Facile Ar-CF3 bond formation at Pd. Strikingly different outcomes of reductive elimination from [(Ph3P)2Pd(CF3)Ph] and [(Xantphos)Pd(CF3)Ph

Facile and highly selective perfluoroalkyl-aryl reductive elimination from a metal center (Pd) has been demonstrated for the first time. At temperatures as low as 50-80 degrees C, [(Xantphos)Pd(Ph)CF3] undergoes remarkably clean decomposition to produce CF3Ph in high yield and selectivity. In contrast, analogous trifluoromethylpalladium aryls stabilized by rigid cis-chelating ligands such as dppe are completely unreactive at temperatures up to 130-140 degrees C. Decomposition of [(Ph3P)2Pd(Ph)CF3] in the presence of PhI in benzene at 60 degrees C does not produce PhCF3 but rather leads to [(Ph3P)2Pd(Ph)I] and [Ph4P]+[(Ph3P)Pd(CF3)3]- in a 2:1 ratio with high selectivity.     

Synthese und Struktur der Komplexe [(n‐Bu)4N]2[{(THF)Cl4Re≡N}2PdCl2], [Ph4P]2[(THF)Cl4Re≡N‐PdCl(μ‐Cl)]2 und [(n‐Bu)4N]2[Pd3Cl8]

Synthesis and Crystal Structure of the Complexes [(n‐Bu)₄N]₂[{(THF)Cl₄Re≡N}₂PdCl₂], [Ph₄P]₂[(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂ and [(n‐Bu)₄N]₂[Pd₃Cl₈] The threenuclear complex [(n‐Bu)₄N]₂[{(THF)Cl₄Re≡N}₂ PdCl₂] ( 1 ) is obtained in THF by the reaction of PdCl₂(NCC₆H₅)₂ with [(n‐Bu)₄N][ReNCl₄] in the molar ration 1:2. It forms orange crystals with the composition 1· THF crystallizing in the monoclinic space group C2/c with a = 2973.3(2); b = 1486.63(7); c = 1662.67(8)pm; β = 120.036(5)° and Z = 4. If the reaction is carried out with PdCl₂ instead of PdCl₂(NCC₆H₅)₂, orange crystals of hitherto unknown [(n‐Bu)₄N]₂[Pd₃Cl₈] ( 3 ) are obtained besides some crystals of 1· THF. 3 crystallizes with the space group P1¯ and a = 1141.50(8), b = 1401.2(1), c = 1665.9(1)pm, α = 67.529(8)°, β = 81.960(9)°, γ = 66.813(8)° and Z = 2. In the centrosymmetric complex anion [{(THF)Cl₄Re≡N}₂PdCl₂]^2— a linear PdCl₂ moiety is connected in trans arrangement with two complex fragments [(THF)Cl₄Re≡N]^— via asymmetric nitrido bridges Re≡N‐Pd. For Pd(II) thereby results a square‐planar coordination PdCl₂N₂. The linear nitrido bridges are characterized by distances Re‐N = 163.8(7)pm and Pd‐N = 194.1(7)pm. The crystal structure of 3 contains two symmetry independent, planar complexes [Pd₃Cl₈]^2— with the symmetry 1¯, in which the Pd atoms are connected by slightly asymmetric chloro bridges. By the reaction of equimolar amounts of [Ph₄P][ReNCl₄] and PdCl₂(NCC₆H₅)₂ in THF brown crystals of the heterometallic complex, [Ph₄P]₂[(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂ ( 2 ) result. 2 crystallizes in the monoclinic space group P2₁/n with a = 979.55(9); b = 2221.5(1); c = 1523.1(2)pm; β = 100.33(1)° and Z = 2. In the central unit ClPd(μ‐Cl)₂PdCl of the centrosymmetric anionic complex [(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂^2— the coordination of the Pd atoms is completed by two nitrido bridges Re≡N‐Pd to nitrido complex fragments [(THF)Cl₄Re≡N]^— forming a square‐planar arrangement for Pd(II). The distances in the linear nitrido bridges are Re‐N = 163.8(9)pm and Pd‐N = 191.5(9)pm.     

