Zur Reaktion der Alkin‐Kupfer(I)‐Komplexe [CuX(S‐Alkin)] (X = Cl,Br, I; S‐Alkin = 3,3,6,6‐Tetramethyl‐1‐thia‐4‐cycloheptin) mit den Phosphanen PMe3 und Ph2PCH2CH2PPh2 (dppe)

Organometallic Compounds of Copper. XVIII. On the Reaction of the Alkyne Copper(I) Complexes [CuX(S‐Alkyne)] (X = Cl, Br, I; S‐Alkyne = 3,3,6,6‐Tetramethyl‐1‐thiacyclohept‐4‐yne) with the Phosphanes PMe₃ and Ph₂PCH₂CH₂PPh₂ (dppe) The alkyne copper(I) halide complexes [CuX(S‐Alkyne)]_n ( 2 ) ( 2 a : X = Cl, 2 b : X = Br, 2 c : X = I; S‐Alkyne = 3,3,6,6‐tetramethyl‐1‐thiacyclohept‐4‐yne; n = 2, ∞) add the phosphanes PMe₃ and Ph₂PCH₂CH₂PPh₂ (dppe) to form the mono‐ and dinuclear copper compounds [(S‐Alkyne)CuX(PMe₃)] ( 6 ) ( 6 a : X = Cl, 6 b : X = Br) and [(S‐Alkyne)CuX(μ‐dppe)CuX(S‐Alkyne)] ( 7 a : X = Cl, 7 b : X = Br, 7 c : X = I), respectively. By‐product in the reaction of 2 a with dppe is the tetranuclear complex [(S‐Alkyne)Cu(μ‐X)₂Cu(μ‐dppe)₂Cu(μ‐X)₂Cu(S‐Alkyne)] ( 8 ). In case of the compounds 7 prolonged reaction times yield the alkyne‐free dinuclear copper complexes [Cu₂X₂(dppe)₃] ( 9 ) ( 9 a : X = Cl, 9 b : X = Br, 9 c : X = I)). X‐ray diffraction studies were carried out with the new compounds 6 a , 6 b , 7 b , 8 , and 9 c .     

Synthesis and Structure of Di［bis（diphenylphosphino）ethane］ Copper（Ⅱ） Dinitrate

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Syntheses and characterization of some new 2-picolylpalladium(II) complexes

The 2-picolylpalladium(II) complex [{Pd(CH₂Py)Cl(PPh₃)}₂] (CH₂Py=2-picolyl) (I), prepared from 2-picolyl chloride and [Pd(PPh₃)₄], was treated with lithium bromide, silver acetate, 4-picoline (pic) and silver perchlorate, thallium acetylacetonate{Tl(acac)}, sodium dimenthyldithiocarbamate-water-(1/2) {Na(dmdc). 2 H₂O}, and 1,2-bis(diphenylphospino)ethane (dppe) to yield [{PdBr(CH₂Py)(PPh₃)}₂] (II), [{Pd(CH₂Py)OAc(PPh₃)}₂] (III), [{Pd(Ch₂Py)(pic)(PPh₃)}₂](ClO₄)₂ (IV), [Pd(CH₂Py)(acac)(PPh₃)] (V), [Pd(CH₂Py)(dmdc)(PPh₃)] (VI), and [Pd(Ch₂Py)Cl(dppe)] (VII), respectively. Halogen abstraction from VII using silver perchlorate afforded an ionic complex [{Pd(CH₂Py)(dppe)}₂](ClO₄)₂ (VIII). It was concluded that the 2-picolyl groups in these eight complexes are σ-bonded to palladium, and that in the dinuclear complexes I, II, III, IV, and VIII, they serve as bridging ligands.     

