Conductivity of Al2(WO4)3–WO3 and Al2(WO4)3–Al2O3 Composites

Russian Journal of Electrochemistry - Composites of (1 – x)Al2(WO4)3–xWO3 and (1 – x)Al2(WO4)3–xAl2O3 are synthesized and their conductivity is studied as dependent on the...     

Unexpected preparation and X-ray crystal structure of the dinuclear complex Mo2(μ-P(O)(OCH3)2)2(CO)4(P(OCH3)3)2(CF3COO)2

Prolonged reaction of CF₃COOH with Mo(CO)₃(P(OCH₃)₃)₃ in CH₂Cl₂ yields the dimer [Mo(CO)₂(μ(O)P(OCH₃)₂)P(OCH₃)₃CF₃COO]₂ in low yield. The complex has been characterized by the usual spectroscopic methods and by an X-ray crystal structure determination. The molybdenum atoms are linked by two OP bridges, the six-membered dimetallacycle adopting a twisted-boat conformation. Each molybdenum is seven-coordinated and has a capped trigonal prism geometry, the capping position being occupied by an oxygen atom of the bridging OP(OCH₃)₂ group. A mechanism similar to the well-known Michaelis-Arbuzov rearrangement is proposed and substantiated by the concomitant apparition of CF₃COOCH₃ during the reaction.     

The formation of metal clusters by the facile condensation of electron-deficient metal centres; X-ray crystal structures of (η-C5H5)2Rh4(CO)4Cl2(CF3C2CF3) and (η-C5H5)4Rh4Pt(CO)2(CF3C2CF3)2

When solutions of (η-C₅H₅)₂Rh₂(CO)(CF₃C₂CF₃) and [Rh(CO)₂Cl]₂ in hexane are mixed and left at room temperature, black crystals of the condensation product (η-C₅H₅)₂Rh₄(CO)₄Cl₂(CF₃C₂CF₃) are deposited. X-ray structure determination shows that one rhodium atom of the [Rh(CO)₂Cl]₂ dimer has added to the RhRh bond of (η-C₅H₅)₂Rh₂(CO)(CF₃C₂CF₃) to form a triangular Rh₃ cluster. This is capped on one side by a semi-face bridging carbonyl and on the other by a μ₃η² bound alkyne. Variable temperature NMR data reveal that two isomers of the complex co-exist in solution and that they rapidly interconvert at room temperature. In similar reactions between (η-C₅H₅)₂Rh₂(CO)(CF₃C₂CF₃) and Pt(COD)₂ in hexane at room temperature, there is loss of cyclooctadine and the formation of two cluster products. One is formulated as (η-C₅H₅)₂Rh₂Pt(COD)(CF₃C₂CF₃) and the other as (η-C₅H₅)₄Rh₄Pt(CO)₂(CF₃C₂CF₃)₂. Determination of the X-ray crystal structure of the latter establishes that the Pt is a common apex for two linked Rh₂Pt triangles. Within each Rh₂Pt unit, a semi-bridging carbonyl spans one Rh-Rh edge, and the hexaluorobut-2-yne occupies a μ₃η² face bridging position.     

Synthesis and Crystal Structure of Mn(phen)(CF3COO)(H2O)3·NO3

The mononuclear manganese complex Mn(phen)(CF3COO)(H2O)3(NO3 (C14H14O8N3F3Mn) has been synthesized, where phen = 1,10-phenanthroline. The molecular and crystal structures were determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/c with a = 8.8550(3), b = 10.6529(3), c = 19.8763(2) A, β = 97.762(2)o, V = 1857.78(8) A3, Z = 4, Mr = 464.22, Dc = 1.660 g/cm3, μ = 0.789 mm-1, F(000) = 940, T = 293(2) K, R = 0.0764 and wR = 0.2441 for 1995 observed reflections with I > 2σ(I). In the crystal the manganese atom is six-coordinated by two chelated nitrogen atoms from phenanthroline, three oxygen atoms from water molecules and one oxygen atom from trifluoroacetate, completing an octahedral geometry.     

