Reactions of pyridine-2-ethyl/methyl cyclopentadienes with metal carbonyls

Abstract

Thermal treatment of pyridine-2-ethyl cyclopentadiene (1) with Fe(CO)₅ and Ru₃(CO)₁₂ gave novel intramolecular C–H activated dinuclear products (3 and 5). In the case of Fe(CO)₅, the reaction also afforded the normal bis(cyclopentadienyl) diiron complex (4). However, similar reaction of pyridine-2-methyl cyclopentadiene (2) with Fe(CO)₅ and Ru₃(CO)₁₂ only afforded the normal bis(cyclopentadienyl) dinuclear metal complexes (7 and 8). For Ru₃(CO)₁₂, the reaction also yielded a pendant η¹-pyridyl-coordinated product (9). In addition, the reactions of 1 and 2 with Re₂(CO)₁₀ formed the corresponding pyridylethyl/pyridylmethyl cyclopentadienyl rhenium tricarbonyl complexes 10 and 11, which further underwent pyridine to rhenium cyclization via photoirradiation to provide the rhenium dicarbonyl complexes 12 and 13. The molecular structures of 3, 5, 6, 7, 8, 9, and 12 were determined by X-ray diffraction.     

Electron spin resonance spectra observed in the course of grafting iron carbonyls on sodium-Y zeolites

The adsorption and/or decomposition pathway of Fe₂(CO)₉ or Fe₃(CO)₁₂ on hydrated or dehydrated NaY zeolites has been studied by an ESR technique. The adsorption resulted in the formation of three paramagnetic species withg _iso=2.0450, 2.0378, and 2.0016, which were attributable to Fe₃(CO)₁₁ ^–, Fe₂(CO)₈ ^–, and Fe(CO)₄ ^– anion radicals, respectively. These radicals have been suggested as intermediates in the formation of HFe₃(CO)₁₁ ^– on the hydrated NaY zeolite and Fe₃(CO)₁₂ on the dehydrated NaY zeolite.     

Ship-in-a-bottle formation of Ru3(CO)12 in zeolite NaY

A NaY zeolite entrapped Ru₃(CO)₁₂ cluster has been synthesized from RuCl₃ ionexchanged NaY, which are well characterized by IR and Raman spectroscopy and CO chemisorption. When the Ru³⁺/NaY sample is heated from 298 to 393 K for 25 h and kept for 10–20 h at 393 K, the sample color changes from dark to brown-yellow. Thein situ infrared spectrum exhibits bands at 2130, 2064, 2040, 2017, 1990, 1953 and 1925 cm⁻¹. The bands at 2064, 2040, 2017 and 1990 cm⁻¹ are assigned to Ru₃(CO)₁₂/NaY, which are close to crystalline Ru₃(CO)₁₂. Furthermore, Raman results provide the bands at 150 and 185 cm⁻¹, which are attributed to Ru-Ru bonds of crystalline Ru₃(CO)₁₂). CO chemisorption on [Ru₃]/NaY gives a CO/Ru ratio of 3.85, which is similar to the stoichiometry of Ru₃(CO)₁₂ (CO/Ru=4.0).     

Reactions of GeMe2-bridged dicyclopentadienes with molybdenum carbonyl: formation of germylidyne trimolybdenum clusters

In thermal reactions of the doubly bridged dicyclopentadienes (C₅H₃R(SiMe₂))(C₅H₃R(GeMe₂)) (R=H (1), ^tBu (5)) with Mo(CO)₆, the bridging GeMe₂ is cleaved to give the corresponding degermylated products [(η⁵-C₅H₃R)₂(SiMe₂)]Mo₂(CO)₆ (3, rac-7), or both GeMe₂ and SiMe₂ are cleaved to afford the nonbridged products [(η⁵-C₅H₄R)Mo(CO)₃]₂ (2, 6). The reactions also produce germylidyne trimolybdenum clusters [(η⁵-C₅H₃R)₂(SiMe₂)](η⁵-C₅H₄R)[Mo(CO)₂]₃(μ₃-GeMe) (4, rac-/meso-7) containing the Mo₃(μ₃-GeMe) units. Similarly, reaction of the single GeMe₂-bridged dicyclopentadienes (C₅H₅)₂GeMe₂ (9) with Mo(CO)₆ also results in the degermylated 2, as well as the similar trimolybdenum cluster [(η⁵-C₅H₅)Mo(CO)₂]₃(μ₃-GeMe) (10). The molecular structures of 4 and trans-5 were determined by X-ray diffraction.     

