溶液中N-乙酸基取代氮氧杂大环及其配合物稳定性研究

用pH电位滴定法在25℃,0.5mol·L~(-1)KNO_3水溶液中测定了三种大环化合物:H_2L~1(1,12-二氮杂-3,4:9,10-二苯并-5,8-二氧杂环十五烷-N,N＇-二乙酸);H_3L~2(1,12,15-三氮杂-3,4:9,10-二苯并-5,8-二氧杂环十七烷-N,N＇,N″-三乙酸)和H_2L~3(1,15-二氮杂-3,4:12,13-二苯并-5,8,11-三氧杂环十八烷-N,N′-二乙酸)的逐级质子化常数.又测定了它们与Cu~(2+)、Ni~(2+)、Pb~(2+)配合物的稳定常数,以及H_2L~3与镧系金属La~(3+)、Pr~(3+)、Nd~(3+)、Eu~(3+)、Sm~(3+)、Gd~(3+)、Dy~(3+)、Yb~(3+)配合物的稳定常数.讨论了三种大环化合物质子化的一般顺序及其与各种离子配位时稳定性选择规律.说明了影响配位稳定性的有关因素.     

双N—乙酸取代氮氧杂大环及其镧系配合物的合成

首次合成了一种新的1.2-双(3,4:9,10-二苯并-5,8-二氧杂-1,12-二氮杂环十五烷-N-乙酸)乙烷大环配体,制备了它的8个镧系元素(La,Pr,Nd,Sm,EU,Gd,Dy,Yb)配合物,用红外光谱、元素分析、核磁共振谱及电导等方法进行了表征,讨论了可能的配位情况。     

腙类配位化合物的研究——Ⅰ.乙酰基一和1,1′—二乙酰基二茂铁苯甲酰腙及其过渡金属螯合物的制备和性质

制备了两个二茂铁基芳酰基腙:乙酰基二茂铁苯甲酰腙,FeCMe=NNHCOC₆H₅(HL^Ⅰ)和1,1′--二乙酰基二茂铁苯甲酰腙,Fe(C₅H₄CMe=NNHCOC₆H₅)₂(H₂L^Ⅱ)。HL^Ⅰ和H₂L^Ⅱ与过渡金屑醋酸盐反应,得到两种螯合物:ML₂^Ⅰ和ML^Ⅱ[M=Co(Ⅱ)、Zn(Ⅱ)和Cd(Ⅱ)]。对这些螯合物的元素分析,差热热重分析、IR、UV及¹HNMR谱进行了详细讨论。     

2,6-二乙酰吡啶类双希夫碱配合物的研究——Ⅰ.VO(Ⅱ)、Mn(Ⅱ)、Fe(Ⅱ)和Fe(Ⅲ)配合物的合成和表征

制备了由2,6-二乙酰吡啶与肼基硫代甲酯衍生的希夫碱C₅H₃N[CH=NN=C(S)XR]₂(X=S,R=CH₃,C₆H₅CH₂;X=O,R=C₆H₅CH₂)。离析出类型为MC₅H₃N[CH=NN=C(S)XR]₂(M=VO²⁺、Mn²⁺和Fe²⁺)和FeC₅H₃N[CH=NN=C(S)SR]₂Cl的希夫碱配合物。希夫碱及其配合物为元素分析、红外、可见一紫外光谱以及磁化率测量所表征,结果与所提出的Mn²⁺、Fe²⁺及Fe³⁺配合物的结构一致.在VO(Ⅱ)配合物的情况,则形成多聚体,其结构为: -(N₃S₂)V-O-V(N₃S₂)-O-V(N₃S₂)-.     

