Fulvene Research Articles

Rhodium complexes with planar-chiral cyclopentadienyl ligands: synthesis from tert-butylacetylene and catalytic performance in C-H activation of arylhydroxamates.

The rhodium complex [(C5H2tBu2CH2tBu)RhCl2]2 with an asymmetric cyclopentadienyl ligand was prepared in 95% yield by the reaction of [(cod)RhCl]2 with tert-butylacetylene in the presence of AlCl3. A similar reaction in the presence of InBr3 gave the cationic fulvene complex [(C5H2tBu2 = CHtBu)Rh(cod)]InBr4 (70%), which can add alcohols ROH and produce more bulky catalysts [(C5H2tBu2CH(OR)tBu)RhCl2]2. The enantiomers of these planar-chiral complexes were separated by thin-layer chromatography in the presence of L-phenylglycinol. The complexes catalyze the reactions of arylhydroxamates with alkenes giving dihydroisoquinolones in excellent yields (80-90%), but with moderate enantioselectivity (typically 20-50% ee).

Frontispiece: The Game of Electrons: Organocatalytic Higher‐Order Cycloadditions Involving Fulvene‐ and Tropone‐Derived Systems

Frontispiece: The Game of Electrons: Organocatalytic Higher‐Order Cycloadditions Involving Fulvene‐ and Tropone‐Derived Systems

Copper-Catalyzed [2+2] Cycloaddition of Quinones and Fulvenes

Copper-Catalyzed [2+2] Cycloaddition of Quinones and Fulvenes

Ruthenocene Precursors for Ruthenium-Containing Thin-Film Deposition: An Example of Solvent Nucleophilic Attack on Fulvene

A new series of ruthenocene complexes were prepared from RuCl3·xH2O and 6,6-dimethylfulvene as potential precursors for thin-film deposition. The formation of these complexes was the result of an unforeseen nucleophilic attack of the solvent molecules (alcohols/amines) on the 6,6-dimethylfulvene ligand during the reaction. Complexes [RuII(C5H4C(CH3)2OCH3)2] (1), [RuII(C5H4C(CH3)2OC2H5)2] (2), [RuII(C5H4C(CH3)2N(CH3)2)2] (3), and [RuII(C5H4C(CH3)2N(CH2CH3)2)2] (4) were isolated in pure form and characterized by Fourier transform (FT) infrared and FT nuclear magnetic resonance spectroscopy as well as elemental and thermogravimetric (TG) analyses. Crystallographic studies of complexes 1–3 revealed a monomeric ruthenocene structure for all complexes and showed that the deprotonated alkylalkoxide or dialkylamide of the solvent molecule was attached to the exocyclic carbon of the fulvene ligand. Although the complexes were formed as ruthenocenes instead of the expected ruthenium fulvene complexes, they all disp...

Trapping of an NiII Sulfide by a CoI Fulvene Complex

The reaction of [LtBuNiII(SCPh3)] (LtBu = {(2,6-iPr2C6H3)NC(tBu)}2CH) with Cp*2Co yields a NiI cobaltocenium thiolate complex, [LtBuNiI(SCH2Me4C5)Co(Cp*)] (1), along with HCPh3. Formation of this complex is proposed to occur via the reaction of a transient NiII sulfide, [Cp*2Co][LtBuNiII(S)], with a CoI fulvene complex, [CoCp*(C5Me4CH2)]. The latter complex is formed in situ by reaction of [Cp*2Co]+ with [CPh3]−. Control experiments, as well as cyclic voltammetry measurements of 1, are used to support the proposed mechanism.

Fulvene–Ruthenium and Cp–Ruthenium Complexes via [2 + 2 + 1] Cyclotrimerization of Phenylacetylene with [RuCl(Tp)(1,5-cod)

