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.     

1,2,3,4,7-Pentamethylindenyl complex [(η5-C9H2Me5)RhI2]2 as a synthon for the [(η5-C9H2Me5)Rh]2+ fragment

The reaction of the iodide complex [(η⁵-C₉H₂Me₅)RhI₂]₂ (1) or the acetonitrile complex [(η⁵-C₉H₂Me₅)Rh(MeCN)₃]²⁺ with Tl[Tl(η-7,8-C₂B₉H₁₁)] afforded rhodacarborane (η⁵-C₉H₂Me₅)Rh(7,8-C₂B₉H₁₁) (2). The cationic triple-decker complex with the bridging boratabenzene ligand [Cp*Fe(μ-η:η-C₅H₃Me₂BMe)Rh(η⁵-C₉H₂Me₅)]²⁺ (3) was synthesized by the reaction of the nitromethane solvate [(η⁵-C₉H₂Me₅)Rh(MeNO₂)₃]²⁺ with the sandwich compound Cp*Fe(η-C₅H₃Me₂BMe). The structure of 2 was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1623–1625, August, 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.     

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.     

Synthesis and structures of fulvene-bridged diruthenium complexes

Three diruthenium carbonyl complexes, namely (η ³:η ⁵-C₅H₄C(CH₂)₂)Ru₂(CO)₅ (1), (η ³:η ⁵-C₅H₄C(CHCH₂)(C₂H₅))Ru₂(CO)₅ (2), and (η ¹:η ⁵-C₅H₄C₅H₈)Ru₂(CO)₆ (3), were obtained from the reactions of C₅H₄C(Me)₂, C₅H₄C(Et)₂, and C₅H₄C(CH₂)₄, respectively, with Ru₃(CO)₁₂ in refluxing xylene. The complexes were characterized by elemental analysis, IR and ¹H NMR spectra. Single-crystal X-ray diffraction analysis for complexes 1 and 2 revealed that the fulvene ligands bridge two ruthenium atoms in η ³:η ⁵ fashion.     

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.     

New 1,3-disubstituted side-chain functionalized indenyl ligands and zirconium complexes derived from them

New functionalized indenyl ligands Ind^X = 1,3-C₉H₅(Prⁱ)(CH₂CH₂X) (X = OMe or NMe₂) and 1,3-C₉H₅(Prⁱ)[CMe₂CH₂(2′-py)] and the zirconium sandwich complexes (Ind^X)Cp*ZrCl₂ (Cp* is pentamethylcyclopentadienyl) were synthesized. The photochemical behavior and the reduction reactions of zirconocene dichlorides were investigated. The properties of these compounds are determined mainly by the high lability of Zr-Ind bonds. The reduction of (Ind^X)Cp*ZrCl₂ (X = NMe₂) selectively affords the complex Cp*[η⁵:η²-(C,N)-C₉H₅(Prⁱ)CH₂CH₂N(Me)CH₂]ZrH as the intramolecular NCH₂-H bond activation product. The molecular structures of the complex (Ind^X)Cp*ZrCl₂ (X = OMe) and its photochemical decomposition product [Cp*ZrCl₂(OMe)]₂ were established by X-ray diffraction.     

Synthesis and structures of bridged biscyclopentadienyl diiron complexes

Three diiron carbonyl complexes, namely [(η ⁵-C₅H₄)(η ³-C(CH₂)₂)]Fe₂(CO)₅ (1), [(C₂H₅)₂C(η ⁵-C₅H₄)₂]Fe₂(μ-CO)₂(CO)₂ (2), and [(CH₂)₄C(η ⁵-C₅H₄)(η ⁵-C₅H₃)(C₅H₉)]Fe₂(μ-CO)₂(CO)₂ (3), have been synthesized by the reactions of C₅H₄C(Me)₂, C₅H₄C(Et)₂, and C₅H₄C(CH₂)₄, respectively, with Fe(CO)₅ in refluxing xylene. The complexes have been characterized by elemental analysis, IR, and ¹H NMR spectra. The molecular structures of the complexes have been determined by single-crystal X-ray diffraction. The structures of the complexes indicate that fulvenes can be bound to transition metal centers by diverse modes.     

