人工神经网络用于锕系离子An3+水解常数pK1预测研究

０引言水解常数是金属离子水溶液化学的基础数据，对于研究水溶液中离子的状态以及进一步研究其在水溶液中的其它化学行为是必不可少的。一般金属离子（包括镧系金属离子）的水解常数数据相对较为完善，对它们水解的规律性也有不少研究，但锕系金属离子的水解常数数据迄今较缺乏，特别是重锕系的水解常数数据基本空缺犤１～５犦。这主要是因为锕系多为放射性元素，重锕系则基本是人工元素，被发现或合成较晚，即使通过核反应合成，量也往往极少（常以多少个原子个数计算），且半衰期大多很短，因而从获取样品到进行有关化学研究都相当困难。…     

镧系金属离子Ln3+定量构效关系的神经网络研究

以Ln³⁺离子的半径、电负性、4f电子排布周期因子q(本文自定义)以及基态L值等为参数,使用函数连接型神经网络(FLN)对Ln³⁺离子的EDTA等络合常数lgK、水化能ΔH、水解常数pK₁及氢氧化物溶解度pK_m分别进行非线性关联和预测,获得了非常好的结果.与对应的线性模型比较表明,神经网络关联效果是较理想的.     

人工神经网络用于金属离子-乙二胺四乙酸络合物稳定性研究

采用函数连接型网络,以金属离子的电荷、离子半径、价电子结构、电负性及适配价轨道数因子为描述参数,成功地关联了近60种已知的金属-EDTA络合物稳定常数logK值,并在此基础上,预报了包括所有锕系元素在内的20种金属-EDTA络合物的logK值.对学习样本的正确选择、高价金属离子与EDTA络合物logK值的报道差异及成因、Co~(3+)离子的“额外”稳定性进行了分析讨论.     

金属离子水解常数pK1的人工神经网络研究

A functional-link net(FLN) was applied to study the relationships between the structural parameters of metal ions and their Hytrosis Constants pK₁. These structural parameters such as radius, electric charge, electronegativity (electricity shouldering) and valence electron structure parameter of the metal ion. The results are satisfactory, and better than that obtained by using linearly statistic methods. Through comparing hytrolysis constants pK₁ with hydration-energy ΔH, the non-linear characteristic of pK₁ have deeply discussed. 19 unknown pK₁ of metal ion were predicted with the method.     

投影寻踪和神经网络方法研究金属离子水解规律

对金属离子水解常数pK1的线性模型的局限性进行了讨论,并采用投影寻踪技术对pK1数据结构进行研究。非线性建模可能是更适宜的方法。采用函数连接型神经网络(FLN),以金属离子的电荷、半径、价电子结构、电负性及空价轨道数等作为描述变量,对60种金属离子水解常数pK1数据进行建模,获得了满意的结果,并对10种金属离子的pK1作出了预测。     

Effects of Different Solvent Characteristics on the Proton-Ligand and Ni2+-, Sm3+-, AND Yb3+- Ligand Formation Constants of 5,5-Dimethyl-Cyclohexane-2-(2-Hydroxyphenyl)Hydrazono- 1,3-Dione (DCPHD) in Various Mixed Aqueous Solvents-(II)

Complex equilibria of DCPHD with proton and Ni²⁺, Sm³⁺, and Yb³⁺ ions has been measured in various mixed aqueous solvents, viz: isopropanol-water, acetone-water, ethanol-water, and methanol-water. Based on potentiometric equilibrium measurements of hydrogen ion concentration at 30°C, ionic strenght 0.10 M (KNO₃) and in the above various mixed aqueous solvents, the values of the protonation constants of DCPHD and the stability constants of DCPHD with Ni²⁺, Sm³⁺, and Yb³⁺ have been evaluated. The variation of protonation and stability constants with the inverse of dielectric constant or mole fraction of the solvent was studied. Application of Fuoss expression and consideration of electrosatic and non-electrostatic effects are made to explain the values of the constants.     

Study on a New Method of Extraction of Metal Ions from Solid Matrices by Supercritical Fluid

TOdate.mostofthepublishedSFEworkshavefocusedonorganiccompound',andsomereportshaverelatedtoSFEofmetalions2.DirectextractionofmetalionsbysupercriticalCO,ishighlyinefficient.OneapproachofextractingmetalionsbysupercriticalCO=issuggestedtoconvertthechargedmetalionsintoneutralmetalcomplexesbyusingchelatingagentinthesupercriticalCO,.Avarietyoforganicchelatingagentssuchasthiocarbamate,D-diketones,andcrownetherhavebeenusedinSFEofmetalions3.8Hydroxyquinolinecontainsdoublecoordinationatoms(N,O-),…     

Study of weak Mn2+ and Cu2+ complexes by a nuclear magnetic resonance method

An NMR method is described and applied, which allows the investigation of the first coordination sphere of certain transition metal ions. It is based on the measurement of the solvent proton nuclear magnetic relaxation times both as a function of magnetic field and of concentration of an admixed diamagnetic salt. This procedure enables an unambiguous separation of dynamic effects from ion-pair formation effects, which both can influence the relaxation times. As an application of this method, the complex formation of Mn²⁺ and Cu²⁺ with Br^–, I^–, ClO ₄ ^– , and SO ₄ ^2– in aqueous solution is studied. Thus the hydration numbersn _H2O of these cations as a function of anion concentration are obtained, allowing the detection of weak inner-sphere or outersphere complexes. Also several complex stability constants are derived and are compared with literature data.     

Effects of Ligand Chain Length and Terminal N-Alkylation on the Protonation Constants and Stability Constants of Some Transition Metal Complexes of Linear Tetraaza and Pentaaza Ligands

A number of terminal N-alkylated linear tetraaza and pentaaza ligands were prepared. Their ligand protonation constants and some transition and post-transition metal (Ni²⁺, Cu²⁺, Zn²⁺, and Cd²⁺) complex stability constants were determined by potentiometric titration methods. In general, methylation and ethylation at the terminal nitrogen atoms caused the corresponding ligand nitrogen basicity to increase; however, the corresponding metal complex stabilities were decreased compared to the non-alkylated structural analogs, presumably due to a steric effect.     

原子团簇离子TinP+m的几何结构与电子性质研究

用量子化学ｂｐｉｎｉｔｉｏ方法研究激光等离子体反应生成的ＴｉｎＰｍ＾＋簇离子,优化了其可能的几何构型,ＴｉＰ＾＋ｍ簇离子中,钛连接两个磷原子形成平面体系,ＴｉＰ＾＋４和ＴｉＰ＾＋６是较稳定构型。