Finally Stable and Homoleptic: Isolation and Characterization of {Cu[Fe(CO)5]2}+ Stabilized with Perfluoroalkoxyaluminate Anion, [Al(OC(CF3)3)4]−

Developments in the chemistry of weakly coordinating anions enabled isolation of numerous unique metal complexes with unusual ligands. An important example is the family of metal-Fe(CO)₅ complexes. In the current paper we present synthesis and thorough characterization of the first truly homoleptic {Cu[Fe(CO)₅]₂}⁺ cation obtained as a salt of weakly coordinating [Al(OR^F)₄]⁻ (R^F=C(CF₃)₃) anion. TGA/DSC/MS study show that its decomposition becomes noticeable only above 110 °C, thus it can be stored as powder in air-free conditions for months. The crystal structure of {Cu[Fe(CO)₅]₂}⁺ shows strong asymmetry of the cation and very short Cu-CO bonds in comparison to analogous {M[Fe(CO)₅]₂}⁺ where M=Ag or Au. Characterization is complemented with analysis of vibrational spectra and extensive DFT calculations which give insight into the energetics of Cu⁺-Fe(CO)₅ systems. Our results show that {Cu[Fe(CO)₅]₂}⁺ is homoleptic only as salt of [Al(OR^F)₄]⁻. Furthermore, in the presence of additional, even weakly basic ligands, the Cu⁺-Fe(CO)₅ bond strength decreases what may contribute to the complex's instability in liquid SO₂ or in the presence of [SbF₆]⁻. These conclusions point at the key role of selection of proper anion and solvent in stabilization of these types of complexes.     

Synthesis and Structure of the Complex [Mo3(μ3-S)(μ2-S2)3(Et2NCS2)3 +Br-

Tri-₂-disulfido-₃-thiotris(diethyldithiocarbamato)-S,S'-triangle-trimolybdenum bromide [Mo₃(₃-S)(₂-S₂)₃(Et₂NCS₂)₃ ⁺Br^- was obtained and characterized.     

Thulium(III) trifluoroacetates Tm(CF3COO)3 · 3H2O and Tm2(CF3COO)6 · 2CF3COOH · 3H2O: Synthesis and crystal structure

Thulium trifluoroacetate compounds have been synthesized, Tm(CF₃COO)₃ · 3H₂O (I) and Tm₂(CF₃COO)₆ · 2CF₃COOH · 3H₂O (II). The structure of I has been refined by the Rietveld method on the basis of the structural data for Cd(CF₃COO)₃ · 3H₂O. The structure of II has been solved in a single-crystal X-ray diffraction study. Compound I has been studied by thermal analysis. Crystals of I and II are monoclinic: for I a = 9.062(2) Å, b = 18.678(3) Å, c = 9.687(2) Å, β = 113.93(1)°, Z = 2, space group P2₁/c, R ₁ = 0.062; for II a = 8.560(4) Å, b = 19.866(5) Å, c = 20.813(7) Å, β = 101.69(4)°, Z = 8, space group C2/c, R ₁ = 0.0392. In the molecular structure of I, thulium atoms are bonded in pairs through four bridging trifluoroacetate anions to form dimers. The coordination polyhedron of the thulium atom also includes the three O atoms of the water molecules and the O atom of the monodentate trifluoroacetate group; the coordination number of the thulium atom is eight. In the chain structure of II, there are two crystallographically independent thulium atoms with coordination numbers 8 and 9. The coordination polyhedra of the Tm(1) and Tm(2) atoms are a distorted monocapped tetragonal antiprism and a distorted tetragonal antiprism, respectively. The Tm-O bond lengths are in the range 2.28(1)–2.85(2) Å. The thulium atoms are bound into chains through carboxylate groups. These chains are linked into layers through hydrogen bonds.     

Synthesis and structure of tetra-p-tolylantimony complexes [(4-MeC6H4)4Sb] 2 + [Hg2I6]2−, [(4-MeC6H4)4Sb] 2 + [HgI4]2−, [(4-MeC6H4)4Sb] 3 + [Sb3I12]2−, and [(4-MeC6H4)4Sb]+[ReO4]−