Synthesis and Structural Analysis of New Palladium(II) Thiosaccharinates with Triphenylphosphane or Diphosphanes

A series of palladium(II) thiosaccharinates with triphenylphosphane (PPh₃), bis(diphenylphosphanyl)methane (dppm), and bis(diphenylphosphanyl)ethane (dppe) have been prepared and characterized. From mixtures of thiosaccharin, Htsac, and palladium(II) acetylacetonate, Pd(acac)₂, the palladium(II) thiosaccharinate, Pd(tsac)₂ (tsac: thiosaccharinate anion) ( 1 ) was prepared. The reaction of 1 with PPh₃, dppm, and dppe leads to the mononuclear species Pd(tsac)₂(PPh₃)₂ · MeCN ( 2 ), [Pd(tsac)₂(dppm)] ( 3 ), Pd(tsac)₂(dppm)₂ ( 4 ), and [Pd(tsac)₂(dppe)] · MeCN ( 5 ). Compounds 2 , 4 , and 5 have been prepared also by the reaction of Pd(acac)₂ with the corresponding phosphane and Htsac. All the new complexes have been characterized by chemical analysis, UV/Vis, IR, and Raman spectroscopy. Some of them have been also characterized by NMR spectroscopy. The crystalline structures of complexes 3 , and 5 have been studied by X‐ray diffraction techniques. Complex 3 crystallizes in the monoclinic space group P2₁/n with a = 16.3537(2), b = 13.3981(3), c = 35.2277(7) Å, β = 91.284(1)°, and Z = 8 molecules per unit cell, and complex 5 in P2₁/n with a = 10.6445(8), b = 26.412(3), c = 15.781(2) Å, β = 107.996(7)°, and Z = 4. In compounds 3 and 5 , the palladium ions are in a distorted square planar environment. They are closely related, having two sulfur atoms of two thiosaccharinate anions, and two phosphorus atoms of one molecule of dppm or dppe, respectively, bonded to the Pd^II atom. The molecular structure of complex 3 is the first reported for a mononuclear Pd^II‐dppm‐thionate system.     

SYNTHESIS AND STRUCTURE OF 1,2-BIS(DIPHENYLPHOSPHINO)ETHANE COMPLEXES OF COPPER(I) ACETATE. CATALYSTS FOR THE DECARBOXYLATION OF CARBOXYLIC ACIDS

Abstract

Several dimeric complexes of copper(I) acetate with bidentate phosphine ligands have been synthesized. The solid-state structure of one of these derivatives, dppe(CuO₂CCH₃)₂, where dppe = 1,2-bis(diphenylphosphino)ethane, has been determined. The complex is shown to exist in the solid-state as a polymeric chain of dimeric copper(I) units containing a dppe and two acetate ligands, with the dimers being linked together via weaker Cu-O interactions. The Cu-Cu bond length in the dimeric units is considerably longer, at 2.712(2) Å, than that observed in copper(I) acetate of 2.556(2) Å. The use of these derivatives as catalyst precursors for the catalytic decarboxylation of cyanoacetic acid to acetonitrile and carbon dioxide is discussed. Crystal data for dppe(CuO₂CCH₃)₂: space group P2_i/n,a = 14.976(6) Å, b = 11.676(3) Å, c = 16.999(6) Å, β = 107.59(3)°, Z = 4, R = 7.33%     

Hydroformylation of alkenes with paraformaldehyde catalyzed by rhodium-phosphine complexes

The hydroformylation of medium-chain C6 olefins and of allyl alcohol was achieved with paraformaldehyde in dioxane solution using rhodium catalysts with mono-, bi-, and tri-dentate phosphine ligands. The highest activities with n/i ratios around 2, were obtained for a system derived from [Rh(dppe)₂]⁺, prepared in situ by reaction of Rh(acac)(CO)₂ with 2 eq of dppe.     