The complex [RuCl(Tp)(1,5-cod)], which bears the labile 1,5-cod ligand, was prepared from a high-yielding route involving the reaction of [RuCl2(1,5-cod)(CH3CN)2] with KTp (Tp = HB(pz)3). The reaction of [RuCl(Tp)(1,5-cod)] with phenylacetylene in either ethanol or methanol gave anti-Markovnikov alkoxide-adduct complexes [Ru(Tp)(η6-C5H2Ph2-CH(Ph)R)] (R = OMe, OEt). These adducts were formed by [2 + 2 + 1] cyclotrimerization reactions of phenylacetylene mediated by the precursor complex, [RuCl(Tp)(1,5-cod)]. The ruthenium(II)–fulvene complex, [Ru(Tp)(η6-C5H2Ph2-CH(Ph))]+, involved in these transformations was successfully isolated in the presence of NH4PF6. These complexes were fully characterized by 1H NMR, 13C NMR, DEPT, HSQC, IR, and ESI-MS spectroscopy. The molecular structures of [Ru(Tp)(η6-C5H2Ph2-CH(Ph)R)] (R = OMe/OEt) and [Ru(Tp)(η6-C5H2Ph2-CH(Ph))]PF6 have been determined by X-ray single-crystal diffraction. These complexes have piano-stool structures around the ruthenium center where half of the...

Solvent Effect on Reaction Rate of Ruthenium–Fulvalene Complexes Intramolecularly Bridged by Alkyl Disulfides and the Effect of Chalcogen

Abstract The reaction rate of [(PPh3)(MeCN)Ru(µ2-η5:η5-C10H8)(µ-MeSSMe)Ru(MeCN)(PPh3)](BF4)2 (2A), the intermediate of oxidative addition of disulfide to produce bis(thiolato)-bridged complex [(PPh3)Ru(µ2-η5:η5-C10H8)(µ2-SMe)2Ru(PPh3)](BF4)2 (2), changed depending on the solvent (CDCl3, CD2Cl2, CD3COCD3, and CD3NO2). The dependency is well explained by the stabilization energy of solvation of eliminated nitrile during the reaction. The corresponding PhCN complexes [(PhCN)2(PPh3)Ru(µ2-η5:η5-C10H8)Ru(PPh3)(PhCN)2](BF4)2 (1C) and [(PPh3)(PhCN)Ru(µ2-η5:η5-C10H8)(µ-MeSSMe)Ru(PhCN)(PPh3)](BF4)2 (2C) were newly synthesized to know the effect of nitrile. The intermediate of oxidative addition of diselenide [(PPh3)(MeCN)Ru(µ2-η5:η5-C10H8)(µ-MeSeSeMe)Ru(MeCN)(PPh3)](BF4)2 (3A) and the corresponding end product [(PPh3)Ru(µ2-η5:η5-C10H8)(µ2-SeMe)2Ru(PPh3)](BF4)2 (3) were also isolated, and the structures were determined by single-crystal X-ray structural analysis.

Synthesis of Zwitterionic Cobaltocenium Borate and Borata-alkene Derivatives from a Borole-Radical Anion

Chemical single-electron reduction of 1-mesityl-2,3,4,5-tetraphenylborole (3) gave a stable radical anion [CoCp*2 ][3] as shown in earlier investigations. Herein, we present the reaction of [CoCp*2 ][3] with the 2,2,6,6-tetramethylpiperidine-N-oxyl radical (TEMPO), a common radical trap. Instead of radical recombination, the reaction proceeds through a redox pathway involving oxidation of the borole radical anion combined with reduction of TEMPO. This electron-transfer process is accompanied by a deprotonation reaction of the cobaltocenium counterion by the base TEMPO(-) to give TEMPO-H and a neutral cobalt(I) fulvene complex (7). The latter was not observed directly during the reaction, because it instantaneously reacts as a nucleophile attacking at the boron center of the in situ generated borole 3 to give the borate 6. However, 7 was synthesized independently by deprotonation of [CoCp*2 ][PF6 ]. In addition, the obtained zwitterionic cobaltocenium borate 6 undergoes a photolytic rearrangement to form the borata-alkene derivative 9 that thermally transforms to the chiral cobaltocenium borate 12. Our investigations are based on spectroscopic evidence, X-ray crystallography, elemental analysis, as well as DFT calculations.

Preparation and characterization of Cp-functionalized cycloheptatrienyl–cyclopentadienyl titanium sandwich complexes (troticenes)

