Olivier Blacque - Academia.edu (original) (raw)
Papers by Olivier Blacque
Journal of Organometallic Chemistry, 2010
Reduction of [NMe4]2[ReBr5(NO)] (1) with zinc in acetonitrile leads to the known trisacetonitrile... more Reduction of [NMe4]2[ReBr5(NO)] (1) with zinc in acetonitrile leads to the known trisacetonitrile compound [ReBr2(CH3CN)3(NO)] (2). Attempts to turn 2 into a dihydrogen or a hydride complex applying direct reaction with H2 or with H2 and a base were unsuccessful. Complex 2 could be transformed into [ReBr(BF4)mer-(CH3CN)3(NO)] (2a) with AgBF4 in acetonitrile and was used as a starting material in
Organometallics, 2008
The tris(acetonitrile)dibromonitrosylrhenium(I) compound (1a) was obtained by reduction of the pa... more The tris(acetonitrile)dibromonitrosylrhenium(I) compound (1a) was obtained by reduction of the paramagnetic [NMe 4 ] 2 [Re(NO)Br 5 ] salt with Zn in MeCN. Subsequent reaction of 1a with THF produced the THF derivative [Re(NO)(THF)(MeCN) 2 Br 2 ] (1b). Reaction of 1b with PiPr 3 , Pcy 3 , or P(p-tolyl) 3 yielded bis(acetonitrile)-cis-dibromo(nitrosyl)-trans-bis(phosphine)rhenium complexes (R ) iPr 2a, cy 2b, p-tolyl 2c). Treatment of 2a,b with excess NaBH 4 produced the known borohydride complexes . Replacement of the BH 3 moiety of 3a,b in THF by ethylene (1 bar) produced the dihydride complexes [Re(H) 2 (η 2 -C 2 H 4 )(NO)(PR 3 ) 2 ] (4) . Protonation of 4a,b with HBF 4 · OEt 2 afforded H 2 and the monohydrido tetrafluoroborato species [Re(H)(NO)(PR 3 ) 2 (η 2 -C 2 H 4 )(BF 4 )] (R ) iPr 5a, cy 5b). X-ray diffraction studies were carried out on 1a, 2b,c, and 5b. Complexes 4a,b are catalytically active in olefin, imine, and ketone hydrogenations and in olefin and ketone hydrosilylations, as well as in the scrambling of H 2 /D 2 to give HD under mild conditions.
Chimia, 2014
The re-investigation of four original tris-bridged dinuclear dicobalt complexes from the Werner c... more The re-investigation of four original tris-bridged dinuclear dicobalt complexes from the Werner collection of the University of Zurich by X-ray diffraction studies is described. The complex [Co2(NH3)6(μ-NH2) (μ-OH)(μ-O2)](NO3)3 was studied recently. As the most interesting feature it was found to contain a μ-superoxo bridge, recognized by Alfred Werner and his coworker as an asymmetric peroxo bridge. The newly established μ-mono- and diacetato structures from crystals of the Werner collection, [Co2(NH3)6(μ-OH)2(μ-O2CMe)](NO3)3·H2O and [Co2(NH3)6(μ-OH)(μ-O2CMe)2](NO3)3·H2O, were assigned by Alfred Werner and his co-workers as mono- or di-bridged systems with the water functioning as η(1)-aqua ligands and not, as revealed by the X-ray diffraction studies, as solvate molecules. Similarly the exact nature of the μ(N, O) nitrito bridge in the structure of the [Co2(NH3)6(μ-OH)2(μ-O2N)](NO3)3·H2O complex from the Werner collection was left open in Werner's and his coworker's descri...
ChemInform, 1999
Reaction of the title imines with diphenyldiazomethane gives ethyl or methyl chloroformate gives ... more Reaction of the title imines with diphenyldiazomethane gives ethyl or methyl chloroformate gives the unexpected 1,1diphenyl-4,4-dichloro-2-aza-1,3-butadiene. a ∆ 3 -1,3,4-triazoline, which leads, after loss of dinitrogen, to a transient azomethine ylide. Subsequent elimination of commonly found as a secondary product of the expected 1,3-cycloadduct of 1 with 2. Indeed, a quantitative gas-Eur.
ChemInform, 1999
New Dipeptides Containing Thiazolidine-4-carboxylic Acid Derivatives: Synthesis and Characterizat... more New Dipeptides Containing Thiazolidine-4-carboxylic Acid Derivatives: Synthesis and Characterization Using NMR Techniques and X-Ray Data.