Solid‐state NMR study of [(Ph3SnF)2(Ph3SnO2PPh2)], a novel coordination polymer prepared from Bu4N[Ph3SnF2] and [Ph3SnOPPh2OSnPh3](O3SCF3)

The coordination polymer [(Ph₃SnF)₂(Ph₃SnO₂PPh₂)] ( 3 ), prepared by the reaction of [Ph₃SnOPPh₂OSnPh₃](O₃SCF₃) ( 4 ) with Bu₄N[Ph₃SnF₂] ( 5 ), was investigated by multinuclear magic angle spinning magnetic resonance spectroscopy and the results compared with those of the polymeric parent compounds Ph₃SnF ( 1 ) and Ph₃SnO₂PPh₂ ( 2 ). The crystal structure of 4 was determined by X‐ray crystallography. Copyright © 2004 John Wiley & Sons, Ltd.     

Metall-Schwefelstickstoff-Verbindungen. 19. Neue Komplexe von CuI mit dem S3N−-Chelatliganden Darstellung und Struktur von [Ph4As][Cu(S3N)(CN)], [(Ph3P)2N][Cu(S3N)(S7N)] und [Ph4As]2[(S3N)Cu(S2O3)Cu(S3N)]

Metal Sulfur-Nitrogen Compounds. 19. Novel Complexes of Cu^I with the S₃N^? Chelate Ligand. Preparation and Structure of [Ph₄As][Cu(S₃N)(CN)], [(Ph₃P)₂N][Cu(S₃N)(S₇N)], and [Ph₄As]₂[(S₃N)Cu(S₂O₃)Cu(S₃N)] In alkaline media S₇NH reacts with Cu salts to yield different products. With Cu(CN) the ion [Cu(S₃N)(CN)]^? is formed, which was isolated as the [Ph₄As]⁺ salt. The crystals are monoclinic, space group P2₁/c, a = 10.499(5), b = 13.418(6), c = 18.032(8) Å, β = 91.84°(3), Z = 4. Besides the known complex ions [Cu(S₃N)₂]^? and [Cu(S₃N)Cl]^? still some more may be obtained when CuCl₂ is reacted with S₇NH: Under special conditions the S₇N ring is partly preserved, and [Cu(S₃N)(S₇N)]^? is formed. Its sparingly soluble [(Ph₃P)₂N]⁺ salt is monoclinic, space group P2₁/n, a = 9.335(6), b = 30.984(11), c = 15.108(8) Å, β = 102.87°(4), Z = 4. Using a longer reaction time a dinuclear complex [(S₃N)Cu(S₂O₃)Cu(S₃N)]^{? ?} results from the reaction of CuCl₂ with S₇NH. The two Cu atoms are bridged by an S atom of the S₂O₃^{? ?} anion. The [Ph₄As]⁺ salt of the dinuclear complex anion is triclinic, space group P1 , a = 11.226(6), b = 12.423(6), c = 19.000(10) Å, β = 76.47°(4), β = 83.98°(4), γ = 84.71°(4), Z = 2. In all these compounds the coordination of Cu^I is trigonal-planar, the S₃N^? chelate group coordinates the Cu in the usual way by two S atoms.     

Metall-Schwefelstickstoff-Verbindungen. 20. Reaktionsprodukte von PdCl2 und Pd(CN)2 mit S7NH. Darstellung und Struktur der Komplexe [Ph6P2N][Pd(S3N)(S5)] und X[Pd(S3N)(CN)2] (X = [Me4N]+, [Ph4P]+)

