Acetylacetonate Anion Research Articles

Concerted mechanisms of acid-base catalysis in coordination sphere of metal complexes

Kinetics and mechanisms of the following reactions in organic solvents have been studied: (i) formation of Schiff bases from aniline and derivatives of salicylic aldehyde coordinated to Cu(II) and Zn(II); (ii) substitution of one β-diketonate ligand coordinated to Fe(III) by another β-diketonate ligand; (iii) formation of coordinated hemiacetals from β-diketonate ligands and alcohols in coordination sphere of Fe(III); and (iv) formation of urethanes in coordination sphere of Fe(III) (acac)2 OR where acac and OR are acetylacetonate and alkoxide anions. Such compounds as aniline, alcohols and phenylacetylene serve as catalysts of these reactions. Their catalytic action is explained by concerted processes of hydrogen atom transfer in cyclic intermediate structures.

Stereochemistry and mechanism of the ligand-coupling reaction of an optically active acetylacetonato(π-allyl) palladium complex

The reaction of optically active acetylacetonato(1-methyl-3-phenyl-π-allyl)palladium(II) with triphenylphosphine in THF gave [1-(( E)-styryl)ethyl]acetylacetone with inversion of configuration, which indicates that the acetylacetonate anion attacked the π-allyl carbon of a cationic phosphine complex from the side opposite to palladium.

ChemInform Abstract: Mixed Oxidation State Trinuclear Cobalt Complexes with Bridging Sulfito and Schiff‐Base Ligands. Part 1. Preparation of the Complexes (Co(II)(μ‐SO3)2(μ‐L)2Co(III)2(ROH)2) (L: Schiff Base Anion, R: Alkyl) and Structure Determination of (Co(II)(μ‐SO3)2(.mu±alpha.,α′‐Me2‐salpd)2Co(III)2(nPrOH)2)·2 nPrOH.

AbstractFor the preparation of the trinuclear title complexes (I) an alcoholic solution of a monomeric Co(III) complex of the corresponding sym. Schiff base containing additionally the anion of acetylacetone, salicylaldehyde, or α‐hydroxyacetophenone (or a reaction mixture of a Co(II) complex of the Schiff base and o‐hydroxyacetophenone in the case of (Ic)) is exposed to SO2 in a closed system.

ChemInform Abstract: Facile Deprotonation of Coordinated Bis(diphenylphosphino)methane by an Acetylacetonate Anion.

AbstractThe reactions of the acetylacetonato complexes (I) and (V) with bis(diphenylphosphino)methane (II) lead to the unexpected formation of the polymeric (III) or monomeric complexes (VII) containing coordinated bis(diphenylphosphino)methanide.

Studies on fluoroalkylation and fluoroalkoxylation. Part 16. Reactions of fluoroalkyl iodides with some nucleophiles by S RN1 mechanism

Fluoroalkyl iodides , XCF 2CF 2I (X=ClCF 2CF 2, Cl(CF 2) 4) ( 1 ), react readily with the anion of ethyl acetoacetate ( 2 ) in DMF to give ▪ ( 3 ), XCF 2CF 2H ( 4 ), (CH 3CO) 2CHCO 2Et ( 5 ) and the dimer of the anion ( 6 ). The reaction can be partly suppressed with 1,4-dinitrobenzene(p-DNB) and the radical intermediate can be trapped by diallyl ether (DAE) to give the tetrahydrofuran derivatives. Anions of acetylacetone and malonitrile react also with 1 in the presence of DAE to yield the five-membered ring compounds. All these results seem to indicate that the reaction is a radical chain process induced by electron transfer. In the case of XCF 2CF 2I (X=Cl,I), tetrafluoroethylene and 6 , instead of 3 and 4 , are produced, showing the occurrence of β-fragmentation of the 2-halotetrafluoroethyl radical in the initiation step.

