Copper Β-diketonates Research Articles

Complexation of Fe3+, Cu2+, and Cr3+ β-diketonates with poly(urethane) and poly(methyl methacrylate) in semi-interpenetrating networks: Effect on phase separation

Complexation of iron, copper, and chromium β-diketonates with poly(urethane) and poly(methyl methacrylate) in semi-interpenetrating polymer networks was studied by IR spectroscopy and ESR using various paramagnetic probes. It was shown that types of complexes arising in semi-interpenetrating polymer networks depend on the central metal ion in a chelate. In the networks containing iron and copper β-diketonates, formation of complexes between chelates of these metals and donor groups of PUR and PMMA promotes mutual penetration of poly(urethane) and poly(methyl methacrylate) phases. As a consequence, the degree of their separation decreases and the interphase region widens.

Standard molar enthalpies of formation of copper(II) β-diketonates and monothio-β-diketonates

The standard ( p ∘ = 0.1 MPa) molar enthalpies of formation of the crystalline complexes of dibenzoylmethane (H dbm), thenoyltrifluoroacetone (H ttfa), monothiodibenzoylmethane (H dbmS), and monothiothenoyltrifluoroacetone (H ttfaS) of copper(II) were determined, at T = 298.15 K, by high precision solution-reaction calorimetry. The standard molar enthalpies of sublimation of the copper(II) β-diketonate complexes were measured by high-temperature Calvet microcalorimetry. From the standard molar enthalpies of formation of the complexes in the gaseous state, the mean molar dissociation enthalpies copper(II)–ligand, 〈 D m〉(Cu–L), were derived. Δ f H m ∘ ( cr ) Δ cr g H m ∘ kJ · mol −1 kJ · mol −1 Bis(dibenzoylmethanate)copper(II), Cu( dbm) 2 −364.0 ± 3.9 230.7 ± 8.2 Bis(thenoyltrifluoroacetonate)copper(II), Cu( ttfa) 2 −1824.3 ± 8.3 167.9 ± 7.4 Bis(monothiodibenzoylmethanate)copper(II), Cu( dbmS) 2 35.6 ± 7.7 [241 ± 15] Bis(monothiothenoyltrifluoroacetonate)copper(II), Cu( ttfaS) 2 −1405.7 ± 8.3 [177 ± 15]

Me 3SiC [tbnd]C–CMe [dbnd]CH 2 copper(I) β-diketonates: Synthesis, solid state structure, and low-temperature chemical vapour deposition

The ene-yne copper(I) β-diketonates [(η 2-TMSMB)Cu(β-diketonate)] (β-diketonate = ac etyl ac etonate/acac, 5; = 1,3- d i-tert- b utyl ac etonate/dbac, 6; = 1,1,1,5,5,5- h exa f luoroacetyl ac etonate/hfac, 7; TMSMB = 4- T ri M ethyl S ilyl-2- M ethyl- B ut-1-ene-3-yne, Me 3SiC C–CMe CH 2) are accessible by the reaction of [(η 2-TMSMB)Cu(μ-Cl)] 2 ( 3) with [Na(β-diketonate)] (β-diketonate = acac, 4a; = dbac, 4b; = hfac, 4c) in a 1:2 molar ratio. Complexes 6 and 7 are also formed, when Cu 2O ( 8) is reacted with H-hfac ( 9a) or H-dbac ( 9b), respectively. The solid state structure of 7 is reported. The copper(I) ion possesses a planar environment caused by the η 2-coordinated TMSMB ligand and the chelate-bound hfac group, while the CMe CH 2 entity stays free. The thermal properties of 5– 7 were determined by applying T hermo G ravimetry (TG) and D ifferential S canning C alorimetry (DSC). All complexes decompose in a two-step process beginning at ca. 85 °C. Elimination of TMSMB produces [Cu(β-diketonate)] which disproportionates to give [Cu(β-diketonate) 2] and elemental copper. Preliminary hot-wall C hemical V apour D eposition experiments (CVD) were carried out with 7. Copper films were deposited onto TiN-coated oxidised silicon wafers at a precursor vaporisation temperature of 50 °C and a deposition temperature of 145 °C. The films were characterised by SEM and EDX.

Mechanism of electrochemical synthesis of copper(II) ?-diketonates

Formation of copper β-diketonates in electrolysis of a solution of acetylacetone in acetonitrile in the presence of oxygen, with tetraethylammonium bromide as supporting electrolyte, was studied.

