Synthesis and catalytic activity of some π-allylic bis(trifluorophosphine)(triphenylphosphine)cobalt(I) complexes

The syntheses of Co(π-all)(PF₃)₂(PPh₃) complexes (π-all = π-allyl, anti-1-Me-π-allyl, syn-1-Me-π-allyl, 1,1-dimethyl-π-allyl, anti-1,2-diMe-π-allyl, syn,syn-1,3-diMe-π-allyl, 2Et-π-allyl, π-cyclooctenyl, h³-π-cycloheptadienyl) are described. ¹H and ¹⁹F NMR data are presented and discussed in relation to the structures of the complexes. The compound Co(π-C₅H₉)(PF₃)(PPh₃)₂ is also reported. Several of the π-allylic complexes are found to be active catalysts for the isomerisation of 1-octene to 2-octene under a hydrogen atmosphere.     

New octahedral bis(diphenylphosphino)methanide derivatives and heterometallic species from mixed ligand isocyanide-dppm iron(II) complexes

The cationic [FeL(dppm)(CNPh)₃]ⁿ⁺ (1a: L = I, n = 1; 1b: L = CNPh, n = 2) are readily deprotonated by KOH to give [FeL(dppm-H)(CNPh)₃]ⁿ⁻¹ (2a and 2b). 2a reacts with [thtAuPPh₃]PF₆ to give mer-[FeI((PPh₂)₂C(H)(AuPPh₃))-(CNPh)₃]PF₆ (3). The new heterotrimetallic species [FeL((PPh₂)₂C(AuPPh₃)₂)-(CNPh)₃]ⁿ⁺ (4a and 4b) have been obtained from 1a and 1b by treatment with ClAuPPh₃ in the presence of KOH.     

Phosphine substitution and phosphine induced reductive elimination reactions: synthesis of zerovalent ruthenium fluorophosphine complexes from hydrido(acetato)tris(triphenylphosphine)ruthenium(II)

Substitution of PPh₃ from the bidentate acetatohydridoruthenium(II) complex RuH(CH₃OCO)(PPh₃)₃ with various ligands, L, leads to unidentate acetatohydrido compounds with replacement of one, two or all PPh₃ ligands depending on L (L = t-BuNC, PF₂NMe₂, P(OCH₂)₃CMe, P(OMe)₃, dppe). On the other hand acetic acid elimination from RuH(CH₃OCO)(PPh₃)₃ occurs with fluorophosphines to yield zerovalent ruthenium complexes RuL′₅ (L′ = PF₂NMe₂, PF₂NC₄H₈), RuL₄(PPh₃) (L′ = PF₃) and RuL₃(PPh₃)₂ (L′ = PF₃).     

Dinuclear Pd(II) and Rh(I) complexes of tetra-acetylethane: Linkage isomerization of tetra-acetylethane dianion in Pd(II) complexes

The Pd(II) and Rh(I) complexes of tetra-acetylethane [H₂dahd (3,4-diacetyl-2,4-hexadiene-2,5-diol)] with O,O′-bonded chelates, represented as [M₂(O₂,O′₂-dahd)(L₂)₂][X]_m {M = Pd, L₂ = (PPh₃)₂ or bdpe [1,2-bis(diphenylphosphino)ethane], X = BF₄ or PF₆, m = 2; M = Rh, L = Co, m = 0}, have recently been prepared. [Pd₂(O₂,O′₂-dahd)-(PPh₃)₄][PF₆]₂ reacts with the potentially bidentate 1,10-phenanthroline (phen) to give the five-coordinate complex [Pd(PPh₃)(phen)₂][PF₆]₂ and [Pd(O₁,O′₁-dahd)(phen)]_n, the latter of which is rather insoluble in organic solvents. [Pd(O₁, O′₁-dahd)(phen)]_n in CH₂Cl₂ readily transforms to a monomer complex [Pd(C³, O′-dahd)phen)]. These anomalous Pd(II) and Rh(I) complexes of the tetra-acetylethane dianion have been characterized from elemental analyses, conductance, IR, ¹H and ¹³C NMR spectroscopy, magnetic susceptibility and ESR spectroscopy.     

