Cyclopentadienyl chromium and tungsten complexes with halide, methyl and σ-phenylethynyl ligands: Structures of (η-C5H5)Cr(NO)2(-CC-C6H5), (η-C5H5)Cr(NO)2I and [(η-C5H4)-COOCH3]W(CO)3Cl

With copper(I) iodide as catalyst, σ-alkynyls, compounds (η⁵-C₅H₅)Cr(NO)₂(CC-C₆H₅) (5), [(η⁵-C₅H₄)-COOCH₃]Cr(NO)₂(CC-C₆H₅) (10), and [(η⁵-C₅H₄)-COOCH₃]W(CO)₃(CC-C₆H₅) (13), were prepared from their corresponding metal chloride 1, 6 and 12. Structures of compound 3, 5 and 12 have been solved by X-ray diffraction studies. In the case of 5, there is an internal mirror plane passing through the phenylethynyl ligand and bisecting the Cp ring. The phenyl group is oriented perpendicularly to the Cp with an eclipsed conformation. The twist angle is 0° and 118.4° for -CC-Ph and two NO ligands, respectively. The orientation is rationalized in terms of orbital overlap between ψ₃ of Cp, dπ of Cr atom, and π^∗ of alkynyl ligand, and complemented by molecular orbital calculation. The opposite correlation was observed on the chemical shift assignments of C(2)-C(5) on Cp ring in compounds 6 and 12, using HetCOR NMR spectroscopy. The electron density distribution in the cyclopentadienyl ring is discussed on the basis of ¹³C NMR data and compared with the calculations via density functional B3LYP correlation-exchange method.     

New ferrocenylmethylphosphines - Preparation, characterisation and coordination chemistry of PH(CH2Fc)2, P(CH2Fc)3 [Fc = Fe(η-C5H5)(η-C5H4)] and their derivatives

The new ferrocenylmethylphosphines PH(CH₂Fc)₂ (1) [Fc = Fe(η⁵-C₅H₅)(η⁵-C₅H₄)] and P(CH₂Fc)₃ (2) and the phosphonium salt [P(CH₂Fc)₃(CH₂OH)]I (3) were synthesised from P(CH₂OH)₃ and [FcCH₂NMe₃]I. [P(CH₂Fc)(CH₂OH)₃]Cl (4) was obtained from P(CH₂Fc)(CH₂OH)₂, CH₂O and HCl. The new phosphines and phosphonium salts were fully characterised by NMR and IR spectroscopy and MS. [Mo(CO)₆] reacts with 1 to give [Mo(CO)₅{PH(CH₂Fc)₂}] (5) in high yield, but attempts to employ 2 as a ligand failed. The reaction of [P(CH₂Fc)₃(CH₂OH)]I (3) and [PH(CH₂Fc)₃]I (obtained in situ from 3 and Na₂S₂O₅) with [WI₂(CO)₃(NCMe)₂] gave the complex salts [P(CH₂Fc)₃(CH₂OH)][WI₃(CO)₄] (6) and [PH(CH₂Fc)₃][WI₃(CO)₄] (7), respectively. [P(CH₂Fc)₄]I (8) was synthesized from PH₂CH₂Fc and [FcCH₂NMe₃]I. Crystal structures were obtained for 1, 3-8.     

Synthesis and X-ray investigation of novel Fe and Mn phenyltellurenyl-halide complexes: (CO)3FeBr2(PhTeBr), (η-C5H5)Fe(CO)2(PhTeI2) and CpMn(CO)2(PhTeI)

New complexes of transition metals with organotellurium halide ligands are reported. Iodination of [CpMn(CO)₂]₂(μ-Ph₂Te₂) leads to the Te-Te bond cleavage and formation of CpMn(CO)₂(PhTeI). Oxidative addition of PhTeBr₃ to Fe(CO)₅ gives the monomeric complex (CO)₃FeBr₂(PhTeBr) which is isostructural with the recently reported (CO)₃FeI₂(PhTeI). Insertion of phenyltellurenyl iodide (PhTeI) into the Fe-I bond of CpFe(CO)₂I forms CpFe(CO)₂(TeI₂Ph). Molecular structures of the reported complexes were determined by single-crystal X-ray diffraction analysis (XRD). A considerable shortening of metal-tellurium distances is observed.     