Ring expansion of a Cp moiety upon CO insertion: Synthesis and characterization of [(η-C6H5OCo)Co3(CO)9]

Reaction of [(CpV)₂(B₂H₆)₂], 1 (Cp = η⁵-C₅H₅) with four equivalents of [Co₂(CO)₈] or [Co₄(CO)₁₂] in hexane at 70 °C leads to the isolation of the tetranuclear carbonyl cluster, [(η⁶-C₆H₅OCo)Co₃(CO)₉], 2 in modest yield. The geometry of 2 is similar to that of [Co₄(CO)₁₂] where all the four Co atoms are arranged in a tetrahedral geometry. The apical cobalt atom in 2 is coordinated to C₆H₅O ring in a η⁶-fashion and the other three cobalt atoms are each coordinated to three carbonyl ligands. Compound 2 has been characterized in solution by IR, ¹H, ¹³C NMR and mass spectrometry and the structural types were unequivocally established by crystallographic analysis.     

Multinuclear NMR studies on substituted derivatives of Rh6(CO)16 in solution

Multinuclear NMR data (¹³C, ³¹P, ¹³C–{³¹P}, ¹³C–{¹⁰³Rh} and ³¹P–{¹⁰³Rh}) for a series of mono- and di-substituted derivatives of Rh₆(CO)₁₆ containing neutral two electron donor ligands [Rh₆(CO)₁₅L, (L=NCMe, py, cyclooctene, PPh₃, P(OPh)₃,1/2(μ₂,η¹:η¹-dppe)); Rh₆(CO)₁₄(LL), (LL=cis-CH₂=CMe-CMe=CH₂, dppm, dppe, (P(OPh)₃)₂)] are reported; these data show that the solid state structure is maintained in solution. Detailed assignments of the ¹³CO NMR spectra of Rh₆(CO)₁₅(PPh₃) and Rh₆(CO)₁₄(dppm) clusters have been made on the basis ¹³C–{¹⁰³Rh} double resonance measurements and the specific stereochemical features of the observed long range couplings in these clusters have been studied. The stereochemical dependence of ³J(P–C) for terminal carbonyl ligands is discussed and the values of ³J(P–C) are found to be mainly dependent on the bond angles in the P–Rh–Rh–C fragment; these data enable the fine structure of the complex multiplets in the ¹³C–{¹H} and ³¹P–{¹H} NMR spectra of Rh₆(CO)₁₄ (dppm) to be simulated. Variable temperature ¹³C–{¹H} NMR measurements on Rh₆(CO)₁₅(PPh₃) reveal the carbonyl ligands in this complex to be fluxional. The fluxional process involves exchange of all the CO ligands except the two terminal CO's associated with the rhodium trans to the substituted rhodium and can be explained by a simple oscillation of the PPh₃ on the substituted rhodium atom aided by concomitant exchange of the unique terminal CO on this rhodium with adjacent μ₃-CO's.     

Kinetics and mechanism of the displacement of CO from Co4(CO)12 by phosphite ligands

Detailed kinetic data are reported for the monosubstitutions of Co₄(CO)₁₂ with phosphite ligands: P(OMe)₂Ph, P(OMe)Ph₂, P(OPr-i)₃ and P(OPh)₃, studied by conventional methods in CHCl₃ as solvent. The reaction rates suggest parallel pathways of dissociation (k ₁) and association (k ₂) and show predominantly an association pathway, the low values of H and negative S adding further support to the proposed mechanism. It is also confirmed that the reaction rates are retarded due to hydrogen-bonding between the H atom of CHC1₃ and the O atoms of the ligands [J. Wang et al., J. Coord. Chem., 23, 345 (1991)]. The results of the reactions of Co₄(CO)₁₂ with P(OMe)₃, P(OMe)₂Ph and P(OMe)Ph₂ in this paper suggest that no quantitative relation exists between the O atoms in the ligand and the reaction rate.     