Some diolefin complexes of iridium(I) and a trans-influence series for the complexes [IrCl(cod)L]

A high-yield synthesis of [IrCl(cod)]₂ (cod = 1,5-cyclooctadiene) is described. The ¹H and ¹³C NMR spectra of a number of complexes [IrCl(cod)L] are interpreted in terms of a trans-effect series Cl^? < sym-collidine < 2-picoline < PCy₃ < P-i-Pr₃ < Pet₃ ～ AsPh₃ < PMe₂Ph < PMePh₂ < PPh₂ <P(MeO)Ph₂ < PClPh₂ < P(OPh)₃ < PCl₂Ph. Some ligand exchange reactions of [IrCl(cod)L] are discussed. A number of complexes of the type [Ir(cod)L_n]PF₆ (L = a variety of amines (n = 2) and phosphines (n = 2 or 3)) are described. Exchange reactions of the sort: [Ir(cod)(PR₃)₂]PF₆ + [Ir(cod)(py)₂]PF₆ ? [Ir(cod)(PR₃)Py]PF₆ are reported in which, surprisingly, the isolable mixed ligand complexes are the only detectable species at equilibrium (py = pyridine).     

Polymerization of arylallenes catalyzed by organo-rhodium(I) and -cobalt (I) complexes to give structurally regulated high-mass polymers

Organorhodium complexes, such as RhH(PPh₃)₄, RhH(CO)(PPh₃)₃, Rh(η³-C₃H₄Ph)(CO)(PPh₃)₂, and RhH(dppe)₂ [dppe = 1,2-bis(diphenylphosphinoethane)], catalyze polymerization of phenylallene and of 4-methylphenylallene at 60 °C. High-molecular-weight polymers (M_n>4×10⁵) are isolated from the reaction products by removing the low-molecular-weight (M_n<3×10³) acetone-soluble fraction. The NMR (¹H and ¹³C{¹H}) spectra of poly(phenylallene) (1) and poly(4-methylphenylallene) (2) show the structure formed through selective 2,3-polymerization of the monomers, while similarly obtained poly(2-naphthylallene) (3) is characterized only by ¹H NMR spectroscopy due to its low solubility in common organic solvents. 4-Fluorophenylallene and 4-(trifluoromethyl)-phenylallene do not polymerize under similar conditions in the presence of RhH(PPh₃)₄ catalyst but are turned into low-molecular-weight oligomers. CoH(N₂)(PPh₃)₃-catalyzed polymerization of phenylallene and 4-methylphenylallene at room temperature gives the corresponding polymers with molecular weights in the range M_n=(9–15)×10⁴, in high yields. © 1997 John Wiley & Sons, Ltd.     

Pentamethylcyclopentadienyl ruthenium(II) complexes of para-substituted N-(pyrid-2-ylmethylene)-phenylamine ligands: syntheses,spectral and structural studies

The reaction of [(η⁵-C₅Me₅)Ru(PPh₃)₂Cl] (1) with acetonitrile in the presence of excess NH₄PF₆ leads to the formation of the cationic ruthenium(II) complex [(η⁵-C₅Me₅)Ru(PPh₃)₂(CH₃CN)]PF₆ (2). The complex (2) reacts with a series of N,N′ donor Schiff base ligands viz. para-substituted N-(pyrid-2-ylmethylene)-phenylamines (ppa) in methanol to yield pentamethylcylopentadienyl ruthenium(II) Schiff base complexes of the formulation [(η⁵-C₅Me₅)Ru(PPh₃)(C₅H₄N-2-CHN-C₆H₄-p-X)]PF₆ [3a]PF₆–[3f]PF₆, where C₅Me₅ = pentamethylcylopentadienyl, X = H, [3a]PF₆, Me, [3b]PF₆, OMe, [3c]PF₆, NO₂, [3d]PF₆, Cl, [3e]PF₆, COOH, [3f]PF₆. The complexes were isolated as their hexafluorophosphate salts. The complexes were fully characterized on the basis of elemental analyses and NMR spectroscopy. The molecular structure of a representative complex, [(η⁵-C₅Me₅)Ru(PPh₃)(C₅H₄N-2-CHN-C₆H₄-p-Cl)]PF₆ [3e]PF₆, has been established by X-ray crystallography.     

