Synthesis of big palladium clusters. Preparation of Pd23(CO)20(PEt3)8

Selective methods for the synthesis of the cluster Pd₂₃(CO)₂₀L₈, L=PEt₃, have been suggested. The compound has been prepared by two routes: by the reaction of Pd₁₀(CO)₁₂L₆ with Me₃NO in the presence of HOAc with removal of CO from the gas phase, and by the reaction of Pd₁₀(CO)₁₂L₆ with Pd(OAc)₂ and CO followed by oxidation by Me₃NO in an inert atmosphere.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1299–1300, July, 1993.     

High Nuclearity Bimetallic Rhodium–Palladium Carbonyl Cluster Complexes. Synthesis and Characterization of Rh6(CO)16[Pd(PBu t 3)]3 and Rh6(CO)16[Pd(PBu t 3)]4

The reaction of Rh₄(CO)₁₂ with Pd(PBu ^t ₃)₂ yielded the high nuclearity bimetallic hexarhodium-tripalladium cluster complex Rh₆(CO)₁₆[Pd(PBu ^t ₃)]₃, 10, in 11% yield. Compound 10 was converted to the hexarhodium-tetrapalladium cluster Rh₆(CO)₁₆[Pd(PBu ^t ₃)]₄, 11, in 62% yield by reaction with an additional quantity of Pd(PBu ^t ₃)₂. Both compounds were characterized crystallographically. Structurally, both compounds consist of an octahedral cluster of six rhodium atoms with sixteen carbonyl ligands analogous to that of the known compound Rh₆(CO)₁₆. Compound 10 also contains three Pd(PBu ^t ₃) groups that bridge three Rh–Rh bonds along edges of the Rh₆ octahedron to give an overall D₃ symmetry to the Rh₆Pd₃ cluster. Compound 11 contains four edge bridging Pd(PBu ^t ₃) groups distributed across the Rh₆ octahedron to give an overall D_2d symmetry to the Rh₆Pd₄ cluster. Each Rh–Pd connection in both compounds contains a bridging carbonyl ligand that helps to stabilize the bond between the Pd(PBu ^t ₃) groups and the Rh atoms. Both compounds can be regarded as Pd(PBu ^t ₃) adducts of Rh₆(CO)₁₆.     

Distribution of ligands in polynuclear palladium complexes: DFT study of isomerism of Pd4(L)4(RCO2)4 (L = CO,CH2, NO) complexes

Structural isomerism of the Pd₄(L)₄(RCO₂)₄ (L = CO, CH₂, NO; R = CC1₃, CF₃, CH₃) complexes was studied in the framework of the density functional theory (DFT). Among the Pd₄(CO)₄(RCO₂)₄ and Pd₄(CH₂)4(RCO₂)₄ complexes the most stable were the isomers with alternate coordination of pairs of carbonyl and carboxylate ligands on the sides of a planar rectangular metal core. The isomers with the pairwise coordination of NO/RCO₂ on one side of the metal core are the most stable between the Pd₄(NO)₄(RCO₂)₄ complexes. The features of mutual coordination of ligands in polynuclear complexes of palladium are clarified using the obtained results.

     

Synthesis and Stereochemical/Electrochemical Analyses of Cuboctahedral-Based Pd23(CO) x (PR3)10 Clusters (x=20 with R3=Bu n 3, Me2Ph; x=20, 21, 22 with R3=Et3): Geometrically Analogous Pd23(PEt3)10 Fragments with Variable Carbonyl Ligations and Resulting Implications