Dalton Transactions, 2004
Me, CH 2 Ph, CH 2 SiMe 3 ) containing a chelating alkene ligand tethered to a cyclopentadienyl ri... more Me, CH 2 Ph, CH 2 SiMe 3 ) containing a chelating alkene ligand tethered to a cyclopentadienyl ring have been synthesized in high yields by reduction with Na/Hg (X = Cl) and alkylation with reductive elimination (X = alkyl) of the corresponding metal(IV) dichlorides [M( 5 -Cp){ 5 -C 5 H 4 SiMe 2 (CH 2 CHCH 2 )}Cl 2 ] (Cp = C 5 H 5 , M = Nb, Ta, Cp = C 5 Me 5 , M = Ta). These chloro-and alkylalkene coordinated complexes react with CO and isocyanides [CNtBu, CN(2,6-Me 2 C 6 H 3 )] to give the ligand-substituted metal(III) compounds [M( 5 -Cp){ 5 -C 5 H 4 SiMe 2 (CH 2 CHCH 2 )}XL] (X = Cl, Me, CH 2 Ph, CH 2 SiMe 3 ). Reaction of the chloro-alkene tantalum complex with LiNHtBu results in formation of the imido hydride derivative [Ta( 5 -C 5 Me 5 ){ 5 -C 5 H 4 SiMe 2 (CH 2 CHCH 2 )}H(NtBu)]. NMR studies for all of the new compounds and DFT calculations for the alkenecoordinated metal complexes are compared with those known for related group 4 metal cations. † Electronic supplementary information (ESI) available: Full synthetic and structural data for compounds 13a-d and 14a-g. 1 H NMR data of the dimethylsilylallyl moiety for complexes 4-12 in C 6 D 6 at 20 °C. DFT Calculations. See http://www.rsc.org/suppdata/dt/b4/b406747a/
Cheminform, 2010
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Organic Letters, 2007
The synthesis of 1,2-bis(1,5,9-triazacyclododecyl)ethane (1) showcases how different bis(alkylati... more The synthesis of 1,2-bis(1,5,9-triazacyclododecyl)ethane (1) showcases how different bis(alkylating) reagents change the reaction from an intra-to an intermolecular pathway. The isolation of the intermediate hexahydro-3a,6a-ethano-1H,4H,7H,9bH-9a-aza-3a,6a-diazoniaphenalene-3a,6a-diium (2) explained why initially the synthesis of 1 was not possible. Both isomers of 2 were found in solution. DFT calculations revealed that isomer 2a is 4.6 kcal/mol lower in energy than 2b. Synthesis of 1 was finally achieved by using oxalyl chloride.
Journal of Organometallic Chemistry, 2002
The Arduengo carbenes 1,3-diisopropyl-, 1-methyl-3-(1-methylpropyl)-, and 1-methyl-3-(2,4,6-trime... more The Arduengo carbenes 1,3-diisopropyl-, 1-methyl-3-(1-methylpropyl)-, and 1-methyl-3-(2,4,6-trimethylbenzyl)imidazol-2-ylidene (3a–c) were reacted with MCl4(thf)2 (M=Zr, Hf) to yield the respective trans-(imidazol-2-ylidene)MCl4 complexes 4a–c (M=Zr) and 5a (M=Hf), respectively. These four Arduengo carbene-Group 4 metal halide complexes were characterized by X-ray diffraction. The pairs of carbene ligands are trans-positioned in a pseudo-octahedral coordination geometry at the Group 4 metals, and adopt a conformational
![Research paper thumbnail of From Alkynes to Carbenes Mediated by [Re(Br)(H)(NO)(PR 3 ) 2 ] (R = Cy, i Pr) Complexes](https://attachments.academia-assets.com/44665248/thumbnails/1.jpg)
](Organometallics, 2009
Five-coordinate rhenium(I) hydride complexes of the type [Re(Br)(H)(NO)(PR 3 ) 2 ] (R=Cy 1a, iPr ... more Five-coordinate rhenium(I) hydride complexes of the type [Re(Br)(H)(NO)(PR 3 ) 2 ] (R=Cy 1a, iPr 1b) were reacted with terminal alkynes R 1 CtCH (R 1 =Ph, SiEt 3 , H), yielding 18-electron η 2 -alkyne adducts [Re(Br)(H)(NO)(PR 3 ) 2 (η 2 -HCtCR 1 )] (R 1 =Ph (R=Cy 2a, iPr 2b), SiEt 3 (R=Cy 4a, iPr 4b), H (R=Cy 6a, iPr 6b)). Alkyne insertion into the Re-H bond led to the formation of rhenium(I) η 1vinyl derivatives [Re(Br)((E)-CHdCHR 1 )(NO)(PR 3 ) 2 ] (R 1 =Ph (R=Cy 3a, iPr 3b), SiEt 3 (R=Cy 5a, iPr 5b), H (R=Cy 7a, iPr 7b)) in good yields. The rate of formation of the vinyl complexes depends on R 1 in the order SiEt 3 > Ph > H, and the reactions of 1b bearing the PiPr 3 ligand are generally faster than those of 1a with PCy 3 . 