Facile deprotonation of coordinated bis(diphenylphosphino)methane by an acetylacetonate anion

Etude des reactions des complexes M(acac) 2 (M=Pt, Pd) avec dppm. Formation inattendue de complexes contenant l'ion [Ph 2 PCHPPh 2 ]

Five and Six Coordinated Anionic Complexes of Cobalt(II) and Nickel(II)

Abstract Compounds of general formula [Ni(Rbg)2] [M(acac)2X2] (A), [M′(Rbg)2] [Co(acac)2X]2 (B), (M = Ni, Co; M′ = Ni, Co, Cu; Rbg = biguanide / N-alkylbiguanide, X = Cl, Br, I; acac = acetylacetonate anion) have been isolated and characterized by physico-chemical means. Chemical properties support their formulations while spectral and magnetic data suggest the presence of octahedral and square pyramidal metal ions in the anions of A and B respectively. The cations are always square planar metal biguanide moieties.

Bimetallic Halide Isopropoxides of Zirconium and Aluminium: Synthesis and Properties

Abstract Mixed bimetallic halide isopropoxides of zirconium and aluminium having the general formula, XnZrAl2(OPri)10-n (where n = 1 or 2; X = Cl, Br, acetylacetone anion) and [X3ZrAl(OPri)4]3·2PriOH have been synthesised and characterised by elemental analyses and molecular weight determinations. The IR and 1H NMR spectra of these newly synthesised complexes throw light on their probable structures.

Synthesis and characterization of triorganoantimony(V) complexes with bidentate ligands

Monochelated organoantimony(V) complexes of the type R 3Sb(OMe)L, where R = Me or Ph, and L is the anion of acetylacetone, 8-hydroxyquinoline, salicylaldehyde, o-hydroxyacetophenone or 2-hydroxy-1-naphthaldehyde have been obtained from triorganoantimony(V) dibromide and the sodium derivative of the ligands in a benzene-methanol mixture. Molecular weight determination in benzene reveals the monomeric nature of these complexes. IR and NMR data suggest that L acts as a bidentate ligand giving an octahedral environment for the antimony atom.

ジメチルスルホキシド中におけるビス（β‐ジケトナト）コバルト（ＩＩ）錯体の溶液内平衡と電気化学的挙動

Homogeneous chemical equilibria and electrochemical behaviors of three bis(β-diketonato)cobalt(II) complexes, viz., [Co(hfac)2], [Co(tfac)2] and [Co(acac)2], in di methyl sulfoxide (DNISO) were studied by means of the conductivity flicl electronic spectral measur ements, poktrography, and cyclic voltaminctry with a platinum electrode; where hfac tfac- and acacrepresent the enolate anions of hexafluoroacetylacetone, trifluoroacetylacetone and acetylacetone, respectively. Tetrabutylammonium Perchlorate (TBAP) of 0.05 mol⋅dm-3 in the concentration was used as the supporting electrolyte fur voltammetric measurements. It was found that these complexes were involved in the following chemical equilibria in the solution:In DC polarography, the first wave of [Co(hfac)2] was presumed to be due to the two-electron reduction of CO2+, [Co(hfac)]+ and [Co(hfac)2], and the wave of [Co(acac)2] to that of monomeric and polymeric bis-comlexes. Furthermore, two waves of [Co(tfac)2] corresponded to the two-electron reduction of [Co(tfac)]+ and [Co(tfac)2], respectively; where the first wave included the kinetic current due to the preceding reaction.

ジメチルスルホキシド中におけるビス（１，３‐ジアルキル‐１，３‐プロパンジオナト）ニッケル（ＩＩ）錯体のポーラログラフィー

The polarography of three bis(1, 3-dialkyl-1, 3-propanedionato)nickel(II)complexes, viz., [Ni(acac)2], [Ni(dppm)2], and [Ni(dpm)2], was studied in dimethyl sulfoxide solution c ontaining one of the supporting electrolytes of NaClO4, TMAP, or TBAP of 0.05 mol⋅dm-3 in concentration, where acac-, dppm-, and dpm- mean the enolate anions of acetylacetone, d i propionylmethane, and dipivaroylmethane respectively. The polarographic behavior of [NiT(acac)2] in all the supporting electrolyte solutions and that of [Ni(dppm)2] and [Ni(dpm)2] in MAP and TBAP solutions were explained by the electrode reaction given in Scheme 1.The dissolved state of ten bis(β-diketonato)nickel(II) complexes was related to the properties of their ligands, where seven complexes had been studied by us.