Ligand adducts of bis(acetylacetonato)iron(II): a 1H NMR study

We report here a thorough (1)H NMR study of Fe(acac)(2) solutions in a wide variety of noncoordinating and coordinating solvents, as well as the interaction of this complex with Et(3)N, pyridine, PMe(2)Ph, and R(2)PCH(2)CH(2)PR(2) [R = Ph (dppe), Et (depe)] in C(6)D(6). The study reveals that Fe(acac)(2) is readily transformed into Fe(acac)(3) in solution under aerobic conditions and that the commercial compound is usually contaminated by significant amounts of Fe(acac)(3). The (1)H NMR resonances of Fe(acac)(2) are rather solvent-dependent and quite different than those reported in the literature. The compound is unstable in CDCl(3) and stable in CD(2)Cl(2), C(6)D(6), CD(3)CN, acetone-d(6), DMSO-d(6), THF-d(8), and CD(3)OD. The addition of the above-mentioned ligands (L) reveals only one paramagnetically shifted band for each type of acac and L proton, the position of which varies with the L/Fe ratio, consistent with rapid ligand exchange equilibria on the NMR time scale. A fit of the NMR data at a high L/Fe ratio allows the calculation of the expected resonances for all protons in the Fe(acac)(2)L(2) molecules. The system with the bidentate depe ligand shows evidence for a slow ligand exchange at low depe/Fe ratios, proposed to involve a species with the cis-chelated mononuclear Fe(acac)(2)(depe) structure, whereas the fast exchange at a higher ratio is proposed to involved a trans-Fe(acac)(2)(κ(1)-depe)(2) complex. Complex Fe(acac)(2)(dppe) cannot be investigated in solution because of low solubility in a noncoordinating solvent and because of the poor dppe competition for binding in coordinating solvents. The compound was crystallized, and its X-ray structure reveals a 1-dimensional polymeric structure with dppe-bridged Fe centers having the trans-octahedral Fe(acac)(2)(κ(1)-dppe)(2) coordination environment.     

trans‐(Methanol)(methyl­di­phenyl­phosphine)­bis­(pentane‐2,4‐dionato)­cobalt(III) hexa­fluoro­phosphate hydrate

The title compound [Co(C₅H₇O₂)₂(C₁₃H₁₃P)(CH₄O)]PF₆·H₂O, (I), which was converted from trans‐[Co(acac)₂(PMePh₂)(H₂O)]PF₆ (acac is pentane‐2,4‐dionato) by recrystallization from aqueous methanol, has been confirmed as have a coordinated methanol ligand. The molecular structure of the complex cation, trans‐[Co(acac)₂(PMePh₂)(MeOH)]⁺, is similar to that of the above aqua complex found in the ClO₄ salt [Kashiwabara et al. (1995). Bull. Chem. Soc. Jpn, 68 , 883–888]. The Co—O bond length for the coordinated methanol is 2.059 (3) Å. There is an intermolecular hydrogen bond between the OH group of the coordinated methanol and one of the O atoms of the acac ligands in an adjacent complex cation [O5?O3′ = 2.914 (4) Å], giving a centrosymmetric dimeric dicationic complex.     

catena‐Poly[tris(μ3‐acetylacetonato)nickelate(II)sodium(I)]

The title complex, [NaNi(C₅H₇O₂)₃]_n, contains an anionic tris(acetylacetonato)nickelate(II) unit, [Ni(acac)₃]⁻ (acac is acetylacetonate), with a highly regular octahedral coordination geometry. The Ni^II cation lies on a Wyckoff a site, resulting in D₃ symmetry of the anion. Charge balance is provided by sodium cations, which occupy Wyckoff type b sites. Each sodium cation is surrounded by two [Ni(acac)₃]⁻ anions, each of which is connected to the alkali metal through three O atoms, in a fac configuration. This arrangement leads to the formation of linear [Na{Ni(acac)₃}]_n chains along the c axis. The Ni...Na distance is 2.9211 (10) Å. The title complex is one of the few examples of heterometallic systems based on alkali and transition metal cations bridged by acetylacetonate ligands.     