Cp-functionalized monotroticenes [(η 7-C 7H 7)Ti(η 5-C 5H 4E)] ( 2, E = Ph 2SiCl; 3, E = tBu 2SnCl; 12, E = I) and bitroticenes [(η 7-C 7H 7)Ti(η 5-C 5H 4)] 2E′ ( 5, E′ = PPh; 6, E′ = BN(SiMe 3) 2; 7, E′ = Cp 2Ti) were prepared by salt elimination metathesis between the monolithiated troticene [(η 7-C 7H 7)Ti(η 5-C 5H 4Li)]·pmdta ( 1b) (pmdta = N, N′, N′, N″, N″-pentamethyldiethylene-triamine) and the appropriate electrophile. The troticenyl-substituted zirconocene monochloride [(η 7-C 7H 7)Ti(η 5-C 5H 4ZrClCp* 2)] (Cp* = η 5-C 5Me 5) ( 8) and hafnocene ethoxide [(η 7-C 7H 7)Ti{η 5-C 5H 4Hf(OEt)Cp 2}] (Cp = η 5-C 5H 5) ( 11), and the heterobimetallic μ-oxo complexes [(η 7-C 7H 7)Ti(η 5-C 5H 4MCp 2)] 2O ( 9, M = Zr; 10, M = Hf) were obtained instead of the expected zircona- and hafna[1]troticenophanes by reaction of the dilithiated troticene [(η 7-C 7H 6Li)Ti(η 5-C 5H 4Li)]·pmdta ( 1a) with [Cp 2MCl 2] (M = Zr, Hf) or [Cp* 2ZrCl 2] in stoichiometric amounts. These compounds were characterized by single crystal X-ray diffraction analyses and, in the case of 2, 3, 5– 7, 9, 10 and 12, also by elemental analyses and 1H, 13C and 119Sn NMR spectroscopy. Exposure of the troticenyl organotin chloride 3 to moisture resulted in its partial hydrolysis and formation of the organostannoxane-bridged bitroticene 4, while palladium-catalyzed Negishi C–C cross-coupling reaction between the troticenylzinc chloride [(η 7-C 7H 7)Ti(η 5-C 5H 4ZnCl)] ( 13) and the iodotroticene 12 or iodobenzene (PhI) led to the fulvalene complexes [(η 7-C 7H 7)Ti(η 5-C 5H 4)] 2 ( 14) and [(η 7-C 7H 7)Ti(η 5-C 5H 4Ph)] ( 15). Compound 4 displays an unsymmetrical structure with the troticenyl fragments cis with respect to the Sn–O–Sn core, whereas compound 14 is centrosymmetrically trans oriented.

Synthesis and reactivity of η 5-tetramethylcyclopentadienyl-propenyl rhenium complexes: Molecular structure of [(η 5:η 2-C 5Me 4CH 2CH [dbnd]CH 2)Re(CO) 2

The fulvene complexes [(η 6-C 5Me 4CH 2)Re(CO) 2(R)] ( 1a, R I; 1b, R C 6F 5) react at the exocyclic methylene carbon with a vinylmagnesium bromide solution to produce the anionic species [(η 5-C 5Me 4CH 2CH CH 2)Re(CO) 2(R)] −. Protonation with HCl at 0 °C produces the hydride complexes [ trans-(η 5-C 5Me 4CH 2CH CH 2)Re(CO) 2(R)(H)] ( 2a, R I; 2b, R C 6F 5). Thermolysis of an hexane solution of the iodo-hydride ( 2a) under a CO atmosphere yields the complex [(η 5-C 5Me 4CH 2CH CH 2)Re(CO) 3] ( 3) and [Re(CO) 5I] as by-product. Thermolysis of 2b produced three new products, mainly the chelated complex [(η 5:η 2-C 5Me 4CH 2CH CH 2)Re(CO) 2] ( 4) and complex 3, with a non-coordinated olefin group, in moderated yield, and traces of [Re(CO) 5(C 6F 5)]. Thermolysis of an hexane solution of 2 in presence of an excess of PMe 3, afforded the phosphine derivative [(η 5-C 5Me 4CH 2CH CH 2)Re(CO) 2(PMe 3)] ( 5). All the complexes were characterized by IR, 1H, 13C and 31P NMR spectroscopies and mass spectrometry. The molecular structure of 4 has also been determined. The molecule exhibits a formal three-legged piano-stool structure, with two CO groups, and the third position corresponding to the η 2-coordination of the propenyl side arm of the η 5-C 5Me 4 ring.

