Cr3+水解聚合作用的研究(Ⅷ)-反丁烯二酸存在下的过渡态

本文研究究了Cr(NO₃)₃与四种浓度的反丁烯二酸共存时Cr³⁺在水溶液中的聚合状态,采用LEMIT程序计算了在四种配体浓度下存在的同一粒子(离子或分子),其水解常数不但彼此吻合,且和高、低浓度区的结果一致。     

C掺杂ZrO_2四方纯相粉体的甲醇溶剂热制备及热稳定性研究

在ZrO(NO_3)_2·2H_2O-CO(NH_2)_2-CH_3OH溶剂热过程中,水的缺乏使得甲醇通过其甲氧基与Zr~(4+)发生亲核取代或以分子配位,直接参与锆盐的水解-缩聚反应,形成具有[ZrO_z(OH)_p(OCH_3)_q·rCH_3OH]_n结构的无机聚合物;同时,甲醇对聚合物低的溶解能力强烈抑制了Ostwald熟化过程,阻碍了溶剂热产物的晶化与热力学支持的结构重排。尿素通过其水解作用与锆盐竞争体系中的水及锆物种骨架上的羟基,这不仅导致无机聚合物中Zr-O-Zr键合相对Zr-OH键合的比例增加,使得溶剂热产物发生结构重排的几率进一步下降;而且也一定程度上增加了溶剂热产物中甲氧基的含量。含有大量甲氧基团的溶剂热产物经400℃焙烧后,形成C掺杂ZrO_2。C掺杂与溶剂效应共同稳定了ZrO_2的四方相。在500-600℃中等温度、空气气氛焙烧过程中,C掺杂ZrO_2四方相结构显示了良好的热稳定性;提高焙烧温度至700℃,游离于颗粒表面的C被完全氧化去除,固溶于晶格中的C也部分脱溶,导致了部分四方相失稳转变成单斜相。     

新型磷-钒-氧层状化合物[H2en]2[H3O]6[Co(H2O)2(VO)8(OH)4(PO4)8]的水热合成与晶体结构

金属磷酸盐材料在吸附、离子交换、离子传导和催化剂方面有潜在的应用前景[1～5]. 近年来, 通过水热反应合成了一些A-V-P-O化合物. 在这些化合物中, A一般为碱金属或有机阳离子, 如层状结构的[H2N(C4H8)2NH2][(VO)4(OH)4(PO4)2][6] 和[H2N(C2H4)3NH2][(VO)8(HPO4)3(PO4)4*(OH)2]*2H2O[6], 一维链状结构的 [H2NCH2CH2NH3(VO)(PO4)][7], 手性双螺旋结构的 [(CH3)2NH2]K4[(VO)10(H2O)2(OH)4(PO4)7]*H2O[8]以及具有三维骨架结构的化合物 [H3N(CH2)3NH3K(VO)3(PO4)3][9], [H3N(CH2)3NH3]2[V(H2O)2(VO)6(OH)2(HPO4)3(PO4)5]*3H2O[10]和[H3N(CH2)2NH3][(VO)3(H2O)2(PO4)2(HPO4)4][11].     

O and N NMR studies of the Co(II), Cu(II) and Mn(II) complexes of glycine in aqueous solution

The ¹⁷O and ¹⁴N paramagnetic relaxation rates and chemical shifts of glycine as well as of water, in aqueous solutions of Co(II), Cu(II), and Mn(II) were measured as a function of pH, temperature and metal ion concentration; the relaxation results were fitted to a theoretical equation linking the Swift-Connick equation to the stability constants of all major complexes in equilibrium. As a result, the stability constants of all major complexes were determined, and from the temperature-dependent measurements the thermodynamic parameters for some of these complexes were also calculated. In addition to the bidentate complexes ML⁺, ML₂ and ML₃⁻, monodentate complexes of the type MHL²⁺ and M(HL)₂²⁺, mixed complexes of the type MHL₂⁺ and MHL₃ were also considered. In the case of the Cu(II)-glycine system at pH> 12 two additional species were considered, namely ML₂(OH)⁻ and ML₂(OH)₂²⁻, suggested by the drastic reduction of the paramagnetic broadening in that pH range.     