Modification of palladium–copper thin film by reduced graphene oxide or platinum as catalyst for Suzuki–Miyaura reactions

This study describes the synthesis of PdCu, PdCu/reduced graphene oxide and PtPdCu nanoparticle thin films via a simple reduction of organometallic precursors including [PtCl₂(cod)] and [PdCl₂(cod)] (cod = cis ,cis ‐1,5‐cyclooctadiene) complexes, in the presence of [Cu(acac)₂] (acac = acetylacetonate) complex at toluene–water interface. The structure and morphology of the thin films were characterized using energy‐dispersive analysis of X‐rays, X‐ray diffraction and transmission electron microscopy techniques. Our studies show that all of these nanoparticles are suitable for the Suzuki–Miyaura coupling (SMC) reaction in water. PtPdCu and PdCu thin films showed higher catalytic activity compared to Pd thin film in the SMC reaction due to the appropriate interaction among palladium, platinum and copper metals.     

Synthesis of trans-[Re(NO)2-(Ph2PCH2CH2PPh2)2][BF4], a formal dinitrosyl complex of rhenium(-I) and its protic denitrosylation. X-Ray structure of trans-[ReF(NO)-(Ph2PCH2CH2PPh2)2][BF4]

Treatment of a THF solution of trans-[ReCl(N₂)(dppe)₂] (dppe = Ph₂PCH₂CH₂PPh₂) with NO, in the presence of Tl[BF₄], forms trans-[Re(NO)₂(dppe)₂][BF₄], a rare formal 20-electron d⁸-rhenium nitrosyl complex which, by reaction with HX (X = BF₄, Cl or HSO₄), gives trans-[ReF(NO)(dppe)₂][BF₄] (2) (the X-ray structure of which is reported) or trans-[ReX(NO)(dppe)₂]X (3, X = Cl or HSO₄), respectively, as well as nitrous oxide.     

Cobalt(I)-catalyzed [4π+2π] cycloaddition reactions of 1,3-diynes with 1,3,5-cyclooctatriene

The cycloaddition reaction between conjugated diynes and 1,3,5-cyclooctatriene in the presence of the catalyst Co(acac)₂/dppe/Zn/ZnI₂, led to the selective formation of tricyclo[4.2.2.0^2,5]deca-7,9-diene derivatives in 72–85% yield.     

Studies on complex compounds of thorium(IV) with pyridine and quinoline carboxylic acid. Part I

Summary Thorium acetylacetonate [Th(acac)₄] reacts with pyridine carboxylic acids in acetone giving eight coordinate thorum(IV) complexes of the compositions [Th(pic)₄] and [Th(picO)₄] (picH = picolinic acid, picOH = picolinic acidN-oxide). The complex [Th(dip)₂] · 3H₂O (dipH₂ = pyridine-2,6-dicarboxylic acid) is also reported. Thorium(IV) complexes of the types [Th(quin)₂] · 2H₂O and [Th(quind)₂(acac)₂] (quinH₂ = quinolinic acid or pyridine-2,3-dicarboxylic acid, quindH = quinaldinic acid) were prepared by the interaction of [Th(acac)₄] with the respective acids in acetone. The lower solubility and i.r. spectral studies of the complex [Th(quin)₂] · 2 H₂O suggest that it is polymeric.     

Bis‐copper(II) Complex of Triply‐linked Corrole Dimer and Its Dication

Copper complexes of corroles have recently been a subject of keen interest due to their ligand non‐innocent character and unique redox properties. Here we investigated bis‐copper complex of a triply‐linked corrole dimer that serves as a pair of divalent metal ligands but can be reduced to a pair of trivalent metal ligands. Reaction of triply‐linked corrole dimer 2 with Cu(acac)₂ (acac=acetylacetonate) gave bis‐copper(II) complex 2Cu as a highly planar molecule with a mean‐plane deviation value of 0.020 Å, where the two copper ions were revealed to be divalent by ESR, SQUID, and XPS methods. Oxidation of 2Cu with two equivalents of AgBF₄ gave complex 3Cu , which was characterized as a bis‐copper(II) complex of a dicationic triply‐linked corrole dimer not as the corresponding bis‐copper(III) complex. In accord with this assignment, the structural parameters around the copper ions were revealed to be quite similar for 2Cu and 3Cu . Importantly, the magnetic spin–spin interaction differs depending on the redox‐state of the ligand, being weak ferromagnetic in 2Cu and antiferromagnetic in 3Cu .     