Metal Sulfur Nitrogen Compounds. 20. Reaction Products of PdCl₂ and Pd(CN)₂ with S₇NH. Preparation and Structure of the Complexes [Ph₆P₂N][Pd(S₃N)(S₅)] and X[Pd(S₃N)(CN)₂] X = [Me₄N]⁺, [Ph₄P]⁺ With PdCl₂ and [Ph₆P₂N]OH S₇NH forms the complex salt [Ph₆P₂N][Pd(S₃N)(S₅)], which could be isolated in two modifications (α- and β-form). The α-form is triclinic, a = 9.347(4), b = 14.410(8), c = 15.440(11) Å, α = 76.27°(5), β = 77.06°(4), γ = 76.61α(4), Z = 2, space group P1 . The β-form is orthorhombic, a = 9.333(2), b = 17.659(4), c = 23.950(6) Å, Z = 4. The structure of the metal complex is the same in the two modifications. One S₃N^? and one S₅^2? are coordinate as chelate ligands to Pd. From S₇NH, Pd(CN)₂, and XOH X = [(CH₃)₄N]⁺ and [(C₆H₅)₄P]⁺ the salts X[Pd(S₃N)(CN)₂] were formed. The (CH₃)₄N-salt is isomorphous with the analogous Ni compound described earlier, the (C₆H₅)₄P-salt is triclinic, a = 9.372(4), b = 10.202(5), c = 13.638(6) Å, α = 86.36α(4), β = 85.66°(4), γ = 88.71°(4), Z = 2, space group P1 . One S₃N^? chelate ligand and two CN^? ions are bound to Pd. In all these complexes the coordination of Pd is nearly square planar.     

Synthesis and characterization of rhenium-copper sulfide cluster complexes [(Ph3P)2N][Re3(CuX)(mu3-S)4Cl6(PMe2Ph)3] (X = Cl, Br, I)

The reaction of a trinuclear rhenium sulfide cluster compound Re3S7Cl7 with dimethylphenylphosphine and CuX2 (X = Cl or Br) or CuX (X = Cl, Br, or I) formed tetranuclear cluster complexes [(Ph3P)2N][Re3(CuX)(mu3-S)4Cl6(PMe2Ph)3] (X = Cl, Br, or I). Their solutions have the characteristic intense blue color with visible spectral bands near 600 nm. Single-crystal X-ray structures show that three mu-S atoms in the intermediate trinuclear rhenium complex coordinate to a copper atom, forming elongated tetrahedral structures in which Re-Cu bonding interaction is negligible (Re-Cu distances are 3.50 to approximately 3.54 A as compared with Re-Re distances ranging from 2.69 to 2.81 A).     

Competition of oxygen insertion and dehydrogenation in the o-phenylenediamine/Ph3P/COBALT(II) catalyst system

In addition to known catalytic dehydrogenations, the o-phenylene- diamine (OPD)/cobalt(II) system also effects the oxidation of PH₃P to Ph₃PO. A green intermediate of the formula [Ph₃P(OPD)₂Co-O₂-Co(OPD)₂- Ph₃P]⁴⁺ has been isolated and characterized. It is formed by the rapid co- ordination of Ph₃P to cobalt(III) in the μ-peroxo precursor [(OPD)₂Co—O₂—Co(OPD)₂]⁴⁺. The relative contribution of OPD dehydrogenation under catalytic conditions depends on the OPD to Ph₃P ratio. Dioxygen is ultimately converted to water and no H₂O₂ is formed. The proposed mechanistic path involves concerted or stepwise O-atom transfer by species mimicking biological ‘oxenoid’ reagents.     

[(Ph3PCH2)(Ph3P)PtCl][AlCl4], ein in CH2Cl2-lösung dreifach koordinierter kationischer platin(II)-komplex

The interaction of cis-[(Ph₃PCH₂)(Ph₃P)PtCl₂] with aluminium(III) chloride in CH₂Cl₂ affords the three coordinate cationic platinum(II) complex [(Ph₃PCH₂)(Ph₃P)PtCl][AlCl₄] which is a useful starting material for platinum complexes with four different ligands. With Ph₃As and Me₂S the cationic phosphorus ylide complexes [(Ph₃PCH₂)(Ph₃P)(Ph₃As)PtCl][AlCl₄] and [(Ph₃PCH₂)(Ph₃P)(Me₂S)PtCl][AlCl₄] are formed. 851 V 3     

Three-coordinate NiII: tracing the origin of an unusual, facile Si-C(sp3) bond cleavage in [(tBu2PCH2SiMe2)2N]Ni+

