磷酸二甲酯阴离子与二价金属离子相互作用的研究

在B3LYP/6-31G(d, p)水平上,用全电子分别研究了Mg2+、Ca2+、Mn2+、Co2+、Ni2+、Cu2+和Zn2+与磷酸二甲酯(DMP-)“双齿”配位模式下的相互作用,且由4个水分子((H2O)4)“饱和”各金属离子六配位模式下的其它位点。结果表明:这种配位模式下,DMP-对上述金属离子的选择性顺序为:Cu2+>Ni2+>Zn2+>Co2+>Mg2+>Mn2+>Ca2+,和Irving-Williams序列基本一致。且具有未充满d层轨道的金属对配体的变化“响应”明显。通过NBO(自然键轨道)方法对配合物电荷布居分析可得出主族金属离子与配体间以静电相互作用为主,非主族金属离子配合物中存在一定的共价作用的结论,同时关于配合物各部分间键轨道相互作用的分析部分的反映了金属离子与配体的作用实质。     

含磷钼酸及2,2’-联吡啶-3,3’-二羧酸配体的铜配位聚合物的合成、晶体结构与电化学性质

在水热条件下合成了一个新的化合物{[Cu4(PMo12O40)(H2O)5(H2bpdc)(Hbpdc)(bpdc)2].6H2O}n(H2bpdc=2,2′-联吡啶-3,3′-二羧酸),并用元素分析、IR、TG和X-射线衍射等手段进行了表征。结果表明本化合物的晶体结构中,最小不对称单元包含1个[Cu4(H2O)5(H2bpdc)(Hbpdc)(bpdc)2]3+阳离子,1个[PMo12O40]3-阴离子和6个结晶水分子。Cu(Ⅱ)与相邻[PMo12O40]3-的桥氧原子配位,形成一维链状结构。电化学研究表明,化合物存在三步氧化还原过程。     

Cu-Ni-Mg-Al-CO_3四元水滑石的合成及结构分析

以Cu(NO3)2 ·3H2 O,Ni(NO3)2 ·6H2 O,Mg(NO3)2 ·6H2 O和Al(NO3)3·9H2 O为原料,以NaOH和Na2 CO3为沉淀剂,采用成核/晶化隔离法合成了Cu Ni Mg Al CO3四元水滑石,通过XRD,FT IR,TG DTA,ICP等手段对样品进行测试和表征,并且对水滑石结构的层板和层间阴离子相互作用进行分析和讨论.结果表明,控制Cu2 +离子与其它二价金属离子的配比,可制备晶体结构规整的M(II)4 M(III)2 (OH)12 CO3·4H2 O型水滑石;Cu2 +离子的引入导致了明显的Jahn Teller效应;且随Mg2 +量的增加,使得这种效应更加显著,另一方面Mg2 +量的增加有利于Cu Ni Mg Al CO3四元水滑石晶体在a方向上生长,增强其热稳定性     

通过g-C_3N_4担载MNi_(12)(Fe,Co,Cu,Zn)纳米团簇调节甲烷化反应性能（英文）

新型二维材料g-C_3N_4由于其独特的电子结构和优异的化学性能受到了极大关注。根据金属载体间的相互作用以及合金的协同效应,本文应用密度泛函理论,对核壳结构MNi_(12)(Fe, Co, Cu, Zn)纳米团簇与载体g-C_3N_4的相互作用进行研究,并通过其对CO的吸附能研究新型催化剂的反应性能。结果表明d层电子越少的"核"原子与"壳"原子Ni的相互作用更强;当MNi_(12)负载在g-C_3N_4上时,-9.40 eV到-8.39 eV之间的结合能说明MNi_(12)可以很好的稳定在g-C_3N_4上;最后,通过MNi_(12)以及MNi_(12)/g-C_3N_4对CO的吸附行为发现,g-C_3N_4的引入导致CO的吸附能和C―O键长减小。根据电荷分析以及静电势(ESP)分析,发现其原因是因为g-C_3N_4担载以后,CO从MNi_(12)获得的电子数更少。通过本次理论计算,可以得出结论:g-C_3N_4担载MNi_(12)(Fe, Co, Cu, Zn)的新型催化剂不仅可以呈现高稳定性,还可以调变反应性能。     