Sterically demanding cyclopentadienyl chemistry: synthesis of iron and zirconium complexes of 1-phenyl-3-methyl-4,5,6,7-tetrahydroindenyl

Reaction of phenyl magnesium bromide with the ,β-unsaturated ketone 3-methyl-2,3,4,5,6,7-hexahydroind-8(9)-en-1-one, followed by an aqueous work-up, generates the pro-chiral tetra-substituted cyclopentadiene, 1-phenyl-3-methyl-4,5,6,7-tetrahydroindene, Cp^‡H, a precursor to the η⁵-cyclopentadienyl ligand in (Cp^‡)₂Fe and [(Cp^‡)Fe(CO)]₂(μ-CO)₂. Both complexes were generated as mixtures of rac-(RR and SS)- and meso-(RS)-isomers, and in either case pure meso-isomer was isolated by crystallisation and characterised by single crystal X-ray structure, both molecules having crystallographic C_i symmetry. Reduction with Na/Hg cleaves meso-(RS)-[(Cp^‡)Fe(CO)]₂(μ-CO)₂ and the resulting mixture of (R)- and (S)-[(Cp^‡)Fe(CO)₂]⁻ anions reacts with MeI to give racemic (Cp^‡)Fe(CO)₂Me, which was characterised by the X-ray crystal structure. The Cp^‡ ligand is more electron donating than (η-C₅H₅) as revealed by the reduction potential of the (Cp^‡)₂Fe⁺/(Cp^‡)₂Fe couple, E°=−0.127 V (vs. Ag  AgCl). Reaction of LiCp^‡ with ZrCl₄ yields the zirconocene dichloride [Zr(Cp^‡)₂Cl₂] as mixture of rac- and meso-isomers, from which pure rac-isomer is obtained as a mixture of RR and SS crystals by recrystallisation. The reaction of rac-[Zr(Cp^‡)₂Cl₂] with LiMe gives rac-[Zr(Cp^‡)₂Me₂]. The structures of RR-[Zr(Cp^‡)₂Cl₂] and rac-[Zr(Cp^‡)₂Me₂] have been determined by X-ray diffraction. The structural studies reveal the influence of the bulky substituted cyclopentadienyl ligand on the metal---Cp^‡ distances and other metric parameters.     

Isotopic exchange reactions between iron-sulphur-nitrosyl clusters and nitrite

The anion [Fe₄S₃(NO)₇]⁻ undergoes slow exchange with labelled nitrite [¹⁵NO₂]⁻ to yield a product [Fe₄S₃(¹⁴NO)(¹⁵NO)₆]⁻ in which complete isotopic exchange has occurred at the basal Fe(NO)₂ groups, but with no exchange at the apical Fe(NO) group. The neutral Fe₄S₄(NO)₄ reacts rapidly with [¹⁵NO₂⁻ to give fully exchanged [Fe₄S₃(¹⁵NO)₇]⁻, and it is proposed that the conversion proceeds by fragmentation, followed by complete isotopic exchange and rapid reassembly. The binuclear anion [Fe₂S₂(NO)₄]²⁻ also yields, with [¹⁵NO₂]²⁻ in CD₂Cl₂ solution, the fully exchanged [Fe₄S₃(¹⁵NO)₇]⁻, and a mechanism involving successive fragmentation, exchange and reassembly steps is proposed; however in aqueous solution, a clean exchange reaction occurs to give [Fe₂S₂(¹⁵NO)₄]²⁻. Neutral binuclear esters Fe₂(SR)₂(NO)₄ (R = Me, Et, or Ph) with [¹⁴NO₂]⁻ yield the mononuclear paramagnetic [Fe(¹⁴NO)₂(¹⁴NO₂)₂]⁻, and with [¹⁵NO₂]⁻ the analogous [Fe(¹⁵NO)₂(₁₅NO₂)₂]⁻.     

