Reactions of [Cp*Ru(H<Subscript>2</Subscript>O)(NBD)]<Superscript>+</Superscript> with diynes

Abstract  Formal [2 + 2 + 2] addition reaction of [Cp*Ru(H₂O)(NBD)][BF₄] (NBD = norbornadiene) with 4,4′-Diethynylbiphenyl generates [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BF₄]₂. The reaction of [Cp*Ru(H₂O)(NBD)][BF₄] with 1,4-diphenylbutadiyne generates the unusual [2 + 2 + 2] additional organic compound Ph–C≡C–C₉H₈–Ph in addition to the organometallic compound [Cp*Ru(η⁶-C₆H₅–C≡C–C≡C–Ph)][BF₄]. [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BPh₄]₂ is generated after the reaction of compound [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BF₄]₂ with Na[BPh₄]. The structure of this compound was confirmed by X-ray diffraction. A possible approach to form Ph–C≡C–C₉H₈–Ph and [Cp*Ru(η⁶-C₆H₅–C≡C–C≡C–Ph)][BF₄] is suggested. Graphical Abstract  Formal [2 + 2 + 2] addition reaction of [Cp*Ru(H₂O)(NBD)]BF₄ (NBD = norbornadiene) with 4,4′-Diethynylbiphenyl generates [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BF₄]₂. The reaction of [Cp*Ru(H₂O)(NBD)][BF₄] with 1,4-diphenylbutadiyne simply generates unusual [2 + 2 + 2] additional organic compound Ph–C≡C–C₉H₈–Ph in addition to the organometallic compound [Cp*Ru(η⁶-C₆H₅–C≡C–C≡C–Ph)][BF₄]. [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BPh₄]₂ is generated after the reaction of compound [C₉H₉-η⁶-C₆H₄(RuCp*)–C₆H₄(RuCp*)-η⁶-C₉H₉][BF₄]₂ with Na[BPh₄]. The structure of this compound was confirmed by X-ray diffraction. And the possible approach to form Ph–C≡C–C₉H₈–Ph and [Cp*Ru(η⁶-C₆H₅–C≡C–C≡C–Ph)][BF₄] was suggested. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

π-complexes of monoanionic carborane ligand [9-(Me2S)-7,8-C2B9H10]− with [η-C5R5Fe]+ (R=H, Me) and [η-C4Me4Co]+ cationic fragments

Compounds (η-C₅R₅)Fe[η-9-(Me₂S)-7,8-C₂B₉H₁₀] (R=H, Me) and (η-C₄Me₄)Co[η-9-(Me₂S)-7,8-C₂B₉H₁₀] were synthesized by the reactions of Na[9-(Me₂S)-7,8-C₂B₉H₁₀] with complexes [(η-C₅H₅)Fe(MeCN)₃]PF₆, [(η-C₅Me₅)Fe(MeCN)₃]BF₄, and [(η-C₄Me₄)Co(MeCN)₃]PF₆, respectively. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 177–179, January, 1999.     

Synthesis of triple-decker iron and cobalt complexes with a central tetramethylphospholyl ligand

30-Electron triple-decker complexes [(η-C₅H₅)Fe(μ-η:η-C₄Me₄P)Fe(η-C₅Me₅)]PF₆ and [(η-C₄Me₄)Co(μ-η:η-C₄Me₄P)Fe(η-C₅Me₅)]PF₆ with a central tetramethylphospholyl ligand were synthesized by stacking reactions of cationic fragments [(η-C₅H₅)Fe]⁺ and [(η-C₄Me₄)Co]⁺ with nonamethylphosphaferrocene (η-C₄Me₄P)Fe(η-C₅Me₅). Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1647–1649, September, 2000.     