Synthesis and Spectra of Cationic Bis(tertiary phosphine) derivatives of cycloheptatrienyliummolybdenum and cyclopentadienyliron complexes

Reaction of [(η-C₇H₇)Mo(CO)₃][PF₆] and [(η-C₅H₅)Fe(CO)₂CH₃CN][PF₆] with ditertiary phosphine ligands afforded products of three types; the monosubstituted complexes [(Ring)M(CO)₂Ph₂P(CH₂)_nPPh₂][PF₆] (Ring = η-C₇H₇, M = Mo, N = 1; Ring = η-C₅H₅, M = Fe, N = 1 and 2), the chelated complexes [(Ring)M(CO)Ph₂P(CH₂)_nPPh₂][PF₆] (Ring = η-C₇H₇, M = Mo, N = 1 and 2; Ring = η-C₅H₅, M = Fe, N = 1 and 2), and the dinuclear complex [{(η-C₇H₇)Mo(CO)₂}₂ -μ- Ph₂PCH₂CH₂PPh₂][(PF₆)₂]. Spectroscopic properties, including ³¹P NMR, are reported.     

Bio-catalysts and catalysts based on ruthenium(II) polypyridyl complexes imparting diphenyl-(2-pyridyl)-phosphine as a co-ligand

Reactions of the ruthenium complexes [Ru(κ³-tpy)(PPh₃)Cl₂], [Ru(κ³-tptz)(PPh₃)Cl₂] and [Ru(κ³-tpy)Cl₃] [tpy = 2,2′:6′,2′′-terpyridine; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine] with diphenyl-(2-pyridyl)-phosphine (PPh₂Py) have been investigated. The complexes [Ru(κ³-tpy)(PPh₃)Cl₂] and [Ru(κ³-tptz)(PPh₃)Cl₂] reacted with PPh₂Py to afford [Ru(κ³-tpy)(κ¹-P-PPh₂Py)₂Cl]⁺ (1) and [Ru(κ³-tptz)(κ¹-P-PPh₂Py)₂Cl]⁺ (2), which were isolated as their tetrafluoroborate salts. Under analogous conditions, [Ru(κ³-tpy)Cl₃] gave a neutral complex [Ru(κ³-tpy)(κ¹-PPh₂Py)Cl₂] (3). Upon treatment with an excess of NH₄PF₆ in methanol, 1 and 2 gave [Ru(κ³-tpy)(κ¹-P-PPh₂Py)(κ²-P,N-PPh₂Py)](PF₆)₂ (4) and [Ru(κ³-tptz)(κ¹-P-PPh₂Py)(κ²-P,N-PPh₂Py)](PF₆)₂ (5) containing both monodentate and chelated PPh₂Py. Further, 4 and 5 reacted with an excess of NaCN and CH₃CN to afford [Ru(κ³-tpy)(κ¹-P-PPh₂Py)₂(CN)](PF₆) (6), [Ru(κ³-tpy)(κ¹-P-PPh₂Py)₂(NCCH₃)](PF₆)₂ (7), [Ru(κ³-tptz)(κ¹-P-PPh₂Py)₂(CN)]PF₆ (8) and [Ru(κ³-tptz)(κ¹-P-PPh₂Py)₂(NCCH₃)](PF₆)₂ (9) supporting hemi labile nature of the coordinated PPh₂Py. The complexes have been characterized by elemental analyses, spectral (IR, NMR, electronic absorption, FAB-MS), electrochemical studies and structures of 1, 2 and 3 determined by X-ray single crystal analyses. At higher concentration level (40 μM) the complexes under investigation exhibit inhibitory activity against DNA-Topo II of the filarial parasite S. cervi and 3 catalyses rearrangement of aldoximes to amide under aerobic conditions.     