Assembly of Three Scandium-containing Heteropolytungstates Based on a Building-block Synthetic Strategy

Three novel scandium-containing heteropolytungstates[Sc₃(H₂O)₃NO₃(PW₉O₃₄)₂]^10-(1a),[Sc₈(H₂O)₂(GeW₉O₃₄)₂(GeW₆O₂₆)₂]^12-(2a) and[Sc₁₁(W₆O₁₀)₂(OH)₂(H₂O)₁₆(BiW₉O₃₃)₆]^27-(3a) were synthesized by reactions of Sc^III ions with trilacunary Keggin precursors,[A-α-XW₉O₃₄]^n-(X=P, Ge, n=9, 10) or[B-α-BiW₉O₃₃]^9-, in NaOAc/HOAc buffer solution under conventional synthetic condition, respectively. All the three compounds were characterized by means of single-crystal X-ray diffraction(XRD), Fourier transform-infrared(FTIR) spectroscopy ultraviolet-visible(UV-Vis) spectroscopy, elemental analysis, and thermogravimetric analysis. The aqueous solution stability of the sandwich polyanion[Sc₃(H₂O)₃NO₃(PW₉O₃₄)₂]^10- was also verified by electrospray ionization mass spectrometry(ESI-MS) due to its good solubility in water.     

Two New Alkaline Metal Borates with Supramolecular Framework Constructed from 1D {B5}/{B6} Helical Chains

Two new alkaline metal borates containing 1D{B5}/{B6}oxoboron helical chains,namely Na0.5[B5O8(OH)2]0.5[B5O6(OH)2]0.5·0.5H3O(1)and NaKCs[B6O9(OH)3](2)were synthesized under solvothermal conditions.Compound 1 contains the interesting alternative left-and right-handed helical{[B5O8(OH)2][B5O6(OH)2]}2-({B5}-1 and{B5}-2)1D chains and compound 2 possesses the similar[B6O11(OH)3]7-({B6})chains.Their 1D chains are further assembled into 2D layers and 3D supramolecular frameworks through O-H…O hydrogen bonds.In addition,the UV cutoff edge of compounds 1 and 2 is both below 190 nm.     

Interaction of antitumor drug Sn(CH3)2Cl2 with DNA and RNA

Sn(CH₃)₂Cl₂ exerts its antitumor activity in a specific way. Unlike anticancer cis-Pt(NH₃)₂Cl₂ drug which binds strongly to the nitrogen atoms of DNA bases, Sn(CH₃)₂Cl₂ shows no major affinity towards base binding. Thus, the mechanism of action by which tinorganometallic compounds exert antitumor activity would be different from that of the cisplatin drug. The aim of this study was to examine the binding of Sn(CH₃)₂Cl₂ with calf thymus DNA and yeast RNA in aqueous solutions at pH 7.1–6.6 with constant concentrations of DNA and RNA and various molar ratios of Sn(CH₃)₂Cl₂/DNA (phosphate) and Sn(CH₃)₂Cl₂/RNA of 1/40, 1/20, 1/10, 1/5. Fourier transform infrared (FTIR) and UV–visible difference spectroscopic methods were used to determine the Sn(CH₃)₂Cl₂ binding mode, binding constant, sequence selectivity and structural variations of Sn(CH₃)₂Cl₂/DNA and Sn(CH₃)₂Cl₂/RNA complexes in aqueous solution. Sn(CH₃)₂Cl₂ hydrolyzes in water to give Sn(CH₃)₂(OH)₂ and [Sn(CH₃)₂(OH)(H₂O)_n]⁺ species. Spectroscopic evidence showed that interaction occurred mainly through (CH₃)₂Sn(IV) hydroxide and polynucleotide backbone phosphate group with overall binding constant of K(Sn(CH₃)₂Cl₂–DNA)=1.47×10⁵ M⁻¹ and K(Sn(CH₃)₂Cl₂–RNA)=7.33×10⁵ M⁻¹. Sn(CH₃)₂Cl₂ induced no biopolymer conformational changes with DNA remaining in the B-family structure and RNA in A-conformation upon drug complexation.     