30-Electron cationic iron- and cobalt-containing triple-decker complexes with a central cyclopentadienyl ligand. The first synthesis of the parent triple-decker iron complex with cyclopentadienyl ligands, [(η-C5H5)Fe(μ-η:η-C5H5)Fe(η-C5H5)]PF6

The parent 30-electron triple-decker iron complex with cyclopentadienyl ligands, [(η-C₅H₅)Fe(μ-η:η-C₅H₅)Fe(η-C₅H₅)]PF₆ (1), was prepared for the first time by visible-light irradiation of ferrocene and [(η-C₅H₅)Fe(η-C₆H₆)]PF₆ in CH₂Cl₂ at 0 °C. An analogous reaction performed with the use of (η-C₅H₅)Co(η-C₄Me₄) (2) instead of ferrocene afforded the thermally labile 30-electron cationic iron-cobalt triple-decker complex [(η-C₅H₅)Fe(μ-η:η-C₅H₅)Co(η-C₄Me₄)]PF₆. The latter reacted with compound 2 at 20 °C to form the symmetrical 30-electron cationic dicobalt triple-decker complex [(η-C₄Me₄)Co(μ-η:η-C₅H₅)Co(η-C₄Me₄)] PF₆. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 7, pp. 1364–1367, July, 1999.     

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.     

Synthesis of the first unsymmetrical 34-electron cationic cobalt-nickel triple-decker complex with a central cyclopentadienyl ligand [(η-C6Me6)Co(μ-η:η-C5H5)Ni(η-C5H5)]PF6

The first unsymmetrical 34-electron cationic cobalt-nickel triple-decker complex with a central cyclopentadienyl ligand [(η-C₆Me₆)Co(μ-η:η-C₅H₅)Ni(η-C₅)PF₆ was prepared by the reaction of [(η-C₆Me₆)₂Co]PF₆ with nickelocene. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 798–799, April, 1999.     

Cu(I), Ag(I) complexes containing (η 5-cyclopentadienyl) [η 5-1-(diphenylphosphino) cyclopentadienyl] cobaltocenium

{Cu₄Br₅[(η ⁵-C₅H₄PPh₂)(η ⁵-C₅H₅)Co]₄}[PF₆]₃, [(η ⁵-C₅H₄PPh₂)(η ⁵-C₅H₅)Co]⁺ = ((η ⁵-cyclopentadienyl)[η ⁵-1-(diphenylphosphino) cyclopentadienyl] cobaltocenium) and {Ag(NO₃)(CH₃COCH₃)[(η ⁵-C₅H₄PPh₂)(η ⁵-C₅H₅)Co]} _n [PF₆] _n have been synthesized and characterized by elemental analyses, infrared spectroscopy, X-ray diffraction techniques, and by cyclic voltammetry. {Cu₄Br₅[(η ⁵-C₅H₄PPh₂)(η ⁵-C₅H₅)Co]₄}[PF₆]₃ contains four coplanar copper atoms bridged by four μ-Br and one central μ ₄-Br occupying the apex of a square pyramid, and {Ag(NO₃)(CH₃COCH₃)[(η ⁵-C₅H₄PPh₂)(η ⁵-C₅H₅)Co]} _n [PF₆] _n affording a 1-D coordination zigzag polymer.     

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.     

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.     

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.     

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.     

Electrochemical behaviour of cobalta-dicarbollide sandwich complexes with different capping units

The redox aptitude of a series of cobalt(III) or cobalt(I) sandwich complexes bearing a charge compensated dicarbollide ligand ([9-L-7,8-C₂B₉H₁₀]⁻) as a constant unit and different counterparts (varying from classical [7,8-C₂B₉H₁₁]²⁻ to charge-compensated [9-L-7,8-C₂B₉H₁₀]⁻ dicarbollides, from cyclopentadienyl [C₅R₅]⁻ (R = Me, H) to cyclobutadiene [C₄Me₄]⁰ ligands) has been studied. All the Co(III) complexes display the reversible sequence Co(III)/Co(II)/Co(I). In contrast, the Co(I) complexes (namely, those capped by tetramethylcyclobutadiene) accede reversibly only to the Co(II) oxidation state, the passage to Co(III) being irreversible. When possible, the Co(II) intermediates have been characterized by EPR spectroscopy. The molecular structures of the monocation [Co(η-9-SMe₂-7,8-C₂B₉H₁₀)₂]⁺ in its DD/LL and meso diastereomeric forms as well as that of heteroleptic (η-7,8-C₂B₉H₁₁)Co(η-9-SMe₂-7,8-C₂B₉H₁₀) have been obtained by single-crystal diffraction. Presented at the 3rd Chianti Electrochemistry Meetings July 3−9, 2004, Certosa di Pontignano, Italy     

