Cross-coupling of vinyldisilacyclobutane with olefins catalyzed by [RuH(Cl)(CO)(PCy3)2]

Cross-coupling of vinyldisilacyclobutane with a variety of olefins in the presence of [RuH(Cl)(CO)(PCy₃)₂] leads to stereoselective formation of functionalized vinyldisilacyclobutanes. Analogous homo-coupling of vinyldisilacyclobutane leads to the formation of E- and gem-bis(silyl)ethenes. The reaction offers a new route for synthesis of attractive monomers for ring opening polymerization (ROP).     

Reaction of trans-[Pt(H)2(PCy3)2] with C60 reductive elimination of H2 and formation of [Pt(PCy3)2(η-C60)]

Reaction of trans-[Pt(H)₂(PCy₃)₂], 1, with [60]fullerene at room temperature affords [Pt(PCy₃)₂(η²-C₆₀)], 2, in nearly quantitative yield. The most probable reaction pattern is the insertion of a fullerene 6,6 junction onto a Pt-H bond yielding an η¹ alkyl derivative which, after hydrogen extrusion, gives 2. On the other hand, addition of 1 to different electron-deficient olefins, such as dimethyl maleate and fumarate, furnishes mixtures of both η¹ metal—alkyl and η² metal—olefin derivatives. If tetrachloroethylene is used as 2π component, trans-[PtCl(H)(PCy₃)₂] forms exclusively.     

Arene-iridium(I) complexes. Crystal structure of [Ir(Me3TFB)(C6Me6)]ClO4

The crystal structure of [Ir(Me₃TFB)(C₆Me₆)]ClO₄ has been determined by X-ray diffraction. Lattice constants are a 16.9092(7), b 17.7120(7), c 16.8635(6) Å and β 97.984(3)° in a C2/c monoclinic lattice. The agreement factors are R, 0.038 and R_w 0.048 for the 3321 reflexions with I > 3σ(I). The coordination characteristics are similar to those of the corresponding rhodium analogues.     

Enantioselective hydrogenations of arylalkenes mediated by [Ir(cod) (JM-Phos) ]+ complexes

Phosphine oxazoline ligands la-j were converted to the corresponding [Ir(cod)(phosphine oxazoline)]+ complexes 2a-j. X-ray diffraction analyses of complexes 2b, 2h, 2i, and 2j were performed. The tert-butyl-, 1,1-diphenylethyl-, and phenyl-oxazoline complexes (2b, 2h, and 2i, respectively) had typical square planar metal environments with chair-like metallocyclic rings. However, the 3,5-di-tert-butylphenyl oxazoline complex 2j was distorted toward a tetrahedral metal geometry. This library of complexes was tested in asymmetric hydrogenations of several arylalkenes. High enantioselectivities and conversions were observed for some substrates. A possible special role for the HPh2C-oxazoline substituent in asymmetric hydrogenations was identified and is discussed. In attempts to rationalize why high enantioselectivities were not observed for some alkenes, a series of deuterium labeling experiments were performed to probe for competing reactions that occurred prior to the hydrogenation step. Double bond migrations were inferred for several substrates, and this is a significant complication in asymmetric hydrogenations of arylalkenes that had not been discussed prior to this study. A mechanistic rationale is proposed involving competing double bond migration for some but not all substrates. Appreciation of this complication will be valuable in further studies aimed at optimization of enantioselection in asymmetric hydrogenations of unfunctionalized alkenes.     

Duroquinonerhodium(I) complexes. Crystal structure of [Rh(DQ)(C6H5Me)]PF6

The preparation of cationic arenerhodiiim(I) complexes of the type [Rh(DQ)-(arene)]PF₆ (DQ = duroquinone; arene = C₆H_6-nMe_n, n duroquinone complexes with Group VB donor ligands are described. The crystal structure of [Rh(DQ)(C₆H₅Me)]PF₆ has been determined by X-ray diffraction. The compound crystallizes in the P2₁/n space group, in a unit cell of dimensions a 15.9866(5), b 11.8438(3), c 9.9968(3) Å, β 98.473(4)Å. The structure was solved by Patterson and Fourier methods and refined to R and R_w values of 0.062 and 0.076, respectively. The Rh atom is coordinated to a toluene group (η⁶) and a duroquinone ligand (η⁴), which eclipse each other. Both ligands are distorted to adopt boat-like conformations.     