This research was an outgrowth of previous reactions with [Pd₁₃Ni₁₃(CO)₃₄]^4? which produced a tetragonal crystal form of Pd₂₃(CO)₂₀(PEt₃)₁₀ (1) that has the same cuboctahedral-based Pd₂₃ framework with an identical number of PEt₃ ligands but two fewer CO ligands than the monoclinic crystal form of Pd₂₃(CO)₂₂(PEt₃)₁₀ (3) originally reported from reactions with Pd₁₀(CO)₁₂(PEt₃)₆. A subsequent investigation presented herein to establish whether the carbonyl capacity is influenced by the nature of the phosphine ligands has led to syntheses of Pd₂₃(CO) _x (PR₃)₁₀ [R₃=Et₃ (1), Bu ⁿ ₃ (4), and Me₂Ph (5)] with 20 CO ligands (x=20) from corresponding Pd₁₀(CO)₁₂(PR₃)₆ precursors either by deligation with Pd(OAc)₂, CF₃CO₂H, Ni(1,5-COD)₂, [NMe₄]₂[Ni₆(CO)₁₂], or HCO₂H or by spontaneous enlargement; yields varied from 15 to 79%. Although attempts to obtain the original Pd₂₃(CO)₂₂(PEt₃)₁₀ (3) were unsuccessful, a highly significant outcome was the isolation (one time) of another monoclinic crystal form possessing the triethylphosphine Pd₂₃(CO) _x (PEt₃)₁₀ cluster with 21 COs (2). Both the compositions and atomic arrangements for each of five Pd₂₃ clusters [1a (solvated); 1b (unsolvated); 2, 4, and 5] were unambiguously established from low-temperature single-crystal CCD X-ray crystallographic determinations in accordance with their nearly identical IR carbonyl frequencies. Solution ³¹P{¹H} NMR spectra of 1 and 4 at room temperature displayed three distinct signals with expected integral ratios of 2/4/4 that are consistent with the solid-state structures of Pd₂₃(CO)₂₀(PR₃)₁₀ [R₃=Et₃ (1), Bu ⁿ ₃ (4)] remaining intact in solution. The metal-core geometries of all of these Pd₂₃(CO) _x (PR₃)₁₀ clusters, including the thermodynamically stable ones with 20 CO ligands and the kinetic products with additional CO ligands (x=21, 22), are essentially the same. The common Pd₂₃ core may be best described as possessing a centered hexacapped cuboctahedral Pd₁₉ kernel (alternatively denoted as a centered ν₂ Pd₁₉ octahedron) with four edge-connected exopolyhedral wingtip Pd(exo) atoms that reduce the pseudo metal-core symmetry from O_h to D_2h. The 10 PR₃ ligands are linked to the six tetracapped Pd(cap) and four edge-capped wingtip Pd(exo) atoms; the latter four Pd(exo) atoms are each composed of four trigonal-planar Pd(μ₂-CO)₂(PR₃) units. These crystallographic results provide compelling geometrical evidence for a heretofore unknown stereochemical example involving variable carbonyl ligation (x=20, 21, 22) of a close-packed nanosized Pd _n (CO) _x (PR₃) _y cluster (in this case with identical PEt₃ ligands) without significant changes being induced in either the overall metal-core architecture or steric dispositions of the same number of PR₃ ligands. These experimental findings have particular relevance to the long-standing Muetterties cluster/surface science analogy in showing that the different number (as well as different modes) of carbonyl ligations observed in these large metal carbonyl clusters are directly related to pressure-induced dissociative/nondissociative migratory coverages in CO chemisorptions on metal surfaces. The observed expanded capacity of CO coordination on the same Pd₂₃ polyhedron without notable changes in geometry is no doubt a consequence of its virtually nanosized metal-core architecture; distances between outermost centrosymmetrically related pairs of Pd(cap) and Pd(exo) atoms in the Pd₂₃ framework are 0.8 and 0.9 nm, respectively. An electrochemical (CV) study revealed that 1 undergoes one quasi-reversible two-electron reduction to 1 ^2? (E_1/2=?0.91 V) and two consecutive quasi-reversible one-electron oxidations to 1/1 ⁺ at E_1/2=0.08 V and 1 ⁺/1 ²⁺ at E_1/2=0.32 V (THF; Ag/AgCl as reference electrode). A stereochemical/electronic analysis with the isostructural Au₂Pd₂₁(CO)₂₀(PEt₃)₁₀ analogue (9) and resulting implications are given.     