Haloalkyl complexes of the transition metals: IV. The formation of a cationic ylide complex of platinum(II) from a chloromethylplatinum(II) complex and the crystal structures of cis-[Pt(CH2PPh3)X(PPh3)2]I (X = Cl or I)

The reactions of Pt(PPH₃)₄ and Pt(C₂H₄)(PPh₃)₂ with CH₂ClI have been investigated. The product of the reaction of Pt(PPh₃)₄ with CH₂ClI is the cationic ylide complex cis-[Pt(CH₂PPh₃)Cl(PPh₃)2][I], whereas the reaction of Pt(C₂H₄)-(PPh₃)₂ gives the oxidative addition product Pt(CH₂Cl)I(PPh₃)₂. Reaction of cis- or trans-Pt(CH₂Cl)I(PPh₃)₂] with PPh₃ gives the complex cis-[Pt(CH₂PPh₃)-Cl(PPh₃)₂][I]. The structures of the complexes cis-[Pt(CH₂PPh₃X(PPh₃)₂][I] (where X = Cl or I) have been determined by X-ray crystallography. Both complexes crystalize in the monoclinic space group P2₁/n. For X = Cl a 1388.6(7), b 2026.7(10), c 1823.9(9) pm, β 96.51(2)° and R converged to 0.075 for 3542 observed reflections; structural parameters Pt-Cl 240(1), Pt-C(3) 212(2), Pt-P(2) (trans to Cl) 235(1) and Pt-P(1) (trans to CH₂PPh₃) 233(1) pm; Cl-Pt-C(3) 86.9(5), C(3)-Pt-P(2) 91.8(5), P(2)-Pt-P(1) 97.0(2) and P(1)-Pt-Cl 85.1(2)°. For X = I, a 1379.4(7), b 2044.4(10), c 1840.0(9) pm, β 96.09(2)° and R converged to 0.071 for 4333 observed reflections; structural parameters Pt-I 266(1), Pt-C(3) 212(2), Pt-P(2) (trans to I) 226(1) and Pt-P(1) (trans to CH₂PPh₃ 233(1) pm; I-Pt-C(3) 87.2(5), C(3)-Pt-P(2) 91.5(5), P(2)-Pt-P(1) 96.5(2) and P(1)-Pt-I 85.6(1)°. Some other complexes of the type cis-[Pt(CH₂PPh₃)X(PPh₃)₂]Y are also described.     

The development of phosphinoamine–Pd(II)–imidazole complexes: implications in room‐temperature Suzuki–Miyaura cross‐coupling reaction

The reaction of N‐methylimidazole (N‐MeIm) and N‐butylimidazole (N‐BuIm) with the complexes [PdCl₂(PPh₂py–P,N)] and [PdCl₂(PPh₂Etpy–P,N)] in the presence of NH₄PF₆ under N₂ at room temperature afforded four new cationic Pd(II) complexes [PdCl(PPh₂py–P,N)(N‐MeIm)](PF₆) ( 1 ), [PdCl(PPh₂py–P,N)(N‐BuIm)](PF₆) ( 2 ), [PdCl(PPh₂Etpy–P,N)(N‐MeIm)](PF₆) ( 4 ) and [PdCl(PPh₂Etpy‐P,N)(N‐BuIm)](PF₆) ( 5 ) in good yields, where PPh₂py is 2‐(diphenylphosphino)pyridine and PPh₂Etpy is 2‐{2‐(diphenylphosphino)ethyl}pyridine). The complexes were fully characterized. The catalytic activities of these complexes were investigated for Suzuki–Miyaura cross‐coupling reactions at room temperature. Complex 2 exhibited excellent activity compared to other analogs. Copyright © 2013 John Wiley & Sons, Ltd.     

Group V complexes of the tricarbonyl(η-cycloheptatrienylium)molybdenum cation and their reduction to monosubstituted derivatives of tricarbonyl(1-6-η-cycloheptatriene)molybdenum

Reaction of [(η-C₇H₇)Mo(CO)₃][PF₆] with certain Group V donor ligands afforded monosubstituted complexes [(η-C₇H₇)Mo(CO)₂L][PF₆] (L = P(OPh)₃, PPh₃, PPh₂Me, PPhMe₂, AsPh₃, SbPh₃). These were reduced by NaBH₄ to the corresponding cycloheptatriene complexes (1-6-η-C₇H₈)Mo(CO)₂L. In addition, the preparation of alkylcycloheptatriene complexes (1-6-η-C₇H₇R)Mo(CO)₂L (R = Me, L = P(OPh)₃, PPh₃, PPh₂Me; R = t-Bu, L = PPh₃) is described. Spectroscopic properties, including ¹³C NMR, are reported.     