1a,b were also reacted with 2-methyl-1-buten-3-yne and 1,7octadiyne, affording dienyl derivatives [Re(Br){(E)-CHdCHC(CH 3 )dCH 2 }(NO)(PR 3 ) 2 ] (R = Cy 8a, iPr 8b) and the binuclear μ-bis-alkenyl compounds [(PR 3 ) 2 (NO)(Br)Re{(E)-CHdCH-(CH 2 ) 4 -CHdCH-(E)}Re(Br)(NO)(PR 3 ) 2 ] (R=Cy 9a, iPr 9b). The reactions of 3a,b or 5a,b with HBF 4 3 OEt 2 afforded the rhenium(I) carbene derivatives [Re(F)(Br)(dCHCH 2 Ph)(NO)(PR 3 ) 2 ] (R=Cy 10a, iPr 10b) or [Re(F)(Br)(dCHCHdC(CH 3 ) 2 )(NO)(PR 3 ) 2 ] (R = Cy 11a, iPr 11b) via protonation at the βand δ-carbon of the vinyl group, respectively. The fluorine ligands are located cis to the carbene ligand and the bromo atom cis to the nitrosyl group. The binuclear species 9a,b were also reacted with HBF 4 3 OEt 2 to afford the binuclear carbene derivatives [(PR 3 ) 2 -(NO)(Br)(F)Re{dCH-(CH 2 ) 6 -CHd}Re(F)(Br)(NO)(PR 3 ) 2 ] (R = Cy 12a, iPr 12b). The molecular structures of 3a, 5a, and 11a were established by X-ray diffraction studies.
Inorganic Chemistry Communications - INORG CHEM COMMUN, 2005
Nucleophilic attack of sodium isopropylthiolate on 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene ... more Nucleophilic attack of sodium isopropylthiolate on 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene [Cl2CC(H)–NCPh2}] (1) affords the 2-azabutadiene derivative [(i-PrS)2CC(H)–NCPh2] (2). Upon irradiation of Mo(CO)6 in THF in the presence of 2, the chelate complex cis-[(OC)4Mo{(i-PrS)2CC(H)–NCPh2}] (3) is obtained. Coordination on Mo occurs through the imine nitrogen and a thioether group. Polydentate dithioether 2 acts as N,C,S-pincer ligand after orthometallation reaction with Pd(II) or Pt(II). The molecular structures of 2 and (C,N,S)-[(i-PrS)2CC(H)–NC(Ph)C6H4)PtCl] (4b) have been determined by X-ray diffraction studies.
Tetrahedron Letters, 1998
The reaction of an open-chain analogue of Reissert compound hydrofluoroborate salt with ethyl acr... more The reaction of an open-chain analogue of Reissert compound hydrofluoroborate salt with ethyl acrylate does not give a [4+2] cycloadduct as previously described, but a [3+2] cycloadduct which
Pure and Applied Chemistry, 2000
The treatment of benzene solutions of the cations [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (R = Cy and R =... more The treatment of benzene solutions of the cations [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (R = Cy and R = i Pr; [BAr F 4 ] = tetrakis{3,5-bis(trifluoromethyl)phenyl}borate) with phenyldiazomethane afforded the moderately stable cationic rhenium(I) benzylidene dinitrosyl bis(trialkyl) phosphine complexes as [BAr F 4 ]salts in good yields. The cationic rhenium dinitrosyl bisphosphine complexes catalyze the ring-opening metathesis polymerization (ROMP) of highly strained nonfunctionalized cyclic olefins to give polymers with relatively high polydispersity indices, high molecular weights, and Z configurations of the double bonds in the polymer chain backbones of over 80 %. The benzylidene derivatives are almost inactive in ROMP catalysis with norbornene and in olefin metathesis. NMR experiments gave first hints for the initial formation of carbene complexes when [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] was treated with norbornene. The carbene formation is initiated by an unique reaction sequence where the cleavage of the strained olefinic bond starts with phosphine migration forming a cyclic ylid carbene complex. The [2+2] addition of a norbornene molecule to the Re=C bond leads to the rhenacyclobutane complex, which is expected to be converted into an iminate complex by attack of the ylid function onto one of the N NO atoms followed by Wittig-type phosphine oxide elimination. The formation of phosphine oxide was confirmed by NMR spectroscopy. This species is thought to drive the ROMP metathesis with alternating rhenacyclobutane formations and cycloreversions. The proposed mechanism is supported by density functional theory (DFT) calculations.