Synthesis and structure of polynuclear carbonylphosphine clusters of palladium

Reductive condensation of Pd(OAc)₂ in dioxane in the presence of CO and PR₃ (R = Et, Buⁿ) with addition of CF₃COOH leads to the formation of decanuclear Pd₁₀(μ₃-CO)₄(μ₂-CO)₈(PBuⁿ₃)₆ (I) and Pd₁₀(CO)₁₄(PBuⁿ₃) (II) at Pd(OAc)₂:PR₃ molar ratios of 1:4–1:10 and 1:1.5–1:2.5, respectively. The use of CH₃COOH instead of CF₃COOH results in tetranuclear clusters Pd₄(CO)₅(PR₃)₄ (III) and Pd₄(μ₂-CO)₆(PBuⁿ₃) (IV). I ? III and III → IV transformations occur in organic media. The structures of I (space group P2₁/n, Z = λMo, 12125 independent reflections, R = 0.047) and IV (Pz:3, Z = λMo, 3254 reflections, R = 0.098) were established by X-Ray diffractions analysis. Cluster I is a 10-vertex Pd₁₀ polyhedron, an octahedron with four unsymmetrically centered non-adjacent faces. The average PdPd distances in the octahedron are 2.825 Å, in the eight short Pd_oct.Pd_cap. bonds with the “equatorial” Pd atoms of the inner octahedron, bridged by the μ₂-CO ligands, are 2.709 Å, and in the four elongated (without bridging CO groups) bonds with the apical Pd atoms of the octahedron are 3.300–3.422 Å. The PBuⁿ₃ ligands are coordinated to the apical Pd atoms and the capping atoms (PdP 2.291–2.324 Å). Cluster IV is tetrahedral, with the CO ligands symmetrically bridged; PdPd 2.778–2.817; PdP 2.232–2.291; PdC 2.06 Å (average).     

An ESR study of photochemical reactions of Co2(CO)6(PBu3)2 with quinones and phenothiazine

The photochemical reactions of Co₂(CO)₆(PBu₃)₂ with various quinones and phenothiazine were studied by ESR. The results indicate that the photolysis of Co₂(CO)₆(PBu₃)₂ in the presence of o-quinones led to the observation of an ESR spectrum, showing a broad 8 or 12 groups of hyperfine lines due to interaction with cobalt (Co, 1 = 7/2). The results show that with o-quinones the cobalt radical adducts are formed via metal chelation to the carbonyl oxygens. However, when Co₂(CO)₆(PBu₃)₂ was irradiated in the presence of p-quinones, only the para-semiquinone radicals were observed. The photolysis of Co₂(CO)₆(PBu₃)₂ with phenothiazine in toluene yields phenothiazine radical. The sixteen and eighteen electrons rule have been used to account for these observations.     

Preparation,Spectroscopic Properties,and Crystal Structures of Fe2(CO)6(μ‐CO)(μ‐CF2)2, Fe2(CO)6(μ‐CO)2(μ‐CF2), and Fe2(CO)6(μ‐CF2)(PPh3)2 – Theoretical Studies of Methylenic vs. Carbonyl Bridges in Diiron Complexes