The dehydroxylation of basic aluminum sulfate: An infrared emission spectroscopic study

The tridecameric aluminum polymer [AlO₄Al₁₂(OH)₂₄(H₂O)₁₂]⁷⁺ was prepared by forced hydrolysis of Al³⁺ up to an OH/Al molar ratio of 2.2. Upon addition of sulfate, the tridecamer crystallized as the monoclinic basic aluminum sulfate Na_0.1[AlO₄Al₁₂(OH)₂₄(H₂O)₁₂](SO₄)_3.55. The dehydroxylation of the basic aluminum sulfate has been studied by Fourier transform in-situ infrared emission spectroscopy over a temperature range of 200° to 750°C at 50°C intervals. The spectrum is characterized by the sulfate ν₁ (1024 cm⁻¹), ν₃ doublet (1117 and 1168 cm⁻¹) and the ν₄ doublet (568 and 611 cm⁻¹) modes. Furthermore, minor bands assigned to nitrate are observed. Upon heating from ≈350° to 400°C major changes are observed, especially in the bandwidth and band intensities. The bands in the hydroxyl stretching region due to the Al₁₃ group disappear, whereas the bands around 1050 cm⁻¹ display various changes in bandwidths, intensities and positions associated with the dehydration and dehydroxylation of the basic sulfate and the changing of the structure into an aluminum oxosulfate. The nitrate bands diminish upon heating.     

Facile Chemical Conversion Synthesis and Luminescence Properties of Uniform YF3 Nanowires

Well-dispersed YF₃ nanowires were synthesized by a designed hydrothermal conversion method with Y(OH)₃ nanowires as precursor. Various equipments were used to characterize the samples. The results show that Y(OH)₃ nanowires precursor was prepared through a simple hydrothermal process, which then served as the precursor for the fabrication of YF₃ nanowires by a hydrothermal process. The whole process was carried out under aqueous conditions without any organic solvent, surfactant or catalyst. The conversion process from Y(OH)₃ precursor to YF₃ nanowires was investigated by time-dependent experiments. The possible formation mechanism of YF₃ nanowires was presented in detail. Under UV excitation, 5%(mass fraction) Eu³⁺ or 5%(mass fraction) Tb³⁺ doped YF₃ samples exhibit strong red or green emission, corresponding to the characteristic lines of Eu³⁺ and Tb³⁺, respectively. Moreover, the luminescence colors of the Eu³⁺ and Tb³⁺ codoped YF₃ samples can be tuned from red, yellow and green-yellow to green by simply adjusting the relative doping concentrations of the activator ions under a single wavelength excitation, which might find potential applications in the fields of, such as, light display systems and opto- electronic devices.     

Complexes of chromium(III) with nitrilotriacetic acid and their extraction by solutions of aliquat-336 in dichloro-ethane

It has been shown that chromium(III) and nitrilotriacetic acid (NTA; H₃Z) form only a series of 1:1 complexes in solution. The violet uncharged species [CrZ(H₂O)₂] cannot be extracted by a solution of the long-chain quaternary ammonium chloride, Aliquat-336, in dichloroethane. Its acid dissociation constant (pK₁ = 5.87) was determined spectrophotometrically. On increasing the pH of the solution the blue anion CrZ(H₂O)(OH)^- of pK₂=8.74 and its conjugate base the binegative anion CrZ(OH)^2-₂ of pK₃= 11.81 are successively formed. Both of these anionic species are extracted by Aliquat-336 with maximal extraction (ca. 60%) at about pH 9. At still higher pH values the olive-green anion, CrZ(OH)₃^3-of much lower or negligible extractability, is formed.     

