Triphospha-Ferrocenes as Ligands. Crystal Structures of [Fe(η5-C5Me5)(η5-C2 TBu2P3)M(CO)5)], (M= Cr,MO, W) and the Novel ruthenium and Nickel Complexes [Fe(η5-C5Me5) (η5-C2 TBu2P3)Ru3(CO)9] and [Fe(η5-C5Me5)(η5-C2 tBu2P3)Ni(Co)2]2

Abstract

Syntheses and structures of penta- and hexaphosphorus analogues of ferrocene have been described recently¹. Unlike their simple ferrocene analogues, these complexes have further ligating potential towards other transition metal centres by virtue of the availability of the ring phosphorus lone-pair electrons that are not involved in the η⁵-coordination. We now describe the first examples of coordination compounds of the triphospha-ferrocene [Fe(η⁵-C₅Me₅) (η⁵-C₂ ^tBu₂P₃]. In the ruthenium complex [Fe(η⁵-C₅Me₅)(η⁵-C₂ ^tBu₂P₃) Ru₃(CO)₉] ² two adjacent phosphorus atoms of the η⁵-C₂ ^tBu₂P₃ ring are interlinked by a ruthenium carbonyl cluster in which all three ruthenium atoms interact with the phosphorus atoms. The tetrametallic nickel complex [Fe(η⁵-C₅Me₅)(η⁵-C₂ ^tBu₂P₃)Ni(CO)₂]₂ ³ represents the first example of intermolecular interlinkage of two phospha-ferrocene systems by two metal centres.     

Tantalocene complexes as bidentate métalloligands: (C5Me5)(C5H4X)Ta(H2)(PPh2) (C5Me5) (C5H4X)Ta(CO) (PPh2) (X = PPh2, CH2CH2NMe2)

The synthesis of new bidentate métalloligands derived from tantalocene(C₅Me₅)(C₅H₄X)Ta(H₂)(PPh₂) (X = PPh₂, 2P; X = CH₂CH₂NMe₂2N) and (C₅Me₅)(C₅H₄X)Ta(CO)(PPh₂) 4(P,N) is described. When opposed to chromium unsaturated fragments the phosphino functionalised complexes 2P and 4P act as chelating bidentate ligands affording Ta(V) (C₅Me₅)(C₅H₄PPh₂)Ta(CH₂) (μ-PPh₂)Cr(CO)₄ or Ta(III) (C₅Me₅)(C₅H₄PPh₂)Ta(CO)(μ-PPh₂)Cr(CO)₄ bimetallic complexes. The same reaction carried out starting from 2N gives rise to a μ-phosphido, μ-hydrido dibridged complex Cp*(C₅H₄CH₂CH₂NMe₂)TaH(μ-H)(μ-PPh₂)Cr(CO)₄.     

Structural chemistry of titanium and aluminium bimetallic hydride complexes VI. Molecular structure and physico-chemical properties of (η5-C5 H5) 2Ti(μ2-H)2 Al(Cl) (μ2 -H)2Ti(η5-C5H 5)2, a catalyst-precursor for hydrogenation in the [(η5-C5H5)2TiCl]2-LiAIH4 system

The complex (Cp₂Ti)₂AlH₄Cl has been isolated from the catalytic system (Cp₂TiCl)₂-LiAlH₄, which is a precursor of the catalyst for the hydrogenation and isomerization of olefins. This complex has been studied by X-ray diffraction. The complex forms rhomboidal crystals with unit cell dimensions a = 10.414, b = 11.998, c = 16.008 Å, space group P2₁2₁2₁, Z = 4, and density ϱ_calc = 1.40 g/cm³. The Cp₂Ti moieties are linked to the Al atom via double hydrogen bridges; the Cl atom is bonded to the Al atom. Analysis of the EPR spectral data and some chemical properties of (Cp₂Ti)₂AlH₄Cl solutions has led us to suggest a mechanism for the formation of the catalytically active species upon interaction of this compound with olefins and solvating solvents.     

