Copper Β-diketonates Research Articles

Exploring C-F···π Interactions: Synthesis, Characterization, and Surface Analysis of Copper β-Diketone Complexes.

Synthesis and characterization of two novel copper β-diketone complexes, where halogen bonds play a pivotal role in shaping their multifaceted structural landscape, have been done in the present study. This study employs X-ray diffraction, ultraviolet-visible (UV-vis) spectroscopy, and infrared (IR) spectroscopy to investigate two copper β-diketone complexes, [Cu(L1)2(ttfa)2]·2CH3OH (1) and [Cu(L1)(dfpb)2] (2), where Httfa is 4,4,4-trifluoro-1-(thiophen-2-yl)butan-3,1-dione and Hdfpb is 4,4-difluoro-1-phenylbutane-1,3-dione. Complex 1 displays a halogen bond, which contributes to its uniqueness. The coordination sphere around the copper atoms was found to be octahedral for complex 1 and pyramid with a square base for complex 2. The study also extensively discusses the interactions present in these complexes. Hirshfeld surface analysis was employed to gain a more detailed understanding of these interactions, and the results showed that hydrogen-bond interactions contributed above 30% of the whole surface area in both complexes. Additionally, the halogen bond in complex 1 was found to contribute approximately 8% of the surface. Overall, this study provides valuable insights into the structural properties and interactions of copper β-diketone complexes, which could have potential applications in various fields.

Crystal structures and charge distribution of partially-fluorinated β-diketonate copper(II) complexes based on Hirshfeld surface analysis and DFT calculations

Two partially-fluorinated coordination complexes, C30H20CuF2O4 (1) and C30H18CuF4O4 (2), were prepared and the corresponding crystals, 1 with a benzene solvate (1•C6H6) and 2, were obtained from a benzene-dichloromethane solution. The crystallographic studies and the Hirshfeld surface analysis of the crystals showed the metal⋯π interactions through an electrophilic property of the Cu ions and the remarkable CH⋯π interactions between the phenyl substitutions; the most important contributions for the crystal packing for 1 in 1•C6H6 are from the C⋯H/H⋯C (36.8%), H⋯H (34.0%), and F⋯H/H⋯F (10.4%) interactions but those for 2 are from the H⋯H (28.8%), F⋯H/H⋯F (22.9%), and C⋯H/H⋯C (19.2%). A density functional theory (DFT) calculation using the optimized structures from the crystal data clearly showed the proportion of the electron-withdrawing effects of the fluorine substitution and the corresponding effects on the central metal ions and the other aromatic rings.

Mechanically Activated Solid-Phase Reaction of Copper(I) Chloride with Sodium β-Diketonates: Formation of Metallic Copper Nanoparticles

Solid-phase reaction of copper(I) chloride with sodium β-diketonates under mechanical activation in a vibration ball mill involves disproportionation of CuCl with the formation of the corresponding copper(II) β-diketonate and highly reactive X-ray amorphous metallic copper nanoparticles. The effect of reaction conditions on the process and some properties of the activated mixtures have been studied.

Quantitative prediction of nuclear-spin-diffusion-limited coherence times of molecular quantum bits based on copper(ii).

We have investigated the electron spin dynamics in a series of copper(ii) β-diketonate complexes both in frozen solutions and doped solids. Double digit microsecond coherence times were found at low temperatures. We report quantitative simulations of the coherence decays solely based on the crystal structure of the doped solids.

An X-ray photoelectron spectroscopy and quantum chemical study of copper(II) β-diketonates and Cu(HFA)2 complexes with imidazoline ligands

An X-ray photoelectron spectroscopy study of the charge and spin state of copper(II) β-diketonates and Cu(hfa)2 (hfa–hexafluoroacetylacetonate) complexes with imidazoline ligands is performed with comparison to the data of quantum chemical calculations. It is shown that the structure of the spectra of copper is described by a superposition of the |2p53d9>and | 2p53d10L> electronic states determined by electron transfer processes between copper and L ligand atoms. It is found that during the coordination of imidazoline ligands to the Cu(hfa)2 complex the spin density is redistributed through the chain of chemical bonds from the ligand nitroxyl group to the copper atom.

Externally and Internally Functionalized Copper(II) β-Diketonate Molecular Squares.