The chemistry of peroxovanadium species in aqueous solutions. Structure and reactivity of a neutral diperoxovanadium complex as provided by V-NMR data, ab initio calculations and kinetic results

The addition of hydrogen peroxide to vanadium (V) precursors in aqueous acidic solutions leads to the formation of a cationic monoperoxospecies [VO(O₂)]⁺ and an anionic diperoxocomplex [VO(O₂)₂]⁻, depending on the pH and on the excess of H₂O₂. The latter may undergo protonation to form the neutral complex [HVO(O₂)₂]. ⁵¹V-NMR data and ab initio calculations suggest that the neutral complex is formed via protonation of a peroxide oxygen and that in such a species, as well as in the other two peroxovanadium derivatives, the usual η² arrangement of the peroxo groups is maintained. The comparison of reactivity data of the three complexes in the self-decomposition reaction and in the oxidation of uracil, indicates that the neutral diperoxocomplex exhibits an oxidizing power considerably larger than that of the other two peroxovanadium species.     

类水滑石[CdxMg6-xAl2(OH)16]2+[S·2H2O]2-的合成与表征

用中温水热法合成了类水滑石[Cd_xMg_6-xAl₂(OH)₁₆]²⁺[S·2H₂O]^2-,探讨了pH值、投入Cd²⁺离子的量以及硫化时间等条件对合成的影响,并用XRD、FT-IR、DTA-TG等手段进行了表征,找出了合成层间嵌入S^2-离子的含Cd类水滑石的最佳条件。     

Emission quenching of binuclear pyrophosphito platinum(II) complexes in aqueous solution by sulphur dioxide. Spectroscopic measurements on sulphur dioxide addition and chromous ion reduction

The emission intensity at 517 nm from Pt₂(pop)₄⁴⁻ (pop = P₂O₅H₂²⁻) is quenched by the addition of sulphur dioxide. The sulphur dioxide coordinates at the axial platinum(II) sites by a η¹-SO₂ bond. This coordination is supported by ³¹p NMR and Raman spectroscopy of aqueous solutions. The electronic spectrum of a sulphur dioxide saturated solution of Pt₂(pop)₄⁴⁻ shows an absorption at 428.5nm ( = 4.1 × 10⁴). From the decrease in the chromophore for uncomplexed Pt₂(pop)₄⁴⁻ the equilibrium constant for SO₂ binding is estimated to be 1.74 M₂l⁻². The effect of adding different quenchers to aqueous solutions of Pt_2(pop)4⁴⁻ is discussed. The compound Pt₂(pop)₄⁴⁻ will undergo 2-electron reduction with chromous ion.     

三丁基氧化膦-离子液体体系萃取UO2(NO3)2的机理和选择性

研究了三辛基氧化膦(TOPO)和三丁基氧化膦(TBPO)在离子液体(ILs) 1-烷基-3-甲基咪唑双三氟甲基磺酰亚胺盐(C_nmimNTf₂, n=2, 4, 6, 8)中萃取分离UO₂(NO₃)₂. TOPO-C₂mimNTf₂和TOPO-C₄mimNTf₂体系萃取UO₂(NO₃)₂时会出现三相, 而TBPO萃取UO₂(NO₃)₂的萃合物可以很好地溶解在所有离子液体中. 论文也考察了萃取过程中的萃取剂浓度效应、酸效应、盐效应. 水相加入HNO₃会降低萃取效率. 盐效应证明了萃取是一种阳离子交换机理. 水相中加入NO₃^-能够提高U的萃取, 这说明NO₃^-参与萃取. 选择性研究表明: 除了在高酸度下对Zr 的显著萃取, TBPO-C₄mimNTf₂萃取体系在低酸度下对U呈现较好的选择性; 去除U后, 在低酸度下该体系对三价Nd 仍保持较好的选择性. 通过定量比较离子液体中NO₃^-进入量, 电喷雾质谱(ESI-MS)和紫外光谱表征确定了TBPO-C_nmimNTf₂中萃取机理的差异性. 萃取中存在两种萃合物, 即UO₂(TBPO)₃(NO₃)⁺和UO₂(TBPO)₃²⁺, 其中UO₂(TBPO)₃(NO₃)⁺的比例从C₂mimNTf₂体系到C₈mimNTf₂体系逐渐增加.     