Polyhedron, 2013
Several crystal structures and a theoretical DFT structure of the important catalyst (BINAP)PdCl ... more Several crystal structures and a theoretical DFT structure of the important catalyst (BINAP)PdCl 2 (BINAP: 2,2 0 -bis(diphenylphosphino)-1,1 0 -binaphthyl) have been determined. The conformational flexibilities of the BINAP backbone and of the phenyl rings do not seem to be coupled. Two novel parameter have been introduced that define the P-P stacking between the phenyl and biaryl rings in systems similar to the BINAP ligand, as well as the delta angle that is sensitive to the important interaction of the exchangeable ligands of the palladium with the equatorial phenyl rings of the BINAP. Furthermore, the calculated bite angle is 3°larger than the experimentally determined bite angles.
Organometallics, 2002
ABSTRACT
Organometallics, 2009
Reactions of the dinitrosyl bisphosphine rhenium cations [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (R = Cy ... more Reactions of the dinitrosyl bisphosphine rhenium cations [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (R = Cy 1a; R = iPr 1b; [BAr F 4 ] -= tetrakis[(3,5-bis(trifluoromethyl)phenyl)borate]) with acetylene yielded the alkynyl (o-vinyl)hydroxylamido nitrosyl bisphosphine complexes [Re(CHdC(H)ONH)(CtCH)-(NO)(PR 3 ) 2 ][BAr F 4 ] (3a and 3b) in the absence of base, while in the presence of 2,6-di(tertbutyl)pyridine formation of the neutral alkynyl complexes [Re(CtCH)(NO) 2 (PR 3 ) 2 ] (4a and 4b) was observed. A plausible mechanism is presented and supported by various NMR techniques, IR spectroscopy, and DFT calculations. Treatment of 4a and 4b with [H(OEt 2 ) 2 ][BAr F 4 ] gave the corresponding vinylidene complexes [Re(CdCH 2 )(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (5a and 5b) in high yields, which only slowly convert into the alkynyl(o-vinyl)hydroxylamido nitrosyl bisphosphine complexes 3a and 3b when treated with a large excess of acetylene. Thiophenol or benzeneselenol underwent 1,2-additions onto the vinylidene ligands of 5a and 5b to yield the cationic Fischer-type carbene complexes [Re(C(XPh)CH 3 )(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (X = S 6a,b; X = Se 7a,b) quantitatively. X-ray diffraction studies were carried out on 4b, 5b, and 7a.
Organometallics, 1996
Reaction of the racemic metallophosphine Cp′CpTa(CO)(PMe 2 ) (1; Cp′ ) 1-t Bu-3,4-Me 2 -C 5 H 2 )... more Reaction of the racemic metallophosphine Cp′CpTa(CO)(PMe 2 ) (1; Cp′ ) 1-t Bu-3,4-Me 2 -C 5 H 2 ) with the tungsten fragment [W(CO) 5 ] affords the corresponding µ-bimetallic phosphido complex 2, which in a photochemical transformation gives the dibridged derivative Cp′CpTa-(µ-CO)(µ-PMe 2 )W(CO) 4 (3). Addition of an optically active phosphine (PAMP) to 3 leads to a pair of optically active diastereoisomers (4a and 4b) which can be separated by fractionnal crystallization. Both diastereoisomers 4a and 4b crystallize in the orthorhombic noncentrosymmetric space group P2 1 2 1 2 1 . X-ray structure determinations of 4a and 4b allowed the assignment of absolute configurations of the tantalum chiral centers (S for 4a and R for 4b). The absolute configuration of the phosphorus atom of the PAMP ligand is the same (S) in both structures.