A Structurally Characterized Fluoroalkyne

The facile synthesis of a stable and isolable compound with a fluoroalkynyl group, M−C≡CF, is reported. Reaction of [Ru(C≡CH)(η⁵‐C₅Me₅)(dppe)] with an electrophilic fluorinating agent (NFSI) results in the formation of the fluorovinylidene complex [Ru(=C=CHF)(η⁵‐C₅Me₅)(dppe)][N(SO₂Ph)₂]. Subsequent deprotonation with LiN(SiMe₃)₂ affords the fluoroalkynyl complex [Ru(C≡CF)(η⁵‐C₅Me₅)(dppe)]. In marked contrast to the rare and highly reactive examples of fluoroalkynes that have been reported previously, this compound can be readily isolated and structurally characterized. This has allowed the structure and bonding in the CCF motif to be explored. Further electrophilic fluorination of this species yields the difluorovinylidene complex [Ru(C=CF₂)(η⁵‐C₅Me₅)(dppe)][N(SO₂Ph)₂].     

Self-assembly in dinuclear, cyclic homotetranuclear and cyclic heterotetranuclear complexes with a picolylhydrazone ligand

Reactions among Cu(ClO₄)₂ · 6H₂O, Cu(acac)₂/VO(acac)₂ and 3-methoxysalicylaldehyde Picoloylhydrazone in different solvents give three complexes, [Cu₂L(acac)(H₂O)₂]ClO₄ (1), [Cu₄L₂(acac)₂(py)₂](ClO₄)₂ (2) and (VO₂)₂L₂Cu₂(acac)₂ (3) (acac = acetyl acetonate and py = pyridine). There is an extended 2D structure in complex 1 constructed by hydrogen bonds between the binuclear complex cation and the ClO₄⁻ anion, and an extended 1D structure in complex 2 constructed by weak ππ stacking interactions between neighboring cyclic tetranuclear complex molecules. Complex 3 is the first oxovanadium–copper complex with a bridging oxo oxygen atom between the V atom and the Cu atom. The solid-state photoluminescent properties of the three title complexes have been studied. There is an antiferromagnetic interaction in 1.     

Platinum thiosemicarbazide and thiourea complexes: the crystal structure of [PtCl(dppe){SC(NHMe)NHNMe2-S}](PF6) and the influence of intramolecular hydrogen bonding on ligand co-ordination mode

The reaction of [PtCl₂(dppe)] [dppe=1,2-bis(diphenylphosphino)ethane] with two equivalents of the thioureas NHRC(S)NHR (R=H, Me, Et) in the presence of NH₄PF₆ led to substitution of both chlorides and formation of the complexes [Pt(dppe){SC(NHR)₂}₂](PF₆)₂ (1a, R=H; 1b, R=Me; 1c, R=Et). In contrast, the reaction of [PtCl₂(dppe)] with one equivalent of the potentially bidentate thiosemicarbazides NHRC(S)NHNR′₂ (R=Me, R′=H; R=Et, R′=H; R=Ph, R′=H; R=Me, R′=Me) in the presence of NH₄PF₆ led to substitution of only one chloride and formation of the complexes [PtCl(dppe){SC(NHR)NHNR₂′-S}](PF₆) (2a, R=Me, R′=H; 2b, R=Et, R′=H; 2c, R=Ph, R′=H; 2d, R=Me, R′=Me). An X-ray analysis of complex 2d revealed that an intramolecular N–H⋯Cl hydrogen bond [N(2)⋯Cl(1)=3.29(2) Å] helps to stabilise the monodentate co-ordination mode. The chloride ligand can be abstracted from complex 2d by treatment with TlPF₆, and this reaction led to formation of [Pt(dppe){SC(NHMe)NHNMe₂-S,N}](PF₆)₂ 3d. Reaction of [PtCl₂(dppe)] with unsubstituted thiosemicarbazide NH₂C(S)NHNH₂ in the presence of NH₄PF₆ resulted in a mixture of products containing mono- and bidentate co-ordinated ligands, [PtCl(dppe){SC(NH₂)NHNH₂-S}](PF₆) 2e and [Pt(dppe){SC(NH₂)NHNH₂-S,N}](PF₆)₂ 3e. [PtCl₂(dppe)] also reacts with two equivalents of NHMeC(S)NHNMe₂ in the presence of NH₄PF₆ to yield [Pt(dppe){SC(NHMe)NHNMe₂-S}₂](PF₆)₂ 1d, in which the thiosemicarbazide is acting as an S-donor, directly analogous to the thiourea ligands in complexes 1a–c.     