2-Polyfluoroalkylchromones. 11. Synthesis and structures of 5-hydroxy-3-(2-hydroxyaryl)-5-polyfluoroalkyl-Δ2-pyrazolines and 3(5)-(2-hydroxyaryl)-5(3)-polyfluoroalkylpyrazoles

The reaction of 2-hydroxy-2-polyfluoroalkylchroman-4-ones with hydrazine affords 5-hydroxy-3-(2-hydroxyaryl)-5-polyfluoroalkyl-²-pyrazolines, whereas 2-polyfluoroalkylchromones under similar conditions produce 3(5)-(2-hydroxyaryl)-5(3)-polyfluoroalkylpyrazoles. 5-(2-Hydroxyaryl)-1-methyl-3-polyfluoroalkylpyrazoles were synthesized in the reaction with methylhydrazine, and the reaction with phenylhydrazine afforded regioisomeric 3(5)-(2-hydroxyphenyl)-1-phenyl-5(3)-polyfluoroalkylpyrazoles.     

Iron atom discrimination by carbon during the fragmentation of a ligand around a FeFe bond. Crystal structure [μ-η3-RCH2OC(S)SMeFe2(CO)5P(OMe)3]

The substituted compound [μ-η³RCH₂OC(S)SMeFe₂(CO)₅P(OMe)₃] (3) (the structure of which was determined by X-ray diffraction), undergoes a ligand fragmentation leading to the known substituted compound [μ-η²(RCH₂OCS)Fe₂- (CO)₅P(OMe)₃μ-SMe] (4). Evidently during the rearrangement the carbon atom of the bridging ligand migrates from one iron atom to the adjacent iron that bears the phosphite ligand.     

Nature of M-Ga bonds in dihalogallyl complexes (η5-C5H5)(Me3P)2M(GaX2) (M = Fe, Ru, Os) and (η5-C5H5)(OC)2Fe(GaX2) (X = Cl, Br, I): a DFT study

Density functional theory (DFT) calculations have been performed on the terminal dihalogallyl complexes of iron, ruthenium, and osmium (η(5)-C(5)H(5))(Me(3)P)(2)M(GaX(2)) (M = Fe, Ru, Os; X = Cl, Br, I) and (η(5)-C(5)H(5))(OC)(2)Fe(GaX(2)) (X = Cl, Br, I) at the BP86/TZ2P/ZORA level of theory. On the basis of analyses suggested by Pauling, the M-Ga bonds in all of the dihalogallyl complexes are shorter than M-Ga single bonds; moreover, on going from X = Cl to X = I, the optimized M-Ga bond distances are found to increase. From the perspective of covalent bonding, however, π-symmetry contributions are, in all complexes, significantly smaller than the corresponding σ-bonding contribution, representing only 4-10% of the total orbital interaction. Thus, in these GaX(2) complexes, the gallyl ligand behaves predominantly as a σ donor, and the short M-Ga bond lengths can be attributed to high gallium s-orbital character in the M-Ga σ-bonding orbitals. The natural population analysis (NPA) charge distributions indicate that the group 8 metal atom carries a negative charge (from -1.38 to -1.62) and the gallium atom carries a significant positive charge in all cases (from +0.76 to +1.18). Moreover, the contributions of the electrostatic interaction terms (ΔE(elstat)) are significantly larger in all gallyl complexes than the covalent bonding term (ΔE(orb)); thus, the M-Ga bonds have predominantly ionic character (60-72%). The magnitude of the charge separation is greatest for dichlorogallyl complexes (compared to the corresponding GaBr(2) and GaI(2) systems), leading to a larger attractive ΔE(elstat) term and to M-Ga bonds that are stronger and marginally shorter than in the dibromo and diiodo analogues.     

Characterization of the bis(pyridine) complex of the butyllithium-pyridine adduct, 2-Bun(C5H5N)Li·(C5H5N)2; its decomposition to 2-butylpyridine via a dihydropyridine

The complexed adduct, 2-Buⁿ(C₅H₅N)Li·(C₅H₅N)₂, (3), synthesized by reaction of BuⁿLi with a three-fold excess of pyridine, has been characterized. ¹H NMR studies on solutions of (3) of various ages and histories (thermal and photochemical) have shown that the adduct deteriorates to the hydrolysis product 2-butylpyridine (1) via 1,2-dihydro-2-butylpyridine (4).     