氮杂冠醚及其Cu(Ⅱ)、Ni(Ⅱ)、Cd(Ⅱ)、Ag(Ⅰ)配合物的合成及性质研究

用直接合成法合成了一种新配体-1,7-N,N′-二(邻氨基苯基)-1,7-二氮杂-4,10-二氧杂环十二烷[L]。经元素分析¹H、¹³C核磁共振、质谱、红外光谱等分析证实了其结构。并藉该配体合成了Cu(Ⅱ),Cd(Ⅱ),Ag(Ⅰ),Ni(Ⅱ)四种固体配合物。经元素分析配合物的组成分别为:[CuCl₂]₂·L,[CdCl₂]₃·2L·2H₂O,[AgNO₃]₂·L,[NiCl₂]₂·L·H₂O.对配合物进行了红外光谱、紫外光谱、摩尔电导和差热分析。配合物的红外特征吸收峰均有明显位移或分裂;紫外特征吸收峰稍有位移。但摩尔吸光系数改变很大;摩尔电导表明配合物为1:1或接近2:1型电解质;差热分析表明配合物的热稳定性顺序为:Cd(Ⅱ)、Ni(Ⅱ)>Cu(Ⅱ)>Ag(Ⅰ)。对Cu(Ⅱ)配合物进行了ESR谱分析,并且对甲醇溶液中Cu(Ⅱ)与配体(L)的掺入反应动力学进行了初步研究,结果表明,掺入反应为典型的二级反应。     

2,6—二乙酰吡啶类双希夫碱配合物的研究——Ⅲ.Co(Ⅱ)、Ni(Ⅱ)、Zn(Ⅱ)、Pb(Ⅱ)和Cd(Ⅱ)配合物的合成和表征

制备了由2,6—二乙酰吡啶和肼基硫代甲酸酯衍生的希夫碱C₅H₃N[CH=NNHC(S)XR]₂(X=S,R=CH₃、C₆H₅CH₂;X=O,R=C₆H₅CH₂).离析出类型为MC₅H₃N[CH=NN=C(S)XR]₂(M=Co²⁺、Ni²⁺、Zn²⁺、Pb²⁺和Cd²⁺)的希夫碱配合物.配合物为元素分析、红外、可见—紫外光谱以及磁化率测量所表征.结果指出:上述希夫碱均为N₃S₂型五齿配体.     

二已基-N,N-二乙基酰胺甲撑磷酸酯从盐酸介质中萃取钯(Ⅱ)的研究

研究了DHDECMP的二甲苯溶液从盐酸溶液中对钯(Ⅱ)的萃取。钯(Ⅱ)的分配比随水相盐酸浓度和有机相萃取剂浓度的增加而增加。当水相盐酸浓度大于0.5mol·l^-1时,萃取平衡可表示为 pd²⁺+2H⁺+4Cl^-+2DHDECMP_(o)⇔[PdCl₄^2-·2H⁺DHDECMP]_(o) DHDECMP以及萃取平衡后有机相的红外吸收谱表明,DHDECMP中的P=O基被质子化后与PdCl₄^2-缔合成离子对进入有机相而使Pd(Ⅱ)被萃取。     

溶液中N—乙酸基取代氮氧杂大环的构象及其配合物的NMR研究

用~1HNMR方法研究了溶液中大环化合物1,12-二氮杂-3,4:9,10-二本并-5,8-二氧杂环十五烷-N,N’-二乙酸盐的构象.NMR变温实验表明,在溶液中大环与Zn(Ⅱ)、Ni(Ⅱ)、Co(Ⅱ)的配合物环上醚氧不参与配位,其中Ni(Ⅱ)配合物为低自旋反磁性的平面四方形配位.     