Synthesis,characterization and reactions of the transition metal halogenoalkyl carbocation complexes [Cp(CO)2M{η2-CH2CH(CH2)nX}]PF6 (n = 1–8, 10, M = Fe; n = 3, 4 M = Ru; X = Br,I)

The halogenoalkyl complexes [Cp(CO)₂M{(CH₂)_nX}] (n = 3–10, 12, M = Fe; n = 5, 6, M = Ru, X = Br, I) react with Ph₃CPF₆ in dry CH₂Cl₂ to give the corresponding carbocation complexes [Cp(CO)₂M{η²-(CH₂CH(CH₂)_n?2X}]PF₆ in high yields. NMR evidence indicates that the metals form metallacyclopropane type structures with the carbocation ligand. The reactions of some of the cationic complexes with NaI, PPh₃, Na[Cp(CO)₂Fe] and Et₃N are discussed. NaI and Na[Cp(CO)₂Fe] displace the halogeno-olefin, while PPh₃ adds at the β-CH^δ+ giving the unstable phosphonium adducts [Cp(CO)₂Fe{CH₂CH(PPh₃)(CH₂)_n?2X}]PF₆ which decompose to the halogeno-olefins and the cationic PPh₃ complex [Cp(CO)₂Fe(PPh₃)]⁺. Et₃N causes allylic deprotonation forming internal olefin complexes of the type [Cp(CO)₂Fe{CH₂CHCH(CH₂)_n?3X}]PF₆.     

NEW RUTHENIUM(II) COMPLEXES CONTAINING ORGANODISULFIDE LIGANDS

Abstract

The new complexes [CpRu(PPh₃)₂(RSSR)PF₆ R=CH₃, iso-Pr, CH₂C₆H₅ and C₆H₅ have been prepared from the reaction of CpRu(PPh₃)₂Cl with RSSR in CH₃OH in presence of NH₄Cl. This result contrasts with the oxidative additions of RSSR to CpFe(dppe)1 dppe=PPh₂ (CH₂)₂PPh₂ to give [CpFe(dppe)SR]PF₆ (C. Diaz et al., J. Organomet. Chem. 516, 59 (1996)). Huckel calculations on model fragments CpFe(PPh₃)₂ and CpRu(PPh₃)₂ suggest that the higher electron density of iron could explain the differences observed in reactivity. Possible biological implications are discussed.     

Photophysical properties of copper(I) and zinc(II) complexes containing phosphinoquinoline ligands

Several copper(I) and zinc(II) complexes with 8-(diphenylphosphino)quinoline (PPh₂qn) or 8-diphenylphosphinoquinaldine (PPh₂qna) have been prepared. These ligands contain both imine and phosphine moieties, which can act as coordinating groups. X-ray analysis of the Cu(I) complexes reveals that [Cu(PPh₂qn)₂]PF₆ (Cu-1) and [Cu(PPh₂qn)₂]PF₆ (Cu-2), coordinated by two PPh₂qn and PPh₂qna ligands respectively, are obtained. In the Zn(II) complexes, a structural study shows that [ZnCl₂(PPh₂qn)] (Zn-1), [ZnBr₂(PPh₂qn)] (Zn-2) and [ZnI₂(PPh₂qn)] (Zn-3) are coordinated by one PPh₂qn ligand and two of the corresponding halogeno ligands (Cl⁻, Br⁻ and I⁻). In the solid state Cu-1 and Cu-2 show luminescence which is assigned to a ³MLCT transition involving π∗ of the quinoline group, as shown in the [Cu(dmp)(diphosphine)]⁺ complexes; due to the reduced bulkiness of the coordination sphere around the copper atom, no emission is observed in solution. Zn-1 shows a similar emission band to that of free PPh₂qn at both room temperature and 77 K. It suggests the emission bands should be assigned to a ligand-centered (LC) transition. In the solid state, it is found that the emissive energy of the complexes shift to lower energy and the energy depends on the halogeno ligands in the zinc complexes.     