Synthesis,Characterization and Crystal Structures of New Difurylphosphido-bridged Dinuclear Ruthenium Carbonyl Complexes Derived from Ferrocenylacetylene Ligands

The difurylphosphido-bridged dinuclear complex [Ru₂(CO)₆(μ-PFu₂)(μ-η¹,η²-Fu)] (Fu = 2-furyl) 1 readily reacts with two equivalents of each of the terminal alkynes HC≡CR (R = Fc, p-C₆H₄Fc, p-C₆H₄NO₂, Fc = Fe(η⁵-C₅H₅)(η⁵-C₅H₄)) by an interesting head-to-tail ynyl coupling with a furan group to form a series of phosphido-bridged diruthenium compounds containing a novel furyl-substituted C₄ hydrocarbyl chain of stoichiometry [Ru₂(CO)₄(μ-PFu₂){μ-η¹,η¹,η²,η³-RCC(H)C(R)C(H)Fu}] (R = Fc 2, p-C₆H₄Fc 3, p-C₆H₄NO₂ 4) in moderate to good yields. Reaction of 1 with an equimolar amount of HC≡CFc and HC≡C(p-C₆H₄NO₂) afforded a pair of isomers of [Ru₂(CO)₄(μ-PFu₂){μ-η¹,η¹,η²,η³-R¹CC(H)C(R²)C(H)Fu}] (R¹ = Fc, R² = p-C₆H₄NO₂ 5a; R¹ = p-C₆H₄NO₂, R² = Fc 5b) together with a small mixture of 4. X-ray crystal structures of 2, 3, 5a and 5b are reported. All of these new alkyne-derived dinuclear complexes are electron precise with 34 cluster valence electrons in which the μ-η¹,η²-furyl ligand acts as a three-electron donor and the μ-phosphido Ru₂ framework is retained in the products upon alkyne coupling reactions. The resulting organic fragment of each complex is coordinated to the Ru atoms via a π, a π-allyl and two σ bonds, and donates seven electrons to the metal core. Dedicated to the memory of Professor F. Albert Cotton.     

1-Methylimidazol-2-yl-functionalized cyclopentadienyl titanium and zirconium complexes. Crystal structure of [η 5:η1-C5H4CPh2CH2-(1-MeC3H2N2)]TiCl3

The new side-chain functionalized cyclopentadienyl ligand LiC₅H₄CPh₂CH₂R (R is 1-methylimidazol-2-yl) as lithium salt 2, the trimethylsilyl derivative Me₃SiC₅H₄CPh₂CH₂R (3), and the ligand in the CH form (4) were prepared starting from 6,6-diphenylfulvene and 1,2-dimethylimidazole lithiated at the 2-Me group (1) and then characterized. The half-sandwich complexes (η⁵:η ¹-C₅H₄CPh₂CH₂R)TiCl₃ (5) and (η⁵:η ¹-C₅H₄CPh₂CH₂R)ZrCl₃ (6) were synthesized. The molecular structure of complex 5 was established by X-ray diffraction. Complexes 5 and 6 exhibit dynamic behavior in solution associated with degenerate interconversion of the pseudo-six-membered metallacycle. For titanium complex 5 in a solvating solvent, a dynamic process due to intramolecular dissociation—coordination of the imidazole fragment was observed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1518–1524, September, 2006.     

Synthesis of the first metallacarborane triple-decker complexes with a central cyclopentadienyl ligand

The previously unknown metallacarboranes (η-C₅R₅)Ru(η-9-Me₂S-7,8-C₂B₉H₁₀) (R=H or Me) and (η-C₅H₅)Ni(η-9-Me₂S-7,8-C₂B₉H₁₀) were prepared and used in the synthesis of the first metallacarborane triple-decker complexes with a central cyclopentadienyl ligand, viz., [(η-C₅R₅)Ru(μ-η:η-C₅Me₅)Ru(η-9-Me₂S-7,8-C₂B₉H₁₀)]PF₆ (R=H or Me), [(η-9-Me₂S-7,8-C₂B₉H₁₀)Ni(μ-η:η-C₅H₅)Ni(η-9-Me₂S-7,8-C₂B₉H₁₀)]PF₆, and [(η-C₅H₅)Ni(μ-η:η-C₅H₅)Ni(η-9-Me₂S-7,8-C₂B₉H₁₀)]BF₄. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1368–1373, July, 1999.     

