ESR study of radical adducts of dialkoxyphosphoryl radicals with (η2-C60)lrH(CO)(PPh3)2 and (η2-C60IrH(8H12)(PPh3)

The reaction of phosphoryl radicals with (η²-C₆₀)lrH(CO)(PPh₃)₂ and (η²-C₆₀IrH(₈H₁₂)(PPh₃) was shown (ESR) to result in the formation of isomers differing in the constants of hyperfine interaction (HFI) with³¹P nuclei,g-factors, and linewidths. It is likely that the addition of phosphoryl radicals at a distance of two-three bond lengths from the metallofragment is predominant. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 870–872, April, 1997.     

The Isolation of a Large Cyclopentadienylcobaltsulfide Cluster. The Synthesis and Crystal Structure of Octahedral closo-(η5-C5H5Co)5S

The title cluster, which was obtained serendipitously when (η⁵-C₅H₅)Co(PPh₃)₂ was added to a (η⁵-C₅H₅)Co metallacyclobutene containing a sulfone group, is the largest cluster known, formed primarily with (η⁵-C₅H₅)Co vertices. The closo-(η⁵-C₅H₅Co)₅S is a closed-shell, octahedral cluster which forms black, monoclinic crystals from methanol.     

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.     

Novel bimetallic Ru-Pt and Fe-Pt Complexes [M(C5R5)(L)2(μ,η1:η2-P4{Pt(PPh3)2})]Y: Synthesis, structure, and exchange processes

Novel bimetallic Ru-Pt and Fe-Pt complexes, [M(C₅R₅)(L)₂(η¹-P₄)]Y (M = Ru, Fe; R = H, Me; L = PPh₃, 1/2Dppf (Ph₂P(C₅H₄)Fe(C₅H₄)PPh₂), 1/2Dppe (Ph₂PCH₂CH₂PPh₂); Y = PF₆, CF₃SO₃, BPh₄) were synthesized for the first time by the reaction of η¹-tetraphosphorus complexes of ruthenium(II) and iron(II), [M(C₅R₅)(L)₂(η¹-P₄)]Y with platinum(0) complex [Pt(η²-C₂H₄)(PPh₃)₂] in acetone. The structures and compositions of the title complexes were studied by the ³¹P NMR, correlated ³¹P-³¹P NMR COSY, NOESY, ¹H-spectroscopy, and elemental analysis. The carbene-like fragment Pt(PPh₃)₂ generated in situ was found to be inserted at the P-P bond of the η¹-coordinated tetraphosphorus and migrate between the phosphorus atoms of the obtained ligand μ, η¹: η²-P₄. The exchange process in the novel complexes was investigated. Original Russian Text ? D.N. Akbayeva, 2007, published in Koordinatsionnaya Khimiya, 2007, Vol. 33, No. 9, pp. 673–680.     

Chiral derivatives ofexo-metallofulierenes: Synthesis and X-ray study of solvate of platinumfullerene cluster with cyclooctene, η2-C60Pt[(+)-D1OP] · C8H14

A novel optically active exo-metallofullerene derivative, ²-C₆₀Pt[(+)-DIOP] (1) (DIOP is 2,3-o,o'-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphinobutane)), is formed as a result of the cleavage of the chelate metallocycle in Pt[(+)-DIOP]2 and the substitution of the bidentate (+)-DIOP ligand with C₆₀. Cluster 1 was also obtained by replacement of the phosphine ligands in ²-C₆₀Pt(PPh₃)₂ by (+)-DIOP. Compound 1 was identified by its electronic absorption spectra,³¹P NMR spectra, and the elemental analysis data. A singlecrystal X-ray study of the 1 cyclooctene solvate, ²-C₆₀Pt[(+)-DIOP] C₈H₁₄ was performed. Packing of the fullerene cores in a crystal of 1 · C₈H 14 corresponds to the diamond structure subjected to the significant orthorhombic distortions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1268–1274, May, 1996.     