Synthesis, reactivity and molecular structure of phosphino tetramethyl cyclopentadienyl complex (η5: η1-C5Me4CH2PPh2)Re(CO)2

The fulvene complex (eta(6)-C(5)Me(4)CH(2))Re(C(6)F(5))(CO)(2) reacts at the exocyclic methylene carbon with potassium diphenylphosphide to yield the anionic species [(eta(5)-C(5)Me(4)CH(2)PPh(2))Re(C(6)F(5))(CO)(2)](-) (). Protonation of with HCl at 0 degrees C produces the hydride complex trans-(eta(5)-C(5)Me(4)CH(2)PPh(2))Re(C(6)F(5))(H)(CO)(2) (). Thermolysis of a hexanes solution of , under nitrogen atmosphere, produces the chelated complex (eta(5):eta(1)-C(5)Me(4)CH(2)PPh(2))Re(CO)(2) () in good yield. The thermolysis under a CO atmosphere affords a mixture of the complexes (eta(5):eta(1)-C(5)Me(4)CH(2)PPh(2))Re(CO)(2) () and (eta(5)-C(5)Me(4)CH(2)PPh(2))Re(CO)(3) (). The reaction of with two electron donor ligands yields (eta(5)-C(5)Me(4)CH(2)PPh(2))Re(CO)(2)(L) (, L = CO; , L = PMe(3); , L = (t)BuNC). Complex also reacts with I(2), HBF(4) and MeOTf to yield the cationic compounds trans-[(eta(5):eta(1)-C(5)Me(4)CH(2)PPh(2))Re(R)(CO)(2)](+) (, R = I; , R = H; , R = Me). Upon treatment with chloroform, the hydride complex converts to the corresponding chloro derivative . The trans stereochemistry for complexes have been assigned on basis of nu(CO) IR intensities and (13)C-NMR chemical shifts. The reaction of the cationic complexes (, ) with KI and Me(3)NO.2H(2)O yields the neutral species cis-(eta(5):eta(1)-C(5)Me(4)CH(2)PPh(2))Re(I)(R)(CO) (, R = I, , R = Me). The molecular structure of and have been determined by X-ray crystallography.

Isolation of Bicyclopropenylidenes: Derivatives of the Smallest Member of the Fulvalene Family

Unbegrenzt stabil ist ein Triafulvalenderivat unter Inertatmosphäre bei Raumtemperatur sowohl in Lösung als auch im Festkörper. Die Verbindung wurde durch eine magnesiumkatalysierte Kupplung von zwei Bis(chlorcyclopropenyl)-Derivaten synthetisiert. Ihre beiden ungesättigten Dreiringe sind über eine 1.303 Å lange, reaktive Kohlenstoff-Kohlenstoff-Doppelbindung verknüpft (siehe Struktur), die bei Raumtemperatur spontan Wasser addiert.

Isolation of Bicyclopropenylidenes: Derivatives of the Smallest Member of the Fulvalene Family

Small and stable: A triafulvalene derivative is indefinitely stable at room temperature both in solution and in the solid state under inert atmosphere. The triafulvalene is synthesized by the magnesium-catalyzed coupling of two bis(chlorocyclopropenyl) derivatives. The two unsaturated three-membered rings are linked together by a carbon–carbon double bond (1.303 Å, see structure), which is so reactive that spontaneous addition of water occurs at room temperature.

Highly Ylidic Imidazoline‐Based Fulvenes as Suitable Precursors for the Synthesis of Imidazolium‐Substituted Metallocenes

Highly Ylidic Imidazoline‐Based Fulvenes as Suitable Precursors for the Synthesis of Imidazolium‐Substituted Metallocenes

Silicon–Carbon bond cleavage reactions of Ansa tungstenocene compounds: The [Me 2 Si] bridge as a site for metallocene functionalization

[Me(2)Si(Cp(Me(2)))(2)]W(H)Cl is obtained via reaction of WCl(6) with a mixture of [Me(2)Si(Cp(Me(2)))(2)]Li(2) and NaBH(4), from which the dichloride [Me(2)Si(Cp(Me(2)))(2)]WCl(2) is obtained via treatment with CHCl(3). [Me(2)Si(Cp(Me(2)))(2)]WCl(2) provides a means to access other ansa tungstenocene compounds, such as [Me(2)Si(Cp(Me(2)))(2)]WH(2), [Me(2)Si(Cp(Me(2)))(2)]WMe(2), and [Me(2)Si(Cp(Me(2)))(2)]WCO. Of most interest, the reactions of [Me(2)Si(Cp(Me(2)))(2)]W(H)Cl with organolithium reagents do not yield simple ansa tungstenocene derivatives. Specifically, the reactions of [Me(2)Si(Cp(Me(2)))(2)]W(H)Cl with MeLi, Bu(n)Li, or PhLi result in the formation of mixed-ring tungstenocene compounds resulting from C-Si cleavage and functionalization of the ansa bridge, namely (Cp(Me(2)))(eta(5),kappa(1)-C(5)H(2)Me(2)SiMe(2)CH(2))WH, (Cp(Me(2)))[eta(5),kappa(1)-C(5)H(2)Me(2)Si(Me)(Bu(n))CH(2)]WH, and (Cp(Me(2)))[eta(5),kappa(1)-C(5)H(2)Me(2)SiMe(2)(C(6)H(4))]WH, respectively. In contrast to the C-Si cleavage achieved by MeLi, Bu(n)Li, and PhLi, the ansa bridge of [Me(2)Si(Cp(Me(2)))(2)]W(H)Cl is inert to Bu(t)Li and the product obtained is the fulvene ("tuck-in") complex [Me(2)Si(Cp(Me(2)))(eta(6)-C(5)MeH(2)CH(2))]WH derived from dehydrohalogenation.

