Dioxouranium (VI) complexes with cellulose acetate

Dioxouranium [UO₂(VI)] complexes with three degrees of substitution of cellulose acetate, prepared from viscose pulp (DS = 2.2, 2.45 and 2.86), have been synthesis and characterized. Degree of substitution (DS) is defined as the average number of CH groups substituted on each anhydrocellulose repeat unit. Probable structures of the cellulose acetate complexes were inferred from the elemental analysis data, conductance measurements, IR, electronic and ¹H NMR spectra. The results obtained show that the formula of UO₂(VI) complex with cellulose acetate of DS = 2.2 and 2.45 [(CA)₄.UO₂] is more probable than [(CA)₂.UO₂].2(CH₃COO), while the reverse is true for the case of a UO₂ complex with CA of DS = 2.86. For the former formula, cellulose acetate acts as a uni-negatively charged bidentate ligand and reacts with UO₂²⁺ through the ether-carbon-oxygen of the secondary acetylated hydroxyl group of the anhydroglucose unit and the oxygen atom of the residual secondary unacetylated hydroxyl group, forming a five-membered chelate ring. For the later formula, cellulose acetate of DS = 2.86 acts as a neutral bidentate chelating agent through the two ether oxygen atoms of the vicinal ester groups of secondary acetylated hydroxyl groups in anhydroglucose units also forming a five-membered chelate ring. The uranium atom in these complexes is 8-coordinate. The thermal behaviour of cellulose diacetate (DS = 2.2) and cellulose triacetate (DS = 2.86) and their complexes with uranyl acetate in nitrogen atmosphere has been also studied by differential thermal analysis from room temperature to 600 °C. The obtained DTA curves were analyzed using the Prout-Tompkins law. The method of least squares was applied to estimate the appropriate order of the reaction (n), and consequently the thermodynamic parameters. The results revealed that chelation of cellulose acetate with uranyl acetate led to increased thermal stability.     

Dioxouranium(VI) complexes of some sulphur donor ligands

Complexes of uranyl chloride and uranyl nitrate of the type UO₂X₂·2L and [UO₂X₂2L′], where X = Cl or NO₃ and L = N,N′-tetramethylthiourea (TMTU); N,N′-dimethylthiourea (DMTU); monomethylthiourea (MMTU), monoethylthiourea (METU), pyridine-2-thiol (PYT) and L′ = 4,6-dimethylpyrimidine-2-thiol (PYMT), have been prepared. The complexes were characterised on the basis of IR spectroscopy and by elemental analysis. In some cases Raman spectra are also reported.     

Dioxouranium(VI) mixed ligand complexes containingo-substituted benzoic acid and α-amino acids

Summary Mixed ligand complexes of general formula [UO₂L¹L²-(H₂O)_n], where L¹ iso-hydroxy-,o-mercapto- oro-aminobenzoic acid and L² is glycine, L-alanine, or L-valine, have been prepared and characterized. The uranium atom in these complexes is 6- or 8-coordinate. Both acid ligands are bidentate, bonding through the ionized –COO^–– group and either O, N or S atoms.     

Chemical properties ofN-(amidomethyl)- andN-(imidomethyl)glycine derivatives

N-Nitroso,N-sulfonyl, andN-acyl derivatives ofN-(amidomethyl)- andN-(imidomethyl)-glycine esters have been synthesized by the reactions of these esters with HNO₂ or with sulfonylating and acylating reagents.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1299–1305, July, 1995.     