Synthesis,structure, and properties of organoplatinum(ii) derivatives of diphenyl ether

New mono- and disubstituted organoplatinum(II) derivatives of diphenyl ether,cis-(PhOC₆H₄-o)PtCl(PPh₃)₂ and (o-C₆H₄OC₆H₄-o)Pt(PPh₃)₂, were synthesized by the reaction of 2,2-dilithium diphenyl oxide withcis-Cl₂Pt(PPh₃)₂. Transmetallation of (PhOC₆H₄-o)AuPPh₃ withcis-Cl₂Pt(PPh₃)₂ was studied using³¹P NMR monitoring. This reaction proceeds with the retention of configuration to afford ClAuPPh₃ andcis-(PhOC₆H₄-o)PtCl(PPh₃)₂ under kinetically controlled conditions. The latter complex irreversibly isomerizes into thetrans isomer in the presence of equimolar quantities of ClAuPPh₃, whereas, in the presence of free PPh₃, this isomerization is reversible. The structures of the obtained diphenyl oxide derivatives of platinum were confirmed by³¹P NMR and FAB mass spectrometry. It was established by X-ray structural analysis that in thecis-(PhOC₆H₄-o)PtCl(PPh₃)₂ complex, the Pt atom is in a nearly square-planar coordination, and secondary intramolecular Pt...O interaction occurs.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1814–1820, October, 1994.We would like to thank A. L. Blyumenfel'd and P. V. Petrovskii for recording the 31p NMR spectra, and D. V. Zagorevskii and K. V. Kazakov for measuring the mass spectrometric characteristics.This work was supported by the International Science Foundation (Project No. MDV 000).     

The reaction of diaryl derivatives of bis(triphenylphosphine)platinum(II) with [60]fullerene as a route to the platinum complex η2-C60Pt(PPh3)2

The reaction ofcis-Ar₂Pt(PPh₃)₂ (Ar=p-MeC₆H₄ (1a) and Ar=Ph (1b)) with [60]fullerene in toluene afforded the metal-fullerene complex η²-C₆₀Pt(PPh₃)₂ (2), which was isolated in the crystalline state. The reductive elimination between C₆₀ and1a or1b also resulted in the formation of biaryls (p-MeC₆H₄)₂ and Ph−Ph. The composition and structure of the compounds were established by¹H and³¹P NMR spectroscopy, electronic absorption spectroscopy, and elemental analysis. The homolytic phosphorylation of2 was additionally studied by the ESR method.     

Synthesis of asymmetrical bis(arene) iron complexes

Visible light irradiation of the [(η-C₆H₇)Fe(η-C₆H₆)]⁺ cation (1) in CH₂Cl₂ in the presence of alkyl-substituted benzenes results in arene exchange forming the [(η⁵-C₆H₇)Fe(η-C₆R₆)]⁺ cations (2a–d: C₆R₆ is toluene, p-xylene, mesitylene, and durene). The mixed bis(arene) [(η-C₆H₆)Fe(η-C₆R₆)]²⁺ iron complexes (3a–d) were synthesized by hydride ion abstraction from 2a–d by [Ph₃C]⁺. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1864–1865, September, 2007.     

Synthesis and characteristics of novel pentanuclear complexes [(OC)3Mn(η1,η5-C5H4)Fe(CO)2(η1,η5-C5H4CO2)]2M(η5-C5H5)2 (M=Ti, Zr)

The reaction of Cp₂MCl₂ complexes (M=Ti and Zr) with 2 equiv. of (OC)₃Mn(η¹,η⁵-C₅H₄)Fe(CO)₂(η⁵-C₅H₄COONa) results in the formation of the pentanuclear complexes (OC)₃Mn(η¹,η⁵-C₅H₄)Fe(CO)₂(η⁵-C₅H₄CO₂)]₂M(η⁵-C₅H₅)₂, which are characterized by IR and¹H NMR spectroscopy and cyclic voltammetry. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1055–1058, May, 1997.     

Synthesis and structures of 1,1′-bis(diphenylphosphino)metallocenyl complexes M(η 5-C5H4PPh2)2Ru(H2O)2(OTs)2 (M = Fe, Ru, or Os)

The reaction of equimolar amounts of M(η⁵-C₅H₄PPh₂)₂ (M = Fe, Ru, or Os) and [Ru(H₂O)₆](OTs)₂ afforded the M(η⁵-C₅H₄PPh₂)₂Ru(H₂O)₂(OTs)₂ complexes, which were characterized by elemental analysis and ¹H, ¹³C, and ³¹P NMR spectroscopy. The structure of the osmocene complex was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 659—661, April, 2006.     