On the reaction Si+(2P) + H2(X1Σ+g) → SiH+ + H. I. Ab initio potential energy surfaces

An ab initio unrestricted Hartree-Fock investigation on the C_∞v (1²Σ⁺, 1²Π) and C_2v (1²A₁, 1²B₁, 1²B₂) potential energy surfaces of the Si⁺ (²P) + H₂ system is presented. In the study, the MIDI-1* minimal gaussian basis set of Huzinaga and co-workers is used. The analysis of the stationary points and main features of the potential energy surfaces involved and the comparison with those of the isovalent C⁺ (²P) + H₂ → CH⁺ + H reaction reported in the literature have allowed us to understand the different dynamical behaviour exhibited by both isovalent systems near their respective threshold energies.     

Comparison of the crystal structures of Co2(X 2O7)·2H2O,X=P and As

Summary Crystals of Co₂(X ₂O₇)·2H₂O,X=P/As were synthesized under hydrothermal conditions. Their crystal structures were determined by single crystal X-ray diffraction:a=6.334(1)/6.531(2),b=13.997(2)/14.206(4),c=7.637(1)/7.615(2)Å, =94.77(2)/94.74(2)°, space group P2₁/n,R=0.032/0.046,R _w=0.028/0.034 for 2423/2042 reflections and 131/119 variables. Within the twoXO₄ tetrahedra connected via a common corner to anX ₂O₇ group the average P-O bond lengths are approximately equal (1.540 and 1.543 Å), but As-O differs significantly (1.685 and 1.696 Å). A comparison with the isotypic Mn and Mg pyrophosphates shows a correlation between the ratio Me-O/X-O and the angle O-X-O.

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Vergleich der Kristallstrukturen von Co₂(X ₂O₇)·2H₂O,X=P und As

Zusammenfassung Kristalle von Co₂(X ₂O₇)·2H₂O,X=P/As wurden unter Hydrothermalbedingungen synthetisiert. Ihre Kristallstrukturen wurden mittels Röntgenbeugung an Einkristallen bestimmt:a=6.334(1)/6.531(2),b=13.997(2)/14.206(4),c=7.637(1)/7.615(2) Å, =94.77(2)/97.74(2)°, Raumgruppe P2₁/n,R=0.032/0.046,R _w=0.028/0.034 für 2423/2042 Reflexe und 131/119 Variable. In den beiden über eine gemeinsame Ecke zuX ₂O₇-Gruppen verknüpftenXO₄-Tetraedern sind die mittleren P-O-Abstände ungefähr gleich (1.540 und 1.543 Å), hingegen differiert As-O signifikant (1.685 und 1.696 Å). Ein Vergleich mit den isotypen Mn- und Mg-Pyrophosphaten zeigt eine Korrelation zwischen dem Quotienten Me-O/X-O und dem WinkelX-O-X.

     

OXO (X=Cl,Br)与X (2P3/2)反应机理的理论研究

用密度泛函B3LYP/6-311+G^**和高级电子相关的组态相互作用QCISD(T)/6-311+G^**方法研究了OXO与X(²P_3/2)双自由基反应的微观机理.研究结果表明:该反应存在两个反应通道,产物分别为XO和X₂+O₂.由于形成产物XO的活化势垒较低,因而是主要反应通道,这与实验观察到的结果是一致的.而形成X₂+O₂的通道从动力学上看是不利的.     

Radical Reactivity of the Biradical [⋅P(μ-NTer)2P⋅] and Isolation of a Persistent Phosphorus-Cantered Monoradical [⋅P(μ-NTer)2P-Et]

