Reactivity of α,α-dipyrrolylmethene in reactions with some Co(II) and Cu(II) complexes

Reactivity of 3,3′,5,5′-tetramethyl-4,4′dibutyldipyrrolylmethene (HL) in reactions Co(II) and Cu(II) acetates, acetylacetonates, and valinates in DMF (298.15 K) was estimated by spectrophotometric and calorimetric titration methods. The product of the exchange reaction between HL and Co acetate or acetylacetonate was found to be CoL₂ complex. With an excess of Cu(II) acetate or acetylacetonate, the reaction resulted in mixed-ligand complexes CuL(AcO) and CuL(Acac), while with an excess of HL, the CuL₂ complex was formed. Irrespective of the reagent concentration ratios, the exchange reactions with Cu(II) and Co(II) valinates gave ML(Val) complexes. Thermodynamic parameters of HL reactions with Cu(II) and Co(II) acetates, acetylacetonates, and valinates were determined.     

Reactions of Cu(II) and Co(II) acetates, acetylacetonates, and valinates with α,α-Dipyrrolylemethen

The reactions of Co(II) and Cu(II) acetates, valinates, and acetylacetonates with 3,3′,5,5′-tetramethyl-4,4′-dibutyldipyrrolylmethen (HL) in DMF at 298.15 K are studied by spectrophotometric method. The compositions and thermodynamic constants of formation of the Cu(II) and Co(II) complexes are determined using the methods of molar ratios and continuous changes. With an excess in Cu(II) acetate or acetylacetonate, the formation of mixed-ligand complexes CuL(OAc) and CuL(Acac), respectively, was observed, whereas CuL₂ complex was detected in the case of HL excess. At either ratio of the reagent concentrations, reactions of Co(II) acetate and acetylacetonate with HL always afforded CoL₂ complex, while in the case of Cu(II) and Co(II) valinates, only one amino acid ligand was replaced to give ML(Val) complexes (HVal is valine). The chelating capability of the ligand HL toward the Cu²⁺ ion was found to be higher than that toward the Co²⁺ ion.     

Thermoluminescent and magnetic properties of a heteroligand adduct of terbium(iii) acetylacetonate containing a 1,10-phenanthrilonium ion in the outer sphere

Russian Chemical Bulletin - Thermoluminescent and magnetic properties of a heteroligand adduct of terbium, [PhenH][Tb(NO3)2(Acac)2Phen], where Phen is 1,10-phenanthroline and Acac is...     

Reaction of Palladium Bis(Acetylacetonate) with Phenylphosphine

The reaction between palladium bis(acetylacetonate) and phenylphosphine was performed at different ratios of reagents and studied by the spectral and X-ray powder diffraction methods. It was shown that the reaction of PH₂Ph with Pd(Acac)₂ does not terminate in complexation but is accompanied by the exchange of acido ligands for organophosphorus ligands and the formation of associates of palladium complexes containing the bridging ³-PPh, ²-PHPh, O,O-chelate Acac ligands and the coordinated phenylphosphine molecules. When the reagent ratio is increased to PH₂Ph : Pd(Acac)₂ > 2, Acac^- is fully replaced by organophosphorus ligands.     

Dipicolylamine Complexes of Copper(II): Two Different Coordination Geometries in the Same Unit Cell of Cu(Dipica)(2)(BF(4))(2)

Bright blue Cu(Dipica)(2)(BF(4))(2) crystallizes in the monoclinic space group P2(1)/n, with unit cell parameters a = 23.406(6) ?, b = 9.338(2) ?, c = 25.573(7) ?, beta = 95.39(2) degrees, and Z = 8. The structure was solved by conventional Patterson and Fourier methods. The R and R(w) values for 5282 observed reflections were 7.06% and 9.10% respectively. Two structurally different complex cations are present in the same unit cell, one hexacoordinate and the other pentacoordinate. In the hexacoordinate cation, the two tridentate bis(2'-picolyl)amine ligands are trans-facially coordinated with two pyridine nitrogens and the two secondary amine nitrogens situated on four positions in a plane [Cu-N(pyr) = 2.189(6), 2.146(6) ?; Cu-N(sat) = 2.207(6), 2.201(5) ?]. The remaining two pyridine nitrogens constitute the axis [Cu-N(pyr) = 2.035(5), 2.038(5) ?] in an equatorially expanded pseudooctahedral geometry. The pentacoordinate cation possesses a square-pyramidal configuration, the two secondary nitrogens being mutually cis, with one Dipica equatorially tridentate [Cu-N(pyr) = 2.044(5), 2.027(5) ?, Cu-N(sat) = 1.995(5) ?]. The other Dipica functions as a bidentate ligand, with one of the pyridine nitrogens occupying the equator [Cu-N(pyr) = 1.986(5) ?] and the aliphatic nitrogen defining the axial copper position [Cu-N(sat) = 2.344(5) ?]. Its second pyridine is uncoordinated but hydrogen-bonded to the coordinated NH of the other ligand. Solution properties offer no clear distinction between the two cation stereochemistries. The ternary chelates [Cu(Dipica)(Acac)]ClO(4) and [Cu(Dipica)(Bipy)](ClO(4))(2) are also described.     