The preparation and crystal structure of (η-C5H5)(OC)3Mo(CH2)3C6H5

The reaction of with p-CH₃C₆H₄S(O)₂O(CH₂)₃C₆H₅ produces (η⁵-C₅H₅)(OC)₃Mo(CH₂)₃C₆H₅. This is only the second structurally characterized organometallic species in which an aromatic moiety is separated by three or more methylene groups. The alkyl chain adopts a staggered conformation, the Mo-C(1)-C(2)-C(3)-C(4) unit is nearly coplanar, and the alkyl chain eclipses the trans-carbonyl group on Mo. NMR evidence indicates that this conformation is preserved in solution.     

Functionalization of linear and cyclic siloxanes and a dendritic carbosilane with (η-C5H5)Fe(CO)2Si(CH3)2CHCH2 via hydrosilylation reaction

A series of multimetallic systems containing silicon-linked cyclopentadienyl dicarbonyl iron moieties including carbosilane dendrimers and cyclic and polymeric siloxanes have been prepared using hydrosilylation reactions. For this purpose the vinyl-substituted silyliron complex (η⁵-C₅H₅)Fe(CO)₂Si(CH₃)₂ CHCH₂ (1) was prepared by salt elimination reaction between Na[(η⁵-C₅H₅)Fe(CO)₂] and ClSi(CH₃)₂CHCH₂ and fully characterized. Hydrosilylation reaction of 1 with the appropriate Si-H functionalized molecules in the presence of Karstedt catalyst afforded the novel silyl carbonyl iron-functionalized cyclotetrasiloxane 2, dendrimer 3 and copolymer 4, in which the organometallic units are attached to the silicon-based frameworks through a two-methylene flexible spacer. The electrochemical behaviour of compounds 1-4 has been examined in dichloromethane, tetrahydrofuran and acetonitrile solutions using cyclic voltammetry.     

Two succinato-pillared coordination polymer: hydrothermal syntheses, crystal structures and properties of Mn5(OH)2L4 and Cd3(OH)2L2 with H2LHOOC(CH2)2COOH

Two succinato-pillared coordination polymers Mn₅(OH)₂L₄1 and Cd₃(OH)₂L₂2 were prepared by hydrothermal reactions of succinic acid (H₂LHOOC(CH₂)₂COOH) and KOH with the corresponding metal chlorides at 180°C. Within 1, the adjacent MnO₆ octahedra are edge shared to generate Mn₅O₂₂ pentamers, which are interconnected to form 2D manganese oxide layers stabilized by the intralayer gauche succinato groups within the aperture. The manganese oxide layers are pillared by the interlayer trans succinato groups to complete 3D framework. The magnetic behavior of 1 obeys Curie-Weiss law χ_m(T−Θ)=4.46(2) cm³ mol⁻¹ K with the Weiss constant Θ=−67.3(3) K over the temperature range 5−300 K. Compound 2 contains CdO₆ octahedra and edge-shared Cd₂O₁₀ bi-octahedra. The former CdO₆ octahedra are each surrounded by four Cd₂O₁₀ bi-octahedra which in turn are each surrounded by four former CdO₆ octahedra and four neighboring Cd₂O₁₀ bi-octahedra, thus resulting in the corrugated cadmium oxide layers. The formed 2D layers are pillared by trans succinato groups to constitute 3D coordination polymer. Additionally, thermal decomposition of both title coordination polymers upon heating in a flowing nitrogen atmosphere from room temperature to 800°C is discussed. Crystal data: (1) monoclinic, P2₁/c, Z=2, a=9.575(2) Å, b=9.611(2) Å, c=12.526(3) Å, β=97.04(2)°, V=1144.0(4) Å³, R₁=0.0289 and wR₂=0.0815 for 2411 observed reflections (I?2σ(I)) out of 2629 unique reflections; (2) orthorhombic, Pbca, Z=4, a=10.679(1) Å, b=6.873(1) Å, c=16.996(2) Å, V=1247.5(3) Å³, R₁=0.0234 and wR₂=0.0585 for 1213 observed reflections (I?2σ(I)) out of 1437 unique reflections.     