Activation of Aryl and Heteroaryl Halides by an Iron(I) Complex Generated in the Reduction of [Fe(acac)3] by PhMgBr: Electron Transfer versus Oxidative Addition

The mechanism of the reactions of aryl/heteroaryl halides with aryl Grignard reagents catalyzed by [Fe^III(acac)₃] (acac=acetylacetonate) has been investigated. It is shown that in the presence of excess PhMgBr, [Fe^III(acac)₃] affords two reduced complexes: [PhFe^II(acac)(thf)_n] (n=1 or 2) (characterized by ¹H NMR and cyclic voltammetry) and [PhFe^I(acac)(thf)]^? (characterized by cyclic voltammetry, ¹H NMR, EPR and DFT). Whereas [PhFe^II(acac)(thf)_n] does not react with any of the investigated aryl or heteroaryl halides, the Fe^I complex [PhFe^I(acac)(thf)]^? reacts with ArX (Ar=Ph, 4‐tolyl; X=I, Br) through an inner‐sphere monoelectronic reduction (promoted by halogen bonding) to afford the corresponding arene ArH together with the Grignard homocoupling product PhPh. In contrast, [PhFe^I(acac)(thf)]^? reacts with a heteroaryl chloride (2‐chloropyridine) to afford the cross‐coupling product (2‐phenylpyridine) through an oxidative addition/reductive elimination sequence. The mechanism of the reaction of [PhFe^I(acac)(thf)]^? with the aryl and heteroaryl halides has been explored on the basis of DFT calculations.     

Site‐Selective Ligand Exchange on a Heteroleptic TiIV Complex Towards Stepwise Multicomponent Self‐Assembly

A series of heteroleptic [Ti 1 ₂X]^? complexes have been selectively constructed from a mixture of Ti^IV ions, a pyridyl catechol ligand (H₂ 1 ; H₂ 1 =4‐(3‐pyridyl)catechol), and various bidentate ligands (HX) in the presence of a weak base, in addition to a previously reported [Ti 1 ₂(acac)]^? (acac=acetylacetonate) complex. Comparative studies of these Ti^IV complexes revealed that [Ti 1 ₂(trop)]^? (trop=tropolonate) is much more stable than the [Ti 1 ₂(acac)]^? complex, which allows the replacement of acac with trop on the [Ti 1 ₂(acac)]^? complex. This Ti^IV‐centered site‐selective ligand exchange reaction also takes place on a heteronuclear Pd^II? Ti^IV ring complex with the preservation of the Pd^II‐centered coordination structures. Intra‐ and intermolecular linking between two Ti^IV centers with a flexible or a rigid bis‐tropolone bridging ligand provided a tetranuclear and an octanuclear Pd^II? Ti^IV complex, respectively. These higher‐order structures could be efficiently constructed only through a stepwise synthetic route.     

Synthesis and Structure of the Copper(I) Complex Containing Bis(diphenylphosphino)ethane

1 INTRODUCTION Procedures to synthesize copper(I) complexes are of great interest because of the diversity of products resulting from almost the same methodology. It has long been known that four-electron-donor diphosphine compounds Ph2P(CH2)nPPh2 are excellent bidentate ligands[1]. The chelating tendency decreases as the chain length increases, so that for the ligands Ph2P(CH2)nPPh2, the tendency to chelation is the greatest for bis(diphenylphosphino)ethane. Copper(I) displays wide…