Novel hydridotris(pyrazolyl)borate ruthenium(II) complexes containing the water-soluble phosphane 1,3,5-triaza-7-phosphaadamantane: Synthesis and evaluation of DNA binding properties

A series of half-sandwich ruthenium(II) complexes containing κ³(N,N,N)-hydridotris(pyrazolyl)borate (κ³(N,N,N)-Tp) and the water-soluble phosphane 1,3,5-triaza-7-phosphaadamantane (PTA) [RuX{κ³(N,N,N)-Tp}(PPh₃)_2−n(PTA)_n] (n = 2, X = Cl (1), n = 1, X = Cl (2), I (3), NCS (4), H (5)) and [Ru{κ³(N,N,N)-Tp}(PPh₃)(PTA)L][PF₆] (L = NCMe (6), PTA (7)) have been synthesized. Complexes containing 1-methyl-3,5-diaza-1-azonia-7-phosphaadamantane(m-PTA) triflate [RuCl{κ³(N,N,N)-Tp}(m-PTA)₂][CF₃SO₃]₂ (8) and [RuX{κ³(N,N,N)-Tp}(PPh₃)(m-PTA)][CF₃SO₃] (X = Cl (9), H (10)) have been obtained by treatment, respectively, of complexes 1, 2 and 5 with methyl triflate. Single crystal X-ray diffraction analysis for complexes 1, 2 and 4 have been carried out. DNA binding properties by using a mobility shift assay and antimicrobial activity of selected complexes have been evaluated.     

Fluoraustauschreaktionen an Metalltrifluorphosphan-Komplexen. X [1]. Zum Reaktionsverhalten von Tetrakis(trifluorphosphan)-nickel(0) mit Metallorganylen [2]

Ni(PF₃)₄ ( 1 ) tauscht mit Lithiumorganylen und Grignard-Reagentien Fluor gegen Organyl-Gruppen aus, wobei die Komplexe ( 10–32 ) Ni(PF₃)_4?n(PF₂R)_n (n = 1, 2 und 3), Ni(PF₃)₃(PFR₂), Ni(PF₃)₂(PF₂R)(PFR₂) und Ni(PF₃)₃(PR₃) (R = organ. Rest) gebildet werden. Für den Reaktionsablauf wird ein Vierzentren-Synchron-Mechanismus vorgeschlagen. Fluorine Exchange in Trifluorophosphane Metal Complexes. X. Reactions of Tetrakis(trifluorophosphane)nickel(0) with Metal Organyls The fluorine atoms in Ni(PF₃)₄ ( 1 ) can be partially substituted by organyl groups yielding the complexes ( 10–32 ) Ni(PF₃)_4?n(PF₂R)_n (n = 1, 2 and 3), Ni(PF₃)₃(PFR₂), Ni(PF₃)₂(PF₂R)(PFR₂) and Ni(PF₃)₃(PR₃) (R = organyl group). The mechanism of these peripheric reactions is discussed by assuming a four centered type intermediate.     

Ruthenium complexes of hexakis(cyanophenyl)[3]radialenes and their di(cyanophenyl)methane precursors: synthesis,photophysical, and electrochemical properties

The coordination chemistry of cross-conjugated ligands and the effect of cross-conjugation on the nature of metal–metal and metal–ligand interactions have received limited attention. To explore the effects of cross-conjugation eight ruthenium complexes were synthesized, mononuclear complexes of two isomeric cross-conjugated [3]radialenes [RuCp(PPh₃)₂(L)]PF₆ and [{RuCp*(dppe)}(L)]PF₆ (L?=?hexakis(4-cyanophenyl)[3]radialene, 2; hexakis(3-cyanophenyl)[3]radialene, 3), and dinuclear complexes [{RuCp(PPh₃)₂}₂(L)](PF₆)₂ and [{RuCp*(dppe)}₂(L)](PF₆)₂ of the diarylmethane precursors (L?=?4,4′-dicyanodiphenylmethane, 4; 3,3′-dicyanodiphenylmethane, 5) to the [3]radialenes. Considerable synthetic challenges allowed only clean isolation of mononuclear complexes of the multidentate radialenes 2 and 3. As expected, coordinating a positively charged metal induces a red shift for the π–π* transition in complexes of ligand 2, but unexpectedly a blue shift for the same transition in complexes of 3 was observed. This points to conformational differences for the [3]radialene in the ruthenium complexes of the para- (2) versus meta- (3) substituted hexaaryl[3]radialenes. Cyclic voltammetry indicates that the methylene spacer in 4 and 5 does not enable any interaction between metal centers and the absorption behavior is essentially as observed for [Ru(NCPh)(PPh₃)₂Cp]PF₆ and [Ru(NCPh)(dppe)Cp*]PF₆ but generally with a slight red shift in absorbance maxima.     