Facile synthesis and X-ray structures of (η-C5Me5)Ti(OAr)3 (OAr = OC6F5, OCH2C6F5, and OCH2C6F2H3)

New half-sandwich titanocene complexes (η⁵-C₅Me₅)Ti(OC₆F₅)₃ (1), (η⁵-C₅Me₅)Ti(OCH₂C₆F₅)₃ (2), and (η⁵-C₅Me₅)Ti(OCH₂C₆F₂H₃)₃ (3) were synthesized via the displacement of methoxide ligands in (η⁵-C₅Me₅)Ti(OMe)₃ by the corresponding aryloxy or benzyloxy ligands. These compounds have been fully characterized by various spectroscopic methods including X-ray crystallography. Compound 1 has a distorted three-legged piano stool structure. However, complexes 2 and 3 have the chariot-like structure, where chariot means a two-wheeled horse-drawn vehicle. The π electron donation of oxygen atom to Ti center in complexes 1-3 is considerable.     

Syntheses and characterization of η-cyclopentadienyl and η-indenyl ruthenium(II) complexes of arylazoimidazoles: The molecular structure of the complex [(η-C5H5)Ru(PPh3)(C6H5-NN-C3H3N2)]

The complex [(η⁵-C₅H₅)Ru(PPh₃)₂Cl] (1) reacts with several arylazoimidazole (RaaiR′) ligands, viz., 2-(phenylazo)imidazole (Phai-H), 1-methyl-2-(phenylazo)imidazole (Phai-Me), 1-ethyl-2-(phenylazo)imidazole (Phai-Et), 2-(tolylazo)imidazole (Tai-H), 1-methyl-2-(tolylazo)imidazole (Tai-Me) and 1-ethyl-2-(tolylazo)imidazole (Tai-Et), gave complexes of the type [(η⁵-C₅H₅)Ru(PPh₃)(RaaiR′)]⁺ {where R, R′ = H (2), R = H, R′ = CH₃ (3), R = H, R′ = C₂H₅ (4), R = CH₃, R′ = H (5), R, R′ = CH₃ (6), R = CH₃, R′ = C₂H₅ (7)}. The complex [(η⁵-C₉H₇)Ru(PPh₃)₂(CH₃CN)]⁺ (8) undergoes reactions with a series of N,N-donor azo ligands in methanol yielding complexes of the type [(η⁵-C₉H₇) Ru(PPh₃)(RaaiR′)]⁺ {where R, R′ = H (9), R = H, R′ = CH₃ (10), R = CH₃, R′ = H (11), R = CH₃, R′ = C₂H₅ (12)}, respectively. These complexes were characterized by FT IR and FT NMR spectroscopy as well as by analytical data. The molecular structure of the complex [(η⁵-C₅H₅)Ru(PPh₃)(C₆H₅-NN-C₃H₃N₂)]⁺ (2) was established by single crystal X-ray diffraction study.     

Unsaturation in binuclear cyclopentadienylchromium carbonyl thiocarbonyls: Viability of (η-C5H5)2Cr2(CS)2(CO)3 in contrast to (η-C5H5)2Cr2(CO)5