Five functionalized bis(β-diketones) and their Cu(II) molecular squares are described. The new bis(β-diketones), m-pbhxH2 (3), 5-MeO-m-pbaH2 (4), 5-BuO-m-pbaH2 (5), 2-MeO-m-pbaH2 (6), and 2-MeO-m-pbprH2 (7), were prepared by reaction of the corresponding aldehydes with phospholenes, as we previously reported for m-pbaH2 (1) and m-pbprH2 (2). Ligand 3 has long alkyl chains in its β-diketone moieties, while ligands 4-7 have alkoxy substituents on their aromatic rings. When treated with Cu(2+), the new bis(β-diketones) 3, 4, 5, and 7 afford molecular squares, Cu4(m-pbhx)4 (10), Cu4(5-MeO-m-pba)4 (11), Cu4(5-BuO-m-pba)4 (12), and Cu4(2-MeO-m-pbpr)4 (13), respectively. Two of the new molecular squares, 10 and 12, contain longer-chain substituents and are soluble in a wider range of organic solvents. The other squares, 11 and 13, contain external and internal methoxy groups, respectively, and they show smaller changes in solubility. Single-crystal X-ray analyses are reported for three of the molecular squares without guest molecules, and for five adducts of the squares with σ- (polypyridine) and π-bonded (fullerene) guests. The Cu···Cu distances in the "empty" squares range from 14.047 to 14.904 Å; those in the adducts vary over a wider range depending on the guest molecule involved.

Chemical and electrochemical oxidation studies on new copper(I) ferrocenyl-functionalised β-diketonates

A two-step synthetic methodology for the preparation of bis(triphenylphosphine) copper(I) β-diketonates, [Cu(FcCOCHCOR)(PPh3)2] (R=CH3 (3a), CF3 (3b) and Fc=Fe(η5-C5H4)(η5-C5H5)) (3c)) is reported using K[FcCOCHCOR] and [CuCl(PPh3)2] (2) as the key starting materials. Organometallics 3a–3c are stable under inert gas atmosphere. However, in ethanol and air it was shown that 3a decomposes to the dimeric μ-ethoxy copper(II) β-diketonate [Cu(FcCOCHCOCH3)(μ-OEt)]2 (4) and [Cu(FcCOCHCOCH3)2] (5a), respectively. The molecular structures of 3c and [Cu(FcCOCHCOCH3)(μ-OEt)]2 (4) in the solid state are reported showing that the coordination geometry about copper(I) for 3c is best described as a somewhat distorted tetrahedron, while the copper(II) ions in 4 possess a square-planar environment constructed from two chelated FcCOCHCOCH3− ligands and two OEt groups. From an electrochemical study in CH2Cl2/0.1moldm−3 [nBu4N][B(C6F5)4], it was found that upon the anaerobic electrochemical irreversible oxidation of the Cu(I) centres to Cu(II), complexes 3a–3c lost both PPh3 ligands and formed square planar [CuII(FcCOCHCOR)2] complexes 5a–5cbefore the ferrocenyl centres are oxidised; homoleptic, cationic [CuI(PPh3)4]+ (6) is also formed. The CuI ion of 6 is oxidised after the ferrocenyl centres of 5a–5c.

Bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)tetrakis(μ4-1,1,1,5,5,5-hexafluoropentane-2,2,4,4-tetraolato)copper(II)octatin(II): a prospective precursor for Cu-doped SnO2films

The crystal structure of a tin-rich heterometallic supramolecular product, [CuSn8(C5HF6O2)2(C5H2F6O4)4] or [Sn4(hfpt)2-Cu(hfac)2-Sn4(hfpt)2], (I), is reported (hfpt is the tetraanion of 1,1,1,5,5,5-hexafluoropentane-2,2,4,4-tetraol and hfac is the anion of 1,1,1,5,5,5-hexafluoropentane-2,4-dione). Reaction between tin(II) tetraolate, [Sn4(hfpt)2], and copper(II) β-diketonate, [Cu(hfac)2], was utilized for the preparation of (I). The asymmetric unit consists of the whole [Sn4(hfpt)2] unit and half of a [Cu(hfac)2] unit, with the Cu atom lying on an inversion center. Intermolecular Cu···O interactions from the axial positions of copper in [Cu(hfac)2] and O atoms of the hfpt ligand in [Sn4(hfpt)2] mediate the formation of a sandwich-type structure for (I). Additional intermolecular Sn···O interactions between neighbouring [Sn4(hfpt)2] units complete a two-dimensional network.