Journal of Organometallic Chemistry, 2010
Reduction of [NMe4]2[ReBr5(NO)] (1) with zinc in acetonitrile leads to the known trisacetonitrile... more Reduction of [NMe4]2[ReBr5(NO)] (1) with zinc in acetonitrile leads to the known trisacetonitrile compound [ReBr2(CH3CN)3(NO)] (2). Attempts to turn 2 into a dihydrogen or a hydride complex applying direct reaction with H2 or with H2 and a base were unsuccessful. Complex 2 could be transformed into [ReBr(BF4)mer-(CH3CN)3(NO)] (2a) with AgBF4 in acetonitrile and was used as a starting material in
Organometallics, 2008
The tris(acetonitrile)dibromonitrosylrhenium(I) compound (1a) was obtained by reduction of the pa... more The tris(acetonitrile)dibromonitrosylrhenium(I) compound (1a) was obtained by reduction of the paramagnetic [NMe 4 ] 2 [Re(NO)Br 5 ] salt with Zn in MeCN. Subsequent reaction of 1a with THF produced the THF derivative [Re(NO)(THF)(MeCN) 2 Br 2 ] (1b). Reaction of 1b with PiPr 3 , Pcy 3 , or P(p-tolyl) 3 yielded bis(acetonitrile)-cis-dibromo(nitrosyl)-trans-bis(phosphine)rhenium complexes (R ) iPr 2a, cy 2b, p-tolyl 2c). Treatment of 2a,b with excess NaBH 4 produced the known borohydride complexes . Replacement of the BH 3 moiety of 3a,b in THF by ethylene (1 bar) produced the dihydride complexes [Re(H) 2 (η 2 -C 2 H 4 )(NO)(PR 3 ) 2 ] (4) . Protonation of 4a,b with HBF 4 · OEt 2 afforded H 2 and the monohydrido tetrafluoroborato species [Re(H)(NO)(PR 3 ) 2 (η 2 -C 2 H 4 )(BF 4 )] (R ) iPr 5a, cy 5b). X-ray diffraction studies were carried out on 1a, 2b,c, and 5b. Complexes 4a,b are catalytically active in olefin, imine, and ketone hydrogenations and in olefin and ketone hydrosilylations, as well as in the scrambling of H 2 /D 2 to give HD under mild conditions.
Chimia, 2014
The re-investigation of four original tris-bridged dinuclear dicobalt complexes from the Werner c... more The re-investigation of four original tris-bridged dinuclear dicobalt complexes from the Werner collection of the University of Zurich by X-ray diffraction studies is described. The complex [Co2(NH3)6(μ-NH2) (μ-OH)(μ-O2)](NO3)3 was studied recently. As the most interesting feature it was found to contain a μ-superoxo bridge, recognized by Alfred Werner and his coworker as an asymmetric peroxo bridge. The newly established μ-mono- and diacetato structures from crystals of the Werner collection, [Co2(NH3)6(μ-OH)2(μ-O2CMe)](NO3)3·H2O and [Co2(NH3)6(μ-OH)(μ-O2CMe)2](NO3)3·H2O, were assigned by Alfred Werner and his co-workers as mono- or di-bridged systems with the water functioning as η(1)-aqua ligands and not, as revealed by the X-ray diffraction studies, as solvate molecules. Similarly the exact nature of the μ(N, O) nitrito bridge in the structure of the [Co2(NH3)6(μ-OH)2(μ-O2N)](NO3)3·H2O complex from the Werner collection was left open in Werner's and his coworker's descri...
ChemInform, 1999
Reaction of the title imines with diphenyldiazomethane gives ethyl or methyl chloroformate gives ... more Reaction of the title imines with diphenyldiazomethane gives ethyl or methyl chloroformate gives the unexpected 1,1diphenyl-4,4-dichloro-2-aza-1,3-butadiene. a ∆ 3 -1,3,4-triazoline, which leads, after loss of dinitrogen, to a transient azomethine ylide. Subsequent elimination of commonly found as a secondary product of the expected 1,3-cycloadduct of 1 with 2. Indeed, a quantitative gas-Eur.