气相和溶液中金属离子与腺嘌呤配位选择性的理论研究

在B3LYP/6-31G(d,p)水平,全优化Mg2+、Ca2+、Mn2+、Co2+、Zn2+、Cu2+、Ni2+、Cd2+ (用有效实势(ECP) 方法处理)与腺嘌呤(A) N(1)、N(7)位点配位的两类配合物气相结构,通过相互作用能和自由能分析分别得出两位点对所研究金属离子的选择性顺序;后采用Onsager模型,优化其在水溶液(=78.39)中的结构,讨论溶剂效应对上述顺序的影响;通过相对自由能分析分别得出气相和溶液中,同种金属对两位点的选择性规律。溶液中金属离子与N(7)位配位的相对优选顺序为:Co2+ > Mg2+ > Cd2+ > Ca2+ > Zn2+ > Mn2+ > Ni2+ > Cu2+。     

三聚氰胺对金属(Ⅱ)卟啉反应活性影响的概念密度泛函研究

选取8个典型的二价金属卟啉MP(M=Ca,Mg,Zn,Cu,Ni,Fe,Co,Mn)与三聚氰胺(L)形成轴向金属配合物(L-MP),应用概念密度泛函工具,系统地计算和比较了L键合前后对其结构和反应性质的影响.结果表明:除钙的特别不稳定物外,L配体对其余6种MP的结构影响较小,它们有较高的化学势指数和较低的总化学硬度而趋向配体的解离;与铁卟啉能形成最稳定的轴向配合物,电子由配体N原子流向铁,中心铁的亲核Fukui指数值大于体系里其他原子的Fukui指数,且发生符号改变.在这些典型的赤道键合配合物中,金属M、配体N之间的二级微扰相互作用能,自然电荷布局以及概念密度泛函指数等方面,存在着一系列线性关系.以上结果可为体内三聚氰胺致结石提供新的启示.     

脯氨酸与Cu、Cu~+和Cu~(2+)配位体系的计算研究

运用M06-2X和ωB97XD方法分别在6-311++G(2d,p)和TZVP基组水平上,对脯氨酸(Pro)的15种构象与Cu、Cu+和Cu2+形成的多种配合物的几何结构、能量学特征、振动光谱和电子结构等进行计算研究.四种水平得到20种[Pro-Cu]、16种[Pro-Cu]+和16种[Pro-Cu]2+稳定结构.[Pro-Cu]和[Pro-Cu]+体系中出现12种Pro构象,而[Pro-Cu]2+体系中出现11种Pro构象,三种体系中最稳定的结构都不是由能量最低的Pro构象生成的.在结构CI3、CI4、CII7和CII8中,Pro的羧基氢转移到亚氨基氮形成两性离子与Cu双配位结合.[Pro-Cu]0/1+/2+体系四种水平计算相对能差范围逐渐增加,结合能分别在-60.0--5.0 kJ·mol-1、-340.0--170.0 kJ·mol-1和-1100.0--860.0 kJ·mol-1范围,配位体系中Pro的变形能逐渐增加.N―H和O―H键伸缩振动频率普遍发生红移,配位体系中部分电荷从Pro转移到Cu上,在[Pro-Cu]2+体系中单配位结构中电荷转移最多,约为单位负电荷.     

苯二酚异构体双电荷离子和单电荷离子的动能谱研究

本文利用质量分析离子动能谱(MIKES)、碰撞诱导解离(CID)技术和电子捕获诱导解离(ECID)技术, 研究了邻、间、对苯二酚分子在电子轰击质谱(EIMS)中产生的双电荷离子[C6H6O2]^2^+, [C6H4O]^2^+和单电荷离子[C6H6O2]^+。根据测定的电荷分离反应动能释放值T和由此计算出的两电荷间距R, 推测出过渡态的结构。有趣的是, 可利用单电荷离子[C6H6O2]^+的MIKES/CID谱区分苯二酚异构体。     