Synthesis of volatile copper(II) β-diketonates, β-ketiminates, and β-diiminates. The problem of synthesis of copper(II) Bis(2,2,6,6-tetramethyl-3-methylaminoheptane-5-onate)

The methods of synthesis of the copper(II) β-diketonates, β-ketiminates, and β-diiminates containing in the composition CH3, CF3, C(CH3)3, and Ph substituents were summarized. At the formation of metallocycles with 2,2,6,6-tetramethyl-3-methylaminoheptane-5-one ligand the intraligand repulsion of tret-butyl group and the methyl group at the nitrogen atom is noted, impeding the complexation.

Synthesis, crystal structure and supramolecularity of [Cu(tba)2] complex (tba = deprotonated of 3-benzoyl-1,1,1-trifluoroacetone)

The copper β-diketonate complex [Cu(tba)2] (3) (tba=deprotonated of 3-benzoyl-1,1,1-trifluoroacetone) was prepared by the direct reaction of Cu(OAc)2·H2O (2) (OAc=O2CMe) with two equivalents of H-tba (1). The formation of 3 was monitored by FT-IR and UV–Vis spectroscopy. Complex 3 crystallized in a monoclinic space group P2(1)/n with unit cell parameters a=10.3719(3), b=5.65410(10), c=16.9974(2)Å, V=995.47(4)Å3, and Z=2. The crystal structure of 3 consists of a neutral [Cu(tba)2] complex sphere, wherein the geometry about the Cu2+ is precisely planar. The complex spheres are self-assembly stacked, face-to-face, via π–π interactions forming 1-D supramolecular chain.

ChemInform Abstract: Reactions of Copper(II) β-Diketonates Under Free Radical Conditions. Preparation of Highly Congested β-Diketones.

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Computational Method for Efficient Screening of Metal Precursors for Nanomaterial Syntheses

A density functional theory (DFT) based method is proposed for efficient screening of metal precursors for nanomaterial syntheses. For this study, we examined the effectiveness of our DFT approach for predicting bulk properties of precursor metal complexes, which is a key of our method. The DFT calculations were applied for a series of copper(II) β-diketonate complexes to estimate values related to complex stabilities such as complex formation energies ΔEtotalcomplex, total energy changes for two-electron reduction ΔEtotalreduction, and so on. The value of ΔEtotalcomplex was compared to the stability constant β2 collected from the relevant literature; ΔEtotalreduction was compared with reduction potentials measured using cyclic voltammetry. Results obtained from these comparisons revealed that simple DFT calculations predicted the trend of the complex stabilities that were determined experimentally as a bulk property. Our method can predict precursor properties and can greatly contribute to efficient prec...

Specific features of the formation of color centers in nanoporous glasses doped with copper β-diketonate through different solvents

The EPR and optical spectra of Cu2+ ions impregnated in the nanoporous Vycor glass in the form of copper β-diketonate (Cu(hfac)2) dissolved in supercritical CO2, ethanol, and benzene are investigated. It is revealed that the spectra recorded immediately after the impregnation of the samples represent a superposition of two EPR spectra with hyperfine structures. This indicates that there are two structural forms of Cu(hfac)2 molecules located in fixed positions in pores. After long-term storage of the samples in air, the EPR spectra irrespective of the solvent type represent a superposition of three spectra. Each spectrum contains four hyperfine-structure components with a large splitting. The form of the third spectrum depends on the duration of storage of the sample and can be associated with water absorbed from the atmosphere and adsorbed on the pore walls. The bonds between the impregnated Cu(hfac)2 molecules and the pore walls are weak, which is confirmed by the experiments with immersion of the impregnated samples in a pure solvent. The EPR spectra of Cu2+ ions introduced into oxide glasses through a batch with subsequent melting differ substantially from the spectra of the silica glasses impregnated with Cu(hfac)2 solutions, even though the former spectra also correspond to Cu2+ complexes with symmetry D4h.

Phenomenon of trans-cis isomerization of copper(II) β-diketonate on co-crystallization with lead(II) hexafluoroacetylacetonate

X-ray diffraction structural study is carried out for crystals of a heterobimetallic complex derived from lead(II) hexafluoroacetylacetonate and copper(II) 2-methoxy-2,6,6-trimethylheptan-3,5-dionate prepared by co-crystallization of Pb(hfa)2 and trans-Cu(zis)2. In the novel compound Cu(zis)2·Pb(hfa)2 the copper complex is found to have cis-configuration. It is demonstrated that the main structural motif of this complex is coordination dimers Cu(zis)2·Pb(hfa)2 joint in polymeric chains of alternating molecules of the complexes. Crystal data for Cu(zis)2·Pb(hfa)2: a = 9.848(2) A, b = 23.871(5) A, c = 18.289(4) A, β = 100.23(3)°, space group P21/n, Z = 4, d x = 1.701 g/cm3. The distance Pb-Cu in the dimer is 3.68 A.

