六聚吡咯大环与铀/超铀酰基离子相互作用:成键、热力学和光谱性质

采用全电子相对论密度泛函理论探索多种六聚吡咯大环锕酰基配合物(nAn;n=1~3;An=U,Np and Pu)的电子结构本质、成键规律和化学反应特性。结构优化发现大环配体空穴大小与锕酰离子尺寸相当时,配合物锕酰基采用性对规则的六角双锥结构,而当空穴尺寸相对大时,配合物则采取扭曲结构以降低体系能量。当配体相同时,随着铀、镎、钚变化,An=O伸缩振动频率逐渐变小,这与优化的键长和键级变化规律相一致。QTAIM(quantum theory of atoms in molecule)拓扑分析显示An-N为弱共价单键特征,具有较大离子性成分。依据不同铀源,得到与大环配体的反应自由能均小于146 kJ·mol~(-1),与实验合成配合物的反应能计算数值相当。对含铀配合物电子吸收光谱计算显示,低能(近红外和可见光区)的吸收带具有全部或较大的配体→金属电荷转移性质贡献。     

A Bis(p-tert-butyloctahomotetraoxacalix[8]arene) Capsule with [(UO2)2(OH)2] Links and a Disordered [Rb4(H2O)4] Inner Core

p-tert-Butyloctahomotetraoxacalix[8]arene (LH⁸) reacts with uranyl nitrate hexahydrate in the presence of rubidium hydroxide to give a mixed complex that can be viewed as a tetrauranate dimer [(UO²)⁴(LH⁴)²(OH)⁴] containing four disordered rubidium ions and water molecules. Two uranyl ions are complexed in an “external” fashion by each macrocycle, each of them bound to two phenoxide groups and one ether group, as well as to two bridging hydroxide ions. The latter ensure the formation of a dimeric capsule that contains the disordered set of alkali metal ions. Apart from water molecules, the Rb⁺ ions are bound to the uranyl oxo groups directed towards the inner cavity, and to phenol and ether oxygen atoms from the macrocycle. The resulting octanuclear complex presents an unprecedented geometry evidencing the assembling potential of uranyl ions.

p-tert-Butyloctahomotetraoxacalix[8]arene (LH₈) reacts with uranyl nitrate hexahydrate in the presence of rubidium hydroxide to give a mixed complex that can be viewed as a tetrauranate dimer [(UO₂)₄(LH₄)₂(OH)₄] containing four disordered rubidium ions and water molecules. Two uranyl ions are complexed in an “external” fashion by each macrocycle, each of them bound to two phenoxide groups and one ether group, as well as to two bridging hydroxide ions. The latter ensure the formation of a dimeric capsule that contains the disordered set of alkali metal ions. Apart from water molecules, the Rb^+| ions are bound to the uranyl oxo groups directed towards the inner cavity, and to phenol and ether oxygen atoms from the macrocycle. The resulting octanuclear complex presents an unprecedented geometry evidencing the assembling potential of uranyl ions.     

Syntheses and structures of two new uranyl complexes [UO2(DPDPU)2(NO3)2](C6H5CH3) and [UO2(PMBP)2(DPDPU)](CH3C6H4CH3)0.5

Two new uranyl complexes [UO₂(DPDPU)₂(NO₃)₂](C₆H₅CH₃) (1) and [UO₂(PMBP)₂ (DPDPU)](CH₃C₆H₄CH₃)_0.5 (2), (DPDPU?=?N,N′-dipropyl-N,N′-diphenylurea, HPMBP?= 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5) were synthesized and characterized. The coordination geometry of the uranyl atom in 1 is distorted hexagonal bipyramidal, coordinated by two oxygen atoms of two DPDPU molecules and four oxygen atoms of two bidentate nitrate groups. The coordination geometry of the uranyl atom in 2 is distorted pentagonal bipyramidal, coordinated by one oxygen atom of one DPDPU molecule and four oxygen atoms of two chelating PMBP molecules.     

