New uranyl(VI) complexes with ons ligand derived from aromatic acid hydrazides and phenyl isothiocyanate. part III

Summary The synthesis and characterization of some dioxouranium(VI) complexes containing potential ONS donor ligands derived from benzoyl,o-chloro-,o-methyl-,P-chloro-,p-nitro-,p-methoxy-,p-aminobenzoylhydrazines and isonicotinylhydrazine with phenyl isothiocyanate are reported. Two types of complexes with general formulae [UO₂(HL)₂(X)₂] and [[UO₂(HL)₂] have been identified and characterized. All the uranyl complexes are of the [UO₂(HL)₂(X)₂] type (HL=bidentate monoanionic ligand, X=H₂O and/or EtOH) and X bridges the uranyl ion and the thioketo groupvia hydrogen bonding. Upon heating to 140 °C, the complexes lose X giving a new complex of formula [UO₂(HL)₂] (HL=tridentate monoanionic ligand) in which the thioketo-group participates in bonding. The latter complexes take up X again on exposure to water and/or ethanol vapour.     

Synthesis and spectroscopic studies of dioxouranium (VI) complexes derived from some oximes and containing dihydroxo bridges

The reaction between uranyl acetate dihydrate and some mono- and dioxime ligands in absolute ethanol and in the presence and/or absence of sodium acetate is reported. The structures of the isolated dioxouranium (VI) complexes as well as the existence of dihydroxo bridge structures are characterized by elemental analyses, molar conductivities, pH, spectra (i.r., u.v., NMR) and magnetic measurements. Molecular weight measurements suggest a dimeric structure for all complexes except that derived from p-dimethylaminobenzaldehyde-oxime in the presence of sodium acetate. Infrared spectral data show that the oximes behave as mononegative monodentate ligands with displacement of a hydrogen atom from an NOH group. Also, the spectral data indicate that the acetate group behaves as a mono- or bidentate ligand. Moreover, the existence of a dihydroxo bridge is confirmed. Finally, simple mechanisms, in solution and/or solid, are proposed for the reactions between ligands containing attracting and/or donor groups and uranyl acetate dihydrate.     

Transition-metal complexes with hydrazides and hydrazones

Several new complexes of dioxomolybdenum(VI) of the general formula [MoO₂(L)S], whereL is the dianion of salicylaldehydep-hydroxybenzoylhydrazone andS denotes H₂O, MeOH, py, PPh₃, DMSO or DMF, were synthesized and characterized by elemental analysis, electronic UV-VIS and IR spectra, thermal analysis, molar conductivity and magnetic susceptibility measurements. Salicylaldehydep-hydroxybenzoylhydrazone participates in the coordination as a tridentate ligand with the ONO set of donor atoms. The complexes contain acis-MoO₂ group and are of octahedral geometry. Complexes of the MoO₂L type were also prepared by synthesis in CHCl₃ solution and by isothermal heating of [MoO₂(L)S] complexes. The MoO₂L complex synthesized in CHCl₃ solution has most probably a pentacoordinated structure while the complex obtained by isothermal heating of [MoO₂(L)S] has a polymeric hexacoordinated structure.The authors are grateful to the Serbian Republic Research Fund for financial support and to academician Prof. M. ui for his interest in this work.     

Transition metal complexes with hydrazides and hydrazones

A study was made of the thermal decomposition of octahedral Co(II) complexes of the type CoL_n X ₂·mH₂O, wheren=2 and 3,m=1,2 and 5 andX=Cl, Br, I, NCS, OAc andv ₂So₄, in both air and nitrogen atmospheres. It was established that the complexes are completely decomposed below 800° and CoO is formed as final product. The most probable decomposition mechanism was proposed. The tris(ligand) complexes were characterized by elemental analysis, and spectral and magnetic measurements, and all the data suggested the presence of a point group symmetry of type O_h.

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Zusammenfassung Sowohl in Luft als auch in Stickstoffatmosphäre wurde die thermische Zersetzung von oktaedrischen Co(II)-Komplexen der allgemeinen Formel CoL_nX₂· mH₂O (n=2 und 3,m=1, 2 und 5,X=Cl, Br, I, NCS, OAc und SO₄) untersucht. Es wurde festgestellt, daß sich die Komplexe unterhalb 800°C vollkommen zu CoO als Endprodukt zersetzen. Der wahrscheinlichste Zersetzungsmechanismus wurde unterbreitet. Die tris-Ligandenkomplexe wurden mittels Elementaranalyse sowie Spektral- und magnetischen Untersuchungen charakterisiert, alle Angaben deuten auf eine Punktsymmetriegruppe vom Typ Oh hin.

     

Synthesis,spectroscopic and thermal studies on ruthenium(III), rhodium(III) and iridium(III) complexes with hydrazones derived from 2,6-diacetylpyridine and different aromatic hydrazides

Summary The reactions of MCl₃·3H₂O (M=Ru, Rh or Ir) with hydrazones have been studied by three different methods and complexes of the types [M(LH₂)(H₂O)₂]Cl₃, [M(L)Cl(H₂O)] and [M(LH₂)Cl₂]Cl·H₂O have been isolated. Tentative structural conclusions are drawn for these products based upon elemental analysis, electrical conductance, magnetic moment, and i.r. and¹H n.m.r. data. The thermal stability and mode of decomposition for the complexes have been studied by t.g.a., d.t.g. and d.s.c. techniques.     