The activation of C−Br bonds in various bromoalkanes by the biradical [⋅P(μ-NTer)₂P⋅] ( 1 ) (Ter=2,6-bis-(2,4,6-trimethylphenyl)-phenyl) is reported, yielding trans-addition products of the type [Br−P(μ-NTer)₂P−R] ( 2 ), so-called 1,3-substituted cyclo-1,3-diphospha-2,4-diazanes. This addition reaction, which represents a new easy approach to asymmetrically substituted cyclo-1,3-diphospha-2,4-diazanes, was investigated mechanistically by different spectroscopic methods (NMR, EPR, IR, Raman); the results suggested a stepwise radical reaction mechanism, as evidenced by the in-situ detection of the phosphorus-centered monoradical [⋅P(μ-NTer)₂P-R].< To provide further evidence for the radical mechanism, [⋅P(μ-NTer)₂P-Et] ( 3Et ⋅) was synthesized directly by reduction of the bromoethane addition product [Br-P(μ-NTer)₂P-Et] ( 2 a ) with magnesium, resulting in the formation of the persistent phosphorus-centered monoradical [⋅P(μ-NTer)₂P-Et], which could be isolated and fully characterized, including single-crystal X-ray diffraction. Comparison of the EPR spectrum of the radical intermediate in the addition reaction with that of the synthesized new [⋅P(μ-NTer)₂P-Et] radical clearly proves the existence of radicals over the course of the reaction of biradical [⋅P(μ-NTer)₂P⋅] ( 1 ) with bromoethane. Extensive DFT and coupled cluster calculations corroborate the experimental data for a radical mechanism in the reaction of biradical [⋅P(μ-NTer)₂P⋅] with EtBr. In the field of hetero-cyclobutane-1,3-diyls, the demonstration of a stepwise radical reaction represents a new aspect and closes the gap between P-centered biradicals and P-centered monoradicals in terms of radical reactivity.     

Synthesis and structural characterization of [SiMe2(C5H4)2][(C5Me5) Zr(μ-S)]2. a dinuclear zirconocenophane complex with a skewed dimethylsilyl-bridged bis(cyclopentadienyl) ligand

The reaction of [SiMe₂(C₅H₄)₂][(C₅Me₅)ZrMe₂]₂ with H₂S at 110°C proceeds with the formation of [SiMe₂(C₅H₄)₂][(C₅Me₅)Zr(-S)]₂]₂. The molecular structure of this dinuclear zirconocenophane compound features a non-planar four-membered Zr₂(-S)_{2 2} ring with two symmetrically-bridging sulfido groups. The bridging dimethylsilyl-bridged bis(cyclopentadienyl) ligand adopts a skewed orientation to accommodate the long Zr ... Zr separation of 3.611(1) Å. This compound crystallizes in the centrosymmetric space group P1 with refined lattice parameters ofa = 10.905(1) Å,b = 10.939(2) Å,c = 14.621(2) Å, = 106.32(1)°, = 91.25(1)°, = 111.25(1)°,V = 1545.1(8) ų, _calc. = 1.512g/cm³,Z=2. Full-matrix refinement converged with final discrepancy indices of R(F _o = 0.045 andR(F _o) = 0.079 with GOF= 1.60 for 4403 data withF _o > 3(F _o).This paper is dedicated to Professor Larry Dahl, a valued friend and mentor, on the occasion of his 65th birthday and in recognition of his significant fundamental contributions to the field of metal cluster chemistry. May the Goddess Fortuna continue to bring distinction and honor to him and his research endeavors.     

Synthesis and conversions of metallocycles. 9. Synthesis of polycyclic aluminocyclopentanes with the participation of (η5-C5H5)2ZrCl2

The Cp₂ZrCl₂-catalyzed (Cp=⁵-C₅H₅) stereoselective cyclometalation of norbornenes and norbornadienes with AlEt₃ was carried out. It led in one stage to the preparation of polycyclic aluminocyclopentanes (ACP). It was shown that the ACP synthesized can be converted into polycyclic thiophanes under the action of elementary sulfur.For previous communication, see [1].Institute of Chemistry, Bashkir Scientific Center, Ural Branch, Academy of Sciences, 450054 Ufa. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 386–391, February, 1992.     

Synthesis of the solvento species [Ru2(CO)5(solvent){μ- (RO)2PN(Et)P(OR)2}2]2+ and its potential as a source for a wide range of dinuclear derivatives of ruthenium