Synthesis and structures of two uranyl β-diketonate complexes [UO2(DBM)2(DEDPU)] and [UO2(PMBP)2(DEDPU)]

Two new uranyl β-diketonate complexes [UO₂(DBM)₂(DEDPU)] (1) and [UO₂(PMBP)₂(DEDPU)](CH₃C₆H₅)_0.5 (2), (HDBM?=?dibenzoylmethane, HPMBP?=?1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, DEDPU?=?N,N′-diethyl-N,N′-diphenylurea) were synthesized and characterized. The coordination geometries of the uranyl atoms in 1 and 2 are distorted pentagonal bipyramidal, coordinated by one oxygen atom of DBDPU molecule and four oxygen atoms of two chelating DBM molecules in 1 and PMBP molecules in 2.     

Synthesis,characterization, and biological activity of metal complexes of azohydrazone ligand

A new azohydrazone, 2-hydroxy-N′-2-hydroxy-5-(phenyldiazenyl)benzohydrazide (H₃L) and its copper(II), nickel(II), cobalt(II), manganese(II), zinc(II), cadmium(II), mercury(II), vanadyl(II), uranyl(II), iron(III), and ruthenium(III) complexes have been prepared and characterized by elemental and thermal analyses as well as spectroscopic techniques (¹H-NMR, IR, UV-Vis, ESR), magnetic, and conductivity measurements. Spectral data showed a neutral bidentate, monobasic bidentate, monobasic tridentate, and dibasic tridentate bonding to metal ions via the carbonyl oxygen in ketonic or enolic form, azomethine nitrogen, and/or deprotonated phenolic hydroxyl oxygen. ESR spectra of solid vanadyl(II) complex (2), copper(II) complexes (3–5), and (7) and manganese(II) complex (10) at room temperature show isotropic spectra, while copper(II) complex (6) shows axial symmetry with covalent character. Biological results show that the ligand is biologically inactive but the complexes exhibit mild effect on Gram positive bacteria (Bacillus subtilis), some octahedral complexes exhibit moderate effect on Gram negative bacteria (Escherichia coli), and VO(II), Cd(II), UO(II), and Hg(II) complexes show higher effect on Fungus (Aspergillus niger). When compared to previous results, metal complexes of this hydrazone have a mild effect on microorganisms due to the presence of the azo group.     

The determination of the stability constants of uranyl and thorium with aminopolycarboxylic acids

The stability of uranyl and thorium ions with ligands N-(2′-carboxy phenyl) iminodiacetic acid (ADA), iminodiacetic acid (IDA) and [(ethylenedioxy)diethylenedinitrilo]tetraacetic acid (EGRA) have been studied using the potentiometric technique in 0.1M, KNO₃ solution at 25°C. The complexes of thorium (IV) ions with IDA and ADA are shown to be more stable than those for uranyl ions, while EGTA forms more stable complexes with uranyl ion.     

Über Metallkomplexe der Heteroarylformazane

Two new heteroarylformazans with two complex forming carboxy groups in the ortho position relative to the formazan chain have been synthesized. These compounds form complexes with uranyl, cobalt and nickel ions. The ratio metal/formazan of these complexes has been investigated.

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Teil der Dissertation,. Kaban, Univ. Istanbul 1975.     

Calixarene Complexes of Anion-bridged Oligouranyl Species

The syntheses and structures of uranyl complexes of p-t-Bu-calix[6]arene (calix[6]H₆) and p-t-Bu-calix[9]arene (calix[9]H₉) are reported, further developing the role of calixarenes as 'cluster keepers'. The calix[6]arene complex, formulated as [(HO){UO₂(calix[6]H₄)(dmso)}₃H], is trinuclear and linked symmetrically by the hydroxyl O atom. The calix[9]arene complex is binuclear, with a carbonate atom bridging between the two uranyl cations to give the complex, (HNEt₃)₃[(OCO₂)(UO₂)₃(calix[9]H₄)].     