All attempts to synthesize (PNP)Ni(OTf) form instead ((t)Bu(2)PCH(2)SiMe(2)NSiMe(2)OTf)Ni(CH(2)P(t)Bu(2)). Abstraction of F(-) from (PNP)NiF by even a catalytic amount of BF(3) causes rearrangement of the (transient) (PNP)Ni(+) to analogous ring-opened [((t)Bu(2)PCH(2)SiMe(2)NSiMe(2)F)]Ni(CH(2)P(t)Bu(2)). Abstraction of Cl(-) from (PNP)NiCl with NaB(C(6)H(3)(CF(3))(2))(4) in CH(2)Cl(2) or C(6)H(5)F gives (PNP)NiB(C(6)H(3)(CF(3))(2))(4), the key intermediate in these reactions is (PNP)Ni(+), [(PNP)Ni](+), in which one Si-C bond (together with N and two P) donates to Ni. This makes this Si-C bond subject to nucleophilic attack by F(-), triflate, and alkoxide/ether (from THF). This σ(Si-C) complex binds CO in the time of mixing and also binds chloride, both at nickel. Evidence is offered of a "self-healing" process, where the broken Si-C bond can be reformed in an equilibrium process. (PNP)Ni(+) reacts rapidly with H(2) to give (PN(H)P)NiH(+), which can be deprotonated to form (PNP)NiH. A variety of nucleophilic attacks (and THF polymerization) on the coordinated Si-C bond are envisioned to occur perpendicular to the Si-C bond, based on the character of the LUMO of (PNP)Ni(+).     

(Ph)3PBr][Br7], [(Bz)(Ph)3P]2[Br8], [(n-Bu)3MeN]2[Br20], [C4MPyr]2[Br20], and [(Ph)3PCl]2[Cl2I14]: extending the horizon of polyhalides via synthesis in ionic liquids

The five polyhalides [(Ph)(3)PBr][Br(7)], [(Bz)(Ph)(3)P](2)[Br(8)], [(n-Bu)(3)MeN](2)[Br(20)], [C(4)MPyr](2)[Br(20)] ([C(4)MPyr] = N-butyl-N-methylpyrrolidinium), and [(Ph)(3)PCl](2)[Cl(2)I(14)] were prepared by the reaction of dibromine and iodine monochloride in ionic liquids. The compounds [(Ph)(3)PBr][Br(7)] and [(Bz)(Ph)(3)P](2)[Br(8)] contain discrete pyramidal [Br(7)](-) and Z-shaped [Br(8)](2-) polybromide anions. [(n-Bu)(3)MeN](2)[Br(20)] and [C(4)MPyr](2)[Br(20)] exhibit new infinite two- and three-dimensional polybromide networks and contain the highest percentage of dibromine ever observed in a compound. [(Ph)(3)PCl](2)[Cl(2)I(14)] also consists of a three-dimensional network and is the first example of an infinite polyiodine chloride. All compounds were obtained from ionic liquids as the solvent that, on the one hand, guarantees for a high stability against strongly oxidizing Br(2) and ICl and that, on the other hand, reduces the high volatility of the molecular halogens.     

Air-stable Pd(R-allyl)LCl (L= Q-Phos, P(t-Bu)3, etc.) systems for C-C/N couplings: insight into the structure-activity relationship and catalyst activation pathway

A series of Pd(R-allyl)LCl complexes [R = H, 1-Me, 1-Ph, 1-gem-Me(2), 2-Me; L = Q-Phos, P(t-Bu)(3), P(t-Bu)(2)(p-NMe(2)C(6)H(4)), P(t-Bu)(2)Np] have been synthesized and evaluated in the Buchwald-Hartwig aminations in detail, in addition to the preliminary studies on Suzuki coupling and α-arylation reactions. Pd(crotyl)Q-PhosCl (9) was found to be a superior catalyst to the other Q-Phos-based catalysts, and the reported in situ systems, in model coupling reactions involving 4-bromoanisole substrate with either N-methylaniline or 4-tert-butylbenzeneboronic acid. Precatalyst 9 also performed better than the catalysts bearing P(t-Bu)(2)(p-NMe(2)C(6)H(4)) ligand; however, it is comparable to the new crotyl catalysts bearing P(t-Bu)(3) or P(t-Bu)(2)Np ligands. In α-arylation of a biologically important model substrate, 1-tetralone, Pd(allyl)P(t-Bu)(2)(p-NMe(2)C(6)H(4))Cl (15) was found to be the best catalyst. The reason for the relatively higher activity of the crotyl complexes in comparison to the allyl derivatives in C-N bond formation reactions was investigated using X-ray crystallography in conjunction with NMR spectroscopic studies.     