过渡金属离子与3-氟邻苯二甲酸和1,10-邻菲啰啉配合物的合成、结构及性质

过渡金属离子与3-氟邻苯二甲酸(H2Fpht)、1,10-邻菲啰啉(phen)通过水热反应得到了5个配合物:[M(Fpht)(phen)(H2O)3]·H2O(M=Ni 1,Co 2),[Cu(Fpht)(phen)(H2O)]·H2O(3),[M(Fpht)(phen)(H2O)]·H2O(M=Zn 4,Cd 5)。通过X-射线单晶衍射分析、元素分析、红外分析、荧光分析以及差热-热重分析对配合物进行了表征。配合物1和2为单核分子,中心离子Ni(Ⅱ)和Co(Ⅱ)与3-氟邻苯二甲酸根的1个氧原子,1,10-邻菲啰啉的2个氮原子以及3个配位水分子的3个氧原子配位,形成六配位的扭曲八面体构型。配合物3为Z字形一维链状结构。中心Cu(Ⅱ)离子与2个3-氟邻苯二甲酸根的2个氧原子,1个1,10-邻菲啰啉的2个氮原子以及水分子的1个氧原子配位,形成四方锥构型。配合物4和5具有相似的一维螺旋结构,中心Zn(Ⅱ)和Cd(Ⅱ)离子与2个3-氟邻苯二甲酸根的3个氧原子、1,10-邻菲啰啉的2个氮原子以及水分子中的1个氧原子配位,形成扭曲的八面体构型。     

(H)FNO~+异构体的结构及异构化反应的量子化学研究

在CCSD(T)/6-311+G(2d,2p)//B3LYP/6-311+G(2d,2p)水平上对八种(H)FNO+异构体的结构和异构化机理进行了研究.用分子生成密度差结合电子密度拓扑分析方法讨论了FNO质子化过程中的电子转移,结果显示FNO质子化过程中除HFNO+中电荷由N,O原子向H,F原子转移外,其他七种异构体中均是H原子上电荷增加,F原子上电荷减小,说明电子由F向H转移.在八种(H)FNO+异构体中,HFNO+,FNOH-cis,FN(H)O+和FNOH+-trans能量较低,较稳定;异构体间通过H原子迁移、F原子迁移、分子内化学键转动及化学键的相对振动四种过程实现异构化,其中原子迁移过程的反应能垒很高,反应不容易进行.用电子定域函数(ELF)理论讨论了反应过程中化学键的变化.     

Effect of metal ions (Li+, Na+, K+, Mg2+, Ca2+, Ni2+, Cu2+, and Zn2+) and water coordination on the structure of glycine and zwitterionic glycine