Spectrophotometric studies on the uranyl-ascorbate complex

A systematic spectrophotometric study on the complexation of uranyl ions with ascorbic acid (vitamin C) is carried out. Factors influencing the sensitivity or selectivity of uranyl ascorbate are studied, and adequate elimination or control of the procedure is suggested. Results of the absorbance of uranyl ascorbate developed in HNO₃, HCl, and H₂SO₄ acid media within the concentration range (1.0–8.0) × 10⁻N show a marked dependence on the nature and concentration of the acid used. The observed decrease in color intensity at higher acidities is explained on the basis of the decomposing effect of hydrogen ions on uranyl ascorbate and the complexing effect on uranyl ions. Study of the stoichiometry of uranium:ascorbic acid complex in acid medium by continuous variation and molar ratio methods indicated the formation of 1:1 and 1:2 complexes. The formation constant of the 1:1 complex as calculated by these two methods was found to be 4.8 × 10⁴ and 5.0 × 10⁴, respectively. Best suitable conditions for stabilizing and increasing the color intensity of uranyl ascorbate, dependent on the nature of the medium and pH of the solution, are suggested for the determination of ascorbic acid in pharmaceutical preparations using this method.     

The synthesis and characterization of copper(II)–<Emphasis Type="Italic">p</Emphasis>-aminosalicylate complexes with diamine ligands

The complexes were synthesized by the reaction between sodium salt of p-aminosalicylic acid (PAS) and Cu(II) for 1 and corresponding ethylenediamine (en) or its derivatives for 2–6. The complexes were characterized by using elemental analyses, FT-IR, UV–Vis, magnetic moment measurements, and thermal analyses techniques. In complex 1[Cu₂(PA)₄(H₂O)₂], two Cu(II) ions were found as bridged by four μ-O:O′ p-aminosalicylato (PA) ligands, forming a cage structure, and two aqua ligands to form dinuclear square-pyramidal geometry around Cu(II) ions. In the complexes 2–6, the PA (anionic form of p-aminosalicylic acid) coordinated to Cu(II) ions as monodentate manner by using its oxygen atom of deprotonated carboxylic acid and ethylenediamine derivatives coordinated to the Cu(II) ions in bidentate manner to form mononuclear octahedral complexes [Cu(PA)₂(L)₂] (L = ethylendiamine, N,N-dimethylethylendiamine, N,N′-dimethylethylendiamine, N,N,N′,N′-tetramethylethylendiamine, and 1,3-propanediamine, for complexes 2, 3, 4, 5, and 6, respectively). In all the complexes OH and NH₂ groups of PA ligands were not coordinated to metals.     

Bent and linear trinuclear nickel complexes with ligands derived from N -acylsalicylhydrazide ligands: structural characterization and bioactivity

Two trinuclear Ni(II) complexes Ni₃(L₁)₂(py)₂(DMF)(H₂O) (1) and Ni₃(L₂)₂(py)₂(DMF)₂ (2) with two new trianionic pentadentate ligands N-(3,5-dimethylbenzoyl)-salicylhydrazide (H₃L₁) and N-(phenylacetyl)-5-nitrosalicylhydrazide (H₃L₂) have been synthesized and characterized by X-ray crystallography. Nickel ions in the two complexes have square-planar/octahedral/square-planar coordination. Central metal ion and two terminal metal ions in the two complexes are combined by two bridging deprotonated ligands, forming a trinuclear structural unit with an M–N–N–M–N–N–M core. Studies on the trinuclear Ni(II) complexes show that the β-branched N-acylsalicylhydrazide ligands with sterically flexible Cα methylene groups yield linear trinuclear Ni(II) complexes, while α-branched N-acylsalicylhydrazide ligands tend to form bent trinuclear Ni(II) complexes. Antibacterial screening data in a previous study indicates that bent trinuclear Ni(II) compound 1 is more active than linear compound 2 and less active than a tetranuclear nickel compound.     