Complexes [(4-MeC₆H₄)₄Sb] ₂ ⁺ [Hg₂I₆]^2? (I), [(4-MeC₆H₄)₄Sb] ₂ ⁺ [HgI₄]^2? (II), [(4-MeC₆H₄)₄Sb] ₃ ⁺ [Sb₃I₁₂]^2? (III), were synthesized by reactions of tetra-p-tolylantimony iodide with mercury iodide and antimony iodide, respectively. Tetra-p-tolylantimony perrhenate [(4-MeC₆H₄)₄Sb]⁺[ReO₄]^? (IV) was prepared from tetra-p-tolylantimony chloride and sodium perrhenate in acetone. Crystal structures of complexes I, II, and IV were determined by X-ray crystallography. Mercury and rhenium atoms have tetrahedral coordinations in these complexes. The Hg-I and Re-O distances in the structures of I, II, and IV vary within 2.7719(13)–2.7908(12)Å, 2.7028(3)–2.9163(3) Å, and 1.693(3)–1.744(3) Å, respectively. Antimony atoms in two crystallographically independent trinuclear centrosymmetric [Sb₃I₁₂]^2? anions of complex III have an octahedral environment. Each terminal SbI₃ fragment (Sb-I_t, 2.8265(9)–2.8333(10)Å) is bound to the central atom through tree bridging iodine atoms (Sb(2)-I_br, 3.2275(9)–3.3620(10)Å). The distances between the central Sb atom and bridging iodine atoms are much shorter (Sb(1)-I_br, 3.0153(6)–3.0316(6) Å; Sb(3)-I_br, 2.9926(6)–3.0074(6) Å).     

Coordination behavior of 1,4-diallylpiperazinium and 1-allyloxybenzotriazole toward silver(I) in the crystalline π-complexes [Ag2(C4H8N2(C3H5)2(H+)2)(H2O)2(NO3)2](NO3)2 and [Ag(C6H4N3(OC3H5)(NO3))]

Reactions of a solution of AgNO₃ in aqueous methanol with solutions of 1,4-diallylpiperazine (acidified with HNO₃ to pH = 4) and 1-allyloxybenzotriazole in ethanol gave the crystalline silver(I) π-complexes [Ag₂(C₄H₈N₂(C₃H₅)₂(H⁺)₂)(H₂O)₂(NO₃)₂](NO₃)₂ (I) and [Ag(C₆H₄N₃(OC₃H₅)(NO₃))] (II). Their crystal structures were determined by X-ray diffraction. Crystals of complexes I and II are monoclinic, space group P2₁/c; for I: a = 7.053(3)Å, b = 9.389(3)Å, c = 15.488(4)Å, β = 91.60°, V = 1025.3(6)ų, Z = 4; for II: a = 10.650(4)Å, b = 15.062(5)Å, c = 7.412(4)Å, β = 104.20(3)°, V = 1152.6(8)ų, Z = 4. In both structures, the organic components act as bidentate ligands forming with AgNO₃ 34- and 14-membered topological rings, respectively. In complex I, the nearly tetrahedral environment of the Ag(I) atom is made up of the olefinic C=C bond, the O atoms of the nitrate anions, and the water molecule. 1-Allyloxybenzotriazole in structure II causes the deformation of the coordination polyhedron of Ag into a trigonal pyramid via inclusion of the ligand N atom in its coordination sphere. The topological units of the complexes form infinite polymer layers linked by anionic NO ₃ ^? bridges. In structure I, these layers are united through a system of hydrogen bonds into a three-dimensional framework.     

Ab initio electron correlated studies on the intracluster reaction of NO+ (H2O)(n) → H3O+ (H2O)(n-2) (HONO) (n = 4 and 5)

Hydrated nitrosonium ion clusters NO(+)(H(2)O)(n) (n = 4 and 5) were investigated by using MP2/aug-cc-pVTZ level of theory to clarify isomeric reaction pathways for formation of HONO and fully hydrated hydride ions. We found some new isomers and transition state structures in each hydration number, whose lowest activation energies of the intracluster reactions were found to be 4.1 and 3.4 kcal mol(-1) for n = 4 and n = 5, respectively. These thermodynamic properties and full quantum mechanical molecular dynamics simulation suggest that product isomers with HONO and fully hydrated hydride ions can be obtained at n = 4 and n = 5 in terms of excess hydration binding energies which can overcome these activation barriers.     

Generation of the dichloromethane complex [(η5-C5Me5)Re(NO)(PPh3)(ClCH2Cl]+ BF4−, and its conversion to the oxidative addition product [(η5-C5Me5)Re(NO)(PPh3)(Cl)(CH2Cl)]+ BF4−

Reaction of (η⁵-C₅Me₅)Re(NO)(PPh₃)(CH₃) and HBF₄ · OEt₂ in CH₂Cl₂ at −78°C gives the dichloromethane complex [η⁵-C₅Me₅Re(NO)(PPh₃)(ClCH₂Cl)]⁺ BF₄⁻, which undergoes the title transformation at −35°C. The ReClCH₂Cl carbon is attacked by halide nucleophiles (X⁻) to give XCH₂Cl and the chloride complex (η⁵-C₅Me₅)Re(NO)(PPh₃)(Cl), and exhibits a ¹³C NMR resonance that is coupled to phosphorus (d, ³J(CP) 5.0 Hz) and geminal hydrogens (t, ¹J(CH) 186 Hz).     