Phase separation in semi-interpenetrating polymer networks based on crosslinked poly(urethane) and linear poly(methyl methacrylate) containing iron, copper, and chromium chelates

Phase separation that occurs during formation of semi-interpenetrating polymer networks of various compositions based on crosslinked poly(urethane) and linear poly(methyl methacrylate) containing 1 wt % iron, copper, and chromium chelates has been studied by the methods of DSC and DMA. It has been shown that, in contrast to chromium chelates, the incorporation of iron and copper β-diketonates into the semi-interpenetrating polymer networks (PU : PMMA = 50 : 50) causes retardation of phase separation owing to high rates of poly(urethane) and poly(methyl methacrylate) formation and the appearance of chelate complexes with both blend components at the interface. A more complete phase separation in metal-containing semi-interpenetrating polymer networks (PU : PMMA = 70 : 30) is associated with the fact that chemical kinetics and complexation processes act in opposite directions. The latter processes prevail, and the influence of the type of metal ion in a chelate that predominantly interacts with PU in the blend is diminished.

1:1 Cross‐Assembly of Two β‐Diketonate Complexes through Arene–Perfluoroarene Interactions

Stack 'em up: Two coordination complexes—one a perfluoroarene-functionalized β-diketonate copper complex (purple, see picture), the other an arene-functionalized metal (M=Cu, Pd, Pt) complex (green)—form alternately layered arrays through arene–perfluoroarene interactions with metal-to-metal distances close to van der Waals contacts to give 1:1 cocrystals as one-dimensional metal wires.

Copper β-Diketonate Molecular Squares and Their Host–Guest Reactions

Copper β-Diketonate Molecular Squares and Their Host–Guest Reactions

Structure and properties of heterocomplex compounds based on lead(II) hexafluoroacetylacetonate and copper(II) β-diketonates

Single crystal X-ray diffraction study has been performed for heterometallic complexes based on lead(II) hexafluoroacetylacetonate and copper(II) β-diketonates. Crystal data for Cu(aa)2·Pb(hfa)2: a = 8.741(2) A, b = 12.124(2) A, c = 13.741(3) A, α = 89.70(3)°, β = 89.50(3)°, γ = 75.06(3)°, space group P-1, Z = 2, d calc = 2.084 g/cm3; for Cu(hfa)2 Pb(hfa)2: a = 9.334(2) A, b = 14.584(3) A, c = 23.102(5) A, β = 96.82(3)°, space group P21/c, Z = 4, d calc = 2.338 g/cm3. It is demonstrated that the principal structural motif for these compounds is a chain coordination polymer, which consists of alternating molecules of the complexes. The results of a thermogravimetric study for the compounds are reported.

Spectra of copper and europium β-diketonates in alcoholic solutions and transparent dielectrics

We have used optical and EPR spectroscopy to study the mechanisms for color center formation in nanoporous glasses, polymethylmethacrylate, and alcoholic solutions containing ?-diketonate molecules: Cu(hfac)2, Ba(hfac)2, Pr(hfac)3, and Eu(fod)3. We have observed and studied the complex structure of the absorption bands in the 300 nm region belonging to the intraligand π-π* transition. Analogous results were obtained when studying the photoluminescence spectra of 5D0 → 7F0 transitions of Eu3+ ions and the EPR spectra of Cu2+ ions in matrices doped with Cu(hfac)2. We propose a model according to which for β-diketonate molecules (except for basic diketonates), a hydrolyzed form exists that is formed during synthesis of the polycrystalline powder due to the presence of water molecules. The model allows us to explain the spectral manifestations of β-diketonates in different matrices.

Synthesis, spectral, and thermal characterizations of Ni(II) and Cu(II) β-diketone complexes with thenoyltrifluoroacetone ligand

Two kinds of nickel(II) and copper(II) β-diketone complexes derived from thenoyltrifluoroacetone ligand with blue–violet light absorption were synthesized by reacting free ligand and different metal(II) ions in sodium methoxide solution. Their structures were postulated based on elemental analysis, ESI-MS, FT-IR spectra and UV–vis electronic absorption spectra. Smooth films on K9 glass substrates were prepared using the spin-coating method. Their solubility in organic solvents, absorption properties of thin film and thermal stability of these complexes were evaluated.