The reaction of Na₂[Fe(CO)₄] with Br₂CF₂ in n‐pentane generates a mixture of the compounds (CO)₃Fe(μ‐CO)_3–n(μ‐CF₂)_nFe(CO)₃ ( 2 , n = 2; 3 , n = 1) in low yields with 3 as the main product. 3 is obtained free from 2 by reacting Br₂CF₂ with Na₂[Fe₂(CO)₈]. The non‐isolable monomeric complex (CO)₄Fe=CF₂ ( 1 ) can probably considered as the precursor for 2 . 3 reacts with PPh₃ with replacement of two CO ligands to form Fe₂(CO)₆(μ‐CF₂)(PPh₃)₂ ( 4 ). The complexes 2 – 4 were characterized by single crystal X‐ray diffraction. While the structure of 2 is strictly similar to that of Fe₂(CO)₉, the structure of 3 can better be described as a resulting from superposition of the two enantiomers 3 a and 3 b with two semibridging CO groups. Quantum chemical DFT calculations for the series (CO)₃Fe(μCO)_3–n(μ‐CF₂)_nFe(CO)₃ (n = 0, 1, 2, 3) as well as for the corresponding (μ‐CH₂) derivatives indicate that the progressively larger σ donor and π acceptor properties for the bridging ligands, in the order CO < CF₂ < CH₂, favor a stronger Fe–Fe bond.     

Mass spectrometry of metal compounds: II—mass spectrometric studies of [CF3EMn(CO)4]2, [CF3EFe(CO)3]2 (E = S,Se), CF3SeFe(CO)2C5H5 and CF3SCr(NO)2C5H5

The electron impact induced mass spectra of [CF₃SMn(CO)₄]₂, [CF₃SeMn(CO)₄]₂, [CF₃SFe(CO)₃]₂, [CF₃SeFe(CO)₃]₂, CF₃SeFe(CO)₂C₅H₅ and CF₃SCr(NO)₂C₅H₅ are reported. These compounds exhibit weak molecular ion peaks and undergo preferential loss of CO or NO groups. The CO or NO free fragments suffer typical loss of ECF₂(E = S, Se) with the simultaneous shift of F from carbon to metal. The ions [FFeC₅H₅]⁺ and [FCrC₅H₅]⁺ in the spectra of the cyclopentadienyl compounds prefer expulsion of π-cyclopentadienyls. The pyrolysis effects on the spectra of the compounds have been studied. An increase in temperature eases the expulsion of ECF₂ groups from all the compounds and favors the formation of [Fe(C₅H₅)₂]⁺ and [Cr(C₅H₅)₂]⁺ in the cyclopentadienyl compounds.     

Kinetics of protonation of tungsten hydrides WH(CO)2(NO)L2 by weak OH-acids

The kinetics of protonation of tungsten hydrides WH(CO)₂(NO)L₂ (1, L = PMe₃, PEt₃, P(OPri)₃, PPh₃) by weak OH-acids (PhOH, (CF₃)₂CHOH, (CF₃)₃COH) in hexane was studied by IR spectroscopy. The study of the reactions of compounds 1 with OH-acids at 190–270 K revealed that the first step involves the formation of dihydrogen-bonded W(CO)₂(NO)L₂(H)...HOR complexes. When the temperature increases to ambient, the proton transfer and evolution of molecular hydrogen occur, affording the final products: organyloxy derivatives W(OR)(CO)₂(NO)L₂. The study of the kinetics at 298 K found that the proton transfer is the rate-determining step. The rate constants k _app are 2.2·10⁻⁵–6.3·10⁻⁴ s⁻¹, and the free activation energies are ΔG ^≠ _298K = 22–23 kcal mol⁻¹. The rate constants depend on the proton-accepting properties of the hydride and the acidic properties of the OH-proton donor and increase in the same order as the enthalpy of hydrogen bond formation. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 837–841, May, 2007.     

Perfluormethyl-Element-Liganden. XVIII. Darstellung und spektroskopische Untersuchung von M(CO)5L und M(CO)4L2-Komplexen [L = MenP(CF3)3−n; n = 0–3; M = Cr,Mo, W]