Syntheses,crystal structures,and electrochemical studies of dinuclear coordination compounds with the Fe2(CO)6 core

Reaction of 2-C₅H₄ NCOSPh, generated from 2-C₅H₄NCO₂H and PhSH in the presence of DCC, with Fe₃(CO)₁₂ affords (μ-κ²C,N-2-C₅H₄N)(μ-PhS)Fe₂(CO)₆ (1) and (μ-PhS)₂Fe₂(CO)₆ (2). Reaction of (NC)₂C=C(SMe)₂, formed from NCCH₂CN, CS₂, and MeI in the presence of NaOH, with Fe₃(CO)₁₂ provides (μ-κ²C,S-(NC)₂C=CSMe)(μ-MeS)Fe₂(CO)₆ (3) and (μ-MeS)₂Fe₂(CO)₆ (4). All complexes have been fully characterized by EA, IR, ¹H NMR, and ¹³C NMR spectroscopy and structurally determined by X-ray crystallography. In 1 and 3, the group attached to the bridging S is at the equatorial position. In 2, two phenyl groups are at equatorial positions. Two isomers of 4, ae-4 and ee-4, can be separated by thin-layer chromatography. DFT calculations reveal that the Gibbs energy difference between ae-4 and ee-4 is ?2.17 kcal mol^?1 in THF and ?2.29 kcal mol^?1 in benzene, and the isomerization barrier between ae-4 and ee-4 is 14.92 kcal mol^?1 in THF and 16.84 kcal mol^?1 in benzene. All these results suggest that ae-4 is more stable than ee-4 in either THF or benzene, and the two isomers do not interconvert. Electrochemical studies of 1 and 3 demonstrate that using HOAc as a proton source 1 and 3 can catalyze H₂ production.     

Synthesis, Structure, and 31P NMR of Sulfur/Oxygen-Bridged Incomplete Cubane-Type Molybdenum and Tungsten Clusters with Triphenylphosphine Ligands

Sulfur/oxygen-bridged incomplete cubane-type triphenylphosphine molybdenum and tungsten-clusters [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·3THF (1A), [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (2A), [Mo₃OS₃Cl₄(H₂O)₂(PPh₃)₃]·2THF (1B), and [W₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (1C) were prepared from the corresponding aqua clusters and PPh₃ in THF/MeOH. On recrystallization from THF, procedures with and without addition of hexane to the solution gave 1A and 2A, respectively, while the procedures gave no effect on the formation of 1B and 1C. Crystallographic results obtained are as follows: 1A: monoclinic, P2₁/n, a=17.141(4) Å, b=22.579(5) Å, c=19.069(4) Å, =96.18(2)°, V=7337(3) ų, Z=4, R(R _w)=0.078(0.102); 1C: monoclinic, P2 ₁/c, a=12.635(1) Å, b=20.216(4) Å, c=27.815(3) Å, =96.16(1)°, V=7062(2) ų, Z=4, R(R _w)=0.071(0.083). If the phenyl groups are ignored, the molecule [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃] in 2A has idealized CS symmetry with the mirror plane perpendicular to the plane determined by the metal atoms, while the molecule in 1A does not have the symmetry. The tungsten compound 1C is isomorphous with the molybdenum compound 2A. ³¹P NMR spectra of 1A, 2A, and 1C were obtained and compared with similar clusters with dmpe (1,2-bis(dimethylphosphino)ethane) ligands.     