REACTIONS OF DI(1-PYRAZOLYL)PROPANE-COPPER(II) COMPLEXES WITH VARIOUS ANIONS

Abstract The reactivity of some di(1-pyrazolyl)propanecopper (II) complexes with various anions in aqueous solutions has been studied. Di(1-pyrazolyl)propanecopper (II) chloride, Cu(Me2CpZ2)Cl2, reacts readily with pseudohalide ions to give complexes of the type, Cu(Me2Cpz2)Z2 (Z=SCN−, NCO−, N3 −). With PF6 − and BPh4 − anions, complexes of the type [Cu(Me2Cpz2)2X] Y (Y=PF6 −, X=Cl−, Br− and NO3 −; Y=BPh4 −, X=Cl−) are formed. However, the reaction of Cu(Me2Cpz2)Cl2 with acetylacetonate (acac), dialkyldithiocarbamate (S2CNMe2, S2CNEt2), or poly(1-pyrazolyl)borate (H2BPz2 −, HBpz3 −) anions leads to the displacement of Me2CPz2 and the subsequent formation of neutral Cu(acac)2, Cu(S2CNR2)2, Cu(H2Bpz2)2 and Cu(HBpz3)2 complexes. Reaction products have been characterised by elemental analysis, magnetic moments and infrared spectral measurements.

Distortion of the coordination polyhedron in mononuclear copper(II) complexes. Optical absorption and electron spin resonance studies on some five-coordinate copper(II) complexes

The preparation and spectral properties are reported for a series of ten mixed-ligand copper(II) complexes of the form [Cu( A)( B) n ]( X), where A is acetylacetonate anion, B represents a mono- or bidentate ligand such as morpholine, piperidine, isonicotinic acid hydrazide, 2,2′-bipyridine, 1,10-phenanthroline and X is variously NO − 3 or ClO − 4 anion and n = 1 or 2. The coordination of the anions and ligands has been demonstrated by infrared and electronic spectral methods. Electron spin resonance spectral data show the square-pyramidal five-coordinated arrangement around copper(II) in these complexes. Parameters such as g ‖, g ⊥, A ‖, A ⊥, 〈 g〉 and 〈 A〉 calculated from electron spin resonance data in solid and solution state at room temperature as well as frozen solution indicate the presence of the unpaired electron in the d x 2 − y 2 or d z 2 orbital. These results are in good agreement with electronic and photoacoustic spectral studies.

Perturbation of the triplet state of the acetylacetonate anion by alkali metal cations

The phosphorescence and triplet state ODMR spectra of Li+, Na+, and K+ acetylacetonate complexes are reported for the neat crystals and for glassy solutions of the complexes in EPA. The phosphorescence origins, phosphorescence lifetimes, and particularly the triplet state fine structure splittings are found to be sensitive to the metal ion. A simple model based on the electrostatic perturbation of the acetylacetonate anion by the alkali metal cation is presented and used to calculate the fine structure splittings in the perturbed triplet state of the acetylacetonate anion. The calculations indicate that perturbation of the π-electronic structure, and consequently of the spin-spin dipolar interactions, can largely explain the observed trends. Changes in the spin-orbit interactions, and their contribution to the fine structure splittings, are also considered.

Preparation of enol lactones of 3,5,7-triketo and 3,5,7,9-tetraketo acids by the condensation of 4,6-dimethoxy-2-pyrone with anions of mono- and diketones

Condensation of the anions of acetone, acetophenone, acetylacetone and benzoylacetone with 4,6-dimethoxy-2-pyrone afforded good yields of the corresponding 6 substituted 4-methoxy-2-pyrones which were converted to the 4-hydroxy analogs by demethylation with iodotrimethylsilane.

COORDINATION-SITE EXCHANGE REACTIONS OF SOME ACETYLACETONATO PALLADIUM(II) COMPLEXES: AUTOCATALYSIS AND SELF-CATALYSIS

Abstract A novel type of palladium(II) complexes containing a chelated acetylacetonate anion, carbon-bonded pyridyl ligand, and triphenylphosphine were prepared. They undergo the coordination-site exchange catalyzed by the phosphine freed from the reacting complex (autocatalysis) or the nitrogen end of the carbon-bonded pyridine in the reacting species (self-catalysis).