Perfluoromethyl-Element-Ligands. XVIII. Preparation and Spectroscopic Investigation of M(CO)₅L and M(CO)₄L₂ Complexes [L = Me_nP(CF₃)_3?n; n = 0–3; M = Cr, Mo, W] M(CO)₅L and cis-M(CO)₄L₂ complexes, respectively [M = Cr, Mo, W; L = Me_nP(CF₃)_3?n; n = 0–3] are prepared reacting M(CO)₅ · THF or M(CO)₄norbor with L at room temperature. The cis-compounds isomerize above 50°C yielding the trans-complexes; the rate of isomerization increases with increasing number of CF₃ groups. Thermal reaction of M(CO)₆ (M = Cr, Mo, W) with P(CF₃)₃ yields M(CO)₅P(CF₃)₃ and trans-M(CO)₄[P(CF₃)₃]₂. Introduction of three P(CF₃)₃ ligands by reaction with M(CO)₃(cycloheptatriene) (M = Cr, Mo) proves unsuccessful; besides little M(CO)₅P(CF₃)₃ trans-M(CO)₄[P(CF₃)₃]₂ is formed. The new compounds are characterized by analytical and spectroscopic (n.m.r., i.r., MS) methods.     

[M(CO)2(NO)], a new core in bioorganometallic chemistry: model complexes of [Re(CO)2(NO)] and [Tc(CO)2(NO)]

In this study selected bidentate (L²) and tridentate (L³) ligands were coordinated to the Re(I) or Tc(I) core [M(CO)₂(NO)]²⁺ resulting in complexes of the general formula fac-[MX(L²)(CO)₂(NO)] and fac-[M(L³)(CO)₂(NO)] (M = Re or Tc; X = Br or Cl). The complexes were obtained directly from the reaction of [M(CO)₂(NO)]²⁺ with the ligand or indirectly by first reacting the ligand with [M(CO)₃]⁺ and subsequent nitrosylation with [NO][BF₄] or [NO][HSO₄]. Most of the reactions were performed with cold rhenium on a macroscopic level before the conditions were adapted to the n.c.a. level with technetium (^99mTc). Chloride, bromide and nitrate were used as monodentate ligands, picolinic acid (PIC) as a bidentate ligand and histidine (HIS), iminodiacetic acid (IDA) and nitrilotriacetic acid (NTA) as tridentate ligands. We synthesised and describe the dinuclear complex [ReCl(μ-Cl)(CO)₂(NO)]₂ and the mononuclear complexes [NEt₄][ReCl₃(CO)₂(NO)], [NEt₄][ReBr₃(CO)₂(NO)], [ReBr(PIC)(CO)₂(NO)], [NMe₄][Re(NO₃)₃(CO)₂(NO)], [Re(HIS)(CO)₂(NO)][BF₄], [⁹⁹Tc(HIS)(CO)₂(NO)][BF₄], [^99mTc(IDA)(CO)₂ (NO)] and [^99mTc(NTA)(CO)₂(NO)]. The chemical and physical characteristics of the Re and Tc-dicarbonyl-nitrosyl complexes differ significantly from those of the corresponding tricarbonyl compounds.     

Übergangsmetallphosphidokomplexe. XIII. P-funktionelle phosphidoverbrückte Heterozweikernkomplexe mit und ohne Metall-Metall-Bindung; P(SiMe3)2-verbrückte cp(CO)xFe-Derivate