Treatment of [Ru₂(μ-CO)(CO)₄{μ-(RO)₂PN(Et)P(OR)₂}₂] (R = Me or Prⁱ), electron-rich derivatives of [Ru₂(CO)₉], with a twice molar amount of a silver(I) salt in aprotic, weakly co-ordinating solvents such as acetone, acetonitrile or benzonitrile leads to the formation of the solvento species [Ru₂(CO)₅(solvent)- {μ-(RO)₂PN(Et)P(OR)₂}₂]²⁺. The structure of the benzonitrile derivative, [Ru₂(CO)₅(PhCN){μ-(PrⁱO)₂PN(Et)P(OPr_i)₂}₂](SbF₆)₂, has been established by X-ray crystallography. The acetone molecule in [Ru₂(CO)₅(acetone){μ- (RO)₂PN(Et)P(OR)₂}₂]²⁺ is readily replaced by various nucleophiles to afford products of the type [Ru₂(CO)₅L{μ-(RO)₂PN(Et)P(OR)₂}₂]²⁺, where L is a neutral ligand such as CO, Me₂C₆H₃NC, PhCN, C₅H₅N, H₂O, Me₂S or SC₄H₈, [Ru₂Y(CO)₅{μ-(RO)₂PN(Et)P(OR)₂}₂]²⁺, where Y⁻ is an anionic ligand such as Cl⁻, Br⁻, I⁻, CN⁻, SCN⁻, MeCO₂⁻, CF₃CO₂⁻ or [Ru₂(μ-Y)(CO)₄{μ-(RO)₂- PN(Et)P(OR)₂}₂]⁺ where Y⁻ is an anionic ligand such as Cl⁻, Br⁻, I⁻, SPh⁻, S₂CNEt₂⁻, MeCO₂⁻ or CF₃CO₂⁻.     

Theoretical study of the energetics of the O3(X̃ 1A1) → O2(X 3Σ−g) + O(3P) dissociation process

The dissociation energy (D_e) for the O₃(X̃ ¹A₁) → O₂(X ³Σ⁻_g) + O(³P) process is computed using MC SCF, CI, MBPT, and CCD methods. A full-valence MC SCF calculation utilizing a [9s5p3d1f/5s3p2d1f] basis set yields a D_e value of 0.43 eV, far below the experimental value of 1.13 eV, demonstrating the importance of correlation effects involving non-valence orbitals. A CI calculation in the same basis set allowing for all single and double excitations from three-reference configuration yields a D_e value of 0.72 eV. This value is increased to 1.06 eV when the Davidson correction is included. When the number of reference configurations is increased to eight, the resulting CI calculation gives a D_e value of 0.82 eV prior to the Davidson correction and 1.10 eV after this correction.     

PREPARATION AND X—RAY CRYSTAL STRUCTURE OF [(C_6H_5)_2PCH_2CH-2P(C_6H_5)_2]Fe(NO)_2

The complex [(C_6H_5)_2PCH_2CH_2P(C_6H_5)_2]Fe (NO)_2, was easily synthesized by the reaction of Fe (CO)_5, NaNO_2 and (C_6H_5)_2PCH_2CH_2P(C_6H_5)_2 (dppe) in methanol and determined by X—ray diffraction which denoted that the title complex has two crystallographically independent molecules in its asymmetric unit.     

Cluster chemistry. 85. Addition of a gold acetylide to an Ru5 cluster. X-ray structure of AuRu5(μ5-C2PPh2)(μ-C2Ph)(μ-PPh2)(CO)13(PPh3)

The reaction between Ru₅(₅-C₂PPh₂)(-PPh₂)(CO)₁₃ and Au(C₂Ph)(PPh₃) afforded AuRu₅(₅-C₂PPh₂)(-C₂Ph)(-PPh₂)(CO)₁₃ (PPh₃), in which the Ru₅ cluster has a scorpion geometry; the Au(PPh₃) group bridges one of the Ru-Ru bonds of the Ru₃ triangle, while the C₂Ph group bridges one of the tail Ru-Ru vectors.For Part 84, see Ref. 1.     

State-to-state quantum dynamics of the N(4S) + OH(X2Π) → H(2S) + NO(X 2Π) reaction

Quantum state-to-state dynamics for the N((4)S) + OH(X(?2)Π) → H((2)S) + NO(X(?2)Π) reaction is reported on an accurate ab initio potential energy surface of the lowest triplet electronic state (a(3)A(")) of HNO∕HON. It was found that the reaction is dominated by long-lived resonances supported by the HNO and HON wells. Significant non-reactive scattering was observed, indicating substantial deviations from the statistical limit. Due to the large exothermicity of the reaction, the NO product has hot internal state distributions: its rotational state distribution is inverted and peaks near the highest accessible rotational level; and its vibrational state distribution extends to υ = 10 and decays monotonically with the vibrational quantum number. In particular, the predicted product vibrational distribution is in reasonably good agreement with experiment. The calculated differential cross section is dominated by scattering in both the forward and backward directions, consistent with the formation of reaction intermediates.