ChemInform, 1999
New Dipeptides Containing Thiazolidine-4-carboxylic Acid Derivatives: Synthesis and Characterizat... more New Dipeptides Containing Thiazolidine-4-carboxylic Acid Derivatives: Synthesis and Characterization Using NMR Techniques and X-Ray Data.
Dalton Transactions, 2004
Me, CH 2 Ph, CH 2 SiMe 3 ) containing a chelating alkene ligand tethered to a cyclopentadienyl ri... more Me, CH 2 Ph, CH 2 SiMe 3 ) containing a chelating alkene ligand tethered to a cyclopentadienyl ring have been synthesized in high yields by reduction with Na/Hg (X = Cl) and alkylation with reductive elimination (X = alkyl) of the corresponding metal(IV) dichlorides [M( 5 -Cp){ 5 -C 5 H 4 SiMe 2 (CH 2 CHCH 2 )}Cl 2 ] (Cp = C 5 H 5 , M = Nb, Ta, Cp = C 5 Me 5 , M = Ta). These chloro-and alkylalkene coordinated complexes react with CO and isocyanides [CNtBu, CN(2,6-Me 2 C 6 H 3 )] to give the ligand-substituted metal(III) compounds [M( 5 -Cp){ 5 -C 5 H 4 SiMe 2 (CH 2 CHCH 2 )}XL] (X = Cl, Me, CH 2 Ph, CH 2 SiMe 3 ). Reaction of the chloro-alkene tantalum complex with LiNHtBu results in formation of the imido hydride derivative [Ta( 5 -C 5 Me 5 ){ 5 -C 5 H 4 SiMe 2 (CH 2 CHCH 2 )}H(NtBu)]. NMR studies for all of the new compounds and DFT calculations for the alkenecoordinated metal complexes are compared with those known for related group 4 metal cations. † Electronic supplementary information (ESI) available: Full synthetic and structural data for compounds 13a-d and 14a-g. 1 H NMR data of the dimethylsilylallyl moiety for complexes 4-12 in C 6 D 6 at 20 °C. DFT Calculations. See http://www.rsc.org/suppdata/dt/b4/b406747a/
Cheminform, 2010
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Organic Letters, 2007
The synthesis of 1,2-bis(1,5,9-triazacyclododecyl)ethane (1) showcases how different bis(alkylati... more The synthesis of 1,2-bis(1,5,9-triazacyclododecyl)ethane (1) showcases how different bis(alkylating) reagents change the reaction from an intra-to an intermolecular pathway. The isolation of the intermediate hexahydro-3a,6a-ethano-1H,4H,7H,9bH-9a-aza-3a,6a-diazoniaphenalene-3a,6a-diium (2) explained why initially the synthesis of 1 was not possible. Both isomers of 2 were found in solution. DFT calculations revealed that isomer 2a is 4.6 kcal/mol lower in energy than 2b. Synthesis of 1 was finally achieved by using oxalyl chloride.
Journal of Organometallic Chemistry, 2002
The Arduengo carbenes 1,3-diisopropyl-, 1-methyl-3-(1-methylpropyl)-, and 1-methyl-3-(2,4,6-trime... more The Arduengo carbenes 1,3-diisopropyl-, 1-methyl-3-(1-methylpropyl)-, and 1-methyl-3-(2,4,6-trimethylbenzyl)imidazol-2-ylidene (3a–c) were reacted with MCl4(thf)2 (M=Zr, Hf) to yield the respective trans-(imidazol-2-ylidene)MCl4 complexes 4a–c (M=Zr) and 5a (M=Hf), respectively. These four Arduengo carbene-Group 4 metal halide complexes were characterized by X-ray diffraction. The pairs of carbene ligands are trans-positioned in a pseudo-octahedral coordination geometry at the Group 4 metals, and adopt a conformational
Organometallics, 2009
Five-coordinate rhenium(I) hydride complexes of the type [Re(Br)(H)(NO)(PR 3 ) 2 ] (R=Cy 1a, iPr ... more Five-coordinate rhenium(I) hydride complexes of the type [Re(Br)(H)(NO)(PR 3 ) 2 ] (R=Cy 1a, iPr 1b) were reacted with terminal alkynes R 1 CtCH (R 1 =Ph, SiEt 3 , H), yielding 18-electron η 2 -alkyne adducts [Re(Br)(H)(NO)(PR 3 ) 2 (η 2 -HCtCR 1 )] (R 1 =Ph (R=Cy 2a, iPr 2b), SiEt 3 (R=Cy 4a, iPr 4b), H (R=Cy 6a, iPr 6b)). Alkyne insertion into the Re-H bond led to the formation of rhenium(I) η 1vinyl derivatives [Re(Br)((E)-CHdCHR 1 )(NO)(PR 3 ) 2 ] (R 1 =Ph (R=Cy 3a, iPr 3b), SiEt 3 (R=Cy 5a, iPr 5b), H (R=Cy 7a, iPr 7b)) in good yields. The rate of formation of the vinyl complexes depends on R 1 in the order SiEt 3 > Ph > H, and the reactions of 1b bearing the PiPr 3 ligand are generally faster than those of 1a with PCy 3 . 