The cyclopentadienylchromium carbonyl thiocarbonyls Cp₂Cr₂(CS)₂(CO)_n (n = 4, 3, 2, 1) have been studied by density functional theory using the B3LYP and BP86 functionals. The lowest energy Cp₂Cr₂(CS)₂(CO)₄ structure can be derived from the experimentally characterized unbridged Cp₂Cr₂(CO)₆ structure by replacing the two terminal carbonyl groups furthest from the Cr-Cr bond with two terminal CS groups. The two lowest energy Cp₂Cr₂(CS)₂(CO)₃ structures have a single four-electron donor η²-μ-CS group and a formal Cr-Cr single bond of length ∼3.1 Å. In contrast to the carbonyl analogue Cp₂Cr₂(CO)₅ these Cp₂Cr₂(CS)₂(CO)₃ structures are viable with respect to disproportionation into Cp₂Cr₂(CS)₂(CO)₄ and Cp₂Cr₂(CS)₂(CO)₂ and thus are promising synthetic targets. The lowest energy Cp₂Cr₂(CS)₂(CO)₂ structures have all two-electron donor CO and CS groups and short CrCr distances around ∼2.3 Å suggesting the formal triple bonds required to give the chromium atoms the favored 18-electron configurations. These Cp₂Cr₂(CS)₂(CO)₂ structures are closely related to the known structure for Cp₂Cr₂(CO)₄. In addition, several doubly bridged structures with four-electron donor η²-μ-CS bridges are found for Cp₂Cr₂(CS)₂(CO)₂ at higher energies. The global minimum Cp₂Cr₂(CS)₂(CO) structure is a triply bridged triplet with a CrCr triple bond (2.299 Å by BP86). A higher energy singlet Cp₂Cr₂(CS)₂(CO) structure has a shorter Cr-Cr distance of 2.197 Å (BP86) suggesting the formal quadruple bond required to give each chromium atom the favored 18-electron configuration.     

Phenyltellurenyl halide complexes of ruthenium and rhenium (CO)2RuBr2(PhTeBr)2 and (CO)3Re(PhTeI)3(μ3-I): Synthesis and crystal and molecular structures

Reactions of Ru₃(CO)₁₂ with PhTeBr₃ and of Re(CO)₅Cl with PhTeI in benzene give the stable complexes (CO)₂RuBr₂(PhTeBr)₂ (I) and (CO)₃Re(PhTeI)₃(μ³-I) (II) containing two and three ligands PhTeX (X = Br or I), respectively. The bonds between these ligands and the central metal atom are fairly shortened (on average, Ru-Te, 2.608 ?; Re-Te, 2.7554(12)-2.7634(13) ?). The Te-X bonds in the ligands PhTeBr (2.5163(5) ?) and PhTeI (2.7893(15) ?) are not lengthened appreciably. In complex II, the iodide anion is not coordinated by rhenium, yet being attached through weak secondary bonds to three Te atoms of the three ligands PhTeI.     

Knoevenagel condensation of [NC-CH2C(O)-NH-CH(CO2Et)-S]2 with ferrocenecarbaldehyde and the activation of the σ(C-S) bond of [(η-C5H5)Fe{(η-C5H4)-CHC(CN)-C(O)-NH-CH(CO2Et)-CH2-S-}]2 induced by palladium(II)

The results obtained from the Knoevenagel condensation between the aldehydes R-CHO {with R=4-MeO-C₆H₄, 4-NO₂-C₆H₄, 4-Cl-C₆H₄, C₆H₅, 2,4,6-Me₃-C₆H₂ or (η⁵-C₅H₅)Fe(η⁵-C₅H₄)} and [NC-CH₂C(O)-NH-CH(CO₂Et)-S]₂ under different experimental conditions are reported. These studies have allowed the isolation and characterisation of three optically pure polyamides of general formula [R-CHC(CN)-C(O)-NH-CH(CO₂Et)-CH₂-S-]₂ with R=4-MeO-C₆H₄ (3a), 4-NO₂-C₆H₄ (3b) or (η⁵-C₅H₅)Fe(η⁵-C₅H₄) (3f). The reactions of 3f with Na₂[PdCl₄] or Pd(AcO)₂ are also studied. The treatment of Pd(AcO)₂ with 3f in a 2:1 molar ratio in refluxing toluene leads to the formation of [(η⁵-C₅H₅)Fe{(η⁵-C₅H₄)-CHC(CN)-C(O)-NH-C(CO₂Et)CH₂}] (5f). Electrochemical studies based on cyclic voltammetry of compounds 3f and 5f are also reported.     