Synthesis,Crystal Structures,and Antibacterial Activity of Manganese(III) Complexes with Schiff Bases

Russian Journal of Coordination Chemistry - Two new manganese(III) complexes, [MnL1(EtOH)(Acac)] (I) and [MnL2(DMF)(Esal)] · H2O (II), where L1 and L2 are the dianionic form of...     

Interpretation of the IR spectra of aluminum, gallium, and indium tris(acetylacetonates)

The IR spectra of M(Acac)₃ (M = Al, Ga, and In; Acac^?1 is the acetylacetonate ion) and their isotope-substituted analogs were calculated by the Hartree-Fock-Roothaan method. The results obtained and available literature data were used to assign the absorption bands. A correlation was found between the force constants of the M-O bond and the stability constants of the complexes M(Acac)₃.     

Reaction of Palladium Bis(acetylacetonate) with Diphenylphosphine: Spectral Studies

Interaction of palladium bis(acetylacetonate) with diphenylphosphine is studied by NMR, IR, and UV methods. Reaction between reagents taken in equimolar amounts gives binuclear and trinuclear palladium complexes with bridging diphenylphosphide and the chelate acetylacetonate [Pd(Acac)PPh₂]₂ and [Pd₃(Acac)₂(PPh₂)₄] ligands. With excess PPh₂H, the trinuclear palladium complex, whose composition is supposed to be [Pd₃(PPh₂)₄(PPh₂–PPh₂) · C₆H₆], is isolated and characterized on the basis of the spectral data.     

Urease inhibition of oxovanadium(V) complexes with hydrazone and hydroxamate ligands

Two new oxovanadium(V) complexes, [VOL¹(SHA)] (I) and [VOL²(BHA)] (II), were prepared by the reaction of [VO(Acac)₂] (Acac = acetylacetonate) with N′-(2-hydroxybenzylidene)isonicotinohydrazide (H₂L¹) and salicylhydroxamic acid (HSHA) and 4-chloro-N′-(2-hydroxy-3-methoxybenzylidene)benzohydrazide (H₂L²) and benzohydroxamic acid (HBHA), respectively, in methanol. Crystal and molecular structures of the complexes were determined by elemental analysis, infrared spectra and single crystal X-ray diffraction (CIF file CCDC nos. 978238 (I) and 978392 (II)). The V atoms are in octahedral coordination. Thermal stability and the inhibition of urease of the complexes were studied.     

Cluster complexes [Mo3O2S2(Acac)3(Amine)3]PF6

New mixed-ligand cluster complexes [Mo₃O₂S₂(Acac)₃(Amine)₃]PF₆ (Amine = morpholine (Mor), 4-cyanopyridine (PyCN), pyrazine (Pz)) have been synthesized. The compounds were characterized by IR spectroscopy and mass spectrometry (ESI-MS). The crystal structure of the Mor complex, which was isolated as [Mo₃(μ₃-S)(μ₂-O)₂(μ₂-S)(Acac)₃(Mor)₃]PF₆ · 0.5Mor · 0.3(CH₃)₂CO was determined. The stability of the complexes in methanolic solutions decreases in a row: Mor > PyCN > Pz.     

Stereoisomerism of dihalodiaryl(acetylacetonato)-antimony(V) compounds

A series of dihalodiaryl(acetylacetonato)antimony(V) compounds, (p-Y-C₆H₄)₂SbX₂Acac (X=F, Cl, Br; Y=NO₂, Cl, H, CH₃, CH₃O), were prepared. All of these compounds are monomeric and exist in solution as a mixture of two isomers both with chelated hexacoordinate configurations. From the temperature- and solvent-dependent PMR spectra of these compounds, it is concluded that the two isomers are in equilibrium in solution. The assignments of the PMR signals to the isomers were made by considering the effects of solvent and the substituents X and Y on the spectra.     