Structures, energetics, and aromaticities of the tetrasilacyclobutadiene dianion and related compounds: (Si4H4)(2-), (Si4H4)(2-)·2Li+, [Si4(SiH3)4](2-)·2Li+, [Si4(SiH3)4](2-)·2Na+, and [Si4(SiH3)4](2-)·2K+

In light of the important recent synthesis of a stable tetrasilacyclobutadiene dianion compound by Sekiguchi and co-workers and the absence of theoretical studies, ab initio methods have been used to investigate this dianion and a number of related species. These theoretical methods predict multiple minima for each compound, and most minima contain folded and bicyclic silicon rings. For (Si(4)H(4))(2-), (Si(4)H(4))(2-)·2Li(+), [Si(4)(SiH(3))(4)](2-)·2Li(+), [Si(4)(SiH(3))(4)](2-)·2Na(+), and [Si(4)(SiH(3))(4)](2-)·2K(+), respectively, the energetically lowest-lying structures are designated A-3 (C(2v) symmetry), B-8 (C(1) symmetry), C-1 (C(2) symmetry), D-1 (C(2) symmetry), and E-1 (C(2h) symmetry). None of these structures satisfies both the ring planarity and the cyclic bond equalization criteria of aromaticity. However, all of the representative NICS values of these lowest-lying structures are negative, indicating some aromatic character. Especially, structures C-1 and D-1 of C(2) symmetry effectively satisfy the criteria of aromaticity due to the slightly trapezoidal silicon rings, which are nearly planar with nearly equal bond lengths. SiH(3) substitution for hydrogen in (Si(4)H(4))(2-)·2Li(+) significantly reduces the degree of aromaticity, as reflected in the substantially smaller NICS absolute values for [Si(4)(SiH(3))(4)](2-)·2Li(+) than those of (Si(4)H(4))(2-) and (Si(4)H(4))(2-)·2Li(+). The aromaticity is further weakened in [Si(4)(SiH(3))(4)](2-)·2Na(+) and [Si(4)(SiH(3))(4)](2-)·2K(+) by replacing lithium with the sodium and potassium cations.     

Study of the process of the hydroxo complexes formation in the Al3+-Hg2+-NO 3 − -H2O and Al3+-Cd2+-NO 3 − -H2O systems

Russian Journal of Applied Chemistry - The process of hydrolysis in the Al3+-Cd2+-NO 3 ? -H2O and Al3+-Hg2+-NO 3 ? -H2O systems is studie by the methods of pH-metric titration and...     

The addition of small molecules to (η-C5H5)2Rh2(CO)(CF3C2CF3): IV. The sunlight assisted making and breaking of alkene CH bonds on the dirhodium centre; the crystal and molecular structures of (η-C5H5)2Rh2(CHCHCN){C(CF3)CF3)H} · H2O and (η-C5H5)2Rh2(CHCF2){C(CF3)C(CF3)H}

Bis-alkenyl complexes of the type (η-C₅H₅)₂RH₂(alkene − H)(alkyne + H) are obtained when the alkyne complex (η-C₅H₅)₂Rh₂(CO)(CF₃C₂CF₃) is treated with the following alkenes: H₂CCH₂, H₂CCHR (R = Me, Bu^t, Ph, CN), H₂CCF₂, RHCCHR′ (R = R′ = Me, Ph, Cl; R = Me, R′ = Et), cyclooctene and norbornene. An approximately equimolar amount of (η-C₅H₅)₂Rh₂(CO)₂(CF₃C₂CF₃) is also formed. The reactions are greatly accelerated when the reaction mixtures are exposed to sunlight. There is some regioselectivity in the reactions with H₂CCHR and MeHCCHet, with a preference for CH bond cleavage at the least crowded alkene-carbon. When the reaction with acrylonitrile is performed in the absence of sunlight, the complex (η-C₅H₅)₂(CO){(H₂CCHCN)(CF₃C₂CF₃)} can be isolated; upon exposure to sunlight, there is loss of CO and H-transfer to form two isomers of the appropriate bis-alkenyl complex.The molecular geometries of (η-C₅H₅)₂Rh₂(CHCHCN){C(CF₃)C(CF₃)H} and (η-C₅H₅)₂Rh₂(CHCF₂){C(CF₃)C(CF₃)H} have been ascertained by X-ray structure determination. Each molecule has two bridging alkenyl units spanning a RhRh single bond; the dihedral angle between the two RhRhCC planes is just above 90°. There is a cyclopentadienyl ring η⁵-attached to each metal. Crystal data: C₁₇H₁₃F₆NRh₂·H₂O, M 569.1, monoclinic, P2₁/n, a 15.014(7), b 14.882(7), c 8.590(5) Å, β 94.57(9)°, Z = 4, final R 0.056 for 2493 observed reflections; C₁₆H₁₂F₈Rh₂, M 562.1, monoclinic, P2₁/c, a 13.037(6), b 8.765(2), c 14.873(3) Å, β 103.16(3)°, Z = 4, final R 0.062 for 1820 observed reflections.     