Hydroxamic Acids and Their Metal Complexes Obtained in situ as Electrode-Active Components in the Membranes of Ion-Selective Electrodes

Metal complexes with a hydroxamic acid, namely, N-phenyl-N-(3-styrylacryloyl)hydroxylamine (PSAHA), are promising reagents for use in the preparation of cation- and anion-selective electrodes. The in situ formation of metal complexes by membrane conditioning in a solution of an appropriate metal salt made it possible to prepare cation-selective electrodes for methyl ester of phenylalanine (UO²⁺ ₂) and anion-selective electrodes for tryptophan, phenylalanine (Sn(IV)), and aspartic acid (Cu(II)). The PSAHA-based membrane is sensitive to nitrate ions in solutions of uranyl nitrate (the metal complex is formed in the membrane even without special conditioning).     

Infrared vibrational spectra,electronic structures,and formation reactions of polypyrrolic mono‐ and bis‐actinyl complexes: A relativistic DFT study

The development of synthetic techniques has enabled synthesis and characterization of a series of mono and bis‐uranyl complexes of octadentate polypyrrolic macrocycles such as aryl‐lined H₄L^Ar and anthracenyl‐linked H₄L, which is complemented by theoretical investigation via extending to more toxic and radioactive transuranics. The relativistic density functional theory (DFT) study has been dedicated to twelve actinyl complexes supported by the H₄L ligand. The actinides include U, Np, and Pu elements, and either one or two is rendered in complexes with oxidation states of V or VI. Calculated symmetric/asymmetric An = O stretching vibrational frequencies show the decreasing trend along U, Np, and Pu, which is consistent with calculated bond orders. The hydrogen bonds between –yl endo‐oxo and remaining hydrogen atoms of pyrrolides in mononuclear complexes cause pronounced redshift of An = O vibrational frequencies compared to those in binuclear complexes, so does the reduction from hexa‐ to penta valent complexes. The electronic structures of actinyl complexes were calculated. For example, B‐ pyU^VI possesses low‐lying U(5f )‐character virtual orbitals, where f (δ) and f (?) orbitals occur in low‐energy region and π‐type ones are residing further high; the σ*(U = O) and σ(U = O) orbitals are significantly split over 7 eV. The previous experimental observation that the 1:1 reactions between uranyl salts and the macrocycle tend to give a mixture of bis‐ and mono‐uranyl complexes, with bis‐ the major product, has been corroborated by computational studies of the thermodynamics of the reactions.     

A new carboxylic chelate ligand and its supramolecular complexes formed with sodium ions and alcohol molecules

The new hydrazone ligand 1, featuring a 2-carboxy group at the aromatic ring and a trifluoromethyl structural modification in the pentane-2,4-dione moiety, has been synthesised via the Japp–Klingemann route. The compound is shown to form binuclear multicomponent chelate complexes (2 and 3) composed of two sodium ions, two charge equalising carboxylates of the hydrazone molecule, two more carboxylic hydrazones and two alcohol solvent molecules, with the latter being either EtOH or n-BuOH. X-ray crystal structures of the free hydrazone ligand as well as of the complexes have been studied. They demonstrate for the free ligand a ribbon-type aggregation of carboxylic dimers, while the isomorphous complexes possess a remarkable binuclear structure with the two sodium ions in a distorted octahedral coordination geometry of six oxygen atoms coming, at the equatorial and apical sites, from the hydrazone carbonyl groups and the hydroxyl of the solvent molecules, respectively. The hydrogen bonds owing to the alcohol molecules give rise to the stack formation of the supramolecular cluster. Weak intermolecular contacts involving the fluorine atoms also contribute to the crystalline packing in the case of both the free ligand and the complexes.     

Binuclear Uranium(VI) Complexes with a “Pacman” Expanded Porphyrin: Computational Evidence for Highly Unusual Bis‐Actinyl Structures

On the basis of uranyl complexes reacting with a polypyrrolic ligand (H₄L), we explored structures and reaction energies of a series of new binuclear uranium(VI) complexes using relativistic density functional theory. Full geometry optimizations on [(UO₂)₂(L)], in which two uranyl groups were initially placed into the pacman ligand cavity, led to two minimum‐energy structures. These complexes with cation–cation interactions (CCI) exhibit unusual coordination modes of uranyls: one is a T‐shaped ( T ) skeleton formed by two linear uranyls {O_exo?U₂?O_endo→U₁(?O_exo)₂}, and another is a butterfly‐like ( B ) unit with one linear uranyl coordinating side‐by‐side to a second cis‐uranyl. The CCI in T was confirmed by the calculated longest distance and lowest stretching vibrational frequency of U₂?O_endo among the four U?O bonds. Isomer B is more stable than T , for which experimental tetrameric analogues are known. The formation of B and T complexes from the mononuclear [(UO₂)(H₂L)(thf)] ( M ) was found to be endothermic. The further protonation and dehydration of B and T are thermodynamically favorable. As a possible product, we have found a trianglelike binuclear uranium(VI) complex having a O?U?O?U?O unit.     