Interactions between metal ions and amino acids are common both in solution and in the gas phase. Here, the effect of metal ions and water on the structure of glycine is examined. The effect of metal ions (Li+, Na+, K+, Mg2+, Ca2+, Ni2+, Cu2+, and Zn2+) and water on structures of Gly.Mn+(H2O)m and GlyZwitt.Mn+(H2O)m (m = 0, 2, 5) complexes have been determined theoretically by employing the hybrid B3LYP exchange-correlation functional and using extended basis sets. Selected calculations were carried out also by means of CBS-QB3 model chemistry. The interaction enthalpies, entropies, and Gibbs energies of eight complexes Gly.Mn+ (Mn+ = Li+, Na+, K+, Mg2+, Ca2+, Ni2+, Cu2+, and Zn2+) were determined at the B3LYP density functional level of theory. The computed Gibbs energies DeltaG degrees are negative and span a rather broad energy interval (from -90 to -1100 kJ mol(-1)), meaning that the ions studied form strong complexes. The largest interaction Gibbs energy (-1076 kJ mol(-1)) was computed for the NiGly2+ complex. Calculations of the molecular structure and relative stability of the Gly.Mn+(H2O)m and GlyZwitt.Mn+(H2O)m (Mn+ = Li+, Na+, K+, Mg2+, Ca2+, Ni2+, Cu2+, and Zn2+; m = 0, 2, and 5) systems indicate that in the complexes with monovalent metal cations the most stable species are the NO coordinated metal cations in non-zwitterionic glycine. Divalent cations Mg2+, Ca2+, Ni2+, Cu2+, and Zn2+ prefer coordination via the OO bifurcated bonds of the zwitterionic glycine. Stepwise addition of two and five water molecules leads to considerable changes in the relative stability of the hydrated species. Addition of two water molecules at the metal ion in both Gly.Mn+ and GlyZwitt.Mn+ complexes reduces the relative stability of metallic complexes of glycine. For Mn+ = Li+ or Na+, the addition of five water molecules does not change the relative order of stability. In the Gly.K+ complex, the solvation shell of water molecules around K+ ion has, because of the larger size of the potassium cation, a different structure with a reduced number of hydrogen-bonded contacts. This results in a net preference (by 10.3 kJ mol(-1)) of the GlyZwitt.K+H2O5 system. Addition of five water molecules to the glycine complexes containing divalent cations Mg2+, Ca2+, Ni2+, Cu2+, and Zn2+ results in a net preference for non-zwitterionic glycine species. The computed relative Gibbs energies are quite high (-10 to -38 kJ mol(-1)), and the NO coordination is preferred in the Gly.Mn+(H2O)5 (Mn+ = Mg2+, Ca2+, Ni2+, Cu2+, and Zn2+) complexes over the OO coordination.     

Theoretical Studies on the Interaction between Metal Cations and Cytosine, Guanine

1 INTRODUCTION The study on the interaction between metal cations and biomacromolecules is one of the important subjects of bioinorganic chemistry. As is well known, the metal ions play an important role in keeping the basic structures and realizing the normal functions of biomacromolecules like proteins, nucleic acid, and peptide hormone[1]. However, at present the interac- tion mechanism has not been understood yet. In recent years remarkable achievements have been obtained in this fie…     

The effect of ‘crystallinity’ and structural disorder on the electrochemical performance of substituted nickel hydroxide electrodes

β_bc-Nickel hydroxide exhibit non-uniform broadening reflections in their PXRD pattern due to the presence of structural disorder. β_bc-Nickel hydroxide electrodes with smaller crystallite size and structural disorder reversibly exchanges 0.9e/Ni. Co/Zn/Ca/Cd-substituted β_bc-nickel hydroxide samples also display non-uniform broadening of reflections in their powder X-ray diffraction patterns with smaller crystallite size and exchanges 0.7–0.8e/Ni. Hydrothermal treatment of β_bc-nickel hydroxide slurry at 170 °C results in an ordering of reflections in their powder X-ray diffraction pattern with an increased crystallite size. Crystalline β-nickel hydroxide electrode reversibly exchanges 0.3–0.4e/Ni. Hydrothermal-treated Co/Zn/Ca/Cd-substituted β_bc-nickel hydroxide slurries at 170 °C display sharp reflections with similar crystallite size and electrochemical activities as that of crystalline β-nickel hydroxide. This clearly demonstrates that partial substitution of Co/Zn/Ca/Cd in the nickel hydroxide matrix does not show any dramatic improvement in their electrochemical activity at 25–30 °C. Structural disordered material with smaller crystallite size delivers electrochemical activity close to theoretical capacity.     

吡咯并[2,1,5-cd]中氮茚酰腙衍生物的合成及Cu2+荧光探针行为

设计合成了吡咯并[2,1,5-cd]中氮茚酰腙衍生物6. 测试了其紫外光谱和荧光光谱, 研究了其对铜离子的选择性识别作用. 结果表明, 化合物6作为铜离子荧光探针, 受常见离子干扰较小, 对于铜离子有着较高的选择性和较低的检出限.     