Electron paramagnetic resonance of color centers in nanoporous glasses impregnated with copper ?-diketonatewith the use of supercritical carbon dioxide

The spectral properties of nanoporous glasses containing Cu2+ ions, which are introduced into glass pores in the form of organometallic compound of copper β-diketonate dissolved in supercritical CO2, are investigated for the first time. The analysis of the EPR and optical absorption spectra demonstrates that Cu2+ ions are located in octahedral sites with symmetry D4h. It is revealed that the intensity of the EPR spectrum decreases by one order of magnitude after annealing of the glass at a temperature of 200°C, which correlates with the temperature of decomposition of copper β-diketonate molecules (∼250°C) with the formation of CuO or metallic copper. This process is accompanied by a change in the spectrum shape and the spin-Hamiltonian parameters, even though these parameters also correspond to the octahedral environment with symmetry D4hIt is assumed that the remaining Cu2+ ions form new complexes with fragments of decomposed molecules. According to the optical data, the inference is made that high-temperature annealing leads to the formation of copper metal nanoparticles in the glass.

Synthesis and characterization of alkynes β-diketonate copper(I) complexes

The reactions of 1,3,5-tris-(trimethylsilylethynyl)benzene (1) with Cu2O and 1,1,1,5,5,5,-hexafluoroacetylacetone in alkyne to Cu ratios 1:0.5, 1:1 and 1:3 in CH2Cl2 at room temperature give copper complexes (η2-1,3,5-tris(trimethylsilylethynyl)benzene)(Cu(hfac)) (2), (η2:η2-1,3,5-tris(trimethylsilylethynyl)benzene)(Cu(hfac))2 (3) and (η2:η2:η2-(1,3,5- tris(trimethylsilylethynyl)benzene))2(Cu(hfac))3(4), respectively. In the same conditions, 2,5-bis-(trimethylsilylethynyl)thiophene (5) reacts with 0.5 or 1 equiv. of Cu2O to give (η2:η2-2,5-bis(trimethylsilylethynyl)thiophene)(Cu(hfac)) (6) and (η2:η2-2,5-bis(trimethylsilylethynyl)thiophene)(Cu(hfac))2 (7), respectively, and 1,4-bis(trimethylsilyl)-1,3-butadiyne (8) with 0.5 equiv. of Cu2O give (η2:η2-1,4-bis(trimethylsilyl)-1,3-butadiyne)(Cu(hfac))2(9). All the new compounds have been characterized by analytical and spectroscopic methods and their thermal properties were examined by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC).

Dissociation reactions of CuI(hfac)L compounds relevant to the chemical vapor deposition of copper

Density functional theory (DFT) calculations have been performed for ligand copper bond energies of typical copper β-diketonate compounds used in chemical vapor deposition (CVD) of copper films. The molecules have the general formula CuI(hfac)L, where hfac is hexafluoroacetylacetonate, and L represents vinyltrimethylsilane (VTMS), trimethylphosphine (PMe3), 2-butyne (2-butyne), or 1,5-cyclooctadiene (COD). The DFT method is used with the three-parameter Becke exchange and the Lee–Yang–Parr correlation functionals (B3LYP) with different basis sets. The optimized structures correspond to the crystal structures determined using crystal X-ray diffraction. Two different structures, CuI(hfac)(η2-COD) and CuI(hfac)(η4-COD), are determined for the CuI(hfac)(COD) complex, the latter being more stable by ∼3 kcal mol−1. The strength of the ligand–copper interaction is studied for the reaction CuI(β-diketonate)L → CuI(β-diketonate) + L. Bond energies of 32.1, 35.6, 33.6 and 38.4 kcal mol−1 are calculated for typical Cu CVD precursors, CuI(hfac)(butyne), CuI(hfac)(COD), CuI(hfac)(VTMS) and CuI(hfac)(PMe3), respectively. The similarity between these bond energies and reported experimental activation energies for CVD suggests that the dissociation of the ligand L could be the rate determining step for the film growth under certain conditions. The rate parameters for the dissociation reaction of CuI(hfac)(VTMS) are evaluated based upon the results of the DFT calculations. A simple reaction mechanism for Cu CVD is proposed and combined with transport phenomena simulations of two reported reactors configurations. Good agreement with experimental observations is obtained with a CuI(hfac)(VTMS) dissociation rate constant of 1.5 × 1014exp(−13.5/T), which is consistent with the computed rate constant.

