金属—血清白蛋白的结构研究——Ⅵ.等离子点附近HSA和BSA中Cu(Ⅱ)和Ni(Ⅱ)金属中心的结构

本文用紫外光谱研究了等离子点附近HSA或BSA ¹Cu(Ⅱ)或Ni(Ⅱ)金属中心的结构。结果表明:在pH₄.0～5.3时,Cu(Ⅱ)—HSA配合物在低浓度时独具五配位的四方锥构型,高浓度时(>10^-4mol·l^-1)为四配位的四方平面构型,Cu(Ⅱ)—BSA、Ni(Ⅱ)—BSA在上述pH范围内均只存在四方平面构型。Cu(Ⅱ)、Ni(Ⅱ)结合位置与生理pH下的相同,均在白蛋白的N端三肽段上,与Asp^{1相似文献}   

金属-血清白蛋白的结构研究 Ⅱ.Cu(Ⅱ)-BSA和Ni(Ⅱ)-BSA的四方锥-四方平面结构

本文用紫外光谱研究Ca(Ⅱ)-BSA和Ni(Ⅱ)-BSA配合物的结构随BSAL浓度的变化,发现当浓度增大并>2×10~(-4)-3×10~(-4)mol·dm~(-3)时,这两种配合物从五配位的四方锥构型转变成四配位的四方平面构型,首次提供了BSA的Asp羧基氧参与同Cu(Ⅱ)和Ni(Ⅱ)配位的证据.计算并讨论了Cu(Ⅱ),Ni(Ⅱ)和有关配体轨道的光学电负性.     

金属-血清白蛋白的结构研究II. Cu(II)-BSA和Ni(II)-BSA的四 方锥-四方平面 结构

本文用紫外光谱研究Cu(II)-BSA和Ni(II)-BSA配合物的结构随BSA浓度的变化,发现当浓度增大并>2×10^-^4～3×10^-^4mol.dm^-^3时,这两种配合物从五配位的四方锥构型转变成四配位的四方平面构型,首次提供了BSA的Asp羧基氧参与同Cu(II)和Ni(II)配位的证据。计算并讨论了Cu(II),Ni(II)和有关配体轨道的光学电负性。     

金属-血清白蛋白的结构研究II. Cu(II)-BSA和Ni(II)-BSA的四 方锥-四方平面 结构

本文用紫外光谱研究Cu(II)-BSA和Ni(II)-BSA配合物的结构随BSA浓度的变化,发现当浓度增大并>2×10^-^4～3×10^-^4mol.dm^-^3时,这两种配合物从五配位的四方锥构型转变成四配位的四方平面构型,首次提供了BSA的Asp羧基氧参与同Cu(II)和Ni(II)配位的证据。计算并讨论了Cu(II),Ni(II)和有关配体轨道的光学电负性。     

N,N′-乙二水杨酰胺合镍(Ⅱ)酸根的双核镍(Ⅱ)及镍(Ⅱ)-铜(Ⅱ)配合物的合成及性能研究

以N,N′-乙二水杨酰胺合镍酸钠同二价金属离子和2,2-联吡啶(bpy)或1,10菲绕啉(phen)反应制得双核配合物,[Ni(samen)Cu(L)]和[Ni(samen)Ni(L)_2](L=bpy,phen).经元素分析。红外、电子光谱等方法已推定[Ni(samen)]~2-中的Ni(Ⅱ)的配位环境为平面四方型,而被bpy或phen配位的Cu(Ⅱ)和Ni(Ⅱ),分别为平面四方型和畸变八面体构型。 据此,本文指派了配合物的电子光谱,评价了Dq,B,β等配位场参数,并且用配位场理论模型算出了有效磁矩,Ni(Ⅱ)-Cu(Ⅱ)配合物的g_(11),与g_1,结果理论值与实验值相当吻合。     

Ni(Ⅱ)与HSA或BSA的结合平衡研究

用平衡透析法研究了生理pH(7.43)及pH(5.0)条件下Ni(Ⅱ)与HSA或BSA的结合平衡。Scatchard图分析表明 ,生理pH条件下 ,Ni(Ⅱ)在HSA或BSA中均有2个强结合部位 ,而在pH(5.0)条件下 ,只有1个强结合部位。Hill图分析表明Ni(Ⅱ)与HSA或BSA的结合均产生较强的正协同效应。通过不同pH对Ni(Ⅱ)与HSA或BSA结合的影响及Ni(Ⅱ)与Cu(Ⅱ)和Ca(Ⅱ)的竞争结合的结果 ,推测了两个强结合部位可能的结合位点和配位原子。竞争结果还表明Cu(Ⅱ)对Ni(Ⅱ)的结合有明显拮抗作用。Ca(Ⅱ)对Ni(Ⅱ)的结合影响很小。     