1a,b were also reacted with 2-methyl-1-buten-3-yne and 1,7octadiyne, affording dienyl derivatives [Re(Br){(E)-CHdCHC(CH 3 )dCH 2 }(NO)(PR 3 ) 2 ] (R = Cy 8a, iPr 8b) and the binuclear μ-bis-alkenyl compounds [(PR 3 ) 2 (NO)(Br)Re{(E)-CHdCH-(CH 2 ) 4 -CHdCH-(E)}Re(Br)(NO)(PR 3 ) 2 ] (R=Cy 9a, iPr 9b). The reactions of 3a,b or 5a,b with HBF 4 3 OEt 2 afforded the rhenium(I) carbene derivatives [Re(F)(Br)(dCHCH 2 Ph)(NO)(PR 3 ) 2 ] (R=Cy 10a, iPr 10b) or [Re(F)(Br)(dCHCHdC(CH 3 ) 2 )(NO)(PR 3 ) 2 ] (R = Cy 11a, iPr 11b) via protonation at the βand δ-carbon of the vinyl group, respectively. The fluorine ligands are located cis to the carbene ligand and the bromo atom cis to the nitrosyl group. The binuclear species 9a,b were also reacted with HBF 4 3 OEt 2 to afford the binuclear carbene derivatives [(PR 3 ) 2 -(NO)(Br)(F)Re{dCH-(CH 2 ) 6 -CHd}Re(F)(Br)(NO)(PR 3 ) 2 ] (R = Cy 12a, iPr 12b). The molecular structures of 3a, 5a, and 11a were established by X-ray diffraction studies.
Inorganic Chemistry Communications - INORG CHEM COMMUN, 2005
Nucleophilic attack of sodium isopropylthiolate on 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene ... more Nucleophilic attack of sodium isopropylthiolate on 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene [Cl2CC(H)–NCPh2}] (1) affords the 2-azabutadiene derivative [(i-PrS)2CC(H)–NCPh2] (2). Upon irradiation of Mo(CO)6 in THF in the presence of 2, the chelate complex cis-[(OC)4Mo{(i-PrS)2CC(H)–NCPh2}] (3) is obtained. Coordination on Mo occurs through the imine nitrogen and a thioether group. Polydentate dithioether 2 acts as N,C,S-pincer ligand after orthometallation reaction with Pd(II) or Pt(II). The molecular structures of 2 and (C,N,S)-[(i-PrS)2CC(H)–NC(Ph)C6H4)PtCl] (4b) have been determined by X-ray diffraction studies.
Tetrahedron Letters, 1998
The reaction of an open-chain analogue of Reissert compound hydrofluoroborate salt with ethyl acr... more The reaction of an open-chain analogue of Reissert compound hydrofluoroborate salt with ethyl acrylate does not give a [4+2] cycloadduct as previously described, but a [3+2] cycloadduct which
Pure and Applied Chemistry, 2000
The treatment of benzene solutions of the cations [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (R = Cy and R =... more The treatment of benzene solutions of the cations [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (R = Cy and R = i Pr; [BAr F 4 ] = tetrakis{3,5-bis(trifluoromethyl)phenyl}borate) with phenyldiazomethane afforded the moderately stable cationic rhenium(I) benzylidene dinitrosyl bis(trialkyl) phosphine complexes as [BAr F 4 ]salts in good yields. The cationic rhenium dinitrosyl bisphosphine complexes catalyze the ring-opening metathesis polymerization (ROMP) of highly strained nonfunctionalized cyclic olefins to give polymers with relatively high polydispersity indices, high molecular weights, and Z configurations of the double bonds in the polymer chain backbones of over 80 %. The benzylidene derivatives are almost inactive in ROMP catalysis with norbornene and in olefin metathesis. NMR experiments gave first hints for the initial formation of carbene complexes when [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] was treated with norbornene. The carbene formation is initiated by an unique reaction sequence where the cleavage of the strained olefinic bond starts with phosphine migration forming a cyclic ylid carbene complex. The [2+2] addition of a norbornene molecule to the Re=C bond leads to the rhenacyclobutane complex, which is expected to be converted into an iminate complex by attack of the ylid function onto one of the N NO atoms followed by Wittig-type phosphine oxide elimination. The formation of phosphine oxide was confirmed by NMR spectroscopy. This species is thought to drive the ROMP metathesis with alternating rhenacyclobutane formations and cycloreversions. The proposed mechanism is supported by density functional theory (DFT) calculations.