Formation study and X-ray structures of dinuclear beta-diketonate copper(I) complexes with conjugated ene-yne Lewis base. Implications for the use of (hfac)Cu(MHY) as a precursor for copper CVD.

Dinuclear [(hfac)Cu](2)(MHY) and [(hfac)Cu](2)(HY) species, where hfac = hexafluoroacetylacetonate, MHY = 2-methyl-1-hexen-3-yne, and HY = hex-3-yn-1-ene), are formed during copper chemical vapor deposition experiments when a bubbler containing the corresponding mononuclear species is used. These compounds and the so far unknown (hfac)Cu(HY) have been characterized by (1)H and (13)C NMR and IR spectroscopy and the two dinuclear species by X-ray crystallography and elemental analysis. As expected, in the structure of the dinuclear species, two roughly perpendicular Cu(hfac) moieties are bound to a single ene-yne: one to the C[triple bond]C, the other to the conjuguated double bond. Weak intra- and intermolecular Cu...Cu interactions have been detected in the solid. [(hfac)Cu](2)(HY) is more stable and more easily formed than [(hfac)Cu](2)(MHY) because of the hindrance character of the additional methyl groups. The formation of the dinuclear species from the mononuclear species is reversible as it has been demonstrated by (1)H NMR. The mononuclear species can be recovered from the dinuclear species when free ene-yne base is added. Crystallographic data for [(hfac)Cu](2)(MHY): C(17)H(12)O(4)F(12)Cu(2), triclinic, P1 (No. 2), Z = 4; at 298 K, a = 11.112(3) A, b = 13.472(4) A, c = 15.747(3) A, alpha = 94.95(2) degrees, beta = 98.15(2) degrees, gamma = 100.27(2) degrees; Crystallographic data for [(hfac)Cu](2)(HY): C(16)H(10)O(4)F(12)Cu(2), orthorhombic, Cc2a (No. 41, Aba2), Z = 8; at 230 K, a = 12.280(3) A, b = 13.531(3) A, c = 25.461(5) A.

2-Methyl-1-hexen-3-yne Lewis Base Stabilized β-Diketonate Copper(I) Complexes: X-ray Structures, Theoretical Study, and Low-Temperature Chemical Vapor Deposition of Copper Metal

Four new β-diketonate copper(I) complexes containing the ene−yne 2-methyl-1-hexen-3-yne (MHY), [Cu(hfac)(MHY)] (hfac = hexafluoroacetylacetonate), [Cu(tfac)(MHY)] (tfac = 1,1,1-trifluoroacetylacetonate), [Cu(pfac)(MHY)] (pfac = perfluoroacetylacetonate), and [Cu(acac)(MHY)] (acac = acetylacetonate), have been synthesized and characterized by FT-IR and 1H and 13C NMR and three of them by an X-ray structural and elemental analysis. In these complexes, the triple bond is η2-coordinated to the copper atom while the double bond stays free. A theoretical study demonstrates that for these complexes a planar coordination around the copper ion is the most stable, with energy differences of 57.7, 44.9, 39.3, and 62.7 kJ/mol for the acac, tfac, hfac, and pfac complexes, respectively, when compared to a tetrahedral structure, which is another possible coordination mode for Cu(I). We also found that the orbital contribution of the fluorine atoms does not seem to be very relevant for the Cu−alkyne bond, but rather weak...

Synthesis and Spectroscopic Studies of Novel β-Diketonate Copper(I) Compounds and Solid State Structure of Tetravinylsilane Tetrakis Copper(I) 1,1,1,5,5,5-Hexafluoroacetylacetonate (TVST[Cu]hfac)

Reactions between tetraalkene silanes SiR4 (R = vinyl and allyl), copper(I) oxide, and 1,1,1,5,5,5-hexafluoroacetylacetonate (hfac) gave novel multicoordinated β-diketonate copper(I) Lewis base ligand complexes. The synthesis and spectroscopic data of tetravinylsilane biscopper(I)hfac complex (TVSB[Cu]hfac) (1), tetravinylsilane tetrakiscopper(I)hfac (TVST[Cu]hfac) (2), and tetrallylsilane triscopper(I)hfac complex (TASTri[Cu]hfac) (3) are presented, and the structural characterization of tetravinylsilane tetrakiscopper(I)hfac (TVST[Cu]hfac) (2) is reported.