Does alpha-fluorination affect the structural trans-influence and kinetic trans-effect of an alkyl ligand? Molecular structures of Pd(TMEDA)(CH(3))(R(F)) and a kinetic study of the trans to cis isomerization of Pt(TMEDA)(CH(3))(2)I(R(F)) [R(F) = CF(2)CF(3), CFHCF(3), CH(2)CF(3)

Reaction of Pd(TMEDA)(CH(3))(2) [TMEDA = tetramethylethylenediamine] with fluoroalkyl iodides R(F)I affords a series of square planar Pd(II) complexes Pd(TMEDA)(CH(3))(R(F)) [R(F) = CF(2)CF(3) (9), CFHCF(3) (10), CH(2)CF(3) (11)], presumably by oxidative addition followed by reductive elimination of CH(3)I. The solid-state structures of each compound have been determined by single crystal X-ray diffraction studies, allowing the effect of increasing alpha-fluorination on the structural trans-influence of alkyl ligands to be examined. In these compounds there is no significant difference observed in the trans-influence of the three fluorinated alkyl ligands toward the trans-N atom, although a significant cis-influence on the neighboring methyl ligand is apparent. Oxidative addition of the same series of fluoroalkyl ligands to the corresponding Pt(TMEDA)(CH(3))(2) affords octahedral Pt(IV) complexes trans-Pt(TMEDA)(CH(3))(2)(R(F))I [R(F) = CF(2)CF(3) (12), CFHCF(3) (13), CH(2)CF(3) (14)] as the kinetic products. In each case, subsequent isomerization to the corresponding all cis-isomers is observed; in the case of 13, the stereocenter at the alpha-carbon results in two diastereomeric cis-isomers, which are formed at different rates. The molecular structures of 13 and its more stable all cis-isomer 16b have been crystallographically determined. Kinetic studies of the trans-cis isomerization reactions show the mechanism to involve a polar transition state, presumably involving iodide dissociation, followed by rearrangement of the cation, and iodide recombination. High dielectric solvents increase the rate, but solvent coordinating ability has no effect. Dissolved salts (LiI, LiOTf) show normal accelerative salt effects, with no inhibition in the case of added iodide, consistent with the formation of an intimate ion pair intermediate. The kinetic parameters show that the trans-effects of fluoroalkyl ligands in these compounds follow the order expected from the relative sigma-donor properties of the ligands, with CF(2)CF(3) < CFHCF(3) < CH(2)CF(3).     

Ligand exchange between metals: synthesis and characterisation of binuclear and trinuclear iron-alkyne complexes. Crystal structures of [(η5-C5H5)2Fe3(CO)3(μ3-CO)(μ-CO)(CF3C2CF3] and [{μ-CF3CC(CF3)S} {Fe(CO)3}2]

Reaction of[(η⁵-C₅H₅)(CO)Fe{μ-C(CF₃)C(CF₃)SMe}₂Fe(CO)(η⁵-C₅H₅)] with Fe₃(CO)₁₂ leads to an exchange of ligands (hexafluorobut-2-yne, cyclopentadienyl or sulphur) between the metal centres and the formation of several new complexes.Two of These, [(η⁵-C₅H₅)₂Fe₃(CO)₃(μ₃-CO)(μ-CO)(CF₃C₂CF₃)] and [{μ-CF₃CC (CF₃)S Fe(CO)₃}₂], have been shown by X-ray diffraction to contain μ₃-η²-| CF₃C₂CF₃ units bridging Fe₃ and Fe₂S triangles, respectively.     