Synthesis of new heterometallic complexes by tin-sulfur bond cleavage of pySSnPh3 (pySH = pyridine-2-thiol) at triruthenium and triosmium centres

The ruthenium-tin complex, [Ru₂(CO)₄(SnPh₃)₂(μ-pyS)₂] (1), the main product of the oxidative-addition of pySSnPh₃ to Ru₃(CO)₁₂ in refluxing benzene, is [Ru(CO)₂(pyS)(SnPh₃)] synthon. It reacts with PPh₃ to give [Ru(CO)₂(SnPh₃)(PPh₃)(κ²-pyS)] (2) and further with Ru₃(CO)₁₂ or [Os₃(CO)₁₀(NCMe)₂] to afford the butterfly clusters [MRu₃(CO)₁₂(SnPh₃)(μ₃-pyS)] (3, M=Ru; 4, M=Os). Direct addition of pySSnPh₃ to [Os₃(CO)₁₀(NCMe)₂] at 70 °C gives [Os₃(CO)₉(SnPh₃)(μ₃-pyS)] (5) as the only bimetallic compound, while with unsaturated [Os₃(CO)₈{μ₃-PPh₂CH₂P(Ph)C₆H₄}(μ-H)] the previously reported [Os₃(CO)₈(μ-pyS)(μ-H)(μ-dppm)] (6) and the new bimetallic cluster [Os₃(CO)₇(SnPh₃){μ-Ph₂PCH₂P(Ph)C₆H₄}(μ-pyS)[(μ-H)] (7) are formed at 110 °C. Compounds 1, 2, 4, 5 and 7 have been characterized by X-ray diffraction studies.     

Rate constant for the reaction of bromine atoms with ethane: Kinetic and thermochemical implications

Relative-rate kinetic experiments were carried-out at T = 310 ± 3 K to determine rate constant ratios for the reactions of Br atoms with C₂H₆(1), CH₂ClBr(2) and neo-C₅H₁₂(3). Br atoms were produced by stationary photolysis of Br₂ and the consumption of the reactants was determined by gas-chromatography. k ₂/k ₁ = 1.174 ± 0.053 and k ₃/k ₁ = 0.458 ± 0.027 were determined (with 1σ precision given). The rate constant ratios were resolved to absolute k ₁ values, and k ₁(310 K) = (2.27 ± 0.30) × 10⁵ cm³ mol⁻¹ s⁻¹ was recommended. The recommended k ₁ was applied in a third law analysis providing Δ_f H ^o ₂₉₈(C₂H₅) = (122.0 ± 1.9) kJ mol⁻¹.     

Synthesis and spectroscopic studies of some new metal carbonyl derivatives of 1-(2-pyridylazo)-2-naphthol

Interaction of 1-(2-pyridylazo)-2-naphthol (PAN) with [Mo(CO)₆] in air resulted in formation of the tricarbonyl oxo-complex [Mo(O)(CO)₃(PAN)], 1. The dicarbonyl complex [Ru(CO)₂(PAN)], 3, was obtained from the reaction of [Ru₃(CO)₁₂] with PAN. In presence of triphenyl phosphine (PPh₃), the reaction of PAN with either Mo(CO)₆ or Ru₃(CO)₁₂ gave [Mo(CO)₃(PAN)(PPh₃)], 2, and [Ru(CO)₂(PAN)(PPh₃)], 4. All the complexes were characterized by elemental analysis, mass spectrometry, IR, and NMR spectroscopy. The thermal properties of the complexes were also investigated by thermogravimetry.     

The synthesis and characterisation of some closed polyhedral metallocarbon clusters

Ligands containing unsaturated C₂ and C₄ units have been reacted with triruthenium dodecacarbonyl to produce new organometallic clusters with simple closo-Ru_xC_y polyhedral frameworks which may be regarded as quasi-carboranes. The thermolysis of [Ru₃(CO)₁₂] with 1,4-diphenybutadiene yields the new clusters [Ru₃(CO)₈(μ₃-CPh(CH)₂CPh)] 2 and [Ru₄(CO)₉(μ₄-CPhCCH₂CH₂Ph)] 3, while treatmentof a solution of [Ru₃(CO)₁₂] and diphenylacetylene with trimethylamine N–oxide (Me₃NO) yields [Ru₂(CO)₆(μ-{C₂Ph₂}₂CO)] 4 as the major product and the new cluster [Ru₄(CO)₁₁(μ₄-C₂Ph₂)₂] 5. The solid-state structures of 2, 3 and 5 have been established by single crystal X-ray diffraction analyses and are shown to possess closo-Ru₃C₄ pentagonal bipyramidal, closo-Ru₄C₂ octahedral and closo-Ru₄C₄ dodecahedral skeletons, respectively. The structure and bonding in all three clusters may be rationalised using the Wade–Mingos polyhedral skeletal electron pair approach.     