Complexes of technetium(I) (Tc, Tc) pentacarbonyl core with π-acceptor ligands (tert-butyl isocyanide and triphenylphosphine): Crystal structures of [Tc(CO)5(PPh3)]OTf and [Tc(CO)5(CNC(CH3)3)]ClO4

A procedure was developed for preparing [^99mTcX(CO)₅] (X = Cl, Br, I) in a reasonable yield by high-pressure carbonylation with CO of ^99mTcO₄⁻ in aqueous solutions. In the synthesis, the substantial part of the target product is accumulated in the gas phase and can be transferred from the autoclave into various solvents when relieving the pressure. Compounds [^99mTcX(CO)₅] (X = Cl⁻, Br⁻, I⁻) are stable in solutions for several hours, but in the course of longer storage they gradually decompose to give the tricarbonyl species. Substitution of the halide ligands in [⁹⁹TcX(CO)₅] and [^99mTcX(CO)₅] with tert-butyl isocyanide and triphenylphosphine was studied. The structures of the complexes [Tc(CO)₅(PPh₃)]OTf and [Tc(CO)₅(CNC(CH₃)₃)]ClO₄ are presented.     

Versatility in the mode of coordination {(N), (N,O), (C,N) or (C,N,O)} of [(η-C5H5)Fe{(η-C5H4)-CHN-(C6H4-2OH)}] to palladium(II)

The study of the reactivity of the ferrocenyliminoalcohol [(η⁵-C₅H₅)Fe{(η⁵-C₅H₄)-CHN-(C₆H₄-2OH)}] (1b) with Na₂[PdCl₄] or Pd(OAc)₂ has allowed the isolation and characterization of the heterotrimetallic complexes: trans-[Pd{(η⁵-C₅H₅)Fe[(η⁵-C₅H₄)-CHN-(C₆H₄-2OH)]}₂Cl₂] (2b), [Pd{[(η⁵-C₅H₃)-CHN-(C₆H₄-2O)]Fe(η⁵-C₅H₅)}{(η⁵-C₅H₅)Fe[(η⁵-C₅H₄)-CHN-(C₆H₄-2OH)]}] (3b) and trans-[Pd{(η⁵-C₅H₅)Fe[(η⁵-C₅H₄)-CHN-(C₆H₄-2O)]}₂] (4b). Ligand 1b acts as a (N) (in 2b) or a (N,O)⁻ (in 4b) ligand; while in 3b the two units of the iminoalcohol exhibit simultaneously different modes of binding {(N) and [C(sp², ferrocene),N,O]²⁻}. The crystal structures of 2b · 3H₂O and 3b · 1/2CHCl₃ are also reported and confirm the mode of binding of the ligand in these compounds. The relative importance of the factors affecting the preferential formation of products (2b-4b) is also discussed. The study of the reactivity of 3b with PPh₃ has enabled the obtention of the cyclopalladated complexes [Pd{[(η⁵-C₅H₃)-CHN-(C₆H₄-2O)]Fe(η⁵- C₅H₅)}(PPh₃)] (6b) and [Pd{[(η⁵-C₅H₃)-CHN-(C₆H₄-2OH)]Fe(η⁵-C₅H₅)}Cl(PPh₃)] (7b), in which 1b behaves as a [C(sp², ferrocene),N,O]²⁻ (in 6b) or [C(sp², ferrocene),N]⁻ (in 7b) ligand. Treatment of 3b with MeO₂C-CC-CO₂Me produces [Pd{[(MeO₂C-CC-CO₂Me)₂(η⁵-C₅H₃)-CHN-(C₆H₄-2O)]Fe(η⁵-C₅H₅)}] (8b), that arises from the bis(insertion) of the alkyne into the σ[Pd-C(sp², ferrocene)] bond. The comparison of the results obtained for 1b and [C₆H₅-CHN-(C₆H₄-2OH)] (1a) has allowed to establish the influence of the substituents on the imine carbon on their reactivity in front of palladium(II) as well as on the lability of the Pd-ligands bond. ⁵⁷Fe Mössbauer studies of 2b-4b and 6b provide conclusive evidence of the effect induced by the mode of binding of 1b on the environment of the iron(II).     