Die Zersetzungsreaktion des Dialan-Radikalanions [R2Al-AlR2]·− in DME: I. Kristallstrukturen von R2Al(Me)OC2H4OMeK(DME) und R2Al(OC2H4OMe)2K (R  CH(SiMe3) 2)

Tetrakis[bis(trimethylsilyl)methyl]dialane(4) (1) reacts as recently reported with potassium in 1,2-dimethoxyethane (DME) to yield after purification the surprisingly stable radical monoanion [R₂AlAlR₂]·⁻ [K(DME)₃]⁺ (2) (R  CH(SiMe₃)₂). With a longer reaction time of some days at room temperature and an excess of potassium, however, complete decomposition occurs under cleavage of ether molecules and formation of several new products. One of these compounds was identified as R₂AlMe(OC₂H₄OMe)K(DME) (3) and characterized by a crystal structure determination. Two further derivatives were synthesized and their spectroscopic data compared to the decomposition products: R₂Al(OC₂H₄OMe)₂K (6), also characterized by crystal structure determination, and [R₂AlMe₂]⁻ [K(DME)₆]⁺ (9), but due to the NMR characterization only 9 could be a component of the above-mentioned reaction mixture. In both aluminium alcoholates (3 and 6) the potassium ion is bound in a chelating manner by oxygen atoms of the aluminate unit, probably for this reason they are very soluble in non-polar solvents. In the solid state 3 polymerizes by intermolecular K…H₃CAl bridges forming one-dimensional chains along a crystallographic glide plane, and 6 forms dimers via KOK bridges and fourfold coordinated oxygen atoms.     

Low-voltage thin-layer electrophoresis of inorganic anions on silica gel-G and titanium (IV) tungstate layers: separation of coexisting F−, Cl−, Br− and I−, I−, IO3− and IO4−, Fe(CN)64− and Fe(CN)63−

The electrophoretic behavior of twenty anions has been studied on silica gel-G, titanium (IV) tungstate and silica gel-G- titanium (IV) tungstate admixture layers using 0.1 M solutions of oxalic acid, citric acid, tartaric acid, succinic acid and acetic acid as background electrolyte. The mechanism of migration is explained in terms of adsorption and the solubility of various sodium or potassium salts of the anions in water. Titanium (IV) tungstate behaves only as an adsorbent and not as an ion exchanger. Being a cation exchanger, there is no exchange phenomenon occurring with anions. The migration of halides increase linearly with an increase in the bare ion radii of these ions. Differential migration of the anions on silica gel-G layers led to binary, ternary and quaternary separations of similar anions such as F⁻ – Cl⁻ – Br⁻ – I⁻, I⁻ – IO₃⁻ – IO₄⁻, BrO₃⁻ – IO₃⁻ and Fe(CN)₆³⁻ – Fe(CN)₆⁴⁻. The two cyanoferrate ions are separated from industrial waste water and from fixer and bleach solutions. The migration of anions has also been found to be in accordance with their lyotropic numbers.

     

Formation of the unusual cluster Cu4(μ4-OH)(μ-(CF3)2pz)4(μ-OOCPh)2(μ-OH)2(OH2)(Et3NH)[O(CH2Ph)2]2 in the thermolysis of a copper μ-aqua complex with bridging pyrazolate and acetate ligands in dibenzyl ether in the presence of atmospheric oxygen

A room-temperature reaction of cupric acetate dihydrate with 3,5-bis(trifluoromethyl)pyrazole ((CF₃)₂pzH) in chloroform in the presence of triethylamine gave a complex of the formula [Cu₂(??-(CF₃)₂pz)₂(??-OH₂)(OC(Me)OHNEt₃)(OH₂)(HCCl₃)(OOCMe)(??-OOCMe)]₂ (2). Heating of this complex at 180°C in dibenzyl ether (DBE) in air yielded the tetranuclear pyrazolate-benzoate cluster Cu₄(??₄-OH)(??-(CF₃)₂pz)₄(??-OOCPh)₂(??-OH)₂(OH₂)(Et₃NH)[O(CH₂Ph)₂]₂. It was suggested that such complexes can be intermediates in the liquid-phase oxidation of DBE with atmospheric oxygen in the presence of copper complexes containing pyrazolate bridges.