Spectroscopic studies of some oxygen-bonded copper(II) β-diketonate complexes

The copper(II) β-diketonate complexes Cu(L 1) 2, Cu(L 2) 2, Cu(L 3) 2, where L 1=H 3C–CO–CH–CO–CH 3, L 2=H 5C 6–CO–CH–CO–C 6H 5, L 3=H 5C 6–CO–CH–CO–OC 2H 5, were prepared and investigated by spectroscopic (FT-IR, UV–VIS, EPR) methods. The coordination of the Cu(II) ion to the oxygen atoms of two β-diketonate molecules is observed by the shift of the ν s ( C C), ν s ( C O) and ν as ( C O) stretching vibrations in the FT-IR spectra of the complexes with reference to those of the ligands. In the visible electronic spectra of the Cu(II) β-diketonate complexes the very broad absorption bands of B 1g→B 2g and B 1g→E g transitions appear at ≈13,500, 16,070 cm −1 for Cu(L 1) 2, 14,500, 16,630 cm −1 for Cu(L 2) 2 and 13,075, 15,410 cm −1 for Cu(L 3) 2. Besides the bands of the intraligand π–π ∗ transitions (29,000–42,000 cm −1) of β-diketonates, the UV spectra of the Cu(II)-complexes contain the L σ→M d bands (45,500–46,100 cm −1). The powder EPR spectrum of the Cu(L 1) 2 complex is quasi-isotropic and asymmetric ( g ∥=2.160, g ⊥=2.050), that of Cu(L 2) 2 is axial ( g ∥=2.216, g ⊥=2.045), and typical for square-planar compounds and that of Cu(L 3) 2 is rhombic, with g 1=2.167, g 2=2.082 and g 3=2.004. The low gyromagnetic factors arise from the delocalization of the unpaired electron in the chelate rings and from some molecular packing effects.

Synthesis of copper(I) β-diketone complexes

At room temperature, the reaction of metallic copper powder with 2-thenoyltrifluoroacetone (tfac) and selected phosphine ligands gives the new copper(I) complexes [Cu(PPh 3) 2(tfac)] ( 1), [Cu(dppm)–(tfac)] 2 ( 2), [Cu(dppe)(tfac)] 2 ( 3), [Cu(dppp)(tfac)] ( 4), [Cu(dppb)–(tfac)] 2 ( 5), Ph 2P(CH 2) n PPh 2 [ n=1 (dppm), 2 (dppe), 3 (dppp), 4 (dppb)]. These complexes have been characterized by physicochemical and spectroscopic methods. X-ray structure analysis of 1 and 3 shows that tfac behaves as a chelating ligand and dppe coordinates as a bridging bidentate ligand to Cu(I) atoms in the Cu(I) complexes.

Steric effect on the formation of columnar phases in β-diketonate copper(II) complexes

A systematic study of the mesomorphic properties of three series of copper(II) complexes based on β-diketonate ligands containing branched side chains is reported. These disc-like compounds have four, six and eight flexible alkoxy side chains appended to the central core, in which two or four side chains were substituted by bulkier secondary alkoxy groups: 1-methylbutyloxy R ' = C5(2°) or 1-methylheptyloxy R ' = C8(2°). The mesomorphic results indicated that at least eight side chains are required to form stable columnar mesophases; other compounds with four or six side chains are not mesogenic regardless of the combination of the carbon length on the alkoxy or secondary alkoxy groups of the side chains. The compounds 3 with shorter R ' = C5(2°) side chains were all non-mesogenic regardless of the carbon length of three alkoxy side chains (R = C8, C10, C12) used. However, when the longer 1-methylheptyloxy side chain R ' = C8(2°) was substituted, the compounds 3b-3e with various alkoxy groups (R = C6, C7, C8, C10, C12) exhibited columnar phases. The mesophases were characterized and identified as columnar hexagonal phases (Colh), as expected, by thermal analysis and optical polarized microscopy. The presence of the introduced secondary alkoxy groups apparently appeared to influence the formation of columnar phases. The clearing points were relatively lower than other similar copper(II) compounds not substituted by secondary alkoxy side chains.

