Preparation,characterization and a kinetic study oftrans-[Ru(NH3)4L(H2O)](PF6)2 [L=PPh3, AsPh3, or SbPh3]

Summary The complexestrans-[Ru(NH₃)₄(H₂O)PPh₃](PF₆)₂ and [Ru(NH₃)₅L](PF₆)₂, (L=AsPh₃ or SbPh₃) have been isolated and characterized by microanalysis, cyclic voltammetry and ultraviolet-visible spectroscopy. The specific rate constants for the aquation of [Ru(NH₃)₅L]²⁺ totrans-[Ru(NH₃)₄L(H₂O)]²⁺ are (2.5±0.1)×10^–5s^–1 and (1.8±0.1)×10^–5s^–1 for L=AsPh₃ and SbPh₃, respectively, at 25.0±0.1°C; =0.10 mol dm^–3, NaO₂CCF₃. Under the same conditions, the second-order rate constants for the substitution of water intrans-[Ru(NH₃)₄(H₂O)L]²⁺ by isonicotinamide (isn) are 1.2±0.1, (6.3±0.3)×10^–2 and (3.8±0.2)×10^–2 m ^–1s^–1 for L=PPh₃, AsPh₃, and SbPh₃, respectively, suggesting that the order of decreasingtrans-effect is: PPh₃AsPh₃>SbPh₃. The formation constants for thetrans-[Ru(NH₃)₄L(isn)]²⁺ complexes are 75±3, (1.40±0.01)×10³ and (1.80±0.02)×10³M^–1 for L=PPh₃, AsPh₃, and SbPh₃, respectively, suggesting that the order of increasingtrans-influence is: SbPh₃3PPh₃.     

A high-yield synthetic approach to trans-[Ir(ER3)2(CO)X] (ER3=PMe3, PEt3, PPhMe2, PPh2Me,P(OMe)3, AsMe3, AsEt3, AsPh3, SbPh3; X=Cl,Br)

The complex [Ir(CO)₂X₂][NBu₄] (X=Cl, Br) forms Vaska-type complexes, trans-[Ir(ER₃)₂(CO)X], when treated with two equivalents of aryl- or alkyl-phosphines, arsines, or stibines under a CO atmosphere. The synthesis is general for a wide range of phosphines, arsines, or stibines irrespective of the cone angle. For small cone-angle ligands, the initial addition of ligand to [Ir(CO)₂X₂][NBu₄] is performed at low temperature. The synthesis and characterisation of three new Vaska-type complexes trans-[Ir(P(OMe)₃)₂(CO)Cl], trans-[Ir(AsMe₃)₂(CO)Cl], and trans-[Ir(AsEt₃)₂(CO)Cl] is also reported.     

Reactions of nitrosyl chloride with [Ni(PPh3)2X2] (X=Cl,Br, NCS or NO3)

Summary Nitrosyl chloride has been treated with [Ni(PPh₃)₂X₂] (X = Cl, Br, NCS or NO₃) to obtain [Ni(PPh₃)XCl]₂ (X=Cl, Br, NCS or NO₃) and [Ni(OPPh₃)(SCN)Cl]₂. The compounds obtained were characterised by analyses, infrared (including far i.r.) and visible spectral studies, magnetic moment and conductivity measurements and many chemical reactions. It is proposed that the compounds have a dimeric structure with a distorted tetrahedral environment around the nickel atom and chloro-bridges.     

Reactions of [ReX5(NO)]2− with triphenylstibine. Spectroscopic investigations of [ReX2(NO)(SbPh3)3], X-ray structures of [ReCl2(NO)(SbPh3)3] and [ReBr2Cl(SbPh3)3] and DFT calculations for [ReCl2(NO)(SbPh3)3]

The reactions of [NBu₄]₂[ReX₅(NO)] (X = Cl, Br) with triphenylstibine have been examined and three new rhenium complexes – [ReCl₂(NO)(SbPh₃)₃] (1), [ReBr₂(NO)(SbPh₃)₃] (2) and [ReBr₂Cl(SbPh₃)₃] (3) – have been obtained. The last one has been isolated in a low yield during slow recrystallization of the complex 2 from a mixture of chloroform and ethanol. The stibine rhenium nitrosyls have been characterized by IR and UV–vis spectroscopy. The X-ray structures of 1 and 3 have been determined. The geometric parameters of 1 have been examined using the density functional theory (DFT) method.     