Polymerization mechanism of trimethylene carbonate carried out with zinc(II) acetylacetonate monohydrate

The proposed mechanism of initiation and course of ring‐opening polymerization of cyclic trimethylene carbonate (TMC) involving zinc(II) acetylacetonate is in accordance with the mechanism of monomer activation. At the first stage of the process, coordination of carbonate to Zn(Acac)₂ · H₂O complex occurs with the release of weakly coordinated water molecules. This free water molecule reacts with active TMC–Zn(Acac)₂ complex. The reaction results in the formation of propanediol and CO₂ emission. During further stages of the investigated process, the formed propanediols, or later the oligomeric diols produced with polymerization, are cocatalysts of the chain propagation reaction. The chain propagation occurs because of repeating activation of the TMC monomer through the creation of an active structure resulting in the exchange/transfer reaction between the zinc complex and the monomer, with its following attachment to the hydroxyl groups, carbonate ring opening, and formation of the carbonic unit of polymer chain. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Two mononuclear molybdenum(VI) oxo complexes with tridentate hydrazone ligands: Synthesis and crystal structures

Reaction of [MoO₂(Acac)₂] (Acac = acetylacetonate) with two similar hydrazone ligands in methanol yielded two mononuclear molybdenum(VI) oxocomplexes with general formula [MoO₂(L)(CH₃OH)], where L = L¹ = (4-nitrophenoxy)acetic acid [1-(3-ethoxy-2-hydroxyphenyl)methylidene]hydrazide (H₂L¹) and L = L² = (4-nitrophenoxy)acetic acid [1-(5-bromo-2-hydroxyphenyl)methylidene]hydrazide (H₂L²). Crystal and molecular structures of the complexes were determined by single crystal X-ray diffraction method. All investigated compounds were further characterized by elemental analysis and FT-IR spectra. Single crystal X-ray structural studies indicate that the hydrazone ligands coordinate to the MoO₂ cores through enolate oxygen, phenolate oxygen, and azomethine nitrogen. The Mo atoms in both complexes are in octahedral coordination.     

Cubane pyridine-acetylacetonate cluster complexes with the M<Subscript>3</Subscript>CuS<Stack><Subscript>4</Subscript><Superscript>5+</Superscript></Stack> core (M = Mo,W)

The reactions between [Mo₃(μ₃-S)(μ₂-S)₃(Acac)₃(Py)₃]PF₆ (HAcac is acetylacetone, Py is pyridine) and CuX (X = Cl, I, SCN) afford heterometallic cubane clusters [Mo₃(CuX)(μ₃-S)₄(Acac)₃(Py)₃]PF₆. The structures of two new compounds, [Mo₃(CuCl)S₄(Acac)₃(Py)₃]PF₆ · 3.25CH₂Cl₂ · 0.5C₆H₅CH₃ and [Mo₃(CuI)S₄(Acac)₃(Py)₃]PF₆ · 4C₆H₆, are determined by X-ray diffraction analysis. All synthesized compounds are characterized by elemental analysis and IR spectra. According to the vibrational spectra, the thiocyanate complex in the solid state is a mixture of the bond isomers [Mo₃(CuNCS)S₄(Acac)₃(Py)₃]PF₆ and [Mo₃(CuSCN)S₄(Acac)₃(Py)₃]PF₆, whereas in solution this complex exists as a isothiocyanate form.     

Reactions of Pd β-Diketonate Complexes with Triethylaluminium

Reactions of Pd(Acac)₂ and Pd(Acac)₂PPh₃ complexes with triethylaluminium in an inert atmosphere are studied by the NMR and IR, electronic microscopy, and X-ray powder diffraction methods. The final products of conversion of the initial Pd(II) complexes are the Pd(0) nanoparticles with the predominant diameter 2–4 nm. The main factors determining the size of Pd(0) particles and the nature of the ligand shell are considered.     