Standard molar enthalpies of formation of eight copper(II) fluorinated β-diketonates. Mean (Cu−O) bond dissociation enthalpies

The standard (p°=0.1 MPa) molar enthalpies of formation of eight copper(II) fluorinated β-diketonates at the temperature 298.15 K were determined by high-precision solution and reaction calorimetry. The standard molar enthalpies of sublimation of the same copper(II) complexes at the temperature 298.15 K were determined by effusion methods. From the enthalpies of formation of the complexes in the gaseous state, the average molar dissociation enthalpies 〈Dm〉 (Cu−O) were derived and compared with identical parameters obtained for non-fluorinated copper(II) β-diketonates.

Ligand behaviour of a nis-pyrazinecarboxamide copper(II) complex towards a copper(II) β-diketone. X-ray crystal structures of [Cu(bpzpn)(H 2O)]·3H 2O and [Cu(bpzpn)Cu(hfacac) 2] 2 (H 2bpzpn = N, N′-bis(2′-pyrazinecarboxamie)-1,3-propane, Hhfacac = hexafluoroacetylacetone)

Deprotonated bis-pyrazinecarboxamide complexes of the type M(bpzpn)(H 2O) n (M = Ni, Cu; H 2bpzpn = N, N′-bis(2′-pyrazinecarboxamide)-1,3-propane) The X-ray structure of [Cu(bpzpn)(H 2O)]·3H 2O has benn determined. The complexe os triclinic, P 1, a = 7.451(4), b = 10.498(6), c = 11.367 A ̊ , α = 97.90(3), β = 98.74(4), γ = 99.81(3)°, Z = 2 . The complex has a square pyramidal structure involving N 4-coordinated bpzpn 2 and an apically coordinajted water. The interaction of these pyrazinecarboxamide complexes. M(bpzpn)(H 2O n with metal β-diketones, M′(hfacac) 2(H 2O) n (M′ = Ni, Cu; Hhfacac = hexafluoroacetylacetone), has been examined. Theer is no evidence for N,N-coordination by M(bpzpn) entitles to M′(thfacac) 2 species, analogous to that produced in the corresponding pyridazine systems. However, the tetranuclear adduct [Cu(bpzpn)Cu(htfacac) 2] 2 has been obtained. An X-ray structure determination of this adduct shows that it is monoclinic, C2/c, a = 30.858(16), b = 9.954(2), c = 20.610(11) A ̊ , β = 109.23(2)°, Z = 4 , involving ‘opened-up’ Cu(bpzpn) species.

Electrochemical Studies of the Stability of Copper β-Diketone Chelates

The voltammetric reduction of copper β-diketone chelates was used to get information on their complex stability. 1,1,1-Trifluoropentane-2,4-dione, pentane-2,4-dione, 1-phenylbutane-1,3-dione, 1,3-diphenylpropane-1,3-dione and 2,2,6,6-tetramethylheptane-3,5-dione were chosen as model ligands. The complexes were reduced in two separate steps the first of which proved to be reversible. The experimental data are suitable for calculation of the relative stability constants of corresponding Cu(I) and Cu(II) complexes. The data well correlate with the overall stability constants determined potentiometrically. The results were applied to some new hydrophobic β-diketones which are not accessible to potentiometric measurements.

Copper CVD precursors and processes for advanced metallization: Invited lecture

In the last decade, extensive progress has been made towards the design and optimization of Chemical vapor deposition (CVD) precursors for pure copper film growth. Pure copper film is deposited from Cu(I) β-diketonate precursors via a thermally induced disproportionation reaction as shown in Eq. (1): 2 LCu(I)(β − diketonate)→ Cu(O)+ Cu(II)(β − diketonate) 2+2 L Besides the Cupra-select, which is by far the most widely used precursor for the deposition of blanket and selectively deposited copper films, several compounds appear well suited for copper CVD and exist as liquids under ambient conditions. We give here our latest results on the performances of new precursors. Moreover, new processes using CVD and CVD precursors have shown interesting and promising results. Selective metallization of surfaces was achieved using β-diketonate copper (I) complexes in a completely dry two step process. Silica surfaces were derivatized with monofunctional silanes by gas phase silylation. UV-exposure of the halogen or sulfur terminated molecules employing a mask resulted in a controlled pattern of the surface affinity towards the copper complex. The nature of the interaction between the chemically functionalized, patterned surface and the copper precursor is discussed.