Lumineszenz von [Co(CN)6]3-[Rh(CH)6]3-[Ir(CN)6]3-mit verschiedenen Gegenionen

Ohne Zusammenfassung     

Crystal and molecular structure of (η3-allyl)carbonylchlorobis(dimethylphenylphosphine)- iridium(III) hexafluorophosphate, [Ir(η3-C3H5)Cl(CO)(P(CH3)2(C6H5))2][PF6

The structure of (η³-allyl)carbonylchlorobis(dimethylphenylphosphine)-iridium(III) hexafluorophosphate, [Ir(η³-C₃H₅)Cl(CO)(P(CH₃)₂(C₆H₅))₂][PF₆], has been determined from three-dimensional X-ray data to add support for a proposed mechanism of the oxidative addition of allyl halides to IrX(CO)(PR₃)₂ (X = halide). The compound crystallizes in space group C⁵_2h-P2₁/c with four formula units in a cell of dimensions a = 11.027(1), b = 12.230(2), c = 19.447(5) Å, and β = 103.16(2)⁰. Least-squares refinement of the structure has led to a value of the conventional R index (on F) of 0.066 for the 3018 independent reflections having F²₀>3—(F²₀). The crystal structure consists of discrete, monomericions. The hexafluorophosphate anion is disordered. The coordination geometry around the iridium atom may be described as octahedral, with the chloro ligand trans to the carbonyl group and each phosphorus atom trans to a terminal carbon of the allyl group. Structural parameters: Ir—P = 2.366(4), 2.347(3);Ir—Cl = 2.389(3); Ir—C(allyl) = 2.28(1), 2.24(1),2.25(1); Ir—C (carbonyl) = 1.85(1) Å; P—Ir—P = 105.7(1); C(terminal)—Ir—C(terminal) = 66.2(8); C—C—C = 125(2)^o. The allyl group makes an angle of 126^o with the P—Ir—P plane. Correlations between geometric structure and number of d electrons are noted among several M—C₃H₅-complexes, and are interpreted in the light of theoretical models of the M—C₃H₅- bond.     

Degradation of the ruthenium-based metathesis catalyst [RuCl2(CHPh)(H2IPr)(PCy3)] with primary alcohols

A new ruthenium hydride species, showing high catalytic isomerization and hydrogenation properties, was isolated via a ligand exchange reaction. The same species was also present in the mixture of degradation products of the monophosphinic complex RuCl(CO)(PCy)₃(IPr)CH(Ph), 3, after reaction with alcohols under basic conditions.     

Reaction of [CpRu(CH3CN)3]PF6 with bidentate ligands: structural characterization of [{CpRu(CH3CN)2}2(μ-η-dppe)](PF6)2 [dppe=1,2-bis(diphenylphosphino)ethane]

The reaction of [CpRu(CH₃CN)₃]PF₆ with the bidentate ligands L-L=1,2-bis(diphenylphosphino)ethane, dppe, and (1-diphenylarsino-2-diphenylphosphino)ethane, dpadppe, affords mononuclear or dinuclear complexes of formula [CpRu(η²-L-L)(CH₃CN)]PF₆, [{CpRu(CH₃CN)₂}₂(μ-η^1:1-L-L)](PF₆)₂ and [{CpRu(CH₃CN)}₂(μ-η^1:1-L-L)₂](PF₆)₂ (L-L=dppe, dpadppe). All of the compounds are characterized by microanalysis and NMR [¹H and ³¹P{¹H}] spectroscopy. The crystal structure of [{CpRu(CH₃CN)₂}₂(μ-η^1:1-dppe)](PF₆)₂ has been determined by X-ray diffraction analysis. The complex exhibits a dppe ligand bridging two CpRu(CH₃CN)₂ fragments.     

