面向未来的化学——绿色化学

综述了绿色化学的发展背景与历史,重点介绍了绿色化学反应的基本原则以及绿色化学在原子经济、绿色原料、绿色催化剂、绿色溶剂、绿色化学产品等领域取得的进展,希望能够推动社会和民众对绿色化学的理解与认知。     

Thorium nanochemistry: the solution structure of the Th(iv)-hydroxo pentamer

Tetravalent thorium exhibits a strong tendency towards hydrolysis and subsequent polymerization. Polymeric species play a crucial role in understanding thorium solution chemistry, since their presence causes apparent solubility several orders of magnitude higher than predicted by thermodynamic data bases. Although electrospray mass spectrometry (ESI MS) identifies Th(iv) dimers and pentamers unequivocally as dominant species close to the solubility limit, the molecular structure of Th(5)(OH)(y) polymers was hitherto unknown. In the present study, X-ray absorption fine structure (XAFS) spectroscopy, high energy X-ray scattering (HEXS) measurements, and quantum chemical calculations are combined to solve the pentamer structure. The most favourable structure is represented by two Th(iv) dimers linked by a central Th(iv) cation through hydroxide bridges.     

Thorium(IV) complexes of bidentate hydroxypyridinonates

The coordination chemistry of actinide(IV) ions with hydroxypyridinone ligands has been initially explored by examining the complexation of Th(IV) ion with bidentate PR-1,2-HOPO (HL(1)()), PR-Me-3,2-HOPO (HL(2)()), and PR-3,4-HOPO-N (HL(3)()) ligands. The complexes Th(L(1)())(4), Th(L(2)())(4), and Th(L(3)())(4) were prepared in methanol solution from Th(acac)(4) and the corresponding ligand. Single-crystal X-ray diffraction analyses are reported for the free ligand PR-Me-3,2-HOPO (HL(2)()) [Ponemacr;, Z = 8, a = 8.1492(7) A, b = 11.1260(9) A, c = 23.402(2) A, alpha = 87.569(1) degrees, beta = 86.592(1) degrees, gamma = 87.480(1) degrees ], and the complex Th(L(2)())(4).H(2)O [Pna2(1) (No. 33), Z = 4, a = 17.1250(5) A, b = 12.3036(7) A, c = 23.880 (1) A]. A comparison of the structure of the metal complex Th-PR-Me-3,2-HOPO with that of free ligand PR-Me-3,2-HOPO reveals that the ligand geometry is the same in the free ligand and in the metal complex. Amide hydrogen bonds enhance the rigidity and stability of the complex and demonstrate that the Me-3,2-HOPO ligands are predisposed for metal chelation. Solution thermodynamic studies determined overall formation constants (log beta(140)) for Th(L(1)())(4), Th(L(2)())(4), and Th(L(3)())(4) of 36.0(3), 38.3(3), and 41.8(5), respectively. Species distribution calculations show that the 4:1 metal complex Th(L)(4) is the dominant species in the acidic range (pH < 6) for PR-1,2-HOPO, in weakly acidic to physiological pH range for PR-Me-3,2-HOPO and in the high-pH range (>8) for PR-3,4-HOPO-N. This finding parallels the relative acidity of these structurally related ligands. In the crystal of [Th(L(2)())(4)].H(2)O, the chiral complex forms an unusual linear coordination polymer composed of linked, alternating enantiomers.     

钍-锌-茜素氨羧络合剂异多核络合物吸附伏安法测定痕量钍

在 0 .2mol LHAc NaAc(pH 4 .5 )缓冲溶液中钍与茜素氨羧络合剂 (ALC)、Zn2 + 形成电活性异多核络合物 ,吸附在静汞滴电极上 ,于 -0 .64V(vs.Ag AgCl)处产生一灵敏的阴极溶出峰 ,其峰高与钍浓度在 3 .0× 1 0 - 9～ 1 .5× 1 0 - 6 mol L范围内呈良好的线性关系 ,检出限为 1 .5× 1 0 - 9mol L。在含 6.0× 1 0 - 8mol LTh 的溶液中连续测定 1 0次RSD为 1 .85 %。对该体系的吸附伏安行为和电极反应机理进行了初步探讨 ,测定了该异多核络合物的组成。方法用于矿石和粘土中痕量钍的测定 ,结果令人满意     

Uran, Thorium und die Seltenen Erden (SE) in Monazitsand

Ohne Zusammenfassung     

The crystal structure of Thorium(IV)tetrakis(trifluoroacetylacetonate)

The crystal structure of the compound thorium(IV)tetrakis(trifluoro-acetylacetonate) was determined by means of a threedimensional X-ray analysis. The space group is C2/c and the cell dimensions are a = 25,05 Å, b = 6.43 Å, c = 21.3 Å, β = 125.4°, with Z = 4. The thorium atom is coordinated by 8 oxygen atoms in the form of an 1111 (D₄–422) antiprism. The mean of the Th–O distances is 2.39 Å with a standard deviation ± 0.04 Å. The trifluoroacetylacetonate rings are approximately planar, except for the CH₃ and CF₃ groups which show significant deviations. The Th–O bonds form angles of approximately 72° and 50° with the theoretical 8 -axis of the antiprism. The structure is stabilized by VAN DER WAALS contacts between neighbouring molecules. The refinement of the atomic positions, the anisotropic temperature parameter of thorium and isotropic temperature parameters of all the other atoms by the least squares method, has given a reliability index of 0.148.     