The synthesis and lyotropic phase behaviour of some aquatetra(cyano)-dodecylaminoferrate(II) complexes

Some alkali and alkaline earth metal salts of the amphiphilic anion [Fe(CN)₄(H₂O)(C₁₂H₂₅NH₂)]^2- have been synthesized by reaction of [Fe(CN)₅NO]^3- with C₁₂H₂₅NH₂. Using optical microscopy, they have been shown to give a hexagonal (H₁) mesophase in water.     

Optically active coordination compounds---XLVIII. Synthesis, resolution and interconversions of isomers of tris-salicylatocobaltate(III)

Stable aqueous solutions of the green ion [Co(sa1)₃]³⁻ (sa1 = dianion, C₆H₄( )(CO ), of salicylic acid, 2-hydroxybenzoic acid) are obtained from [Co(NH₃)₅ C1]C1₂ and an excess of salicylic acid. Several salts, [C][Co(sa1)₃] have been characterized, where C = [Co(NH₃)₆]³⁺ and [M(en)₃]³⁺ (M = Co or Rh, EN = 1,2-diamino-ethane). By using (+)-[Rh(en)₃]³⁺, optical resolution via less soluble diastereoisomeric salts has been achieved, and isomerization and racemization have been studied. Resolved tris-malonatocobaltate(III) has been used as a model. A novel thermochromism (77-293 K) in solid Δ(+)-[Rhen₃]Λ[Co(sa1)₃ is described.     

Synthesis and Characterization of Zinc Succinate, Zn(C4H4O4)

Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｓｕｃｃｉｎａｔｅｉｏｎ (Ｃ4Ｈ4Ｏ4) 2 -(—ＯＯＣＣＨ2 ＣＨ2 ＣＯＯ— )ｉｓａｖｅｒｓａｔｉｌｅｌｉｇａｎｄｓｉｎｃｅｅａｃｈｏｆｔｈｅｆｏｕｒｔｅｒｍｉｎａｌｃａｒｂｏｘｙｌｏｘｙｇｅｎｓｉｓａｂｌｅｔｏｐａｒｔｉｃｉｐａｔｅｉｎｃｏｏｒｄｉｎａｔｉｏｎｔｏｃｅｎｔｒａｌｍｅｔａｌａｔｏｍ(ｓ)ｉｎａｄｄｉｔｉｏｎｔｏｔｈｅｆｌｅｘｉｂｉｌｉｔｙｏｆｔｈｅＣ—Ｃｂｏｎｅ .Ｓｕｃｈｃｏｏｒｄｉｎａｔｉｎｇｖｅｒｓａｔｉｌｉｔｙｈａｓｂｅｅｎｒｅｆｌｅｃｔｅｄｉｎｓｅｖｅ…     

新型桥联双四面体簇合物的合成与表征

利用(μ₃-CCO₂Et)Co₃(CO)₉与单阴离子试剂[Mo(CO)₃(η⁵-C₅H₄R)]-[R=H,C(O)Me]的反应合成了2个新的含CCo₂Mo骨架的簇合物(μ₃-CCO₂Et)Co₂Mo(CO)₈(η⁵-C₅H₄R)[R=H(1);R=C(O)Me(2)],进而用其与双阴离子试剂{-M(CO)₃[η⁵-C₅H₄C(O)]}₂-1,4-C₆H₄[M=Mo,W]反应合成了4个双四面体簇合物{(μ₃-CCO₂Et)CoMoM(CO)₇(η⁵-C₅H₄R)[η⁵-C₅H₄C(O)]}₂-1,4-C₆H₄[M=Mo,R=H(3);M=Mo,R=C(O)Me(4);M=W,R=H(5);M=W,R=C(O)Me(6)].这6个化合物的C和H元素分析,IR,¹HNMR等表征都与其结构一致.晶体X射线衍射分析表明,化合物2属单斜晶系,C₂/c空间群,晶胞参数a=1.1264(3)nm,b=1.1879(3)nm,c=3.3565(10)nm,β=93.320(5)°,V=4.484(2)nm₃,Z=8,D_c=1.867g·cm^-3,F(000)=2480,R=0.0369,wR=0.1150.