Synthesis and photoluminescence of Zinc(II) complexes with tetrafluoroterephthalic acid (H2L). Crystal structure of coordination polymer [Zn(H2O)4(L) · 4H2O]n

Complexes Zn(H₂O)₄(L) (I) and Zn(H₂O)(L) (II) (H₂L = p-HOOCC₆F₄COOH) are synthesized. Single crystals of compound [Zn(H₂O)₄(L) · 4H₂O] _n (III) are grown. According to the X-ray diffraction data, the crystal structure of compound III is built of zigzag chains of coordination polymer Zn(H₂O)₄(L) and molecules of water of crystallization. The chain contains ions Zn²⁺, whose octahedral coordination sphere includes the O atoms of four water molecules and two O atoms of the deprotonated carboxyl groups. The chains in structure III are joined by a system of hydrogen bonds of coordinated water molecules and molecules of water of crystallization. The photoluminescence spectrum of H₂L exhibits the band with λ_max = 368 nm. The spectra of compounds III, I, and II contain bands at 322, 340, and 353 nm, respectively.     

Crystal structure and spectral characteristics of {[(C6H5)NH]2C=NH(C6H5)}[B(C6H5)4]·C2H5OH

A novel compound of {[(C₆H₅)NH]₂C=NH(C₆H₅)}[B(C₆H₅)₄]·C₂H₅OH is prepared and examined by single crystal X-ray diffraction. Crystal data: C₄₅H₄₄BN₃O, M = 653.64, monoclinic, space group P2₁/c, unit cell parameters: a = 24.375(2) Å, b = 17.5829(15) Å, c = 18.090(1) Å, β = 105.277(2)°, V = 7479.0(11) ų, Z = 8, d _calc = 1.161 g/cm³, T = 293 K, R ₁ = 0.064. The structure contains two crystallographically independent cations, two anions, and two solvate ethanol molecules. Three types of interactions occur between them: interionic N-H(N)⋯π and N(H)⋯π⋯H(C), π-delocalized system of Ph rings of the anions, and interaction of ions with ethanol molecules N-H⋯O-H(O)⋯π. The compound is characterized by IR and luminescence spectra. At room temperature, the emission intensity grows with time of exposure to UV irradiation. Original Russian Text Copyright ? 2008 by T. M. Polyanskaya, E. A. Il’inchik, V. V. Volkov, M. K. Drozdova, O. P. Yur’eva, and G. V. Romanenko __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 3, pp. 512–521, May–June, 2008.     

Reactions of the rhenium fragment (η-C5Me5)Re(CO)2 with chlorinated ethylenes: Coordination and C-Cl bond activation

Photochemical reactions of the dinitrogen complex Cp^∗Re(CO)₂N₂ with tetrachloroethylene and trichloroethylene yield the coordination complexes Cp^∗Re(CO)₂(η²-tetrachloroethylene) (1) and Cp^∗Re(CO)₂(η²-trichloroethylene) (2), respectively. Complex 1 reacts thermally in polar organic solvents to produce the C-Cl bond activation product cis-Cp^∗Re(CO)₂(C₂Cl₃)Cl (3). All complexes were isolated and characterized by IR, ¹H and ¹³C NMR spectroscopies and mass spectrometry. Complex 3 was also characterized by X-ray crystallography.     

Synthesis and crystal structure of [Fe4O2(H2O)10(C5H5NCOO)4](NO3)8 · 2H2O

Crystals of the tetranuclear complex [Fe₄O₂(H₂O)₁₀(C₅H₅NCOO)₄](NO₃)₈ · 2H₂O are obtained by the slow evaporation of an aqueous solution of iron(III) nitrate and isonicotinic acid. According to the X-ray diffraction data, four metal atoms lie in the same plane and together with two μ₃-O oxygen atoms form the fragment [Fe₄(μ₃-O)₂]¹⁰⁺. The [Fe₄O₂(H₂O)₁₀(C₅H₅NCOO)₄]⁸⁺ cation has been obtained and structurally characterized for the first time.