2,4-双(3,5-二甲基吡唑)-6-甲氧基均三嗪及其镍锌配合物的合成与晶体结构

通过三聚氯氰的甲氧基化、肼基化及与乙酰丙酮的缩合这种新的简单、通用的方法合成了2,4-双(3,5-二甲基吡唑)-6-甲氧基均三嗪(bpt),在甲醇溶液中与Ni(ClO₄)₂·6H₂O,Zn(ClO₄)₂·6H₂O作用,分别得到了单核二元镍配合物[Ni(bpt)₂](ClO₄)₂·H₂O和三元锌配合物[Zn(mpt)₂(dmp)](ClO₄)₂(mpt=2,4-二甲氧基-6-(3,5-二甲基吡唑)均三嗪,dmp=3,5-二甲基吡唑).mpt和dmp为bpt在Zn²⁺作用下的醇解产物,提出了该反应的可能机制.用X射线衍射法测定了配体的水合高氯酸盐[Hbpt·H₂O·ClO₄]及镍锌配合物的晶体结构.[Hbpt·H₂O·ClO₄]中质子位于一侧吡唑环的2-位N上,Hbpt呈共面cis-cis构型,以锯齿状排列成层状结构,层间依靠非质子化吡唑环间的p-p重叠连接.[Ni(bpt)₂](ClO₄)₂·H₂O中bpt以三齿径向方式与Ni配位,[Ni(bpt)₂]²⁺配阳离子呈压扁的八面体构型,4个吡唑氮原子构成赤道平面,2个均三嗪氮原子占据轴向顶点.[Zn(mpt)₂(dmp)](ClO₄)₂中Zn²⁺离子为五配位的三角双锥的配位构型,均三嗪及dmp的3个氮原子位于赤道平面,mpt的2个吡唑氮原子位于轴向位置.     

1-苯基-3-甲基-4-苯甲酰基-5-吡唑酮与甲基膦酸二(1-甲基庚基)酯对Pb(Ⅱ)、Cd(Ⅱ)和Cu(Ⅱ)的萃取机理研究

本文用两相滴定法研究了1-苯基-3-甲基-4-苯甲酰基-5-吡唑酮(PMBP,简写为HA)与甲基膦酸二(1-甲基庚基)脂(P₃₅₀,简写为B)对Pb²⁺、Cd₂₊和Cu²⁺离子在不同的有机溶剂中的萃取机理.确定了萃合物的组成分别为:MA₂(M=Pb²⁺、Ca²⁺、Cu²⁺);MA₂·HA(M=Cd²⁺);MA₂·B(M=Pb²⁺、Cd²⁺)和MA₂·2B(M=Cd²⁺),同时求得了相应的萃合常数β值.     

单N-乙酸取代O2N2大环配体及其稀土配合物的合成与表征

Aseries of new rare earth complexes LnL(NO₃)₂·2H₂O(Ln=La,Pr,Nd,Sm,Eu,Gd,Dy,Yb;L=1,2-diaza-3,4: 9,10-dibenzo-5,8-dioxyacyclopentadecane-N-acetic ion) were prepared. The complexes were characterized by elemental analysis, ICPmethod, IRspectra, 1H NMRand Molar conductance. It was found that the ether oxygen, carboxy oxygen and nitrogen atoms of the ligand are coordinated to the metal ion, as well as a free nitrate and coordianted nitrate ion in the complex.     

Synthesis and Metal Complex Formation of Nitrogen-Oxygen Donor Macrocyclic Ligands

Reduction of 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacylotetradecane-5,11-diene( 1 ) with sodium borohydride in ethanol generates 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacyclotetradecane( 2 ) in high yield. The macrocyclic ligand 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacyclotetradecane-N,N′-diacetic acid ( 3 ) has been synthesized and characterized. In addition, reaction of ( 2 ) with an excess of acrylonitrile gives 2,3:9,10-dibenzo-5,12-diaza-1,8-dioxacyclotetradecane-N,N′-di(2-cyanoethyl) ( 4 ). Several new complexes of these ligands with nickel(II), copper(II) and cobalt(II) have been prepared and identified. The structures of these complexes are proposed on the basis of elemental analysis, ¹H, ¹³C-NMR, IR, UV-VIS spectra, magnetic susceptibility and conductivity data.     

Complexation of iminodisuccinic acid (IDS) and 3-hydroxy-2,2′-iminodisuccinic acid (HIDS) with Cd2+, Hg2+, and Pb2+ in aqueous solution

In a search for environmentally friendly metal-chelating ligands for industrial applications, the protonation and complex formation equilibria of iminodisuccinic acid (IDS) and 3-hydroxy-2,2′-iminodisuccinic acid (HIDS) with Cd²⁺, Hg²⁺, and Pb²⁺ in aqueous 0.1?mol?L^?1 NaNO₃ solution were studied at 25°C by potentiometric titration. Models for complexation and stability constants of the different complexes were determined for each metal ion using the computer program SUPERQUAD. In all cases, complex formation was dominated by stable ML^2? complexes.     