Copper (II) as an Amperometric Indicator: Determination of Thorium

Abstract

It has been demonstrated that copper (II) is an attractive amperometric indicator for the titration of small amounts of thorium in solution. EDTA was used as the titrant. Best results are obtained in the titration when the mole ratio of thorium to copper is high. The method should be applicable to several other metal ions that form more stable EDTA complexes than does copper.     

Metal Negatrode Supercapatteries: Advancements,Challenges, and Future Perspectives for High-Performance Energy Storage

Metal negatrode supercapattery (MNSC) is an emerging technology that combines the high energy storage capabilities of batteries with the high-power delivery of supercapacitors, thereby offering promising solutions for various applications, such as energy storage systems, electric vehicles, and portable electronics. This review article presents a comprehensive analysis of the potential of MNSCs as a prospective energy storage technology. MNSCs utilize a specific configuration in which the negatrode consists of a metal or metal-rich electrode, such as sodium, aluminum, potassium, or zinc, whereas the positrode functions as a supercapacitor electrode. The utilization of negatrodes with low electrochemical potential and high electrical conductivity is crucial for achieving high specific energy in energy storage devices, despite facing numerous challenges. The present study discusses the design and fabrication aspects of MNSCs, including the selection of appropriate metal negatrodes, electrolytes, and positrodes, alongside the fundamental operational mechanisms. Additionally, this review explores the challenges encountered in MNSCs and proposes solutions to enhance their performance, such as addressing dendrite formation and instability of metal electrodes.     

Thorium(IV) and zirconium(IV) complexes of oxygen donor ligands,part 12. Thorium(IV) complexes of monoN-oxides of 2,2′-bipyridine and 1,10-phenanthroline

Summary Crystalline thorium(IV) chelates with monoN-oxides of 2,2-bipyridine (bipyNO) and 1,10-phenanthroline (phenNO), ThX₄ · 2L (X = Cl, Br, NO₃ or NCS) and ThX₄ · 3L (X = I or ClO₄, and I = bipyNO or phenNO) have been synthesised and characterized on the basis of i.r. spectra, molar conductance, molecular weights, t.g.a. and d.t.a. data. All the complexes are weakly diamagnetic and contain bipyNO and phenNO bonded to thorium(IV) through nitrogen and oxygen. The coordination number of thorium(IV) varies from six to twelve depending on the nature of the anions.Author on leave from L. R. Postgraduate College, Sahibabad (Ghaziabad) and to whom all correspondence should be directed.     

Maleanilic Acids as Highly Selective Reagents for the Amperometric Determination of Thorium (IV)

Abstract

Thorium has been determined amperometrically at an applied e. m. f. of -1.2V with fifteen maleanilic acids. Out of these o-tolyl, p-tolyl, 1-naphthyl, 2-naphthyland 4-amino maleanilic acid were found promising analyticalreagentsand most effective. Th(IV) in the range 6.60 to 2350.0 mg per 100 ml can be determined with an error of ± 0.2%. The interference of fifty-five ions were studied and only five ions Zn(II), Pb(II), Fe(III), UO₂ (II) and Zr(IV) interfered. which could be masked by the addition of S₂O² ₃ or SCN^?, Cl^? or SO^2- ₄, SCN^? or citrate, citrate or tartrate and P₂O^4- ₇ respectively.     

Synthesis and Structure of the Layered Thorium Telluride CsTh(2)Te(6)

The compound CsTh(2)Te(6) has been synthesized at 800 degrees C by the reaction of Th with a Cs(2)Te(3)/Te melt as a reactive flux. The compound crystallizes in the space group -Cmcm of the orthorhombic system with two formula units in a cell of dimensions a = 4.367(2) ?, b = 25.119(10) ?, c = 6.140(3) ?, and V = 673.5(5) ?(3) at T = 113 K. The structure of CsTh(2)Te(6) has been determined from single-crystal X-ray data. The structure comprises infinite, two-dimensional double layers of ThTe(8)-bicapped trigonal prisms. The structural motif of the trigonal prisms resembles that found in UTe(2). Cs(+) cations, disordered equally over two crystallographically equivalent sites, separate the layers and are coordinated by eight Te atoms at the corners of a rectangular parallelepiped. Short Te-Te distances of 3.052(3) and 3.088(3) ? form linear, infinite, one-dimensional chains within the layers. Simple formalisms describe neither the Te-Te bonding in the chain nor the oxidation state of Th. The compound shows weak semiconducting behavior along the Th/Te layers perpendicular to the Te-Te chain.     