Radical functionalization of [60]fullerene and its derivatives initiated by the C(CF3)2C6H4F radical

It was found that the 2-(p-fluorophenyl)hexafluoroisopropyl radical produced by thermal dissociation of the Polishchuk dimer [C(CF₃)₂C₆H₄F]₂ can withdraw, under mild conditions, the H atom from the methyl group of toluene and mesitylene to form the corresponding radicals, whose addition to [60]fullerene occurs more selectively than in the case of photochemical production of these radicals. Dynamics of the step-by-step multiaddition of the radicals to C₆₀ was studied by ESR. It was found that the addition of benzyl radicals affords adducts containing from 3 to 5 benzyl groups, whereas no spin-adducts with five addends were observed for more bulky 3,5-dimethylphenylmethyl radicals. The interaction of 3,5-dimethylphenylmethyl radicals with the metal complexes (η²-C₆₀[IrH(CO)(PPh₃)₂] and (η²-C₆₀[Pd(PPh₃)₂] was studied for the first time. It was shown that the palladium derivative undergoes only demetallation. In the case of the Ir complex, up to 3 radicals add to the fullerene ligand in the same hemisphere where the transition metal is coordinated. The reaction rates are ∼5 times lower than those for C₆₀. The ability of 2-(p-fluorophenyl)hexafluoroisopropyl radicals to dehydrogenate C₆₀H₃₆ was found. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1119–1123, June, 1999.     

Influence of the nature of ligands in iridium complexes with C60 fullerene and ·P(O)(OPri)2, ·CMe3, and ·CCl3 radicals on regioselectivity of addition and stability of spin-adducts formed: an EPR study

The addition of ^·P(O)(OPrⁱ)₂ (R¹), ^·CMe₃ (R²), and ^·CCl₃ (R³) radicals to metallofullerenes (η²-C₆₀)IrH(CO)(CNBu^t)₂(o-HCB₁₀H₉CCH₂PPh₂-B,P) (1), (η²-C₆₀)IrH(CO)(DIOP) (DIOP is (4R,5R)-(+)-4,5-bis(diphenylphosphinomethyl)-2,2-dimethyl-1,3-dioxolane, 2), and (η²-C₆₀)IrH(CO)(PPh₃)₂ (3) was studied by EPR spectroscopy. A stability study of spin adducts (SAs) of R¹ radicals with complexes 1 and 2 showed that when the reactions are initiated by illumination with 366-nm light, the EPR spectra exhibit only signals of those isomers that are formed upon attack of the R¹ radicals on the carbon atoms of the cis-1 and cis-2 bonds (i.e., carbon atoms of the fullerene hemisphere to which the metallofragment is attached). Investigations of the reactions of R² and R³ radicals with complexes 1–3 initiated with 366-nm light made it possible to detect (i) regioisomers formed by adding these radicals to carbon atoms of the cis-n bonds and (ii) SAs formed by adding the radicals to carbon atoms of other bonds in complexes 1–3. The hyperfine structure of the EPR spectrum essentially depends on the spatial structure of substituents at the metal atom and allows individual regioisomers of not only phosphoryl radicals, but also carbon-centered radicals R² and R³ with metallofullerenes 1–3 to be identified. The rate constants for addition of R² and R³ radicals to complexes 2 and 3 were determined. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1302–1309, July, 2007.     

Benzene complex [(η-9-SMe2-7,8-C2B9H10)Fe(η-C6H6)]+ as a synthon for the cationic ferracarborane moiety

The photochemical reaction of [(η⁵-C₆H₇)Fe(η-C₆H₆)]⁺ (1) with the [(η-9-SMe₂-7,8-C₂B₉H₁₀)]⁻ anion followed by the treatment of the resulting ferracarborane (η-9-SMe₂-7,8-C₂B₉H₁₀)Fe(η⁵-C₆H₇) (2) with hydrochloric acid afforded the benzene complex [(η-9-SMe₂-7,8-C₂B₉H₁₀)Fe(η-C₆H₆)]⁺ (3). The reaction of cation 3 with Bu^tNC produced the isonitrile complex [(η-9-SMe₂-7,8-C₂B₉H₁₀)Fe(^tBuNC)₃]⁺ (4). The structure of the complex [4]PF₆ was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2046–2048, October, 2007.     