Complexation of 3-hydroxy-2,2′-iminodisuccinic acid (HIDS) with Mg2+, Ca2+, Mn2+, Fe3+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+ ions in aqueous solution

In a search for environmental-friendly metal chelating ligands for industrial applications, the protonation and complex formation equilibria of 3-hydroxy-2,2′-iminodisuccinic acid with Mg²⁺, Ca²⁺, Mn²⁺, Fe³⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ ions in aqueous 0.1 mol L^?1 NaCl solution were studied at 25°C by potentiometric titration. The model for complexation and the stability constants of the different complexes were determined for each metal ion using the computer program SUPERQUAD. In all cases, complex formation was dominated by stable ML ^{n ?4} complexes.     

Spectroscopic and Solution Studies of Some Transition Metal Complexes of New 4-Hydroxy Coumarin Semi- and Thiosemicarbazone Complexes

Two new ligands, 4-hydroxy coumarin-3-thiosemicarbazone (H₂L¹) and 4-hydroxy coumarin-3-semicarbazone (H₂L²) were synthesized and used for the preparation of a series of transition metal complexes (Cr³⁺, Co²⁺, Ni²⁺, Cu²⁺, and Fe³⁺), derived from these ligands. These complexes have the forms [ML¹Cl₂]·nX (1–5) and [ML²Cl]·nX (6–9) (X = H₂O or ethanol). The structures of these complexes were elucidated by elemental analyses, IR, UV–Vis, and electrical conductivity, as well as magnetic susceptibility measurements and thermal analyses. IR spectral data indicates that in all complexes, the ligands act as monobasic tridentate, coordinated through keto oxygen or sulfur, azomethine nitrogen and deprotonated phenolic oxygen atom. On the basis of other physicochemical investigations, tetrahedral or square planar geometries are assigned for Cu²⁺ complexes in monomeric structures. In the case of the Co²⁺, Ni²⁺ and Fe³⁺ complexes, octahedral stereochemistries in monomeric structures are suggested. The dissociation constants of the ligands and the stability constants of their Cu(II), Co(II), Ni(II), and Fe(III) complexes have been also determined using potentiometric pH-metric titration in mixed solvents of dioxane: H₂O and DMF: H₂O with different ratios and different temperatures.     

Metal Complexes with Macrocyclic Ligands. Part XXXI. Protonation studies and complexation properties of tetraazamacrocyclic methylenephosphonates with earth-alkali ions

The three ligands 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylenephosphonic acid) ( 1 ), 1,4,7,11-tetraazacyclotridecane-1,4,7,11-tetrakis(methylenephosphonic acid) ( 2 ), and 1,4,8,11-tetraazacyclotetradecane-1,4,8,1 1-tetrakis(methylenephosphonic acid) ( 3 ) have been synthesized by condensation of the corresponding macrocycles with formaldehyde and phosphorous acid. The protonation and stability constants with the earth-alkali ions have been determined at 25° and I = 0.1 M (Me₄)N(NO₃) by potentiometric titrations. Because of the high values of the first two protonation constants, ¹H-NMR measurements were necessary to determine them. Titrations in different supporting electrolytes (NaNO₃, KNO₃, RbNO₃, CsNO₃, and Me₄N(NO₃)) show that their choice is of paramount importance, as the above ligands can form complexes with alkali-metal ions. The potentiometric results for the earth-alkali ions show that beside mononuclear complexes of different degrees of protonation ([MLH_n], n = 0–4), also binuclear species are formed ([M₂LH_m], m = 0–2). It is interesting that 1 with the smallest macrocyclic ring has the greatest tendency to form binuclear complexes, which are so stable that they partially prevent the formation of the corresponding mononuclear species. For [ML], [MLH], [M₂L], and [M₂LH], the stability sequence is Mg²⁺ < Ca²⁺ > Sr²⁺ > Ba²⁺, whereas for [MLH₂], [MLH₃], and [MLH₄], the stability steadily decreases from Mg²⁺ to Ba²⁺.     