Reactions of [ReOX3(PPh3)2] Complexes (X = Cl,Br) with Phenylacetylene and the Structures of the Products

Oxorhenium(V) complexes [ReOX₃(PPh₃)₂] (X = Cl, Br) react with phenylacetylene under formation of complexes with ylide‐type ligands. Compounds of the compositions [ReOCl₃(PPh₃){C(Ph)C(H)(PPh₃)}] ( 1 ), [ReOBr₃(OPPh₃){C(Ph)C(H)(PPh₃)}] ( 2 ), and [ReOBr₃(OPPh₃){C(H)C(Ph)(PPh₃)}] ( 3 ) were isolated and characterized by X‐ray diffraction. They contain a ligand, which was formed by a nucleophilic attack of released PPh₃ at coordinated phenylacetylene. The structures of the products show that there is no preferable position for this attack. Cleavage of the Re–C bond in 3 and dimerization of the organic ligand resulted in the formation of the [{(PPh₃)(H)CC(Ph)}₂]²⁺ cation, which crystallized as its [(ReOBr₄)(OReO₃)]^2– salt.     

Substitution reactions of trans-[PdXPh(SbPh3)2J (X=Cl or Br) with nitrogen,phosphines and arsenic donor ligands. Crystal structures of trans-[PdClPh(PPh3)2], [PdClPh(bipy)], [PdClPh(dppm)]2, and [PdBrPh(dppm)]2

Exchange reactions of trans-[PdXPh(SbPh₃)₂] (1) (X=Cl or Br) with ligands L in refluxing dichloromethane give the palladium phenyl complexes [PdXPhL₂] (X=Cl, L=PPh₃, AsPh₃, L₂=2,2′-bipyridine (bipy), 4,4′-dimethyl-2,2′-bipyridine (dmbipy), 1,10-phenanthroline (phen); X=Br, L=PPh₃, L₂=bipy). Treatment of the complexes with bis(diphenylphosphino)methane (dppm) in refluxing dichloromethane gives [PdXPh(dppm]₂. These complexes have been characterised by microanalysis, IR and ¹H NMR spectroscopic data together with single crystal X-ray determinations of the phenyl palladium complexes, trans-[PdClPh(PPh₃)₂], [PdClPh(bipy)], [PdClPh(dppm)]₂, and [PdBrPh(dppm)]₂.     

Reactions of nitrilium triflate salts with trans-[IrCl(CO)(PPh3)2

Low yields of the ionic carbene complexes [Ir(RCNHMe)Cl(CO)(PPh₃)₂-(O₃SCF₃)]O₃SCF₃]O₃SCF₃ (R  Ph or PhCH₂) have been isolated from the reactions of trans-[IrCl(CO)(PPh₃)₂] with the nitrilium triflate salts, [RCNMe]O₃SCF₃. The major products from these, and the similar reactions of the nitrilium salts where R  Me or Bu^t, are amorphous, yellow complexes [Ir(RCNHMe)Cl(CO)(PPh₃)₂O₃SCF₃.     

Structural Characterization of trans-[Cr(NH3)4(H2O)Cl]Cl2 and trans-[Cr(NH3)4Cl2]l

Trans-[Cr(NH₃)₄(H₂O)Cl]Cl₂ (A) crystallizes in the monoclinic space group P2₁/m (No. 11) with a = 6.556(1), b = 10.630(5), c = 6.729(2) Å and β = 96.15(3)°. Trans-[Cr(NH₃)₄Cl₂]I (B) has monoclinic C2/m (No. 12) space group and a = 9.877(2), b = 8.497(2), c = 6.047(2) Å and β = 108.98(2)°. Both unit cells contain two formula units. Cr? Cl, Cr? O(H₂O) and three independent Cr? N(NH₃) distances for A are 2.98(1), 2.023(2), 2.067(2), 2.086(3) and 2.064(3) °. Cr? Cl and Cr? N(NH₃) bonds in B are 2.325(1) and 2.071(2) °. All octahedral angles are close to 90 and 180°. Both structures were refined to very low R values. Water molecule from trans-[Cr(NH₃)₄(H₂O)Cl]²⁺ is hydrogen bonded to both ionic chlorides. Cation and two anions form the motive which repeats itself in the crystal. Cations and anions of the second structure are distributed in layers. Each cation and anion have coordination number eight.     