Cationic methyl complexes of rhodium(III): synthesis, structure, and some reactions

Cationic methyl complex of rhodium(III), trans-[Rh(Acac)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄] (1) is prepared by interaction of trans-[Rh(Acac)(PPh₃)₂(CH₃)I] with AgBPh₄ in acetonitrile. Cationic methyl complexes of rhodium(III), cis-[Rh(Acac)(PPh₃)₂ (CH₃)(CH₃CN)][BPh₄] (2) and cis-[Rh(BA)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄] (3) (Acac, BA are acetylacetonate and benzoylacetonate, respectively), are obtained by CH₃I oxidative addition to rhodium(I) complexes [Rh(Acac)(PPh₃)₂] and [Rh(BA)(PPh₃)₂] in acetonitrile in the presence of NaBPh₄. Complexes 2 and 3 react readily with NH₃ at room temperature to form cis-[Rh(Acac)(PPh₃)₂(CH₃)(NH₃)][BPh₄] (4) and cis-[Rh(BA)(PPh₃)₂(CH₃)(NH₃)][BPh₄] (5), respectively. Complexes 1-5 were characterized by elemental analysis, ¹H and ³¹P{¹H} NMR spectra. Complexes 1, 2, 3 and 4 were characterized by X-ray diffraction analysis. Complexes 2 and 3 in solutions (CH₂Cl₂, CHCl₃) are presented as mixtures of cis-(PPh₃)₂ isomers involved into a fluxional process. Complex 2 on heating in acetonitrile is converted into trans-isomer 1. In parallel with that isomerization, reductive elimination of methyl group with formation of [CH₃PPh₃][BPh₄] takes place. Replacement of CH₃CN in complexes 1 and 2 by anion I⁻ yields in both cases the neutral complex trans-[Rh(Acac)(PPh₃)₂(CH₃)I]. Strong trans influence of CH₃ ligand manifests itself in the elongation (in solid) and labilization (in solution) of rhodium-acetonitrile nitrogen bond.     

The Structure of Pd2(CH≡CC6H5)2(C5H7O2)3(BF3)2BF4

IR and NMR data showed that the ionic complex Pd₂(CHCC₆H₅)₂(C₅H₇O₂)₃(BF₃)₂BF₄ isolated in the reaction Pd(Acac)₂ + PA + 5BF₃OEt₂ (Acac is C₅H₇O₂, PA is phenylacetylene) is an adduct of two complexes, namely, (Acac)PdBF₄ and [(PA)₂Pd(C³-Acac · BF₃)]⁺(Acac · BF₃)^– (coordinatively unsaturated). On dissolution in deuteroacetone or deuteromethanol, the [(Acac)PdF₂BF₂Pd(C³-Acac · BF₃)(PA)₂]⁺(Acac · BF₃)^– adduct decomposed to Pd(Acac)₂, 2BF₃ · L (L = (CD₃)₂CO, CD₃OD) and the [L(PA)₂Pd(C³-Acac]⁺BF₄ ^– complex.     

Formation and the nature of activity of Ziegler systems based on palladium β-diketonate complexes in hydrogenation catalysis

The catalytic properties and nature of Ziegler-type Pd(Acac)₂ and Pd(Acac)₂PPh₃ based catalysts are studied in the hydrogenation of unsaturated compounds. The causes of an extremum appearing in the dependence of the specific activity of the catalyst in styrene and phenylacetylene hydrogenation on the proportions of the starting components are considered. The increase in the specific activity of the Pd(Acac)₂ + AlEt₃ catalytic system in hydrogenation as a function of the Al/Pd ratio arises from an increase in the degree of dispersion of the microheterogeneous system, an increase in the fraction of reduced palladium, and changes in the nature of the ligand shell. The inhibiting effect is caused by triethylaluminum adsorption on palladium nanoparticles. Palladium nanoparticle models are suggested.     

Normal Vibration Calculations for Iron Tris(acetylacetonate)

The frequencies, shapes, and intensities of the absorption bands in IR spectrum of Fe(Acac)₃ complex are calculated. The experimental data are adequately described using the force constants suggested for the complex. The spectral bands are unambiguously assigned on the basis of the theoretical analysis. In particular, the positions of the bands due to the FeO bond vibrations are determined.     

A study of complexation between crystalline <Emphasis Type="Italic">trans</Emphasis>-[Pd(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>(NO<Subscript>3</Subscript>)<Subscript>2</Subscript>] and acetylacetone

Complexation between crystalline trans-[Pd(H₂O)₂(NO₃)₂] and acetylacetone was studied. The complexes Pd₂(Acac)₂(μ-NO₃)₂(I) and Pd₂(Acac)₂(μ-Acac)(μ-NO₃)(II) were obtained and examined by elemental analysis, X-ray powder diffraction analysis, differential scanning calorimetry, simultaneous thermal analysis, mass spectrometry, and vibrational spectroscopy.