Barreleneiridium(I) complexes. Crystal structures of [Ir(Me3TFB)(η6-C6H4Me2)]ClO4 and [Ir(TFB)(η5-PhNPh2)]BF4·CH2Cl2 (TFB = tetrafluorobenzobarrelene)

A new series of cationic areneiridium(I) complexes of formula [Ir(barrelene)(arene)]⁺ or [Ir(barrelene)(PhNRPh)]⁺ (R= Ph or H) have been synthesized from neutral iridium complexes of the type [IrY(barrelene)]_x (barrelene = Me₃TFB, Y = Cl or OMe (x = 2), Y = acac (x = 1); barrelene = TFB, Y = OMe (x = 2), Y = acac (x = 1)). The crystal structures of [Ir(Me₃TFB)(1,4-C₆H₄Me₂)]ClO₄ and [Ir(TFB)(PhNPh₂)]BF₄·CH₂Cl₂ have been determined by X-ray diffraction. They crystallize in the space groups Pbca and Pna2₁ respectively with lattice constants of 17.6947(11), 15.8072(10), 16.0019(11) Å and 9.8059(2), 20.8097(9), 14.3367(4) Å. Final R factors were 0.063 and 0.042 for the observed data. Both complexes show a staggered arrangement between the arene and the TFB moieties and deviation from planarity of the coordinated arene ligands. In the second complex the IrC and NC distances, the CNC angle, the type of arene puckering, and the spectroscopic data indicate a distortion of the coordinated arene towards a η⁵-coordinated iminocyclohexadienyl form.     

[Rh3O(OAc)6 (H2O)3]OAc as a homogeneous catalyst for selective enone formation by allylic oxidation of olefins

Treatment of several cyclic olefins and allybenzene with a catalytic amount of [Rh₃O(OAc)₆(H₂O)₃]OAc in acetic acid in the presence of t-butyl hydroperoxide affords the corresponding α,β-unsaturated carbonyl compounds (enones) highly seletively via an ionic pathway.     

Synthesis and complexation of a new facultative tridentate S2Te donor ligand MeS(CH2)3Te(CH2)3SMe: crystal structures of [Rh(Cp*)(S2Te)][PF6]2 and [PtCl(S2Te)]PF6

The syntheses and spectroscopic characterisation of the new facultative tridentate tellurium containing ligands MeS(CH₂)₃Te(CH₂)₃SMe (S₂Te) and H₂N(CH₂)₃Te(CH₂)₃NH₂ are described. The complexes of the former, fac-[Mn(CO)₃(S₂Te)]CF₃SO₃, [Rh(Cp*)(S₂Te)][PF₆]₂, [MCl(S₂Te)]PF₆ (M=Pd or Pt), [Cu(S₂Te)]BF₄ and [Ag(S₂Te)]CF₃SO₃ have been prepared and characterised by analysis, IR, ¹H-, ¹³C{¹H}-, ¹²⁵Te- and ¹⁹⁵Pt-NMR spectroscopy and mass spectrometry. The X-ray crystal structures of [Rh(Cp*)(S₂Te)][PF₆]₂ and [PtCl(S₂Te)]PF₆ are described. The results are compared with those obtained from complexes of the related tridentates Te{(CH₂)₃TeR}₂, Se{(CH₂)₃SeMe}₂ and S{(CH₂)₃SR}₂.     

[Ru(phen)2(H2bbim)](PF6)2配合物的阴离子识别研究

利用紫外-可见吸收光谱和核磁研究了[Ru(phen)2(H2bbim)](PF6)2配合物与Cl-,Br-,I-,NO3-,HSO4-,H2PO4-,OAc-和F-离子之间的作用。结果表明OAc-和F-可以使该配合物苯并联咪唑上的质子逐步脱去,相应的溶液颜色由黄色变为橙棕色,最后变为紫色。因此该配合物可以对阴离子实现目视识别。     