铂氢化物trans-[PtH(tu)(PPh_3)_2]Cl(tu)(THF)_2(tu=SC(NH_2)_2)的结构

制得含硫脲配体的铂氢化物单晶trans-[PtH(tu)(PPh_3)_2]Cl(tu)(THF)_2,其结构测定结果为:C_(46)H_(55)N_4O_2P_2S_2ClPt M=1052.6,单斜晶系,空间群为 P2_1/c,a=12.103(1),b=21.619(3),c=20.189(4)(?),β=103.31(0)°,V=5140(2)(?)~3,Z=4,D_c=1.360g·cm~(-3),F(000)=2128,R=0.050,R_w=0.063.Pt(Ⅱ)与两个磷、一个硫脲分子的硫和一个氢相配合,形成四边形配位。     

The vibrational spectra of isotopically substituted metal carbonyls : V. C18-O-substituted cis-Mn(CO)4LBr (L = PPh3, AsPh3, SbPh3)

The reactions of cis-Mn(CO)₄LBr (L = PPh₃, AsPh₃, SbPh₃) with 96%¹⁸O-enriched CO in cyclohexane solution at 35°C have been investigated by IR spectroscopy in the ν(CO) region and the vibrational modes of the parent molecules and the various C¹⁸O-substituted species produced have ben assigned with the aid of approximate force field calculations for the energy-factored CO stretching blocks of the (FG) matrices. The IR data for the reaction of the triphenylphosphine complex indicate that, while all four carbonyl groups are eventually replaced by C¹⁸O, there is initially a stereochemical preference for axial CO substitution. For the other two complexes, both carbonyl and L substitution take place.     

Synthesis of RuHCl(CO)(Hdmpz)(L)2 (L=PPh3, AsPh3, and Hdmpz=3,5-dimethylpyrazole) and crystal structure of RuHCl(CO)(Hdmpz)(AsPh3)2

Treatment of RuHCl(CO)(L)₃ with a slight excess amount of K[HB(3,5-Me₂pz)₃] in boiling MeOH solution yielded unusual 3,5-dimethylpyrzaole (Hdmpz) complexes, RuHCl(CO)(Hdmpz)(L)₂ (L=PPh₃, 1 or AsPh₃, 2). Unexpectedly the dissociation of the bonds between the boron atom and the nitrogen atoms of the potentially tridentate [HB(3,5-Me₂pz)₃]⁻ ligand during the coordination of the ligand to the Ru^II metal has been observed. In a separate preparation, the RuHCl(CO)(Hdmpz)(PPh₃)₂ complex has also been synthesized from the reaction between RuHCl(CO)(PPh₃)₃ and the monodentate Hdmpz ligand. Complexes 1 and 2 have been characterized by elemental analysis, IR and ¹H NMR spectroscopies. Compound 1 has also been prepared by the reaction between RuHCl(CO)(PPh₃)₃ and K[H₂B(3,5-Me₂pz)₂] in boiling toluene solution. The crystal structure of 2 has been studied by X-ray crystallography. The geometrical structure around Ru^II of 2 is a distorted octahedral structure. The crystal structure of 2 consists of a discrete monomeric compound. It is interesting to find that the sterically-demanding [HB(3,5-Me₂pz)₃]⁻ or [H₂B(3,5-Me₂pz)₂]⁻ ligands break up during the reaction with the Ru^II complexes to form the neutral 3,5-dimethylpyrazole complexes. In contrast to these observations, [H₂Bpz₂]⁻ and [H₂B(4-Brpz)₂]⁻ ligands form very stable Ru^II complexes.     

Structural, dynamic, and theoretical studies of [AunPt2(PPh3)4(mu-S)2-n(mu 3-S)nL][PF6]n [n = 1, L = PPh3; n = 2, L = Ph2PCH2PPh2, (C5H4PPh2)2Fe