Neue neutrale und kationische Mono‐Aziridin‐Komplexe des Typs [CpMn(CO)2Az], [CpCr(NO)2Az]+ und [(Ph3P)(CO)4ReAz]+ über CO‐, Hydrid‐ und Chlorid‐Abspaltungsreaktionen

Novel Neutral and Cationic Mono‐Aziridine Complexes of the Type [CpMn(CO)₂Az], [CpCr(NO)₂Az]⁺, and [(Ph₃P)(CO)₄ReAz]⁺ via CO‐, Hydride‐, and Chloride‐Elimination Reactions The monoaziridine complexes 1 — 5 are obtained by three differently induced substitution reactions. The photolytically induced CO substitution reaction of [CpMn(CO)₃] with 2, 2‐dimethylaziridine leads to the neutral N‐coordinate aziridine complex [Cp(CO)₂Mn{$\overline{N(H)CMe₂C}$ H₂}] ( 1 ). The protonation of [(Ph₃P)(CO)₄ReH] with CF₃SO₃H and consecutive treatment with 2, 2‐dimethylaziridine or 2‐ethylaziridine gives the salt‐like aziridine complexes [(Ph₃P)(CO)₄Re{$\overline{N(H)CMe₂C}$ H₂}](CF₃SO₃) ( 2 ) or [(Ph₃P)(CO)₄Re{ H₂}](CF₃SO₃) ( 3 ) by hydride elimination reactions. The like‐wise salt‐like complexes [Cp(NO)₂Cr{$\overline{N(H)CMe₂C}$ H₂}](BF₄) ( 4 ) and [Cp(NO)₂Cr{ H₂}](CF₃SO₃) ( 5 ) are synthesized from [CpCr(NO)₂Cl] by chloride elimination with AgX (X = BF₄, CF₃SO₃) in the presence of 2, 2‐dimethylaziridine or 2‐ethylaziridine, respectively. As a result of X‐ray structure analyses, the metal atoms are trigonal pyramidally ( 1, 4, 5 ) or octahedrally ( 2, 3 , cis‐position) configurated; the intact three‐membered rings coordinate through the distorted tetrahedrally configurated N atoms. All compounds 1‐5 are stable with respect to the directed thermal alkene elimination to give the corresponding nitrene complexes; the IR, ¹H‐ and ¹³C{¹H}‐NMR, and MS spectra are reported and discussed.     

Fragmentation pathways of [(Ph3P)AuM(CO)3(n5-C5H4CHO)] upon electron impact in the gas phase or upon photolysis in solution

Conclusions In heterobimetallic complexes of the type (⁵-formylcyclopentadienyl)(triphenylphosphine-gold)tricarbonylchromium (molybdenum, tungsten) the Au-transition metal bond is easily cleaved either in the gas phase via electron impact (ionization), or in the liquid phase by photolysis.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2702–2708, December, 1987.     

Dihydrogen activation with (t)Bu3P/B(C6F5)3: a chemically competent indirect mechanism via in situ-generated p-(t)Bu2P-C6F4-B(C6F5)2

A chemically competent indirect pathway for the activation of dihydrogen by the nonmetal Lewis acid/Lewis base pair (t)Bu(3)P/B(C(6)F(5))(3) is described. The reaction between (t)Bu(3)P and B(C(6)F(5))(3) produces [(t)Bu(3)PH](+)[FB(C(6)F(5))(3)](-) and the known phosphinoborane p-(t)Bu(2)P-C(6)F(4)-B(C(6)F(5))(2) (1-(t)Bu) with elimination of isobutylene. At 1:1 stoichiometry, 1-(t)Bu is produced rapidly in detectable quantities and can act as a catalyst for the formation of [(t)Bu(3)PH](+)[HB(C(6)F(5))(3)](-) from (t)Bu(3)P and B(C(6)F(5))(3) in the presence of H(2). The extent to which this indirect path competes with the direct path is explored.