Dimethylchalkogenide als liganden in kationischen cyclopentadienyleisen-bis(phosphin)-komplexen: synthese, reaktivität und kristallstruktur von [C5H5Fe(P(OCH3)3)2(S(CH3)2)]PF6

Thermal displacement of coordinated nitriles RCN (R = CH₃, C₂H₅ or n-C₃H₇) in [C₅H₅Fe(L₂)(NCR)]X complexes (L₂ = P(OCH₃)₃)₂, (P(OC₆H₅)₃)₂ or (C₆H₅)₂PC₂H₄P(C₆H₅)₂ (DPPE)) by E(CH₃)₂ affords high yields of [C₅H₅Fe(L₂)(E(CH₃)₂)]X compounds (E = S, Se and Te; X = BF₄ or PF₆). Spectroscopic data and ligand displacement reactions are presented and discussed together with related observations on [C₅H₅Fe(CO)₂(E(CH₃)₂)]BF₄ compounds. The molecular structure of [C₅H₅Fe(P(OCH₃)₃)₂(S(CH₃)₂)]PF₆ was determined by a single-crystal X-ray diffraction study: monoclinic, space group P2₁/n-C⁵_2h (No. 14) with a = 8.4064(12), b = 11.183(2), c = 50.726(8) Å, β = 90.672(13)° and Z = 8 molecules per unit cell. The coordination sphere of the iron atom is pseudo-tetrahedral with an Fe---S bond distance of 2.238 Å.     

Field desorption mass spectra of [M(CO)3(η-arene)]X (MMn,Re; XBF4, PF6) salts

Field desorption mass spectra are reported for a range of [M(CO)₃(η-arene)]X (MMn or Re, XBF₄ or PF₆) salts. In most cases the spectra are simple, being dominated by molecular, [M]^+·, [M + 1]⁺, and [MCO]⁺ ions for the cationic part of their structure. However, with the π-chloroarene complexes [Mn(CO)₃(η-ClC₆H₅)]PF₆ and [Mn(CO)₃(η-1-Cl, 4-MeC₆H₄)]PF₆, facile loss of the chloro substituent and further fragmentation leads to unusually complex spectra, which include strong peaks arising from recombination of fragment species. Cluster ions are also noted in several cases, allowing identification of the anion.     

The reactivity of [ReBr3(MeCN)(dppe)] towards gaseous nitric oxide. The X-ray structure of [ReBr3(MeCN)(dppe)] and [ReBr3(NO)(dppe)]0.57[ReOBr3(dppe)]0.43 and DFT calculations for [ReBr3(NO)(dppe)] and [ReOBr3(dppe)]

The [ReOBr₃(dppe)] (dppe=bis(diphenylophosphino)ethane) complex reacts with acetonitrile in the presence of excess of triphenylphpsphine to give a new monomeric nitrile rhenium(III) complex—[ReBr₃(MeCN)(dppe)] (1). The reaction of 1 with gaseous nitric oxide leads to the mixed [ReBr₃(NO)(dppe)]_0.57[ReOBr₃(dppe)]_0.43 complex (2) with rhenium atoms on +2 and +5 oxidation states. This paper presents the synthesis, spectroscopic characterisation and X-ray structure of 1 and 2. The geometries of [ReBr₃(NO)(dppe)] and [ReOBr₃(dppe)] have been optimized using the density functional theory (DFT) and the electronic transitions of [ReBr₃(NO)(dppe)] and [ReOBr₃(dppe)] have been calculated with the time-dependent DFT method (TDDFT). The UV–vis spectrum of 2 has been interpreted on the basis of the experimental data for [ReOBr₃(dppe)] and the calculated transitions for [ReOBr₃(dppe)] and [Re(NO)Br₃(dppe)].     

B(C6F5)3-catalyzed metal-free hydrogenations of 2-quinolinecarboxylates

A metal-free hydrogenation of 2-quinolinecarboxylates has been realized by using 5?mol% of B(C₆F₅)₃ as catalyst. A variety of tetrahydroquinolines were obtained in 57–99% yields. An attempt for the asymmetric hydrogenation with chiral boron Lewis acids generated from chiral dienes afforded very low ee’s.     