Three heterometallic Au-Pt complexes [Pt2(PPh3)4(mu-S)(mu 3-S)Au(PPh3)][PF6] (2), [Pt2(PPh3)4(mu 3-S)2Au2(mu-dppm)]-[PF6]2 (3), and [Pt2(PPh3)4(mu 3-S)2Au2(mu-dppf)][PF6]2 (4) have been synthesized from Pt2(PPh3)4(mu-S)2 (1) [dppm = Ph2PCH2PPh2; dppf = (C5H4PPh2)2Fe] and characterized by single-crystal X-ray crystallography. In 2, the Au(I) atom is anchored on only one of the sulfur centers. In 3 and 4, both sulfur atoms are aurated, showing the ability of 1 to support an overhead bridge structure, viz. [Au2(P-P)], with or without the presence of Au-Au bond. The change of dppf to dppm facilitates such active interactions. Two stereoisomers of complex 3 (3a,b) have been obtained and characterized by single-crystal X-ray crystallography. NLDFT calculations on 2 show that the linear coordination mode is stabilized with respect to the trigonal planar mode by 14.0 kJ/mol. All complexes (2-4) are fluxional in solution with different mechanisms. In 2, the [Au(PPh3)] fragment switches rapidly between the two sulfur sites. Our hybrid MM-NLDFT calculations found a transition state in which the Au(I) bears an irregular trigonal planar geometry (delta G++ = 19.9 kJ/mol), as well as an intermediate in which Au(I) adopts a regular trigonal planar geometry. Complexes 3a,b are roughly diastereoisomeric and related by sigma (mirror plane) conversion. This symmetry operation can be broken down to two mutually dependent fluxional processes: (i) rapid flipping of the dppm methylene group across the molecular plane defined by the overhead bridge; (ii) rocking motion of the two Au atoms across the S...S axis of the (Pt2S2) core. Modeling of the former by molecular mechanics yields a steric barrier of 29.0 kJ/mol, close to that obtained from variable-temperature 31P(1Hz) NMR study (33.7 kJ/mol). In 4, the twisting of the ferrocenyl moiety across the S...S axis is in concert with a rocking motion of the two gold atoms. The movement of dppf is sterically most demanding, and hence, 4 is the only complex that shows a static structure at lower temperatures. Pertinent crystallographic data: (2) space group P1, a = 15.0340(5) A, b = 15.5009(5) A, c = 21.9604(7) A, alpha = 74.805(1) degrees, beta = 85.733(1) degrees, gamma = 78.553(1) degrees, R = 0.0500; (3a) space group Pna2(1), a = 32.0538(4) A, b = 16.0822(3) A, c = 18.9388(3) A, R = 0.0347; (3b) space group Pna2(1), a = 31.950(2) A, b = 16.0157(8) A, c = 18.8460(9) A, R = 0.0478; (4) space group P2(1)/c, a = 13.8668(2) A, b = 51.7754(4) A, c = 15.9660(2) A, beta = 113.786(1) degrees, R = 0.0649.     

Electronic and steric effects on molecular dihydrogen activation in [CpOsH4(L)]+ (L = PPh3, AsPh3, and PCy3)

Single-crystal neutron diffraction, inelastic neutron scattering, and density functional calculations provide experimental and theoretical analyses of the nature of the osmium-bound, "elongated" dihydrogen ligands in [Cp*OsH(4)(L)][BF(4)] complexes (L = PPh(3), AsPh(3), or PCy(3)). The PPh(3) and AsPh(3) complexes clearly contain one dihydrogen ligand and two terminal hydrides; the H(2) ligand is transoid to the Lewis base, and the H-H vector connecting the central two hydrogen atoms lies parallel to the Ct-Os-L plane (Ct = centroid of Cp* ring). In contrast, in the PCy(3) complex the H-H vector is perpendicular to the Ct-Os-L plane. Not only the orientation of the central two hydrogen atoms but also the H-H bond length between them depends significantly on the nature of L: the H...H distance determined from neutron diffraction is 1.01(1) and 1.08(1) A for L = PPh(3) and AsPh(3), respectively, but 1.31(3) A for L = PCy(3). Density functional calculations show that there is a delicate balance of electronic and steric influences created by the L ligand that change the molecular geometry (steric interactions between the Cp* and L groups most importantly change the Ct-Os-L angle), changing the relative energy of the Os 5d orbitals, which in turn govern the H-H distance, preferred H-H orientation, and rotational dynamics of the elongated dihydrogen ligand. The geometry of the dihydrogen ligand is further tuned by interactions with the BF(4)(-) counterion. The rotational barrier of the bound H(2) ligand in [Cp*OsH(4)(PPh(3))](+), determined experimentally (3.1 kcal mol(-)(1)) from inelastic neutron scattering experiments, is in reasonable agreement with the B3LYP calculated H(2) rotational barrier (2.5 kcal mol(-)(1)).     

Seven-coordinate complexes of molybdenum(II) and tungsten(II). Preparation and spectral properties of [MI2(CO)3LL′] {M=Mo or W; L=PPh3, AsPh3 or SbPh3; L′=SC(NH2)2, SC(NMe2)2 or SC(NH2)Me}

Summary The seven-coordinate complexes [MI₂(CO)₃(NCMe)₂] (M=Mo or W) react either in acetone or methanol with one equivalent of L (L=PPh₃, AsPh₃ or SbPh₃) to give [MI₂(CO)₃(NCMe)L], which when reactedin situ with one equivalent of L {L=SC(NH₂)₂, SC(NMe₂)₂ or SC(NH₂)Me} affords good yields of the new mixed complexes [MI₂(CO)₃LL]via successive displacement of acetonitrile ligands.     