Vanadium(V) Complexes of O,N,O-Donor Tridentate Ligands Containing the {VVO(OMe)}2+ Unit: Syntheses,Structures and Properties

Abstract

Syntheses, characterisation and properties of two complexes containing the oxovanadium(V) methoxide unit have been described. Deprotonated benzoylhydrazones of 2–hydroxy–5–methoxy‐benzaldehyde (H₂bhsOMe) and 2–hydroxy–5–chlorobenzaldehyde (H₂bhsCl) were used as coligands. Crystal structures of both the complexes were determined. In solid state one of them is a dinuclear species [VO(bhsOMe)(OMe)]₂ (1) whereas the other one is a mononuclear complex [VO(bhsCl)(OMe)(HOMe)](2). The dinegative ligands coordinate the metal ions via phenolate–O, imine–N and deprotonated amide–O atoms. In 1, the metal ions of two square pyramidal VO(bhsOMe)(OMe) units share the methoxide groups to form a dinuclear species. The oxygen of a methanol molecule completes the hexacoordination of the metal centre in 2. In each of the two distorted octahedral VO₅N moieties of 1 the bridging methoxide oxygen and in that of 2 the methanol oxygen is trans to the corresponding oxo group. Both the complexes are redox active. The VO³⁺ to VO²⁺ reduction potentials (vs Ag/AgCl) of 1 and 2 are observed at ?0.25 and ?0.04 V, respectively. The band positions in the electronic spectra and the redox potentials reflect the influence of the substituents present on the ligands.     

Synthesis and crystal structures of [UO2(C6H4NO2)2(C6H5NO2)] and [UO2SO4(C6H5NO2)(H2O)] · H2O

The complexes [UO₂(C₆H₄NO₂)₂(C₆H₅NO₂) (I) and [UO₂SO₄(C₆H₅NO₂)(H₂O)] · H₂O (II) were synthesized and studied by X-ray diffraction analysis. Crystals I are monoclinic: a = 7.0081(3), b = 14.9624(7), c = 9.1837(5) ?, β = 96.594(2)°, Z = 2, space group P2₁/m. Crystals II are triclinic: a = 6.8097(6), b = 9.3837(8), c = 10.4556(10) ?, α = 85.279(3), β = 75.434(3), γ = 69.180(3)°, Z = 2, space group . The main structural unit of crystal I is a mononuclear fragment, which belongs to the crystal chemical group AB ₂ ⁰¹ M¹ (A = UO ₂ ²⁺ , B⁰¹ are ions of pyridine-2-carboxylic (picolinic) acid, M¹ are molecules of picolinic acid) of the uranyl complexes. The main structural unit of crystal II is a chain, which belongs to the crystal chemical group AT³M ₂ ¹ (where T³-SO ₄ ²⁻ , M¹ are water and picolinic acid molecules) of the uranyl complexes. Picolinic acid in complexes I, II was found to have a zwitterion structure. Original Russian Text ? E.V. Grechishnikova, E.V. Peresypkina, A.V. Virovets, Yu.N. Mikhailov, L.B. Serezhkina, 2007, published in Koordinatsionnaya Khimiya, 2007, Vol. 33, No. 6, pp. 468–475.     