Trinuclear copper(I) complex of 1,3-bis(2-pyridinylmethyl)imidazolylidene as a carbene-transfer reagent for the preparation of catalytically active nickel(II) and palladium(II) complexes

Reactions of 1,3-bis(pyridin-2-ylmethyl)-1H-imidazol-3-ium hexafluorophosphate, ([HL1](PF₆), L1 = 1,3-bis(pyridin-2-ylmethyl)imidazolylidene) and 1,3-bis(pyridin-2-ylmethyl)-1H-benzimidazol-3-ium hexafluorophosphate ([HL2](PF₆), L2 = 1,3-bis(pyridin-2-ylmethyl)benzoimidazolylidene) with cuprous oxide in acetonitrile readily yielded trinuclear complexes [Cu₃(L1)₃(PF₆)₃] (1) and [Cu₃(L2)₃(PF₆)₃] (2). Treatment of 1 with Ni(PPh₃)₂Cl₂ and Pd(cod)Cl₂ gave [Ni(L1)Cl](PF₆) (3) and [Pd(L1)Cl](PF₆) (4), respectively, due to transmetalation. [Ni(L1)₂](PF₆)₂ (5) was obtained from the reaction of [Cu₃(L1)₃(PF₆)₃] and Raney nickel in acetonitrile. All these complexes have been fully characterized. Both 1 and 2 consist of a triangular Cu₃ core with each Cu–Cu bond capped by an imidazolylidene group. Each imidazolylidene acts as a bridging ligand in a μ₂ mode and is bonded equally to two Cu(I) ions. The pincer nickel and palladium complexes are square-planar and contain a tridentate NCN ligand. Complexes 3 and 4 are efficient catalyst precursors for Kumada–Corriu and Suzuki–Miyaura coupling reactions of aryl halides with organometallic reagents.     

Trinuclear copper(I) complex of 1,3-bis(2-pyridinylmethyl)imidazolylidene as a carbene-transfer reagent for the preparation of catalytically active nickel(II) and palladium(II) complexes

Reactions of 1,3-bis(pyridin-2-ylmethyl)-1H-imidazol-3-ium hexafluorophosphate, ([HL1](PF₆), L1 = 1,3-bis(pyridin-2-ylmethyl)imidazolylidene) and 1,3-bis(pyridin-2-ylmethyl)-1H-benzimidazol-3-ium hexafluorophosphate ([HL2](PF₆), L2 = 1,3-bis(pyridin-2-ylmethyl)benzoimidazolylidene) with cuprous oxide in acetonitrile readily yielded trinuclear complexes [Cu₃(L1)₃(PF₆)₃] (1) and [Cu₃(L2)₃(PF₆)₃] (2). Treatment of 1 with Ni(PPh₃)₂Cl₂ and Pd(cod)Cl₂ gave [Ni(L1)Cl](PF₆) (3) and [Pd(L1)Cl](PF₆) (4), respectively, due to transmetalation. [Ni(L1)₂](PF₆)₂ (5) was obtained from the reaction of [Cu₃(L1)₃(PF₆)₃] and Raney nickel in acetonitrile. All these complexes have been fully characterized. Both 1 and 2 consist of a triangular Cu₃ core with each Cu–Cu bond capped by an imidazolylidene group. Each imidazolylidene acts as a bridging ligand in a μ₂ mode and is bonded equally to two Cu(I) ions. The pincer nickel and palladium complexes are square-planar and contain a tridentate NCN ligand. Complexes 3 and 4 are efficient catalyst precursors for Kumada–Corriu and Suzuki–Miyaura coupling reactions of aryl halides with organometallic reagents.