Dioxouranium(VI) complexes of aliphatic (mono- and di-) hydrazone-oximes

Summary Uranyl acetate dihydrate reacts with several hydrazone-oximes, derived from aliphatic (mon-annd di-) hydrazides and 2,3-butanedione monoxime in the absence of NaOAc, to form complexes of general formulae [UO₂(HL)₂] and [UO₂(HL)₂SZ] (where H₂L=aliphatic acid monohydrazone-oximes; S=EtOH and Z=H₂O). With aliphatic acid dihydrazone and monomaleoyl-hydrazone-oximes, different complexes have been synthesized in 50% EtOH and in the absence of NaOAc. The products have been characterized by elemental analyses, molar conductivities, spectral (u.v., i.r., n.m.r.), pH, conductometric titrations, molecular weights and magnetic measurements. I.r. spectral data indicate that the aliphatic hydrazone-oximes, except monomaleoyl-hydrazone-oxime, behave in a similar way to tridentate ligandsvia the azomethine nitrogen and the NOH groups, with replacement of a hydrogen atom from the latter group. On the other hand, malonyl dihydrazone- and adipoyldihydrazone-oximes coordinate in a bi-, and tridentate manner, respectively, towards one uranyl ion, while monomaleoyl- and oxaloyldihydrazone-oximes behave in a penta-and hexadentate fashion, respectively, towards two uranyl ions. Elemental analyses, molecular weight measurements as well as spectral data confirm the existence of a binuclear complex for monomaleoyl- and oxaloyldihydrazone-oximes, whereas a monomer for the rest. Finally, the role of solvent, absence of NaOAc and the type of ligand on the structure of the complexes are discussed.     

Dioxouranium(VI) complexes of 3-benzamidorhodanine and its substituted derivatives

The synthesis and characterization of some dioxoyranyl(VI) complexes containing-3-benzamidorhodanine and its substituted derivatives as ligands are reported. The structure of complexes is discussed on the basis of spectral (UV, IR and NMR), elemental analyses, conductivities, molecular weights and thermal analysis (DSC, DTA, TGA and TG) results. IR spectra show that the ligands are bidentate coordinating via the amide nitrogen (NH) and the carbonyl oxygen of rhodanine in the enol form with displacement of a proton from the latter group. Also, NMR studies suggest that the enolization and coordination occurs via the carbonyl oxygen of rhodanine and not through the carbonyl of the amide moiety. Finally, the thermal studies suggest the existence of a cis-form for the isolated uranyl complexes.     

Schiff base complexes of dioxouranium(VI), III. Commun.: Dioxouranium(VI) complexes of bibasic tetradentateSchiff bases

Bibasic tetradentateSchiff bases having the donor system OH–NX–NX–OH have been shown to form UO₂(NO₃)₂(SBH₂) type of derivatives [SBH₂ is the molecule of the bibasic tetradentateSchiff bases such as HOC₆H₄C(R) N(CH₂) _n NC(R)C₆H₄OH (where R=H or CH₃ andn=2 or 3) and HOC(R)CHC(CH₃)N(CH₂) _n NC(CH₃)CH C(R)OH (where R=CH₃ or C₆H₅ andn=2 or 3)]. The 11 stoichiometry of these complexes is shown by elemental analysis and conductometric titrations. The molar conductence values in nitrobenzene indicate the non-electrolytic behaviour and the magnetic susceptibility measurements by the Gouy method show these complexes to be diamagnetic.With 1 Figure     

Schiff base complexes of dioxouranium(VI). VII. Dioxouranium(VI) acetate complexes with monobasic bidentate and bibasic tridentateSchiff bases

11 and 12 molar reactions of dioxouranium(VI) acetate dihydrate with the monobasic bidentateSchiff bases,o-HOC₆H₄CH=NR oro-HOC₁₀H₆CH=NR (R=C₂H₅,n-C₃H₇,n-C₄H₉ or C₆H₅) and bibasic tridentateSchiff bases,o-HOC₆H₄CH=NR(OH) oro-HOC₁₀H₆CH=NR(OH) (R=–CH₂CH(CH₃)- or —CH₂CH₂CH₂–) have been studied and derivates of the type UO₂(OAc)₂(SBH), UO₂(OAc)₂(SBH)₂, UO₂(OAc)₂(SBH ₂) and UO₂(OAc)₂(SBH ₂)₂ (whereSBH andSBH ₂ represent monobasic bidentate and bibasic tridentateSchiff base molecules respectively) have been isolated. These have been characterized by elemental analysis, conductance measurements and IR spectral studies.

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UO₂ ²⁺-Komplexe von Schiff-Basen. VII. Uranylacetat-Komplexe mit monobasischen zweizähnigen und bibasischen dreizähnigen Schiff-Basen

Zusammenfassung Es wurden in 1:1- und 1:2-molaren Reaktionen von UO₂(OAc)₂·2H₂O mitSchiff-Basen (L) Komplexe des Typs UO₂(OAc)₂ L bzw. UO₂(OAc)₂ L ₂ isoliert. Die Komplexe wurden mittels Elementaranalyse, Leitfähigkeitsmessungen und IR-Spektren untersucht.