FT-IR photoacoustic spectra of the surface of Ru3(CO)12/Al2O3 system

The FT-IR photoacoustic spectra of Ru₃(CO)₁₂/Al₂O₃ (acidic and basic alumina) system have been measured for different ageing times. The behaviors of oxidation states of Ru on the surface of basic or acidic alumina and their difference are discussed on the ground of CO stretching bands of their spectra.     

Syntheses,crystal structures,and electrochemistry of novel Fe2SN and FeSN carbonyl complexes with pendant bases

Reactions of Fe₂(CO)₉ with thioacylhydrazones ArCH=NNHCSPh in THF afford Fe₂(CO)₆(μ-κ²S:κ²N-PhC(S)=NNCHArCHArN(CHAr)N=CSPh) (1, Ar?=?C₆H₅; 3, Ar?=?4-CH₃C₆H₄) and Fe(CO)₃(κ²S:N-PhC(=S)NHNCHArCHArN(CHAr)N=CSPh) (2, Ar?=?C₆H₅; 4, Ar?=?4-CH₃C₆H₄). They have been characterized by elemental analyses, IR, ¹H NMR, and ¹³C NMR and structurally determined by X-ray crystallography. Electrochemical studies reveal that when using HOAc as a proton source, they exhibit high catalytic H₂-production.     

Reaction of Os3(μ-Cl)2(CO)10 with Ph2PCH2PPh2. The formation of a novel 12-membered macrocycle containing C, P, Cl, and Os atoms in the ring

The reaction of Os₃(μ-Cl)₂(CO)₁₀ (1) with Ph₂PCH₂PPh₂ (dppm) in a toluene solution at 65°C results in novel osmium complexes [Os₃(μ-Cl)₂(CO)₉]₂(dppm) (2) and [Os₃(μ-Cl)₂(CO)₈]₂(dppm)₂ (3). Compounds 2 and 3 were characterized by¹H and³¹P NMR, and IR spectroscopy and their structures were established by X-ray analysis. In both compounds, dppm is a bridging ligand between the two cluster units. Molecule3 can be considered as an unusual 12-membered macrocycle containing C, P, Cl, and Os atoms in the ring. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1844–1851, September, 1998.     

Volcano relationships in metal cluster catalysis: An infrared spectroscopic monitor of site character

Active osmium cluster catalysts (derived from Os₃(CO)₁₂, H₂Os₃(CO)₁₀, H₄Os₄(CO)₁₂, Os₆(CO)₁₈ and H₂Os₁₀C(CO)₂₄ supported on silica, alumina, titania, and ceria) contain, in their infrared spectra, a band in the region 1930–1985 cm⁻¹ that is characteristic of the cluster/support combination. The activities of these catalysts for reactions of hydrogen with ethene, carbon monoxide, carbon dioxide, and ethane, relate to their characteristic CO stretching frequencies, giving ‘volcano’ curves. Evidence from ethene hydrogenation kinetics confirms that the characteristic CO-frequency is a monitor of strength of adsorption at the catalytically active site. Dedicated to Professor Pál Tétényi on the occasion of his 70th birthday     

Degradation thermique et etude vibrationnelle de MII(NH4)4(P3O9)2x4H2O(M II=Cu2+, Ni2+, Co2+)