Electrochemical and spectral study of intramolecular charge transfer in dinuclear and polynuclear ladder complexes

The potentials of electrochemical oxidation and reduction of the polynuclear ladder complexes Cp(CO)LM-η ¹, η⁵-C₅H₄Mn(CO)₂L (M = Fe or W(CO); L = PPh₃ or CO), μ-(C≡ C)[C₅H₄(CO)₂Fe-η¹, η⁵-C₅H₄Mn(CO)₃]₂, and MeSi[C₅H₄(CO)₂Fe-η¹, η⁵-C₅H₄Mn(CO)₃]₃ were measured, and the mechanism of these processes is proposed. The change in the electron density at the atom of one metal (Fe or W) is transferred along the σ-and σ-bond chain in the cyclopentadienyl bridge to the atom of another metal (Mn) and, on the contrary, the perturbing effect of the substituent is somewhat weakened. Published In Russian In Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, Pp. 761–765, May, 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.     

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.     

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.     

Electrochemical reductive carbon-to-carbon coupling of σ-ethynyl complexes of transition metals

The electrochemical properties of σ-ethynyl complexes of chromium subgroup metals were studied by cyclic voltammetry and preparative-scale electrolysis. The redox cycle of C₅H₅(CO)₃CrC=CPh was shown to give the bis-carbyne complex (η⁵-C₅H₅)(CO)₂Cr≡C-C(Ph)=C(Ph)-C-Cr(CO)₂(η⁵-C₅H₅) formedvia the reductive C_β−C_β coupling of ethynyl moieties. The influence of the nature of the metal atom and the ligand environment on the course of this reaction was considered. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1955–1958, October, 1998.     

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.     

Synthesis of the cyclooctadiene and cyclooctenediyl cobalt complexes. Structures of [(η2,η2-cyclooctadiene)Co(η-1,2,4,5-C6H2Me4)]BF4 and [(η1,η3-cyclooctenediyl)Co(η-9-SMe2-7,8-C2B9H10)

Cobaltacarboranes (η¹, η³-cyclooctenediyl)Co(Carb) (Carb = η-9-SMe₂-7,8-C₂B₉H₁₀, η-1-tBuHN-1,7,9-C₃B₈H₁₀) were synthesized by the reaction of the carborane anions [Carb]⁻ with the acetonitrile complex [(η¹, η³-cyclooctenediyl)Co(MeCN)₃]⁺ generated in situ upon the dissolution of [(η¹, η³-cyclooctenediyl)Co(η-1,4-C₆H₄Me₂)]⁺ in MeCN. The structures of (η¹,η³-cyclooctenediyl)Co(η-9-SMe₂-7,8-C₂B₉H₁₀ and [(η²,η²-cyclooctadiene)Co((η-1,2,4,5-C₆H₂Me₄)]BF₄ were determined by X-ray diffraction analysis.     

Photochemical arene exchange in the ferracarborane complex [1-(η-C6H6)-12-ButNH-1,2,4,12-FeC3B8H10]+

The benzene complex [1-(η-C₆H₆)-12-Bu^tNH-1,2,4,12-FeC₃B₈H₁₀]⁺ (3a) was synthesized by the photochemical reaction of [(η⁵-C₆H₇)Fe(η-C₆H₆)]⁺ (1) with the anion [7-Bu^tNH-7,8,9-C₃B₈H₁₀]⁻ followed by the treatment of ferracarborane 1-(η⁵-C₆H₇)-12-Bu^tNH-1,2,4,12-FeC₃B₈H₁₀ (2) with hydrochloric acid. The benzene ligand in cation 3a is replaced by alkyl-substituted benzenes under visible light irradiation in CH₂Cl₂ to form [1-(η-C₆R₆)-12-Bu^tNH-1,2,4,12-FeC₃B₈H₁₀]⁺ (3b–e; C₆R₆ is toluene (b), mesitylene (c), hexamethylbenzene (d), or anisole (e)). The structure of [3c]PF₆ was established by X-ray diffraction.