Anion effect on the thermolysis of double complexes [Co(NH3)6][Fe(CN)6] and [Co(NH3)6]4[Fe(CN)6]3

The thermolysis of complexes [Co(NH₃)₆][Fe(CN)₆] and [Co(NH_{3 6}]₄[Fe(CN)₆]₃ under an air or hydrogen atmosphere at 200, 350, and 500°C is studied. The composition and properties of thermolysis products are determined. The oxidative thermolysis yields mixtures of oxides of the central metals; the reductive thermolysis yields intermetallic compounds CoFe. The density of the complexes and the specific surface area of the intermetallic compounds are measured. Average particle sizes are calculated. The morphology and dispersion of the powders are dictated by the shape and density of the crystals of the precursor double salts and the thermolysis temperature. The thermolysis chemism in the oxidative and reductive atmospheres is discussed in the context of the nature of the complex anion. Original Russian Text ? S.I. Pechenyuk, D.P. Domonov, D.L. Rogachev, A.T. Belyavskii, 2007, published in Zhurnal Neorganicheskoi Khimii, 2007, Vol. 52, No. 7, pp. 1110–1115.     

The reactions of Ir(CO)Cl(PPh3)2 with HSnPh3

A reinvestigation of the reaction of Ir(CO)Cl(PPh₃)₂, 1 with HSnPh₃ has revealed that the oxidative-addition product Ir(CO)Cl(PPh₃)₂(H)(SnPh₃), 2 has the H and SnPh₃ ligands in cis-related coordination sites. Compound 2 reacts with a second equivalent of HSnPh₃ by a Cl for H ligand exchange to yield the new compound H₂Ir(CO)(SnPh₃)(PPh₃)₂, 3. Compound 3 contains two cis- related hydride ligands. Under an atmosphere of CO, 1 reacts with HSnPh₃ to replace the Cl ligand with SnPh₃ and one of the PPh₃ ligands with a CO ligand and also adds a second equivalent of CO to yield the 5-coordinate complex Ir(CO)₃(SnPh₃)(PPh₃), 4. Compound 4 reacts with HSnPh₃ by loss of CO and oxidative addition of the Sn-H bond to yield the 6-coordinate complex HIr(CO)₂(SnPh₃)₂(PPh₃), 5 that contains two trans-positioned SnPh₃ ligands.     

One-and two-dimensional silver-tetramethylpyrazine coordination polymers with uncoordinated anions: Synthesis and structure of [Ag(Me4Pyz)]PF6 and [Ag2(Me4Pyz)3](BF4)2·H2O

Coordination polymers [Ag(Me₄Pyz)] PF₆(I) and [Ag₂(Me₄Pyz)₃](BF₄)₂·H₂O (II) have been synthesized, and their structures have been determined. The crystals of I are monoclinic, space group C2/c, a = 9.440(2) ?, b = 10.587(2) ?, c = 13.165(3) ?, β= 107.19(3)°, V = 1257.0(5) ?³, d = 2.056 g/cm³, Z = 4. The crystals of II are monoclinic, space group P2₁/n, a = 13.062(3) ?, b = 12.259(2) ?, c = 18.996(4) ?, β = 97.73(3)°, V = 3014.1(11)?³, ρ = 1.798 g/cm³, Z = 4. The structure of I is built of linear polymeric cations [Ag(C₈H₁₂N₂)] _∞ ⁺ and octahedral anions [PF₆]⁻. Upon the interaction of tetramethylpyrazine molecule with Ag⁺ ions, intersecting polymeric chains [Ag(C₈H₁₂)] _∞ ⁺ (1D polymer) are formed extending in mutually perpendicular diagonal directions. The structure of II consists of layers (2D polymers) formed by fused sixmembered rings. These rings consist of Ag⁺ ions linked by bridging ligands Me₄Pyz. Original Russian Text ? Yu.V. Kokunov, Yu.E. Gorbunova, 2007, published in Zhurnal Neorganicheskoi Khimii, 2007, Vol. 52, No. 5, pp. 743–750.