Transition Metal Phosphido Complexes. XIII. P-functional Phosphido-Bridged Heterobimetallic Complexes with and without a Metal-Metal Bond; P(SiMe₃)₂-Bridged cp(CO)_xFe Derivatives cp(CO)₂FeP(SiMe₃)₂ 1 reacts with the carbonyl nitrosyl complexes Co(CO)₃(NO), Fe(CO)₂(NO)₂,Mn(CO)(NO)₃ substituting a CO ligand and with the THF complexes M′(CO)₅THF(M′ = Cr, Mo, W), Mncp(CO)₂THF MnMecp(CO)₂ which can be obtained in solution substituting the THF ligand to give the phosphido-bridged bimetallic complexes cp(CO)₂Fe[μ-P(SiMe₃)₂]M′L_m 2 (M′L_m = Co(CO)₂(NO) b , Fe(CO)(NO)₂ c , Mn(NO)₃ d , Cr(CO)₅ f , Mo(CO)₅ g , W(CO)₅ h , Mncp(CO)₂ i , MnMecp(CO)₂ j ). Solutions of Li(Me₃Si)₂PM′L_m 4e–l (M′L_m = Fe(CO)₄ e , Crcp(CO)(NO) k , Vcp(CO)₃ l ) are available by a selective cleavage reaction of a Si? P bond in the complexes (Me₃Si)₃PM′L_m 3e–l using n-BuLi. Reactions of cp(CO)₂FeBr with 4e–l give the bimetallic complexes 2e–l . The open-chain complexes 2c, 2f, 2h–k undergo a photochemical decarbonylation reaction to form the phosphido-bridged bimetallic complexes cp(CO)Fe[μ-CO, μ-P(SiMe₃)₂]M′L_m?1(Fe-M′) 5 (M′L_m?1 = Fe(NO)₂ c , Cr(CO)₄ f , W(CO)₄ h , Mncp(CO) i , MnMecp(CO) j , Crcp(NO) k ) containing a metal-metal bond. Equilibria between various isomers can partially be observed in solutions of the complexes 5. I.R., N.M.R., and mass spectral data are reported.     

Reactions of nitrosoarenes containing electron-withdrawing substituents with coordinated CO. Synthesis and structure of complexes Pd2(OAc)2(p-ClC6H4N[p-ClC6H3NO])2 and Pd2(OAc)2(o-ClC6H4N[o-ClC6H3NO])2

The reaction of tetranuclear Pd₄(μ-COOCH₃)₄(μ-CO)₄ cluster (1a) with p- and o-chloronitrosobenzenes was found to give dinuclear nitrosoamide complexes, Pd₂(OAc)₂(p-ClC₆H₄N[p-ClC₆H₃NO])₂ (4) and Pd₂(OAc)₂(o-ClC₆H₄N[o-ClC₆H₃NO])₂ (5), respectively. The formation of complexes 4 and 5 is accompanied by evolution of CO₂, resulting from oxidation of CO coordinated in cluster 1. Complexes 4 and 5 were characterized by elemental analysis and IR and ¹H NMR spectroscopy; their structures were studied by EXAFS. The reactions of dinuclear complex 4 with molecular hydrogen and CO were studied. The major products of reduction of 4 with hydrogen include metallic palladium, acetic acid, cyclohexanone, and molecular nitrogen. Treatment of complex 4 with CO under mild conditions (1 atm, 20 °C) affords p-chlorophenyl isocyanate.     

Synthesis and characterization of the [Ru(η5-C5Me4CF3)(CO)2]2 and Ru6(μ3-H)(η2-μ4-CO)2(μ-CO)(CO)12(η5-C5Me4CF3) complexes

The reaction of Ru₃(CO)₁₂ with tetramethyltrifluoromethylcyclopentadiene at various ratios of the reagents was studied. Refluxing of Ru₃(CO)₁₂ with a sixfold excess of tetramethyltrifluoromethylcyclopentadiene in octane in an inert atmosphere gave a complex, which is, according to X-ray diffraction data, a dimer,trans-[Ru(η⁵-C₅Me₄CF₃)(CO)₂]₂. The reaction under the same conditions but starting from Ru₃(CO)₁₂ and C₅Me₄CF₃H in 2∶1 molar ratio gave a hexaruthenium cluster [Ru₆(μ₃-H)(η₂-μ₄-CO)₂(μ-CO)(Co)₁₂(η⁵-C₅Me₄CF₂)], which was characterized by IR as well as¹H,¹³C, and¹⁹F NMR spectroscopy. According to X-ray diffraction data, an Ru₄ tetrahedron, in which two edges are bound by additional “briding” Ru atoms, constitutes the frame of this compound. This complex has one (η⁵-C₅Me₄CF₃) ligand, as well as one (μ₃-H) and two (η²-μ₄-CO) groups. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 507–512, March, 1998.     