2-Phosphinothioyl- and 2-phosphinoylethylcyclopentadienyl zirconium and titanium complexes. Crystal structure of [η5:η1-C5H4CH2CH2P(O)Ph2]TiCl3

The intracomplex conversion of (2-diphenylphosphanoethyl)cyclopentadienyl zirconium and titanium complexes into the corresponding 2-phosphinothioyl and 2-phosphinoyl derivatives, viz., (η⁵-C₅H₅)[η ⁵-C₅H₄CH₂CH₂P(S)Ph₂]ZrCl₂, [η⁵-C₅H₄CH₂CH₂P(S)Ph₂]ZrCl₃, [η⁵:η¹C₅H₄CH₂CH₂P(O)Ph₂]ZrCl₃·THF, and [η⁵:η ¹-C₅H₄CH₂CH₂P(O)Ph₂]TiCl₃ (7), was performed. The NMR spectroscopy data revealed the following order of the coordination ability of the functional groups with respect to the Zr center: Ph₂P=O > Ph₂P > Ph₂P=S. An analogous order was found for the monodentate ligands (Ph₃P=O > Ph₃P > Ph₃P=S) with respect to (η⁵-C₅H₅)ZrCl₃. The molecular structure of complex 7 was established by X-ray diffraction analysis. Coordination of the Ph₂P=O group to the titanium atom was found retained both in the crystalline state and solution.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 116–122, January, 2005.     

Synthesis and Characterizations of Ferrocenyl Carbonyl Chromium and Cobalt Clusters

Two novel bimetallic complexes, [Cr(CO)₃(η ⁶-C₆H₅)–C≡C–C₆H₄–Fc] (Fc = C₅H₅FeC₅H₄] (1) and [Cr(CO)₃(η ⁶-C₆H₅)–C ≡ C–Fc–C(CH₃)₂–Fc] (3), were synthesized by the Sonogashira coupling reaction. By using of (1) and (3) as ligands to react with Co₂(CO)₈, two others novel polymetallic complexes, [Cr(CO)₃(η ⁶-C₆H₅){Co₂(CO)₆-η ²-μ ²-C≡C–}–C₆H₄–Fc] (2) and [Cr(CO)₃(η ⁶-C₆H₅){Co₂(CO)₆-η ²-μ ²-C≡C–}Fc–C(CH₃)₂–Fc] (4) were obtained. Four carbonyl complexes were characterized by elemental analysis, FT-IR, NMR and MS. The molecular structures of complexes (1), (2) and (4) were determined by single crystal X-ray diffraction. The interactions among the ferrocenyl, Cr(CO)₃ and Co₂(CO)₆-η ²-μ ²-C≡C– units were investigated by cyclic voltammetry.     

Sandwich iridium complexes with the monoanionic carborane ligand [9-SMe2-7,8-C2B9H10]−

The reaction of the [(η-9-SMe₂-7,8-C₂B₉H₁₀)IrBr₂]₂ complex with Tl[Tl(η-7,8-C₂B₉H₁₁)] afforded the iridacarborane compound (η-9-SMe₂-7,8-C₂B₉H₁₀)Ir(η-7,8-C₂B₉H₁₁). The cationic complex [Cp*Ir(η-9-SMe₂-7,8-C₂B₉H₁₀)]⁺PF₆ ⁻ (5 · PF₆, Cp* is pentamethylcyclopentadienyl) was synthesized by the reaction of [Cp*IrCl₂]₂ with Na[9-SMe₂-7,8-C₂B₉H₁₀]. The structures of (η-9-SMe₂-7,8-C₂B₉H₁₀)Ir(η-cod) (cod is 1,5-cyclooctadiene) and 5 · PF₆ were established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 81–84, January, 2006.     