Reactions of the Complexes ReNCl2(PMe2Ph)3, [ReNCl4]—, [OsO3N]—, and Cl3VNCl with Metal Halides

The nitrido complexes ReNCl₂(PMe₂Ph)₃ and [OsO₃N]^— have strong basic terminal nitrido ligands which can react with Lewis acidic metal halides to form nitrido bridges. The synthesis and structure of complexes with ReNCl₂(PMe₂Ph)₃ and nitrido bridges Re≡N‐M (M = B, Ga, Sn, Ti, Zr, V, Nb, Ta, Mo, Re, Pd, Au, and Zn) as well as of complexes with [OsO₃N]^— and nitrido bridges Os≡N‐M (M = Pd and Pt) are reported. Strong Lewis acids can also remove phosphine or chloro ligands from ReNCl₂(PMe₂Ph)₃. The resulting complex fragments subsequently combine to yield oligomeric complexes with nitrido bridges Re≡N‐Re. If the reaction with strong Lewis acids is carried out in a chlorinated solvent the solvent can be decomposed to form HCl which then protonates the nitrido ligand affording an imido complex. [ReNCl₄]^— is able to form nitrido bridges to electrophilic halides if a donor ligand is coordinated in trans position to the nitrido ligand to enhance its basicity sufficiently. The synthesis and structure of examples with nitrido bridges Re≡N‐M (M = Pd, Pt, Ta) are reported. The chloro imido complex Cl₃V≡N‐Cl can act as a nitride ion transfer reagent. Its reaction with MoCl₅ yields Mo₂NCl₈ whereas with MoCl₃ the nitride chlorides Mo₃N₂Cl₁₁ and MoNCl₃ are obtained. Cl₃VNCl can also act as an reactive intermediate by the reaction of VN with a halide as was shown by the reaction of MoCl₅ with VN yielding Mo₂NCl₇. The structures of these molybdenum nitride chlorides are discussed.     

Syntheses, structural determinations of [Ru(ROCS2)2(PPh3)2](+/0) pairs, and kinetic analyses of thermal reactions involving transient trans-[Ru(iPrOCS2)2(PPh3)2] species (ROCS2(-) = ethyl- or isopropyldithiocarbonate and PPh3 = triphenylphosphine)

Controlled-potential electrochemical oxidation of cis-[Ru(ROCS2)2(PPh3)2] (R = Et, iPr) yielded corresponding Ru(III) complexes, and the crystal structures of cis-[Ru(ROCS2)2(PPh3)2] and trans-[Ru(ROCS2)2(PPh3)2](PF6) were determined. Both pairs of complexes exhibited almost identical coordination structures. The Ru-P distances in trans-[Ru(III)(ROCS2)2(PPh3)2](PF6) [2.436(3)-2.443(3) A] were significantly longer than those in cis-[Ru(II)(ROCS2)2(PPh3)2] [2.306(1)-2.315(2) A]: the smaller ionic radius of Ru(III) than that of Ru(II) stabilizes the trans conformation for the Ru(III) complex due to the steric requirement of bulky phosphine ligands while mutual trans influence by the phosphine ligands induces significant elongation of the Ru(III)-P bonds. Cyclic voltammograms of the cis-[Ru(ROCS2)2(PPh3)2] and trans-[Ru(ROCS2)2(PPh3)2]+ complexes in dichloromethane solution exhibited typical dual redox signals corresponding to the cis-[Ru(ROCS2)2(PPh3)2](+/0) (ca. +0.15 and +0.10 V vs ferrocenium/ferrocene couple for R = Et and iPr, respectively) and to trans-[Ru(ROCS2)2(PPh3)2](+/0) (-0.05 and -0.15 V vs ferrocenium/ferrocene for R = Et and iPr, respectively) couples. Analyses on the basis of the Nicholson and Shain's method revealed that the thermal disappearance rate of transient trans-[Ru(ROCS2)2(PPh3)2] was dependent on the concentration of PPh3 in the bulk: the rate constant for the intramolecular isomerization reaction of trans-[Ru(iPrOCS2)2(PPh3)2] was determined as 0.338 +/- 0.004 s(-1) at 298.3 K (deltaH* = 41.8 +/- 1.5 kJ mol(-1) and deltaS* = -114 +/- 7 J mol(-1) K(-1)), while the dissociation rate constant of coordinated PPh3 from the trans-[Ru(iPrOCS2)2(PPh3)2] species was estimated as 0.113 +/- 0.008 s(-1) at 298.3 K (deltaH* = 97.6 +/- 0.8 kJ mol(-1) and deltaS* = 64 +/- 3 J mol(-1) K(-1)), by monitoring the EC reaction (electrode reaction followed by chemical processes) at different concentrations of PPh3 in the bulk. It was found that the trans to cis isomerization reaction takes place via the partial dissociation of iPrOCS2(-) from Ru(II), contrary to the previous claim that it takes place by the twist mechanism.