Thorium(IV) complexes with tetradentate Schiff base ligands

Summary Some thorium(IV) complexes were synthesized with the tetradentate Schiff base ligands (N₂O₂ donor set) obtained by the condensation of ethylenediamine with salicylaldehyde (H₂salen) or acetylacetone (H₂ acacen). In all cases the neutral Schiff bases and not their anions are coordinated to the central thorium(IV) atom. The complexes have the general formula: ThL₂Xa (L = H₂ salen; X = Cl, Br, 1, NCS and L = lie acacen; X = Cl, 1, NCS, ClO₄) or ThLX₄ (L = H₂ salen; X = NO₃, ClO₄ and L = H₂ acacen; X = Br, NO₃). The stoichiometry and coordination number of the complexes was determined on the basis of elemental analysis, conductivity measurements, i.r. spectra and t.g.a./d.t.a. data. The coordination number of the complexes is either 12 or 8 for the bisor monocomplexes respectively.     

Recovery of Thorium(IV) and Radium(II) from Chloride Solutions

Recovery of thorium(IV) and radium(II) by precipitation methods in the chloride technology of perovskite processing was studied.     

Poly (Ethyl Methacrylate) (PEMA) and its Composites for Various Applications: Background,Recent Progress,and Future challenges

This overview looks critically at the present prospects and future challenges in development of polyethyl methacrylate (PEMA) and its composites. It is shown herein to be a promising candidate for various applications, including energy storage, textile, electronics, biomedical, packaging, coatings and adhesives, etc. Due to its high ionic conductivity, thermal stability, and low cost of synthesis, PEMA is also used as a solid electrolyte in supercapacitors. This polymer has the ability to transport ions efficiently between the two electrodes of the supercapacitor, thereby leading to improved performance and efficiency. Additionally, PEMA can withstand high temperatures without breaking down, thus making it suitable for a range of applications. Further, it is shown due to its unique properties and versatility, PEMA has significant potential for a range of biomedical applications. This review of existing literature strongly suggests that the use of PEMA as a solid electrolyte in supercapacitors can be of significant potential for advancing energy storage technology. It also warrants further research to optimize its use in many other challenging practical applications.     

Synthesis and Characterization of Solid Coordination Complexes of Diamides for Uranium(VI) and Thorium(IV)

Five kinds of solid coordination complexes of uranium(VI) and thorium(IV) with the diamide (N,N,N,N-tetrabutylmalon-amide (TBMA), N,N,N,N-tetrabutylsuccinylamide (TBSA), N,N,N,N-tetrabutylglutaramide (TBGA), N,N,N,N-tetrabutyl-adipicamide (TBAA)) were synthesized. All these complexes of UO₂(NO₃)₂·TBMA, UO₂(NO₃)₂· TBSA, [UO₂(NO₃)₂·(TBGA^1/2)₂] _x , UO₂(NO₃)₂·TBAA and Th(NO₃)₄·2TBMA were characterized by elemental analysis, UV spectra, IR spectra and ¹³C NMR spectra. The coordination form and proposed structures of the complexes are also discussed.     

Thorium(IV) molecular clusters with a hexanuclear Th core

Three polynuclear thorium(IV) molecular complexes have been synthesized under ambient conditions from reactions of an amorphous Th precipitate, obtained via hydrolysis, with carboxylate functionalized ligands. The structures of Th(6)(OH)(4)O(4)(H(2)O)(6)(HCO(2))(12)·nH(2)O (1), Th(6)(OH)(4)O(4)(H(2)O)(6)(CH(3)CO(2))(12)·nH(2)O (2), Th(6)(OH)(4)O(4)(H(2)O)(6)(ClCH(2)CO(2))(12)·4H(2)O (3) each consist of a hexanuclear Th core wherein six 9-coordinate Th(IV) cations are bridged by four μ(3)-hydroxo and four μ(3)-oxo groups. Each Th(IV) center is additionally coordinated to one bound "apical" water molecule and four oxygen atoms from bridging carboxylate functionalized organic acid units. "Decoration" of the cationic [Th(6)(μ(3)-O)(4)(μ(3)-OH)(4)](12+) cores by anionic shells of R-COO(-) ligands (R = H, CH(3), or CH(2)Cl) terminates the oligomers and results in the formation of discrete, neutral molecular clusters. Electronic structure calculations at the density functional theory level predicted that the most energetically favorable positions for the protons on the hexanuclear core result in the cluster with the highest symmetry with the protons separated as much as possible. The synthesis, structure, and characterization of the materials are reported.