We have studied the thermal behaviour under atmospheric pressure of isotypic tetrahydrate cyclotriphosphates M^II(NH₄)₄(P₃O₉)₂x4H₂O (M ^II=Cu, Ni and Co), between 25 and 1400°C, by X-ray diffraction, thermal analyses (TG and DTA) and infrared spectrometry. This study shows that the series of the compounds M^II(NH₄)₄(P₃O₉)₂x4H₂O (M ^II=Cu, Ni and Co) after elimination of water, in two different stages, and ammonia leads, at 400°C to cyclotetraphosphate M₂ ^IIP₄O₁₂ crystallized and to a thermal residue with a formula H₄P₄O₁₂ which undergoes under a thermal degradation by evolving water and pentoxide phosphorus. The kinetic characteristics of the dehydration and elimination of ammonia have been determinated. The vibrational spectra of Cu(NH₄)₄(P₃O₉)₂x4H₂O were examined and interpreted, in the domain of the valency frequencies, on the basis of the crystalline structure of its isotypic compound Co(NH₄)₄(P₃O₉)₂x4H₂O whose cycle has the site symmetry C₁, of our results of the calculation of the IR frequencies and the successive isotopic substitutions of the equivalent atoms (3P, 3Oi and 6Oe belonging to the P₃Oi₃Oe₆ ring) of the P₃O₉ ³⁻ cycle with high symmetry D_3h. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis and chemistry of tris(2-pyridyl)phosphine and bis(2-pyridyl)phenylphosphine complexes of mercury(II) X (X = Br,Cl) and X-ray crystal structural determination of [HgBr2(PPh(2-py)2)2]

Mercury(II) halide complexes [HgX₂(P(2-py)₃)₂] (X?=?Br (1), Cl (2)) and [HgX₂(PPh(2-py)₂)₂] (X?=?Br (3), Cl (4)) containing P(2-py)₃ and PPh(2-py)₂ ligands (P(2-py)₃ is tris(2-pyridyl)phosphine and PPh(2-py)₂ is bis(2-pyridyl)phenylphosphine) were synthesized in nearly quantitative yield by reaction of corresponding mercury(II) halide and appropriate ligands. The synthesized complexes are fully characterized by elemental analysis, melting point determination, IR, ¹H, and ³¹P-NMR spectroscopies. Furthermore, the crystal structure of [HgBr₂(PPh(2-py)₂)₂] determined by X-ray diffraction is also reported.     

Formation of antiferromagnetic thiolate-bridged and sulfide-bridged complexes

Reactions of Cp₂Cr₂(SCMe₃)₂S (1) with rhenium complexes (CO)(NO)Re(PR₃)₂X₂ [R=Et, X=Cl (7a); R=Et, X=O₃SCF₃ (7b); R=OMe, X=O₃SCF₃ (7c)] containing strongly bound phosphine ligands and with Pd(PPrⁱ ₃)₂Cl₂ (8) containing bulky P donors were studied. The reaction between compounds1 and7a does not occur in various solvents within a temperature range of 22–80 °C. Interaction of1 with triflat derivatives7b and7c yields the paramagnetic tetrahedral homonuclear cationic cluster Cp₄Cr₄S₄ ⁺O₃SCF₃ ⁻ (10) and the binuclear methylated complex Cp₂Cr₂(SCMe₃)₂(SMe)⁺O₃SCF₃ ⁻ (11), respectively. The reaction of compound1 with8 affords the antiferromagnetic heteronuclear cluster Cp₂Cr₂(SCMe₃)S₂PdCl(PPrⁱ ₃) (12). The structure of the core of12 is analogous to the structures of the rhodium-containing complexes Cp₂Cr₂(μ-SCMe₃)(μ₃-S)₂RhL₂. Although compound8 reacts with Fe₃S₂(CO)₉ (5), the major products are the homometallic trinuclear clusters Fe₃S₂(CO)₈(PPrⁱ ₃) (14) (as a mixture of isomers) and Fe₃S₂(CO)₇(PPrⁱ ₃)₂ (15), whereas the heteronuclear complex (CO)₆Fe₂S₂Pd(PPrⁱ ₃)₂ (16) was found only in trace amounts. The reasons for the difference in the reactivities of the rhenium and palladium derivatives toward compounds1 and5 are discussed. The structures of complexes10 (two crystal modifications),11, 12, 15, and16 were established by X-ray structural analysis of the single crystals. For Part 4, see I. L. Eremenko, S. E. Nefedov, H. Berke, B. I. Kolobkov, and V. M. Novotortsev,Organometallics, 1995,14, 1132. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 141–152, January, 1997.