水杨酰胺合铜(Ⅱ)酸根和5-硝基-1,10-菲绕啉配位的Cu(Ⅱ)-Ni(Ⅱ)配合物的合成和磁性

本文合成了两个新型双核配合物,[Cu(samcn)Ni(L)_2]和[Cu(sampn)Ni(L)_2].samcn~(4-),sampn~(4-)及L分别表示N,N′-乙二水杨酰胺根阴离子,N,N′-1,2-丙二水杨酰胺根阴离子和5-硝基-1,10-菲绕啉(NO_2-phcn).经元素分析,IR和电子光谱等方法已推定配合物具有酚氧桥结构和Cu(Ⅱ)及Ni(Ⅱ)的配位环境分别为平面四方及八面体构型.配合物的变温磁化率已测(4-300K),其数值已用最佳拟合方法和从自旋哈密顿算符,H=-2JS_1·S_2导出的磁方程拟合,求得交换参数为J=-1.77cm~(-1)(samcn)和J=-1.74cm~(-1)(sampn),表明两个Cu(Ⅱ)-Ni(Ⅱ)双核配合物中有很弱的反铁磁性自旋交换相互作用.     

Mn(Ⅱ)与HSA或BSz的结合平衡研究

作者[1]曾在紫外区观察LMCT谱带,研究了1∶1Mn(Ⅱ)-HSA和Mn(Ⅱ)-BSA在生理pH(7.43)下金属中心的结构,认为Mn(Ⅱ)在人血清白蛋白(Human Serum Albumin,简称HSA)和牛血清白蛋白(Bovine Serum Albumin,简称BSA)中的优先结合部位最可能位于HSA或BSA的N-端三肽段上,涉及4个含氮基团,第5个配位原子是ASP1上的羧基氧.用平衡透析法进一步研究了生理pH条件下Mn(Ⅱ)在HSA和BSA中的结合部位的类型、数目及结合能力,并探讨了优先结合部位的可能位置和(或)配体.......     

金属-血清白蛋白的平衡透析——Ⅱ.Ni(Ⅱ)-血清白蛋白体系的别构效应

详细研究了Ni～(2+)离子结合于人血清白蛋白(human serum albumin,HSA)和牛血清白蛋白(bovine serum albumin,BSA)的平衡透析.Ni(II)-HSA和 Ni(II)-BSA体系都得到可以划分成两组的8个结合位置,这2个体系都存在2个优先的结合位置,结合于这 2个位置的 Ni～(2+)离子可以看作是别构效应的效应子,诱导的别构效应符合Monod等人建议的模型.别构参数表明,R-态结合Ni～(2+)离子的能力约为T-态的100倍,HSA的构象显著紧于BSA的.     

血清白蛋白的铜(Ⅱ)-乙酰丙酮络合吸附波法测定

在pH6．8的磷酸盐缓冲溶液中,血清白蛋白与铜(Ⅱ)-乙酰丙酮络合物反应作用生成一种在汞电极上吸附性很弱的铜(Ⅱ)-血清白蛋白惰性络合物,使铜(Ⅱ)-乙酰丙酮络合物在-0．28V(vs．SCE)络合吸附波还原峰电流降低,电流降低值与1～30mg/L范围内牛血清白蛋白(BSA)或1～32mg/L范围内人血清白蛋白(HSA)呈线性关系;检出限分别为0．5和0．6mg/L。运用该法测定了人血清样品中蛋白质含量,结果满意。     

草酸根桥联的不对称双核铜(Ⅱ)和铜(Ⅱ)-锌(Ⅱ)配合物的合成与磁性

本文合成了一组新的不对称的双核配合物,[Cu_2(C_2O_4)_2terp]和〔Cu Zn(C_2O_4)_2terp〕(图1),terp表示联三吡啶。配合物〔Cu_2(C_2O_4)2terp〕的变温磁化率已测,其数值已用最小二乘法与Bleaney-Bowers方程拟合,求得交换积分J=-47.20cm~(-1)。文中还用Kahn理论解释了这种较弱的反铁磁自旋交换作用。     

以氯醌酸二价阴离子为桥联配体的Fe(Ⅲ)-Fe(Ⅲ)和Mn(Ⅱ)-Mn(Ⅱ)双核配合物的合成与磁性

基于铁和锰的双核配合物在生物氧化还原过程中的重要作用及在化学的氧化还原过程中可能做为催化剂的应用前景,本文合成了两个新的以氯醌酸二价阴离子为桥联配体的Fe(Ⅲ)双核和Mn(Ⅱ)双核配合物:[Fe_2(phen)_4(μ-CA)](ClO_4)_4·2H_2O(1)和[Mn_2(phen)_4(μ-CA)](ClO_4)_2·3H_2O(2)(phen=1,10菲咯啉;CA=氯醌酸二价阴离子)。经元素分析、IR、电子光谱及磁性等测定,对两配合物进行了表征。     