Spectroscopic,thermal and X-ray crystal structure studies of some bis-(pyrazine-2-carboxylato) nickel(II) complexes

Three nickel(II) complexes [Ni(PC)₂(H₂O)₂], 1, [Ni(PC)₂(TU)₂], 2 and [Ni(PC)₂(ABI)₂]· 2(H₂O), 3, PC?=?pyrazine-2-carboxylate, TU?=?thiourea and ABI?=?2-aminobenzimidazole, were synthesized and characterized by elemental analysis, IR spectroscopy and thermal analysis. The complexes were also investigated by single crystal X-ray diffraction analysis. Structures of the monomeric complexes showed nickel(II) chelated to two PC ions from an oxygen atom of carboxylate ion and the adjacent hetero nitrogen atom. The three complexes were crystallized in a monoclinic system with P2 ₁ /c space group for 1, while 2 and 3 had C2/c space groups. The structure of 1 showed two coordinated water molecules occupying the trans positions of a slightly elongated octahedron. The structure of 2 consisted of two PC ions and two thiourea molecules in trans positions. The structure of 3 was different and showed a highly distorted octahedron with two ABI molecules chelated to the nickel ion in cis positions through their hetero nitrogen atoms. Two water molecules of crystallisation were shown in the structure of 3.     

Syntheses,crystal structures,and characterization of three metal–organic complexes with 2,2′-biphenyldicarboxylic acid and phenanthroline ligands

Three complexes constructed with 2,2′-biphenyldicarboxylic acid, multidentate nitrogen donors, and metal salts, {[Cd(2,2′-dpdc)(tppp)(H₂O)]₂?·?2H₂O} _n (1), {[Pb(2,2′-dpdc)(pyphen)]₂} _n (2), and {[Pb(2,2′-dpdc)(dppz)]} _n (3) (H₂dpdc = 2,2′-diphenyldicarboxylic acid; tppp = 4-(1H-1,3,7,8-tetraazacyclopenta[l]phenanthren-2-yl)phenol; pyphen?=?pyrazino[2,3-f]-[1,10]phenanthroline; and dppz = dipyrido[3,2-a:2′,3′-c]phenazine), are synthesized under hydrothermal conditions. These complexes are characterized by single-crystal X-ray diffraction, elemental analysis, IR, TGA, and photoluminescence. In 1, two 2,2′-dpdc ions bridge two Cd(II) ions to form an isolated cluster with Cd?···?Cd distance of 5.023(4)?Å. These clusters are further linked by intermolecular hydrogen bonds, yielding a 2-D supramolecular structure. Complex 2 contains two crystallographically independent Pb(II) ions in the asymmetric unit. Pb1 ions are bridged by 2,2′-dpdc anions to form a chain along the x-axis. Two Pb2 ions are coordinated by two 2,2′-dpdc anions and two pyphen ligands to form a cluster. These clusters are linked by π–π interactions to yield a 1-D supramolecular chain along the y-axis. In 3, neighboring Pb(II) atoms are bridged by 2,2′-dpdc anions to form a 1-D chain structure. Further, the chains are linked into a 3-D supramolecular network through aromatic π–π interactions.     

Self-assembly of three Cd(II) complexes: 0-D, 1-D,and 3-D structures based on 2-(1H-imidazol-1-methyl)-1 H-benzimidazole

Three new complexes, [Cd(L)I₂]₂ (1), {[Cd(L)I₂]?·?DMF} _n (2), and [Cd₂(L)₄(μ ₂-I)I(H₂O)] _n (3), have been obtained through self-assembly of an unsymmetrical ligand 2-(1H-imidazol-1-methyl)-1H-benzimidazole (L) with Cd(II) salts. Single-crystal X-ray diffraction shows that 1 displays a dimeric structure in which two Cd(II) ions are bridged by two bidentate bridging L. Complex 2 exhibits a 1-D chain structure (···Cd–L–Cd–L···) constructed by L bridging Cd(II) ions. In 3, the Cd(II) ions are five-connected nodes and linked by L and iodide leading to the 3-D network. Complexes 2 and 3 are synthesized maintaining the same solvents and stoichiometric ratio of metal and ligand at different reaction temperature. The different structures of the complexes indicate that the temperature plays a significant role in construction of the complexes. Luminescent properties of 1–3 have been investigated in the solid state at room temperature.