Crystal structure of copper(II) pivaloyltrifluoracetonate adducts with o-phenanthroline and 2,2′-dipyridyl

The crystal structure of Cu(pta) 2·Phen has been determined. The phenanthroline ligand occupies a position in the equatorial plane of the tetragonally distorted octahedron with equal CuN distances and equivalent β-diketonate-anions. Cu(pta) 2·2,2′-Dipy is isostructural to Cu(pta) 2·Phen. The volatility of adducts decreases in the sequence Cu(thd) 2·Phen, Cu(pta) 2·Phen and Cu(hfa) 2·Phen changing inversely to that of the β-diketonates. The variation of packing mode caused by the difference of the molecular structure is considered to be responsible for the effect. The changes of the electronic spectra of copper(II) β-diketonates caused by adduct formation are discussed.

In situ quadrupole mass spectroscopy studies of water and solvent coordination to copper(II) β-diketonate precursors: implications for the chemical vapor deposition of copper

The incorporation of Cu(II) β-diketonates in technologically useful chemical vapor deposition (CVD) processes requires identifying the nature of the coordinated complexes that result from variations in the methods used for precursor preparation, and exploring their effects on its stability and performance. Accordingly, in situ quadrupole mass spectrometry (QMS) was employed to investigate the gas-phase evolution of various coordinated forms of Cu II(hfac) 2 and Cu II(tdf) 2, where tdf = 1,1,1,2,2,3,3,7,7,8,8,9,9,9-tetradecafluorononane-4,6-dione and hfac = hexafluoroacetylacetonate, to determine the nature of these coordinated complexes and elucidate the desorption energetics of associated additives. Careful analyses of complex fragmentation patterns during its sublimation and transport to the CVD reactor were performed under a variety of electron energies to develop an understanding of the effects of synthetic variations on precursor coordination, determine the fragmentation modes of the parent molecular ions and associated ionic fragments, and identify the mechanisms of precursor-additive interactions. In particular, it was found that Cu(hfac) 2 coordinates with water, methanol, or ethanol, but not with 2-propanol. Additionally, QMS studies of Cu(hfac) 2 seem to indicate that the use of methanol in the final recrystallization step involved in its synthesis yields a mixture of the coordinated complexes Cu II(hfac) 2 · H 2O · CH 3OH, Cu II(hfac) 2 · 2H 2O, and Cu II(hfac) 2 · 2CH 3OH. Similarly, in the case of Cu II(tdf) 2, the use of ethanol and trichloromethane appears to produce a mixture of the coordinated complexes Cu II(tdf) 2 · C 2H 5OH · H 2O, Cu II(tdf) 2 · C 2H 5OH, and Cu II(tdf) 2 · 2H 2O. By determining the temperature above which solvent molecules decoordinate from the copper precursor, reliable and reproducible processing windows were identified for the delivery of the pure precursors to the reaction zone, regardless of the synthetic technique used. It is thus shown that, by eliminating the effects of synthesis-induced variations in source coordination, copper β-diketonates can be successfully and reliably incorporated in industrially compatible CVD processes for ULSI applications without the need for costly precursor purification procedures.

Hydrogen-atom assisted CVD of copper at low temperatures and in-situ gas-phase spectroscopy studies

A novel low-temperature chemical vapour deposition (CVD) process has been developed by using hydrogen-atom reactions with metal compounds to produce copper thin films for ULSI applications. High-purity copper films, with low resistivity, good step coverage and strong adhesion to various substrates were obtained by using hydrogen-atom assisted CVD with CuCl at 200 °C, and with β-diketonate copper (II) complexes Cu(fod) 2 and Cu(hfa) 2 at 100–150 °C. Gas-phase Cu atoms (10 10–10 11 cm −3) and concentration as a function of time were measured in-situ by atomic absorption spectroscopy during deposition. The diatomic molecule CuF was measured by atomic emission spectroscopy using oxygen-atom reactions with β-diketonate copper (II) complexes Cu(fod) 2 and Cu(hfa) 2. Thermodynamic calculations of enthalpy, ΔH 0 showed that these reactions were exothermic and spontaneous at room temperature. The spectroscopy measurements of Cu atoms and CuF diatomic molecules in the reaction were studied as a means to develop insight into the gas-phase reaction. The reaction mechanisms were evaluated on the basis of atomic absorption spectroscopy measurements.