顺二氨二水合铂(Ⅱ)与膜磷脂及膜蛋白相互作用的荧光光谱研究

用Tb~(3+)分别对用和未用顺二氨二水合铂(Ⅱ)(AAP)处理的红细胞膜和磷酰胆碱(PC)脂质体进行荧光滴定,测Tb~(3+)荧光。用AAP滴定红细胞膜,测蛋白质自身荧光变化。用间接Scatchard法求结合参数。表明蛋白质及磷脂均与AAP结合,蛋白质结合能力较强。     

CHROMOTROPIC CHANGES OF Cu(II) AND Ni(II) COMPLEXES WITH N2O2 AND N3O2 SCHIFF-BASE LIGANDS IN THE SOLID PHASE

Abstract

Four new Schiff-base ligands have been prepared from the condensation of 3-formyl-4-hy-droxy-1,8-naphthyridin-2-one with different diamines and a triamine, H₂L_a-H₂L_d. Two series of Ni(II) and Cu(II) complexes with the four ligands were also prepared. The ligands and their metal complexes were characterized by chemical analyses, IR, Far-IR, electronic, ESR and mass spectra as well as magnetic measurements and X-ray diffraction patterns.

Different products for Ni(II) and Cu(II) were obtained in similar reactions with the same metal salt, depending on the nature of the ligand. Different geometries were also obtained depending on the counter anion of metal salt. Thus, violet square-planar Cu(II) complexes were obtained with Cu(OAc)₂. H₂O and green octahedral ones with CuCl₂. 2H₂O, except the reaction with ligand H₂L_d which gave only an octahedral product whether the anion was acetate, chloride or perchlorate. Electronic and ESR spectra were used to differentiate between the two geometries of the Cu(II) complexes. The green octahedral Cu(II) complexes undergo irreversible thermochromism to the violet square-planar complexes except the copper complex of the ligand H₂L_d which did not not show any color change and retained its octahedral geometry. Based on the magnetic moments and thermal analyses, only one Ni(II) complex of the Schiffbase ligand H₂L_c undergoes reversible thermochromism from green (octahedral) to red (squareplanar). The reverse change of the thermal product (red) to the parent complex (green) proceeded on exposure to atmospheric air for a few minutes. On the other hand, Ni(II) complexes of ligands H₂L_a and H₂L_b have stable square-planar geometry and all efforts to add other ligands such as H₂O or pyridine to these complexes failed to yield other products. The corresponding Cu(II) complexes were easily transformed to their octahedral geometry by adding H₂O or pyridine and heating.     

SYNTHESIS AND STRUCTURES OF DICHLOROTETRAKIS-(PHENYLTHIOUREA) CADMIUM(II) AND CATENA-BIS(THIOCYANATE) BIS(PHENYLTHIOUREA)CADMIUM(II)

Abstract

Two new cadmium(II) complexes with phenylthiourea (PTU), namely Cd(PTU)₄Cl₂ (1) and [Cd₂(NCS)₂(μ₂-SCN)₂(PTU)₂(μ₂-PTU)₂] _n (2), have been prepared and characterized structurally by X-ray diffaction. Complex 1 crystallizes in the monoclinic space group C2/c, with a = 27.057(13), b = 8.108(3), c = 16.751(8) Å, β = 114.46°, V = 3345(3) ų, Z = 4. Complex 2 crystallizes in the triclinic space group P-1, with a = 9.336(3), b = 14.686(5), c = 16.911(5) Å, α = 71.36(2), β = 84.31(2), γ = 72.470(10)°, V = 2095.0(12) ų Z = 4. The structural analysis shows that each metal atom in both the mononuclear complex 1 and polynuclear complex 2 is octahedrally coordinated by four sulfur atoms and two chloro ligands or two nitrogen atoms from the thiocyanate groups, respectively. The PTU ligand can serve as either a monodentate ligand or a μ₂-bridging ligand upon coordination to a metal atom.     