Synthesis and characterization of divalent manganese, cobalt, nickel, copper and zinc complexes with nicotinic acid

Coordination compounds of the transition metal(II) acetylacetonates of the formula [M(NA) 2(acac) 2 ] n (M = Mn, Co, Ni, Cu and Zn; NA = nicotinic acid and acac = acetyl-acetonate anion) have been synthesized and characterized by chemical analysis, magnetic susceptibility, ligand-field spectra, IR and far-IR spectral measurements as well as photoacoustic spectroscopy in the solid state. Tentative stereochemistries for the complexes isolated in the solid state are suggested. The ligand-field parameters 10 Dq, B, β, λ and CFSE are calculated for cobalt and nickel complexes and are in good agreement with the proposed geometries. The metal ions attain six-coordination through the four oxygens of the anion and two donor atoms of the nicotinic acid ligands acting always as monodentate ligands. The formation of the compound results in a considerable shift of v(M-O) to lower frequencies in all the compounds related to parent acetylacetonates.

Kinetic and Equilibrium Studies on Substitution Reactions of the Chlorobis(β-diketonato)manganese(III) Complexes with Other β-Diketones

Abstract The MnCl(β-dik)2 complexes, where β-dik stands for an anion of acetylacetone, benzoylacetone, and dibenzoylmethane, were confirmed to have the five-coordinate structure in dichloromethane and their adduct formation constants with various donor solvents were measured. Equilibria and kinetics of substitution reactions of MnCl(β-dik)2 with other β-diketones were determined by the spectrophotometric method and the mechanism for these reaction is proposed.

The isolation and characterization of some iron(III) complexes with mixed uni-, bi-, and tridentate ligands

Ligand substitution in the Fe(diketo) 3 (diketo = the anion of either acetylacetone (Hacac), benzoylacetone (Hbzac), or dibenzoylmethane (Hdbzac), by its 1:1 molar ratio reaction with either pyridine-2,6-dicarboxylic acid (H 2pdc), picolinic acid (Hpc), or with chloroacetic acids (HR; R A, R B, R C = mono-, di-, or trichloroacetate respectively) produced the mixed iron(III) complexes (diketo)Fe(Pdc) (diketo = acac, bzac, or dbzac), (diketo) 2Fe(pc), (diketo = acac or dbzac), and (acac) 2Fe(R)·nH 2O (for R = R A and R C, n =1 and for R = R B, n = 0) respectively. The reaction of the latter (R = R C; 1:1 molar ratio) with either HR(R = R B or R A) afforded the mixed complex (acac)Fe(R C(R B·H 2O and (acac)Fe(R CR A· H 2O respectively, while its reaction with H 2pdc (1:1) led to the formation of (acac)Fe(pdc). The acetylacetonate anion in the complex could be replaced by oxinate and trichloroacetate in its reaction with oxine (1:1) or HR C (1:5), whereas (acac)Fe(pdc) urea was obtained from the reaction of the complex with urea (1:2). The tridentate (pdc), bidentate (diketone, pc, R C, R B, R A, and oxinate) and monodentate (urea, FeO bonding) coordinations of the ligands and the suggested polymerization of the (pdc) mixed ligand complexes are based on anlytical, spectral and magnetic moment evidence.

The infrared spectra (3500-140 cm?1) of the 2,2'-bipyridine, 2-aminomethylpyridine and ethylenediamine adducts and the sodium tris-compounds of cobalt(II), nickel(II) and zinc(II) acetylacetonates

The M(acac)2B and NaM(acac)3 complexes (M = Coll, Nill orZnll; acac=acetylacetonateanion; B=2,2′=bipyridine, 2-aminomethylpyridine or ethylenediamine) have been prepared and their i.r. spectra determined over the 3500-140 cm−1 range. Complete band assignments have been made on a comparative basis, with the effects of ligand substitution and metal ion substitution being considered. Bands in the i.r. spectra of the complexes which are associated with 2,2′-bipyridine, 2-aminomethylpyridine and ethylenediamine arc in excellent agreement with values previously established for these ligand and metal-ligand vibrations, in related complexes. Band assignments for acetylacetonate anion and metal-acetylacetonate vibrations substantiate those made in certain of the previously published papers. The method of assignment adopted has allowed the complete assignment of bands in the i.r. spectra of the metal complexes.