     

Chemical properties ofN-(amidomethy)- andN-(imidomethyl)glycine derivatives 2. Reactions at alkoxycarbonyl and carboxyl groups

N-(Aroylarnmomethylfglycine amides were synthesized by reactions ofN-(aroyllminomethyl) glycine esters with ammonia. Alkaline hydrolysis ofN-(amidomethyl)glycine,N-(irnidornethyl)glycine, andN-(amidomethyl)pheriylalariiiie esters afforded the correspondingN-(amidowthyVa-amirio acids- Reactions of the Last-mentioned compounds with ethyl esters of glycine, alanine, and phenylalanine in the presence of dicyclohexylcarbodiimide yielded dipeptides containingNh-amidomethyl substituents.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1770–1771, July, 1996.     

Dioxouranium(VI)--carboxylate complexes. Interaction with dicarboxylic acids in aqueous solution: speciation and structure

In this paper we report the results of an investigation performed by potentiometric (H+-glass electrode) and visible spectrophotometric measurements on the interaction of UO2(2+) ion towards some carboxylic ligands (acetate, malonate, succinate, azelate). The measurements were carried out at T= 25 degrees C in different ionic media (KNO3 and NaCl) at different ionic strengths (0.1 < or = I/mol L(-1) < or = 1.0, NaCl; I/mol L(-1) = 0.1, KNO3). The dependence on ionic strength of formation constants was taken into account by using both a simple Debye-Hückel type equation and the SIT (Specific ion Interaction Theory) approach. Different speciation models (depending on concentration of reagents, ionic strength, pH-range) both for different carboxylates and different ionic media have been obtained. Linear combinations between formation constants, stoichiometric coefficients and length of alkyl chain of dicarboxylates have been observed and predicted formation constants at I= 0 mol L(-1) are reported for the interaction of UO2(2+) with HOOC-(CH2)n-COOH with 1 < or = n < or = 7. Finally, a visible absorption spectrum for each complex reaching a significant percentage of formation in solution (KNO3 medium) has been calculated to characterise the compounds found by pH-metric refinement.     

Synthesis ofN-(3-azido-2-nitroxypropyl)-,N-(2,3-diazidopropyl)-, andN-(2-azido-3-methoxypropyl)-N-alkylnitramines

N-(3-Azido-2-nitroxypropyl)-N-alkylnitramines andN-(2,3-diazidopropyl)-N-alkylnitramines were prepared by nitration and azidation ofN-alkyl-N-(2-hydroxy-3-chloropropyl)sulfamates andN-(3-azido-2-hydroxypropyl)-N-alkylsulfamates. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 206–208, January, 1999.     

Tungsten(VI) and mixed tungsten,molybdenum(VI) complexes of tartaric acid

A number of studies of species formed in the tungsten(VI) oxide-R,R-(+)-tartaric acid-water system have been carried out(^1–3). While various species have been proposed, it is generally accepted that three main ones predominate. Two have tungsten: (+)-tartaric acid [(+)-tartH₄] ratios of 11 and the third has the same ratio of 12. This latter species cannot be that proposed by Avaloset al. ⁽³⁾ since both ligands in their structure would have to be present as unidentates.Recently we have shown⁽⁴⁾ that high resolution¹H and¹³C n.m.r. studies were particularly useful in delineating the complexes formed in aqueous solution in the analogous molybdenum(VI) system. Thus, we turned our attention to the corresponding tungsten(VI) complexes, especially in view of the controversy surrounding the nature of the species formed in aqueous solution with (+)-tartH₄. The results of our studies, presented below, indicate that only a few species are formed, and that these are quite analogous, as might be expected, to the previously described molybdenum(VI) species⁽⁴⁾. In addition we have observed the formation of a mixed dimeric species [MoWO⁴{(+)-tart}₂]^4–, whose structure is akin to the mono-metallic complexes, as well as the well-characterized antimony(III) and arsenic(III) dimers of (+)-tartH₄ ⁽⁵⁾.     

