrahedron coordination geometry.  相似文献   

12.
通过水热法合成得到1个以1,8-萘二酸(1,8-nap)为配体的Ba(Ⅱ)配合物 [Ba(μ5-1,8-nap)]n(1)。X射线单晶衍射测定结果表明:配合物属于单斜晶系,空间群P21/c。配合物最小不对称单元由1个九配位的钡原子和1个1,8-萘二酸配体构成。每个1,8-萘二酸配体连接五个钡原子,每个钡原子连接五个1,8-萘二酸配体,在(100)平面上形成二维双层结构。此外,对配合物的固态荧光性质做了测定,结果显示其在紫光区有荧光发射。  相似文献   

13.
A new polynuclear silver complex with bridging diphorsphine ligand has been synthesized and characterized by :single cryatsl X-ray diffraction method The compound crystallizes in the triclinic space group P1 with a=1.27489, b=1.34715, c=1.47015 nm; α=59.747, β=63.949, γ=70.196°; V=1.9369 nm. The simplest formularis [Ag_4· dppe)_3(NO_3)_4], Mr=1874.79, D_c=1.607 g·cm~(-3), Dm=1.62 g·cm~(-3), μ(MoKa)=11.69 cm~(-1), F(OOO)=942. The structure was solved by conventional heavy-atom techniques and refined by full-matrix least squares to give discrepany indices of R=0.048 and RW=0.060(W=1/[σ(Fo)~2+(PWT*Fo)~2+QWT]-Fo) for 5052 reflections. An empirical absorption correction program DIFABS was performed.Silver atoms are linked by bridging ligands of dppe and nitrate, forming a network extending in space. Each structural unit contains two binuclear subunits, of which silver atoms are bridged by nitrates. The two subunits are connected by one dppe ligand. Silver atoms are not equivalent in subunit and one of the nitrates functions not only as a monodentate bridging ligand, but also as an asymmetric bidentate chelating lingand. All coordinate configurations of silver are shown as distorted tetrahedron.  相似文献   

14.
1INTRoDUrnoNSomecomplexessynthesizedaccordingtotheideaof"combiningtheinorganicdistOrtedpoyhedronwithasymmetricconjugateorganicmo1ecules"areacategoryof,..promisingnonlinearopticalmaterialtl3.Thecomplexcrystalsareundoubtedlyanewimportantfieldfortheexplorationoffrequencydoublingandotherfunctionalmateri-alswhichwillbecomethefocusoftheworld'sattentiont2i.Inordertostudytherela-tionshipbetweenthestructure,synthesis,propertiesandapplicationsfurthermore,wereportthesynthesisandcrystalstructureofanewt…  相似文献   

15.
CrystalStructuresofN,N'-Bis(4-chlorophenyl)-1,10-diaza-18-crown-6andItsComplexwithBa(SCN)_2¥ZhangLi-Juan;LiuXiao-Lan;MaShi-Ku?..  相似文献   

16.
早有文献[1]报导,二硫代乙酸丙酮C5H8S2(记为SacSac)能以下列三种形式存在于金属配合物中:(I)(SacSac)2M,如M=Ni,Co等,其中SacSac呈负一价,通过两个S原子和金属直接螫合;(11)(SacSaChMCI。;如M二Mn,CdSn等,(S。Sac)呈正一价,且以阳离子状态存在干晶体和溶  相似文献   

17.
陈爱香  刘罡  李辉  王吉德  岳凡 《结构化学》2010,29(2):177-180
A novel two-dimensional coordination polymer [Ba2(phen)4(tp)2]n(phen=1,10-phenanthroline,tp=terephthalic acid) has been synthesized with tp as bridge ligands and structurally determined by X-ray crystallography.The crystal belongs to the monoclinic system,space group C2/c,with a=18.877(4),b=18.489(4),c=15.658(3),β=103.61(3)o,V=5311.5(19)3,C32H20O4N4Ba,Mr=661.86,Z=8,F(000)=2624,μ=1.542mm-1,Dc=1.655 g/cm3,the final R= 0.0228 and wR=0.0554 for 6063 observed reflections(I2σ(I)).The structural analysis shows that each tp ligand bridges barium atoms to form a two-dimensional infinite layer.There are aromatic π-π stacking interactions between neighboring layers,and aromatic π-π interactions further extend such layers into a three-dimensional supramolecular framework.  相似文献   

18.
<正> The crystal and molecular structure of the title compound was determined by single crystal X-ray diffraction. The complex crystallizes in the triclinic space group P1,a=8. 450(4),b=11. 730(3),c=14. 718(6)A ,α=104. 50(3),β=103. 71 (4),γ=69. 20(3)°,Z=4,V=1302. 4(9) A3,Dc,= 1.67g/cm3, λ(MoKa) = 0. 71069 A ,μ=30. 7/cm,F(000) = 646,Mr = 327. 6,final R=0. 037 for 2198 reflections with I<3σ(I). There are two molecules of different conformation in an asymmetric unit. Atom Ge is coordinated by three chlorine atoms and one carbon atom to form an irregular tetrahedron.  相似文献   

19.
陈长章  林州斌 《结构化学》1994,13(6):468-471
报道了氰尿酸钡[Ba(C_3H_2N_3O_3)_2·(H_2O)_2]的晶体结构。晶体属三斜晶系,空间群为P1,晶胞参数为:a=8.884(3).b=9.422(4),c=7.201(4)A,α=97.75(4),β=101.76(4),γ=85.05(3)°;M_r=429.49,Z=2,D_c=2.44g/cm~3。V=583.6(4)A~3,μ=34.56cm~(-1),λ(MoKα)=0.71069A,F(000)=412,I>3σ(I)的衍射点2091个。结构用TEXSAN程序包以直接法解出,经全距阵最小二乘法修正,最后R因子为0.029,R_ω=0.037.中心离子Ba~(2+)的配位数为10,Ba~(2+)离子处于6个配位原子形成的平面的中心位置上,另外4个配位原子则处于平面外,分布在Ba~(2+)离子的周围。  相似文献   

20.
A two‐dimensional barium(II) coordination polymer, [Ba(4‐FBA)2(4‐FBAH)]n (4‐FBA? = 4‐formylbenzoate), has been synthesized by the reaction of barium carbonate and 4‐formylbenzoic acid. The barium(II) ion is nine‐coordinated by eight O atoms from six deprotonated 4‐FBA? ligands and one O atom from the terminal 4‐FBAH ligand. Adjacent barium(II) ions are linked by the 4‐FBA? ligand to furnish a two‐dimensional lamellar structure which exhibits blue fluorescent emission in the solid state at room temperature. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

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