An electrochemical investigation on the reduction path of the arene complexes [CpM(arene)]2+ and [(η-9-SMe2-7,8-C2B9H10)M(arene)]2+ (M=Rh, Ir)

The reduction behavior of the isoelectronic complexes [CpM^III(η⁶-C₆R₆)]²⁺ (M=Rh, Ir; R=H, Me) and [(η-9-SMe₂-7,8-C₂B₉H₁₀)M^III(η⁶-C₆R₆)]²⁺ (M=Rh, Ir; C₆R₆ = C₆H₆, C₆H₅OMe, C₆H₃Me₃) has been studied by cyclic voltammetry and controlled potential coulometry in acetonitrile and propylene carbonate at 253 and 298 K, respectively. The extent of chemical reversibility of the pertinent sequences Rh(III)/Rh(II)/Rh(I) and Ir(III)/Ir(I) is highly dependent on both the nature of the solvent and the intrinsic electronic properties of the arene substituents. The arene η⁶ coordination makes the derivatives in their lower oxidation states notably short lived, even if, in some cases, the use of propylene carbonate improves their stability or causes the increase in their lifetimes before changing the arene coordination from η⁶ to η⁴. Cations [(η-9-SMe₂-7,8-C₂B₉H₁₀)M(η⁶-C₆R₆)]²⁺ were obtained by the bromide abstraction from [(η-9-SMe₂-7,8-C₂B₉H₁₀)MBr₂]₂ with Ag⁺ in the presence of benzene and its derivatives. The structure of [(η-9-SMe₂-7,8-C₂B₉H₁₀)Ir(η⁶-C₆H₅OMe)](BF₄)₂ was determined by X-ray diffraction.     

Interaction of the iridium(III) trihydridophosphine complex with fullerene C60 under thermal and photochemical excitation

The interaction of the PPh₃-stabilized iridium trihydrido complex H₃Ir(PPh₃)₃ with fullerene C₆₀ under thermal and photochemical excitation was studied under anaerobic conditions. Heating (100 °C) or photolysis by the visible light of the H₃Ir(PPh₃)₃-C₆₀ 650 nm, which are characteristic of the ·²-coordinated C₆₀ in several fullerene-containing metal complexes. The kinetic behavior of the H₃Ir(PPh₃)₃)-C₆₀ system in benzonitrile was investigated using a Nd³⁺-YAG laser (λ=532 nm). The quenching rate constant determined from the dependence of the effective first-order quenching constant of C₆₀(T) on the concentration of H₃Ir(PPh₃)₃ is equal to 1.1·10⁹ L mol⁻¹ s⁻¹. The quenching of C₆₀(T) by the iridium hydridophosphine complex follows the reductive mechanism to form a C₆₀ monoanion. The ESR signal with g=2.000 and ΔH=0.17 mT (at room temperature) and characteristic absorption bands in the near-IR region at 940, 1004, and 1076 nm support the formation of the C₆₀ monoanion during the interaction of the triplet-excited C₆₀ with H₃Ir(PPh₃)₃. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2145–2148, December, 1997.     

Formation and structure of diruthenium complexes Ru2(CO)6−n (PPh3) n {μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} (n=1, 2)

Ruthenium carbonyl triphenylphosphine complexes Ru₂(CO)_6−n (PPh₃) _n {μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} (n=1, 2) were obtained by the reaction of complex Ru₂(CO)₆{μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} containing the ruthenacyclopentadiene moiety with PPh₃ in refluxing toluene. The complexes were characterized by IR and by¹H,¹³C, and³¹P NMR spectroscopy, and by X-ray analysis. The monophosphine derivative is identical to the complex formed by fragmentation of the Ru₃(CO)₈(PPh₃){μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} cluster and contains the PPh₃ ligand at the ruthenium atom of the ruthenacyclopentadiene moiety. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1836–1843, September, 1998     