Photochemical substitution of benzene in the iron cyclohexadienyl complex [(η<Superscript>5</Superscript>-C<Subscript>6</Subscript>H<Subscript>7</Subscript>)Fe(η-C<Subscript>6</Subscript>H<Subscript>6</Subscript>)]<Superscript>+</Superscript>

The visible light irradiation of the [(η⁵-C₆H₇)Fe(η-C₆H₆)]⁺ cation (1) in acetonitrile resulted in the substitution of the benzene ligand to form the labile acetonitrile species [(η⁵-C₆H₇)Fe(MeCN)₃]⁺ (2). The reaction of 1 with Bu^tNC in MeCN produced the stable isonitrile complex [(η⁵-C₆H₇)Fe(Bu^tNC)₃]⁺ (3). The photochemical reaction of cation 1 with pentaphosphaferrocene Cp*Fe(η-cyclo-P₅) afforded the triple-decker cation with the bridging pentaphospholyl ligand, [(η⁵-C₆H₇)Fe(μ-η:η-cyclo-P₅)FeCp*]⁺ (4). The latter complex was also synthesized by the reaction of cation 2 with Cp*Fe(η-cyclo-P₅). The structure of the complex [3]PF₆ was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2088–2091, November, 2007.     

Stacking reactions of the borole complex Cp*Rh(η5-C4H4BPh) with the dicationic fragments [Cp*M]2+ (M = Rh or Ir)

The reaction of the (borole)rhodium iodide complex [(η-C₄H₄BPh)RhI]₄ with Cp^*Li afforded the sandwich compound Cp^*Rh(η-C₄H₄BPh) (4). The reactions of compound 4 with the solvated complexes [Cp^*M(MeNO₂)₃]²⁺(BF ₄ ⁻ )₂ gave triple-decker cationic complexes with the central borole ligand [Cp^*Rh(η-η⁵:η⁵-C₄H₄BPh)MCp^*]²⁺(BF ₄ ⁻ )₂ (M = Rh (5) or Ir (7)). The structure of complex 4 was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1525–1527, September, 2006.     

Reactions of metallocenes during intercalation into the layered TiSe2 lattice

The intercalation of metallocenes (Cp₂Co, Cp₂Fe, and Cp₂Ni, where Cp is η⁵-C₅H₅) from the gas phase into the TiSe₂ lattice and of cobaltocene from solutions in acetonitrile, carbon tetrachloride, and chloroform into TiSe₂ was studied. The insertion of metallocenes from the gas phase into the TiSe₂ lattice gives rise to the TiSe₂(Cp₂M)_0.3 compounds (M = Co or Fe) having the same stoichiometry. The reactions with the use of acetonitrile as the solvent for metallocenes, which facilitates the insertion, afford not only the intercalation complex but also the reaction product of metallocene and acetonitrile, viz., (η ⁵-C₅H₅)Co(η⁴-C₅H₅CH₂CN) (1). In the reactions of cobaltocene with chloroform or carbon tetrachloride in the presence of titanium diselenide, only the addition product, viz., (η ⁵-C₅H₅)Co(η₄-C₅H₅CCl₃) (2), was isolated. The structures of complexes 1 and 2 were studied by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 876–880, May, 2007.     

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.     

Photochemical replacement of benzene in the tetramethylcyclopentadienyl complex of iron, [η-C<Subscript>5</Subscript>Me<Subscript>4</Subscript>H)Fe(η-C<Subscript>6</Subscript>H<Subscript>6</Subscript>)]<Superscript>+</Superscript>

Irradiation of the cation [η-C₅Me₄H)Fe(η-C₆H₆)]⁺+ (1) and Bu^tNC with visible light in acetonitrile results in the displacement of the benzene ligand, giving [(η-C₅Me₄H)Fe(Bu^tNC)₃]+ (2). Reactions of complex 1 with P(OR)₃ and dppe in M_eCN yield the complexes [(η-C₅Me₄H)-Fe(M_eCN)P(OR)_{3 2}]+ (R = Me (3) and Et (4)) and [(η-C₅Me₄H)Fe(MeCN)(dppe)]+ (5) containing two Fe—P bonds. The same reactions in CH₂Cl₂ give the tris(phosphite) complexes [(η-C₅Me₄H)FeP(OR)_{3 3}]+ (6, 7). A photochemical reaction of complex 1 with pentaphos-phaferrocene Cp*Fe(η-cyclo-P₅) yields the triple-decker cation [(η-C₅Me₄H)Fe(μ-η:η-cyclo-P₅)FeCp*]+ (8) with a bridging pentaphospholyl ligand. Structures [2]PF₆ and [3]PF₆ were identified by X-ray diffraction.