Coupling Reactions of an Allenylcarbene Complex with Alkynes and Styrene

AbstractThe allenylcarbene complex [OsCl2{=CPh(η2‐CH=C=CHPh)}(PPh3)2] undergoes coupling reactions with HC≡CSiMe3 and PhC≡CC≡CPh to produce the fulvene complexes [OsCl2{η6‐C5H2(Ph)(SiMe3)(=CHPh)}(PPh3)] and [OsCl2{η6‐C5H(Ph)2(C≡CPh)(=CHPh)}(PPh3)], respectively. A similar coupling reaction also occurs between [OsCl2{=CPh(η2‐CH=C=CHPh)}(PPh3)2] and styrene.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Unusual Endoperoxide Isomerizations: A Convenient Entry into 2‐Vinyl‐2‐cyclopentenones from Saturated Fulvene Endoperoxides.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Theoretical 49Ti NMR chemical shifts

49Ti chemical shifts for a total of 20 titanium complexes are reported, and several levels of theory are evaluated in order to identify a reliable approach for the calculation of titanium NMR data. The popular B3LYP/6-31G(d)//B3LYP/6-31G(d) proves to give very good agreement with experimental data over a range from 1,400 to -1,300 ppm. The MP2/6-31G(d)//MP2/6-31G(d) level computes even smaller average deviations but fails for TiI(4). This behavior together with its huge demand for computational resources requires careful handling of this theoretical level. In addition, NMR data for five titanium fulvene (or related) complexes are given.

Ansa-titanocene pyrrolyl complexes: The synthesis and structural characterization of [Me 2Si(C 5Me 4) 2]Ti(NC 4H 4)X (X = H, Me, Cl and NC 4H 4) and [Me 2Si(C 5Me 4)(C 5Me 3CH 2)]Ti(NC 4H 4)

A series of titanium–pyrrolyl compounds, namely [Me 2Si(C 5Me 4) 2]Ti(NC 4H 4)X (X = H, Me, Cl, NC 4H 4) and [Me 2Si(C 5Me 4)(C 5Me 3CH 2)]Ti(NC 4H 4) has been synthesized and structurally characterized by X-ray diffraction. Analysis of the Ti NC 4H 4 bond lengths in these complexes indicates that pyrrolyl does not, by comparison to dialkylamido, act as an efficient π-donor ligand. The fulvene complex [Me 2Si(C 5Me 4)(C 5Me 3CH 2)]Ti(NC 4H 4) is obtained via thermal elimination of CH 4 and H 2 from [Me 2Si(C 5Me 4) 2]Ti(NC 4H 4)Me and [Me 2Si(C 5Me 4) 2]Ti(NC 4H 4)H, respectively. The latter transformation is reversible, with [Me 2Si(C 5Me 4)(C 5Me 3CH 2)]Ti(NC 4H 4) reacting with H 2 to give [Me 2Si(C 5Me 4) 2]Ti(NC 4H 4)H at room temperature. In accord with this reversibility, treatment of [Me 2Si(C 5Me 4) 2]Ti(NC 4H 4)H with D 2 results in incorporation of deuterium into the hydride and one ring methyl group of each cyclopentadienyl ring of the [Me 2Si(C 5Me 4) 2] ligand.

Aspects of Organoselenium and Organotellurium Chemistry

The Chemistry of several condensed selenophenes, and tellurophenes (1–4) will be presented. The synthesis of mixed selenium-tellurium fulvenes (5) and generation of 2,4-bis-methyleneditelluretane (6) will be discussed.