Permetalloplumbanes: Preparation of [Pb{Co(CO)3(L)}4] and [Pb{Fe(CO)2(NO)(L)}4].: Complexes containing four transition metal to lead bonds (L = tertiary arsine,phosphine or phosphite).

The sole and unexpected products from the reactions of a variety of lead (II) and lead (IV) compounds with [Co₂(CO)₆(L)₂] complexes (L = tertiary arsine, phosphine, or phosphite) in refluxing benzene solution are the blue, air-stable percobaltoplumbanes [Pb{Co(CO)₃(L)}₄]. These have also been obtained from the reaction of Na[Co(CO)₃(L)] (L  PBu₃ⁿ) with lead (II) acetate which with Na[Fe(CO)₂(NO)(L)] forms the isoelectronic [Pb{Fe(CO)₂(NO)(L)}₄] [L  P(OPh)₃]. The IR spectra of the complexes in the v(CO) and v(NO) regions are consistent with tetrahedral PbCo₄ or PbFe₄ fragments, trigonal bipyramidal coordination about the cobalt or iron atoms and linear PbCoAs, PbCoP, or PbFeP systems. Unlike [Pb{Co(CO)₄}₄], our complexes do not dissociate to [Co(CO)₃(L)]^? or [Fe(CO)₂(NO)(L)]^? ions when dissolved in donor solvents.     

Synthesis and characterisation of HRuRh3(CO)12. Crystal structures of HRuRh3(CO)12, HRuRh3(CO)10(PPh3)2 and HRuCo3(CO)10(PPh3)2

A new ruthenium-rhodium mixed-metal cluster HRuRh₃(CO)₁₂ and its derivatives HRuRh₃(CO)₁₀(PPh₃)₂ and HRuCo₃(CO)₁₀(PPh₃)₂ have been synthesized and characterized. The following crystal and molecular structures are reported: HRuRh₃(CO)₁₂: monoclinic, space group P2₁/c, a 9.230(4), b 11.790(5), c 17.124(9) Å, β 91.29(4)°, Z = 4; HRuRh₃(CO)₁₀(PPh₃)₂·C₆H₁₄: triclinic, space group P$\text{1}$, a 11.777(2), b 14.079(2), c 17.010(2) Å, α 86.99(1), β 76.91(1), γ 72.49(1)°, Z = 2; HRuCo₃(CO)₁₀(PPh₃)₂·CH₂Cl₂: triclinic, space group P$\text{1}$, a 11.577(7), b 13.729(7), c 16.777(10) Å, α 81.39(4), β 77.84(5), γ 65.56°, Z = 2. The reaction between Rh(CO)₄^? and (Ru(CO)₃Cl₂)₂ tetrahydrofuran followed by acid treatment yields HRuRh₃(CO)₁₂ in high yield. Its structural analysis was complicated by a 80–20% packing disorder. More detailed structural data were obtained from the fully ordered structure of HRuRh₃(CO)₁₀(PPh₃)₂, which is closely related to HRuCo₃(CO)₁₀(PPh₃)₂ and HFeCo₃(CO)₁₀(PPh₃)₂. The phosphines are axially coordinated.     

Products from the reaction of M3(CO)12 (M = Ru or Os) with water

Reaction of the carbonyl Ru₃(CO)₁₂ with water leads to the formation of polynuclear hydrides α-H₄Ru₄(CO)₁₂, α-H₂Ru₄(CO)₁₃; the corresponding reaction with Os₃(CO)₁₂ yields the complexes (H)(OH)Os₃(CO)₁₀, H₂Os₄(CO)₁₃, H₄Os₄(CO)₁₂, H₂Os₅(CO)₁₆, H₂Os₅(CO)₁₅, H₂Os₆(CO)₁₈ and H₂Os₇(CO)₁₉C.     