Separation of magnesium isotopes by NTOE bonded merrifield peptide resin

Separation of magnesium isotopes was investigated by chemical ion exchange with synthesyzed 1,12-diaza-3,4:9,10-dibenzo-5,8-dioxacyclo pentadecane(NTOE) bonded merrifield peptide resin using elution chromatographic technique. The capacity of novel diazacrown ion exchanger was 0.29 meq/g dry resin. The heavier isotopes of magnesium were concentrated in the solution phase, while the lighter isotopes were enriched in the resin phase. The glass ion exchange column used in our experiment was 32 cm long with inner diameter of 0.2 cm, and 0.5M NH₄Cl solution was used as an eluent. The single stage separation factor was determined according to the method of GLUECKAUF from the elution curve and isotopic assays. The separation factors of ²⁴Mg²⁺–²⁵Mg²⁺, ²⁴Mg²⁺–²⁶Mg²⁺, and ²⁵Mg²⁺–₂₆Mg²⁺ were 1.063, 1.080, and 1.021, respectively.     

Dissociation constants of some Schiff bases and stability constants of their copper,cobalt, nickel and zinc complexes

The stoichiometry and stability constant of metal complexes with 4-(3-methoxy-salicylideneamino)-5-hydroxynaphthalene-2,7-disulfonic acid monosodium salt (H₂L) and 4-(3-methoxysalicylideneamino)-5-hydroxy-6-(2,5-dichlorophenylazo)-2,7-naphthalene disulfonic acid monosodium salt (H₂L¹) were studied by potentiometric titration. The stability constants of H₂L and H₂L¹ Schiff bases have been investigated by potentiometric titration and u.v.–vis spectroscopy in aqueous media. The dissociation constants of the ligand and the stability constants of the metal complexes were calculated pH-metrically at 25 °C and 0.1 m KCl ionic strength. The dissociation constants for H₂L were obtained as 3.007, 7.620 and 9.564 and for H₂L¹, 4.000, 6.525, 9.473 and 10.423, respectively. The complexes were found to have the formulae [M(L)₂] for M = Co(II), Ni(II), Zn(II) and Cu(II). The stability of the complexes follows the sequence: Zn(II) < Co(II) < Cu(II) < Ni(II). The high stability of H₂L¹ towards Cu(II) and Ni(II) over the other ions is remarkable, in particular over Cu(II), and may be of technological interest. Concentration distribution diagram of various species formed in solution was evaluated for ligands and complexes. The formation of the hydrogen bonds may cause this increased stability of ligands. The pH-metric data were used to find the stoichiometry, deprotonation and stability constants via the SUPERQUAD computer program.     

Studies of Size-Based Selectivity in Aqueous Ternary Complexes of Americium(III) or Lanthanide(III) Cations

Spectrophotometric and calorimetric titrations were used to determine the equilibrium constants (log₁₀ K ₁₁₁) and enthalpies of formation (ΔH ₁₁₁) for aqueous ternary complexes of the form M(L^a)(L^b) (M = Nd³⁺, Sm³⁺, Tb³⁺, Ho³⁺, Er³⁺, or Am³⁺; L^a = DTPA^5?, DO3A^3?, or CDTA^4?; L^b = oxalate (Ox), malonate (Mal), or iminodiacetate (IDA)). Inner-sphere ternary complexes were readily formed with the septadentate DO3A (1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid) and hexadentate CDTA (trans-1,2-diaminocyclohexanetetraacetic acid) ligands, whose binary complexes have residual metal-coordinated water molecules that are readily displaced by the smaller secondary ligands. The stability constants for the formation of lanthanide–CDTA complexes with Ox, Mal, and IDA generally increase with decreasing ionic radius when steric hindrance is minimal, with the trend in the M(CDTA)^? formation constants overshadowing any size-based reversal in the stepwise ternary complexation constants. Similar ternary complexes with DO3A showed little increase in thermodynamic stability compared to analogous CDTA complexes and no preference for larger Ln cations. The octadentate DTPA (diethylenetriaminepentaacetic acid) ligand proved too large to form ternary complexes to a measurable extent with any of the secondary ligands investigated, despite the presence of one residual inner sphere water molecule.