Mixed ligand complexes of tungsten(VI) containing aroyl hydrazones and isothiocyanate

Five complexes [WO(NCS)₄L–L] (where L–L = benzoic acid[1-(Furan-2-yl)methylene]hydrazide(BFMH), benzoic acid[(thiophen-2-yl)methylene]hydrazide(BTMH), benzoic acid[1-(thiophen-2-yl)ethylidene]hydrazide(BTEH), benzoic acid(phenylmethylene)hydrazide(BPMH) and benzoic acid[1-(anisol-3-yl) methylene]hydrazide(BAMH)) have been prepared by reaction of ammonium tetraisothiocyanatodioxotungstate(VI) with the corresponding ligand in aqueous medium in the presence of hydrochloric acid. The complexes have been characterized by elemental analysis, molar conductivity, magnetic moment measurements, IR, electronic spectra, thermogravimetric analysis TGA/DTA and ¹H NMR.     

Reactions of uranyl(VI) complexes of acid dihydrazides with β-diketones

Summary Uranyl(VI) complexes of malonic acid dihydrazide (MDH₂) and phthalic acid dihydrazide (PDH₂) and the products of their reactions with four -diketones have been characterised by elemental analysis and by electrical conductance, and spectral (i.r. and electronic) measurements. The MDH₂ and PDH₂ complexes UO₂(L)₂(H₂O)₂ are eight coordinate whereas the macrocyclic UO₂(L)(H₂O)₂ complexes are six coordinate. In each complex MDH₂ and PDH₂ act as bidentate liglands having the coordination sites at secondary amide-nitrogen atoms.     

Five coordinated complexes of divalent nickel and copper with ligands derived from acid hydrazides and acetylacetone

Summary Picolinic acid hydrazide (PH) and isonicotinic acid hydrazide (INH) react with acetylacetone to form complexes, containing open chain tetradentate ligands, through anin situ process in the presence of nickel and copper salts. The complexes were isolated and characterised as five-coordinate with the aid of analyses, magnetic, e.s.r., electronic and i.r. spectral studies.Attempts to obtain the free ligand were unsuccessful, but its solid complexes can be isolated. Acetylacetonebispicolinoyl hydrazone Ac(PH)₂ coordinates through azomethine and pyridine nitrogen atoms while acetylacetonebisisonicotinoyl hydrazone Ac(INH)₂ does so through azomethine nitrogens and amido oxygen atoms, giving rise to complexes of the MAc(PH)₂X or MAc(INH)₂X type where X=Cl, Br, NO₃ or NCS and M=nickel(II) and copper(II). Magnetic, e.s.r. and electronic spectra are consistent with five coordinate geometries incorporating one anion on the axial positions. Various ligand field parameters have been calculated and the amount of distortion assessed in terms of DT/DQ. The metal-ligand vibrations in the far i.r. are discussed.     

Some platinum(II) complexes derived from aromatic alkynes

Several trans‐platinum(II) complexes, of the type R′? {Pt(PBu₃)₂}? R″? {Pt(PR₃)₂}? R′, where R′ and R″ are groups derived from a series of aromatic alkynes and diynes, have been prepared and characterized. Extensive spectroscopic data for these and other known related complexes are presented. A more precise structural study of trans‐Pt(C≡CC₆H₄C≡CPh)₂(PBu₃)₂ (cf. Z. Kristallogr. 1998; 213: 483) is reported. Copyright © 2002 John Wiley & Sons, Ltd.     

Oxomolybdenum(VI) and (V) complexes with 6–methyl-4–hydroxypyrimidinyl hydrazones

Dioxomolybdenum(VI) complexes [MoO2(L)H2O] and oxomolybdenum(V) complexes [Mo2O3(LH)2Cl2] (where LH2=hydrazones derived from 6–methyl-4–hydroxy-2–hydrazinopyrimidine with salicylaldehyde, 5–methyl-, 5–chloro-, 5–bromo-, 3–methoxy-salilcylaldehyde, or 2–hydroxy-1–naphthaldehyde) have been prepared and characterised by spectroscopic and physico-chemical methods. The MoVI complexes are diamagnetic octahedral structures, whilst the MoV complexes are paramagnetic and probably dimeric, via oxobridging.     

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.     

Infrared and thermal studies of uranyl(VI) complexes of antipyrine

Recently, the isolation and characterisation of a large number of uranyl(VI) complexes with neutral unidentate oxygen donor ligands having XO bonds (XC, N, P, S or As) have been reported [1–5]. Antipyrine (1-phenyl-2,3-dimethyl-5-pyrazolone), containing a polar carbonyl group, is found to form complexes with metal ions [6-13]. This communication describes the isolation and physico-chemical properties of the complexes formed by uranyl(VI) ions.     

Extraction of uranyl(VI) ion with N,N-diethyloctadecanamide from nitric acid solution

The extraction of U(VI) with newly synthesized alkylamide, N,N-diethyloctadecanamide (DEODA), has been studied. The dependence of the extraction on nitric acid concentration, DEODA concentration and temperature from nitric acid solution has been considered. The extracted species has also been investigated using FT-IR spectrometry. The related themodynamic functions were calculated.     

Synthesis,crystal structures,and catalytic property of dioxomolybdenum(VI) complexes with hydrazones

Two new dioxomolybdenum(VI) complexes, [MoO₂(L₁)] _n · 0.5 _n CH₃OH (I) and [MoO₂(L₂)(CH₃OH)] (II), where L1 and L₂ are the dianionic form of N′-[1-(4-diethylamino-2-hydroxyphenyl)methylidene]isonicotinohydrazide and N′-(2-hydroxy-4-methoxybenzylidene)-3-methylbenzohydrazide, respectively, were prepared and structurally characterized by physicochemical and spectroscopic methods and single-crystal X-ray determination. For complex I, a polymeric structure is obtained, which is linked by coordination of the pyridine N atoms to the Mo atoms of other [MoO₂(L₁)] units. Complex II is a mononuclear molybdenum compound. In both complexes, the Mo atoms are in octahedral coordination. The catalytic properties of the complexes indicate that they are efficient catalysts for sulfoxidation.