Al掺杂Ni(OH)2的结构及电化学性能

用化学共沉淀法合成了A l掺杂N i(OH)2,用XRD表征了合成样品的结构特征:研究了合成样品的循环伏安性能,以及用A l掺杂N i(OH)2为正极活性物质的Zn/N i试验电池的充放电性能。研究结果表明:所合成的A l掺杂N i(OH)2为具有α-型晶体结构的材料,A l掺杂N i(OH)2具有优良的电化学可逆性、良好的充放电性能和较好的电化学循环性能;A l掺杂N i(OH)2作为正极活性物质的Zn/N i试验电池等250次充放电循环容量保持率130.1%,最高放电比容量为420.5mAh/g。     

内含式化合物X@Al12P12的结构与稳定性研究

采用B3LYP／6—31G*方法,对内含式化合物X@Al12P12(X=Li^0/ ,Na^0/ ,K^0/2 ,Be^0/2 ,Mg^0/2 ,Ca^0/2 ,H和He)的不同对称性构型进行计算,讨论其最稳定构型的几何参数、布居分析、偶极矩、电离势、包含能、频率、HOMO—LUMO能隙和自旋密度．发现X@Al12P12化合物中,客体X=Na^0/ ,K^0/ ,Mg和He几乎处在笼的中心,Be和Ca^0/2 处在中心附近0．033nm的半径内,Li^0/ ,Be^2 ,Mg^2 和H很大程度上偏离笼的中心位置．大部分金属内含式化合物的C3对称性构型稳定．Li^0/ 。,Be^0/2 ,Mg^2 ,Ca^2 和H与其它离子相比更易嵌入笼内形成稳定的内含式化合物．     

两种磺酰胺类化合物的合成及其对Fe3+的氧化-还原荧光“开-关”性质

合成了两种磺酰胺类化合物, 并研究了其荧光性能. 通过它们对金属阳离子的选择性识别实验, 发现其在乙醇水溶液中均对Fe3+有专一性的识别作用, 并在NH2OH·HCl和H2O2的存在下, 两种化合物对Fe3+都具有氧化-还原荧光“开-关”作用.     

Thermodynamic and kinetic aspects of metal binding to the histidine-rich protein, Hpn

The histidine-rich protein, Hpn, binds to essential metals Ni2+, Cu2+, Zn2+ and a therapeutic metal Bi3+ with the in vitro affinities in the order of Cu2+ > Ni2+ > Bi3+ > Zn2+. In contrast, the in vivo (in E. coli) protection by the protein is in the order of Ni2+ > Bi3+ > Cu2+ approximately Zn2+. The release of Ni2+ from the protein follows a two-step process consisting of a rapidly established equilibrium and subsequently a rate-determining step (dissociation of Hpn-Ni...EDTA to Ni-EDTA). Our work suggests the nickel storage and homeostasis in H. pylori as the primary role of Hpn.     

Hydration of gaseous copper dications probed by IR action spectroscopy

Clusters of Cu (2+)(H 2O) n , n = 6-12, formed by electrospray ionization, are investigated using infrared photodissociation spectroscopy, blackbody infrared radiative dissociation (BIRD), and density functional theory of select clusters. At 298 K, the BIRD rate constants increase with increasing cluster size for n >or= 8, but the trend reverses for the smaller clusters where Cu (2+)(H 2O) 6 is less stable than Cu (2+)(H 2O) 8. This trend in stability is consistent with a change in fragmentation pathway from loss of a water molecule for clusters with n >or= 9 to loss of hydrated protonated water clusters and the formation of the corresponding singly charged hydrated metal hydroxide for n 相似文献   

开链冠醚Schiff碱配体与过渡金属离子相互作用研究

合成了开链冠醚Schiff碱配体H₂L(H₂L=N,N′-双(邻羟苯亚甲基)-3,6-二氧杂-1,8-二氨基辛烷).详细研究了该配体在不同溶剂中和过渡金属离子存在下的荧光光谱,探讨了溶剂极性和不同金属离子对其荧光光谱的影响.结果表明:溶剂的极性和金属离子对其荧光性质有较大影响,随着溶剂极性的减小,配体的荧光增强,且谱峰发生蓝移.金属离子Zn²⁺、Cd²⁺对配体具有荧光增敏作用,Ni²⁺、Cu²⁺具有荧光猝灭作用.探讨了配体与金属离子结合的pH范围,结果显示最佳pH值为7—8.