Polyhedron, 2013
Several crystal structures and a theoretical DFT structure of the important catalyst (BINAP)PdCl ... more Several crystal structures and a theoretical DFT structure of the important catalyst (BINAP)PdCl 2 (BINAP: 2,2 0 -bis(diphenylphosphino)-1,1 0 -binaphthyl) have been determined. The conformational flexibilities of the BINAP backbone and of the phenyl rings do not seem to be coupled. Two novel parameter have been introduced that define the P-P stacking between the phenyl and biaryl rings in systems similar to the BINAP ligand, as well as the delta angle that is sensitive to the important interaction of the exchangeable ligands of the palladium with the equatorial phenyl rings of the BINAP. Furthermore, the calculated bite angle is 3°larger than the experimentally determined bite angles.
Organometallics, 2002
ABSTRACT
Organometallics, 2009
Reactions of the dinitrosyl bisphosphine rhenium cations [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (R = Cy ... more Reactions of the dinitrosyl bisphosphine rhenium cations [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (R = Cy 1a; R = iPr 1b; [BAr F 4 ] -= tetrakis[(3,5-bis(trifluoromethyl)phenyl)borate]) with acetylene yielded the alkynyl (o-vinyl)hydroxylamido nitrosyl bisphosphine complexes [Re(CHdC(H)ONH)(CtCH)-(NO)(PR 3 ) 2 ][BAr F 4 ] (3a and 3b) in the absence of base, while in the presence of 2,6-di(tertbutyl)pyridine formation of the neutral alkynyl complexes [Re(CtCH)(NO) 2 (PR 3 ) 2 ] (4a and 4b) was observed. A plausible mechanism is presented and supported by various NMR techniques, IR spectroscopy, and DFT calculations. Treatment of 4a and 4b with [H(OEt 2 ) 2 ][BAr F 4 ] gave the corresponding vinylidene complexes [Re(CdCH 2 )(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (5a and 5b) in high yields, which only slowly convert into the alkynyl(o-vinyl)hydroxylamido nitrosyl bisphosphine complexes 3a and 3b when treated with a large excess of acetylene. Thiophenol or benzeneselenol underwent 1,2-additions onto the vinylidene ligands of 5a and 5b to yield the cationic Fischer-type carbene complexes [Re(C(XPh)CH 3 )(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (X = S 6a,b; X = Se 7a,b) quantitatively. X-ray diffraction studies were carried out on 4b, 5b, and 7a.
Organometallics, 1996
Reaction of the racemic metallophosphine Cp′CpTa(CO)(PMe 2 ) (1; Cp′ ) 1-t Bu-3,4-Me 2 -C 5 H 2 )... more Reaction of the racemic metallophosphine Cp′CpTa(CO)(PMe 2 ) (1; Cp′ ) 1-t Bu-3,4-Me 2 -C 5 H 2 ) with the tungsten fragment [W(CO) 5 ] affords the corresponding µ-bimetallic phosphido complex 2, which in a photochemical transformation gives the dibridged derivative Cp′CpTa-(µ-CO)(µ-PMe 2 )W(CO) 4 (3). Addition of an optically active phosphine (PAMP) to 3 leads to a pair of optically active diastereoisomers (4a and 4b) which can be separated by fractionnal crystallization. Both diastereoisomers 4a and 4b crystallize in the orthorhombic noncentrosymmetric space group P2 1 2 1 2 1 . X-ray structure determinations of 4a and 4b allowed the assignment of absolute configurations of the tantalum chiral centers (S for 4a and R for 4b). The absolute configuration of the phosphorus atom of the PAMP ligand is the same (S) in both structures.