Sandwich complexes of Si, Ge, Sn, and Pb with cyclopentadienyl type derivatives of corannulene and fullerene C60: stability estimates and molecular and electronic structure prediction by the MNDO/PM3 method

The ability of cyclopentadienyl type derivatives of corannulene C₂₀H₁₀ and fullereneI _h -C₆₀ to form η⁵-π-complexes and the problem of their existence is discussed. MNDO/PM3 calculations of half-sandwich complexes η⁵-π-MC₂₀H₁₅, η⁵-π-MC₂₀H ₁₅ ⁺ , η⁵-π-MC₆₀H₅, η⁵-π-MC₆₀H₅ and sandwich complexes 2η⁵-π-M(C₂₀H₁₅)₂, 2η⁵-π-M(C₂₀H₁₅)₂, 2η⁵-π-M(C₆₀H₅)₂ (M=Si, Ge, Sn, Pb) were performed. For all systems studied, local minima were found on corresponding potential energy surfaces and the heats of formation, geometric parameters, and distributions of effective atomic charges were calculated. Sandwich complexes are most likely to exist with M=Si and Ge. The energy and geometric characteristics of η⁵-π-complexes of corannulene were compared with those of η⁵-π-complexes of fullereneI _h -C₆₀. It was concluded that the results of quantum-chemical calculations of sandwich type corannulene derivatives can be used for simulation of the geometry and electronic structure of analogous complexes of fullereneI _h -C₆₀. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1649–1656, September, 1999.     

Fullerene complexes with bis(η6-hexamethylbenzene)chromium, hexamethylbenzene, and hexaethylbenzene

The [60]fulleride of bis(η-hexamethylbenzene)chromium(I) [(η⁶-C₆Me₆)₂Cr]^⋅+[C₆₀]^⋅−, and the complexes C₆₀·C₆Me₆ and C₆₀·C₆Et₆ were synthesized. Thermal decomposition of [(η⁶-C₆Me₆)₂Cr]^⋅+[C₆₀]^⋅− was studied. The molecular structures of C₆₀·C₆Me₆ and C₆₀·C₆Et₆ were determined. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 220—224, February, 2006.     

Correlations between 13C NMR chemical shifts of [(1-R-η3-C3H4)PdCl]2 and Na[(1-R-η3-C3H4)PdCl2] and substituent constants

Linear correlations between ¹³C NMR chemical shifts of unsubstituted terminal carbon atom of the allylic ligand in [(1-R-η³-C₃H₄)PdCl]₂ and Na[(1-R-η³-C₃H₄)PdCl₂] and the modified Hammett constants were established. Two-parameter correlations using the Swain-Lupton parameters R ⁺, R ⁻, and F were obtained. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1171–1174, June, 2008.     

Oxidation of (η5-6-exo-cyclopentadienylcyclohexadienyl)- (η5-cyclopentadienyl) iron by trityl hexafluorophosphateby trityl hexafluorophosphate

Oxidation of the cyclohexadienyl complex Fe(η⁵-C₅H₅)(1-5-7⁵-6-exo-C₅H₅-C₆H₆) (2) by (Ph₃C)PF₆ (CH₂Cl₂, from −30 to +20 °C) occurs as two concurrent processes: elimination of an H atom from the cyclohexadienyl ligand and replacement of an H atom in the cyclopentadienyl ring by a CPh₃ fragment. A mixture of cationic complexes [Fe(η⁵-C₅H₅) (η⁶-Ph-C₅H₅]⁺ (1⁺) and [Fe(η⁵-C₅H₄CPh₃) (η⁶-Ph-C₅H₅]⁺ (4⁺) (4 ⁺) with PF₆ ⁻ anions is obtained. Deprotonation of the mixture of 1⁺ and 4⁺ complexes under the action of Bu ^t OK inm-xylene followed by boiling of the reaction mixture gives phenylferrocene (7) as the product of η⁶:η⁶ haptotropic rearrangement. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, NO. 5, pp. 1045–1047, May, 1997.