The reaction of H2Os3(CO)10 with trifluoroacetonitrile and the x-ray crystal structure of HOs3(CO)9(μ3-η2-HNCCF3)

The reaction of H₂Os₃(CO)₁₀ with CF₃CN in hexane at 80°C leads to two isomeric products. The isomer constituting the major product contains a 1,1,1-tri-fluoroethylidenimido ligand which bridges one edge of the Os₃ triangle via the nitrogen, atom and may be formulated as (μ-H)Os₃(CO)₁₀(μ-NC(H)CF₃) (I). The minor product, formulated as (μ-H)Os₃(CO)₁₀(μ-η²-HNCCF₃) (II), contains a 1,1,1-trifluoroacetimidoyl ligand which is also edge-bridging, being N-bonded to one Os atom and C-bonded to the other. Thermolysis of I and II in solution results in loss of a CO group in each case to give (μ-H)Os₃(CO)_9^? (μ₃-η²-NC(H)CF₃) (III) and (μ-H)Os₃(CO)₉(μ₃-η²-HNCCF₃) (IV), respectively, which, it is proposed, are structurally related to I and II, but with the CN group coordinated also to the third Os atom in place of a CO group. In the case of IV this proposal has been confirmed by an X-ray crystallographic analysis. The compound crystallises in space group C2/c with a = 14.258(7), b = 13.486(10), c = 18.193(8) Å, β = 92.68(4)°, and Z = 8. The structure was solved by a combination of direct methods and Fourier difference techniques, and refined by full-matrix least squares to R = 0.054 for 2489 unique observed diffractometer data. Reaction of I with Et₃P gives a 1 : 2 adduct which is formulated as (μ-H)Os₃(CO)₁₀[μ-N?C(H)(CF₃)PEt₃] (V) on the basis of NMR evidence.     

Perfluormethyl-Element-Liganden. IX.. Synthese und Eigenschaften von (CF3)2EMn(CO)5 (E = P,As)

Preparation and Properties of (CF₃)₂EMn(CO)₅ (E ? P, As) The complexes (CF₃)₂EMn(CO)₅ (E ? P, As) are formed by the reaction of E₂(CF₃)₄ with HMn(CO)₅. They can be converted quantitatively to the binuclear compounds [Mn(CO)₄E(CF₃)₂]₂ in a thermal (E ? P) or photochemical (E ? P, As) process. u. v. irradiation of a 1:1 mixture gives the mixed derivative Mn₂(CO)₈As(CF₃)₂P(CF₃)₂ together with the symmetrical systems. The Mn? E bond is less reactive with HBr and Me₃SnBr than the M? E bond in derivatives of the type Me₃ME(CF₃)₂ (M ? Si, Ge, Sn; Me ? CH₃). The terminal (CF₃)₂E groups are found to be strong π-acceptor ligands.     

Reactions of Bis(Trifluoromethyl)Phosphine and Tetrakis(Trifluoromethyl)Phosphine with Ruthenium Carbonyl Clusters

Abstract

The reaction of (CF₃)₂P-P(CF₃)₂ with [Ru₃(CO)₁₂] yielded compounds : [Ru₁₄(CO)₁₃{μ-P(CF₃)₂)₂] (1), [Ru₄(CO)₁₄{μ-P(CF₃)₂}₂] (2), and [Ru₄(CO)₁₁{μ-P(CF₃)₂}₄] (3); reaction with [μ-H)₄Ru₄(CO)₁₂] yielded (1) and [(μ-H)₃Ru₄(CO)₁₂{μ-P(CF₃)₂}] (4). The reaction of (CF₃)₂PH with [Ru₃(CO)₁₂] yielded compounds (1) and (4) and compounds (1) and (2) using cluster : ligand ratios of 1:1 and 1:2 respectively. All the compounds have been characterised by X-ray crystallography; a schematic diagram of their structures is shown in Figure 1. The fluxional behaviour of the hydrides in (4) was studied using variable temperature ¹H NMR spectroscopy (see Figure 2). The result of this study was used in the assignment of hydride positions of (4) in the solid state.