THE INTERACTION OF 2-AMINO-2-HYDROXYMETHYL-1,3-PROPANEDIOL WITH COBALT(II) AND MANGANESE(II) IONS

Abstract

The stepwise complex formation between 2-amino-2-hydroxymethyl-1,3-propanediol (TRIS) with Co(II) and Mn(II) was studied by potentiometry at constant ionic strength 2.0 M (NaClO₄) and T = (25.0 ± 0.1)°C, from pH measurements. Data of average ligand number (Bjerrum's function) were obtained from such measurements followed by integration to obtain Leden's function, F ₀(L). Graphical treatment and matrix solution of simultaneous equations have shown two overall stability constants of mononuclear stepwise complexes for the Mn(II)/TRIS system (β₁ = (5.04 ± 0.02) M^?1 and β₂ = (5.4 ± 0.5) M^?2) and three for the Co(II)/TRIS system (β₁ = (1.67 ± 0.02) × 10² M^?1, β₂ = (7.01 ± 0.05) × 10³ M^?2 and β₃ = (2.4 ± 0.4) × 10⁴ M^?3). Slow spontaneous oxidation of Co(II) solutions by dissolved oxygen, accelerated by S(IV), occurs in a buffer solution TRIS/HTRIS⁺ 0.010/0.030 M, with a synergistic effect of Mn(II).     

Complexes of Co(II), Ni(II) and Cu(II) with lapachol

Complexes of naturally occurring hydroxynaphtho-quinone, lapachol (2-hydroxy-3(3-methyl-2-buthenyl)-1,4-naphthoquinone = HL) with Co(II), Ni(II) and Cu(II) have been prepared by reaction of the corresponding acetates with the ligand (HL) in ethanol. The molecular and crystal structures were determined for [CoL₂(EtOH)₂] (1), [NiL₂(EtOH)₂] (2), and [CuL₂(py)₂] (3). In all cases the deprotonated lapachol behaves as chelating bidentate ligand. The complexes were also characterized by elemental analyses, cyclic voltammetry, and FAB-MS.     

LIGAND-EXCHANGE REACTION BETWEEN TRIS(1,10-PHENANTHROLINE)METAL(II) AND TRIS(4,7-DIPHENYL-1,10-PHENANTHROLINE)METAL(II) IONS

Abstract

The ligand exchange reaction between [M(phen)₃]²⁺ and [M(DIP)₃]²⁺ (where M is the same and M = Fe^II or Ni^II, phen = 1,10-phenanthroline, DIP = 4,7-diphenyl-1,10-phenanthroline) has been investigated by reversed phase ion-paired chromatography (RP-IPC). The effect of pH and solvent on the ligand-exchange reaction is studied by monitoring the variation in chromatograms with time after mixing. The results have shown that the ligand exchange reaction between [M(phen)₃]²⁺ and [M(DIP)₃]²⁺ takes place in the pH range of 3–8 and the rate of reaction for nickel(II) complexes is about two times slower than that for iron(II) complexes. Experiments on the effect of various solvents on the ligand-exchange reaction have revealed that the rate of reaction is enhanced by the solvent in the following order: (CH₃)₂CO > CHCl₃ ≥ CH₂Cl₂ > CH₃CN > CH₃OH. Elemental analysis and UV-visible spectroscopy confirmed that the products obtained from the ligand-exchange reaction are mixed-ligand complexes containing phen and DIP ligands, i.e., [M(phen)₂(DIP)]²⁺ and [M(phen)(DIP)₂]²⁺.     

New Ni(II)Cu(II)Ni(II) trinuclear complexes with an 5=3/2 high-spin ground

Four new heterotrinuclear complexes have been synthesized and characterized, namely {[Ni(L)₂]₂[Cu(opba)]}(ClO₄)₂, where opba denotes o-phenylenebis(oxamato) and L stands for 1,10-phenanthroline(phen) (1), 5-nitro-l,10-phenanthroline(NO₂-phen) (2), 2,2′-bipyridyl(bpy) (S) and 4,4′-dimethyl-2,2′-bipyridyl(Me₂bpy) (4). The temperature dependence of the magnetic susceptibility of {[Ni(phen)₂]₂[Cu(opba)]}(ClO₄)₂3H₂O has been studied in the 4–300 K range, giving the exchange integral J—109 cm^?1. The HMT vs. T plot exhibits a minimum at about 100 K, characteristic of this kind of coupled polymetallic complex with an irregular spin-state structure.     

Complexes of substituted dipyridylpyridazines with palladium(II) and platinum(II)

Reactions of 3,6-bis(2′-pyridyl)pyridazine derivatives (n-dppn)¶ ¶For the n-dppn ligands, n stands for the size of the cyclic aliphatic ring on positions 4 and 5 of the pyridazine ring, n?=?5, 6, 8, and 12. with MX₂(PhCN)₂ (M?=?Pd, Pt; X?=?Cl,?Br) have been investigated. The new complexes cis-[PdCl₂(n-dppn)] (n?=?5,?6,?8,?12), cis-[PtCl₂(n-dppn)]?·?H₂O (n?=?5,?6), cis-[PtCl₂(8-dppn)] and cis-[PtBr₂(5-dppn)] have been characterized by elemental analyses, conductivity measurements, infrared, electronic and ¹H-NMR spectra.