Zirconium(IV) Thorium(IV) and Dioxouranium(VI) Complexes of Salicylidene o-Aminobenzothiol

Salicylidene-o-aminobenzothiol and its 5-chloro and 5-bromo derivatives, dibasic tridentate Schiff bases, dervied from the condensation of o-aminothiol and Salicylaldehyde, 5-chloro salicylaldehyde and 5-bromo salicylaldehyde, were used for coordination with Zr(IV), Th(IV) and UO₂(VI) metal inos. The I:I (metal-ligand) stoichiometry of these complexes is shown by elemental analysis and conductometric titrations. Molecular structure of these complexes are proved by Infra-red spectroscopy and thermogravimetric analysis. Magnetic susceptibility measurements of Zr(IV), Th(IV) and UO₂(VI) complexes show their diamagnetic and octahedral geometry. Results show that all the complexes have solvent molecules in coordination with metal ion.     

1:1 Molybdenum(VI) citric acid complexes

Summary The complexes obtained by crystallisation from an aqueous solution of molybdate and citric acid (H₄cit) at pH 4–8 have Mo:cit ratio 11. The new complexes have been characterised by a variety of methods in the solid state and in solution. On this basis two dimeric species, [(MoO₂)₂O(citH)₂]^4– and [(MoO₂)₂O(cit)₂]^6–, and a monomeric species [MoO₃(cit)OH₂]^4– are proposed.     

Dioxouranium(VI) and oxouranium(IV) fluorosulphates and double fluorosulphates of uranium(IV)

UO₂(SO₃F)₂, UO(SO₃F)₂, U(SO₃F)₄ and MU(SO₃F)₆, MMg, Zn have been prepared by reacting UO₂(O₂CCH₃)₂, U(O₂CCH₃)₄, U(O₂CCF₃)₄ and MU(O₂CCH₃)₆ with HSO₃F. The analysis of i.r. spectral data of UO₂(SO₃F)₂, UO(SO₃F)₂ and MU(SO₃F)₆ shows the presence of only one type of SO₃F group with reduced symmetry C_s. In U(SO₃F)₄, two SO₃F groups are bidentate, while the other two are monodentate. A sharp band at 925 cm^?1 in UO₂(SO₃F)₂ is diagnostic of UO₂²⁺. The diffuse reflectance spectra of UO(SO₃F)₂, U(SO₃F)₄ and MU(SO₃F)₆ reveal hexacoordination of U(IV), while the magnetic moments of these compounds support the existence of U(IV). UO₂(SO₃F)₂ and UO(SO₃F)₂ decompose thermally in a single step with the evolution of SO₂F₂ and formation of their respective sulphates.     

Synthesis of organo-platinum(II) and -palladium(II) complexes ofN-phenyl- andN-(p-Tolyl)pyrazole

Summary When platinum(II) chloride dissolved in acetic acid containing concentrated hydrochloric acid was refluxed withN-phenylpyrazole(liphpz) andN-(p-tolyl)pyrazole (Htlpz), complexes of composition [Pt(N-C)Cl]₂ (N-C = phpz, tlpz) were obtained, in which phpz and tlpz are coordinated through nitrogen and carbon forming a five membered metallocycle. Similar palladium(II) complexes [Pd(N-C)Cl]₂ were easily prepared by the reaction of palladium(II) chloride with Hphpz and Htlpz in methanol in the presence of lithium chloride. These [M(N-C)CI]₂ complexes reacted with tri-n-butylphosphine (PBu₃) and pyridine (py) to give the adducts [M(N-C)ClL](L = PBu₃, py). Ethylenediamine(en) and acetylacetone(Hacac) gave IPd(phpz)(en)]Cl and [Pd(phpz)(acac)] respectively. These new complexes are characterized by means of¹H-n.m.r. and i.r. spectra, and probable structures are proposed.Reprints of this article are not available.     

镧系与邻氨基苯甲酸型Schiff碱配合物的合成、表征及催化活性

本文合成2,4-二羟基苯甲醛缩邻氨基苯甲酸Schiff碱(H~3L),以改进的合成方法得到此配体与镧系元素形成的九种新配合物.经分析确定其组成[Ln(H~2L)~2NO~3],(Ln=La、Pr、Nd、Sm、Gd、Dy、Ho、Er、Yb.以热重-差执分析、紫外、红外光谱以及核磁共振谱等表征,证明Schiff碱具有稳定的分子内氢键并以三卤形式同镧系离子形成稳定的共轭双六元螯合环.经研究表明,此系列配合物对甲基丙烯酸甲酯的聚合有明显的催化活性.