Conversion of a (methoxymethyl)iridium(I) acetylene complex to a metallacyclobutene iridium(III) complex. Crystal and molecular structures of Ir(CH2OMe)(p-tol-C.tplbond.C-p-tol)(PMe3)3 and [cyclic] fac-Ir[CH2C(p-tol):C(p-tol)]Br(PMe3)3 (p-tol = p-tolyl)

Calabrese, J. C.; Roe, Diana C.; Thorn, David L.; Tulip, T. H.

doi:10.1021/om00086a014

Cited by 36 publications

(7 citation statements)

References 5 publications

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“…The ring is slightly puckered with the plane of the three carbons tilted 8.1° toward the Cp* ring relative to the C(1)−Re−C(2) plane. The 104 (1)° C−CC angle of the metallacyclobutene ring of 4a is similar to those observed for other third-row metallacycles: 104.7 (7)° for (PPh 3 ) 2 Pt(C 3 F 4 ) ( 6 ) and 106.1 (5)° for (PMe 3 ) 3 (Br)IrCH 2 C( p -tolyl)C( p -tolyl) ( 7 ) . The analogous angle in Tebbe's first-row metallacycle (C 5 H 5 ) 2 TiCH 2 C(Ph)C(Ph) ( 8 ) is 112.8 (6)°.…”

Section: Resultssupporting

confidence: 75%

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Kinetic Addition of Nucleophiles to η³-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes

Casey

Nash

et al. 1998

J. Am. Chem. Soc.

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Kinetic addition of nucleophiles occurs at the center carbon of η3-propargyl rhenium complexes to produce rhenacyclobutenes. Reaction of P(CH3)3 with C5Me5(CO)2Re[η3-CH2C⋮CC(CH3)3]+BF4 - (3a) gave the metallacyclobutene C5Me5(CO)2ReCH2C(PMe3)CC(CH3)3 +BF4 - (4a), which was characterized by X-ray crystallography. Malonate and acetylide nucleophiles reacted with C5Me5(CO)2Re[η3-CH2C⋮CCH3]+PF6 - (3b) to give metallacyclobutene complexes. Pyridine added to the central propargyl carbon of 3b at low temperature to produce the metastable metallacyclobutene C5Me5(CO)2ReCH2C(NC5H5)CCH3 +PF6 - (14b) which rearranged to the η2-allene complex C5Me5(CO)2Re[η2-H2CCC(NC5H5)CH3]+PF6 - (15K) at room temperature. 4-(Dimethylamino)pyridine (DMAP) added to the central carbon of the tert-butyl-substituted η3-propargyl complex 3a below −38 °C to give the rhenacyclobutene complex C5Me5(CO)2ReCH2C(NC5H4NMe2)CC(CH3)3 +BF4 - (22a) which rearranged to the η2-alkyne complex C5Me5(CO)2Re[η2-(CH3)3CC⋮CCH2NC5H4NMe2]+BF4 - (23) at room temperature. Reaction of water with C5Me5(CO)2Re[η3-CH2C⋮CH]+BF4 - (3c) gave the hydroxyallyl complex C5Me5(CO)2Re[η3-CH2C(OH)CH2]+BF4 - (29) by a process proposed to involve nucleophilic addition of water to the central propargyl carbon of 3c followed by protonation of the metallacyclobutene intermediate.

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Section: Resultssupporting

confidence: 75%

“…The 13 C NMR resonance of the ReCH 2 carbon appeared at very low frequency at δ −28.3. Similar NMR parameters have been observed for other metallacyclobutenes; Thorn assigned a 1 H NMR resonance at δ 1.16 and a 13 C NMR resonance at δ −18.0 to the for IrCH 2 group in (PMe 3 ) 3 BrIrCH 2 C( p -tolyl)C( p -tolyl) …”

Section: Resultssupporting

confidence: 69%

Kinetic Addition of Nucleophiles to η³-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes

Casey

Nash

et al. 1998

J. Am. Chem. Soc.

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“…We note that these negative values are obtained only in the region where the resummation is not sure, i.e., z > 4. Nevertheless, this strange crossover, if reproduced from the three-dimensional series [15], might explain some doubtful experimental results, where a negative η was found.…”

Section: B Renormalization-group Flow and Crossovermentioning

confidence: 93%

“…With the precision of our calculations, we are not able to fully clarify if there is a region of values of N, where the chiral transition is first order. It is worthy to note that the parallel work on the three-dimensional models [15] reveals a full analogy between chiral critical behaviors in two and three dimensions.…”

Section: Introductionmentioning

confidence: 99%

Chiral critical behavior of frustrated spin systems in two dimensions from five-loop renormalization-group expansions

et al. 2003

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We analyze the critical behavior of two-dimensional N-vector spin systems with noncollinear order within the five-loop renormalization-group (RG) approximation. The structure of the RG flow is studied for different N leading to the conclusion that the chiral fixed point governing the critical behavior of physical systems with N=2 and N=3 does not coincide with that given by the 1/N expansion. We show that the stable chiral fixed point for Nless than or equal toN(*), including N=2 and N=3, turns out to be a focus. We give a complete characterization of the critical behavior controlled by this fixed point, also evaluating the subleading crossover exponents. The spiral-like approach of the chiral fixed point is argued to give rise to unusual crossover and near-critical regimes that may imitate varying critical exponents seen in numerous physical and computer experiments

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“…In general, silylene complexes are much more difficult to prepare than the analogous carbene compounds, which are often obtained from unsaturated starting materials (e.g., CO or N 2 CR 2 ) that do not have stable silicon analogues or by use of an electrophilic reagent to abstract a substituent (e.g., hydride, methoxide, or halide) from an alkyl complex . Early attempts to apply the latter method to transition metal−silicon compounds were unsuccessful, because the extreme Lewis acidity of the resulting silylene ligand can give rise to secondary reactions (such as halide ion transfer) which form new bonds to silicon .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Study of Ruthenium Silylene Complexes of the Type [(η⁵-C₅Me₅)(Me₃P)₂RuSiX₂]⁺(X = Thiolate, Me, and Ph)

et al. 1998

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Various ruthenium silyl complexes of the type Cp*(Me3P)2RuSiR3 (Cp* = η5-C5Me5; SiR3 = SiCl3 (1), Si(NMe2)3 (2), Si(SEt)3 (3), Si(S-2-Naph)3 (4), (5), Si(SCy)2Cl (6), and Si(SMes)2Cl (7, Mes = 2,4,6-trimethylphenyl)) were prepared by the reaction of Cp*(Me3P)2RuCH2SiMe3 with the appropriate silane HSiR3. Compound 3 was converted to the triflate Cp*(Me3P)2RuSi(SEt)2OTf (8) by the reaction of 3 with Me3SiOTf. Similar reactions produced Cp*(Me3P)2RuSi(NMe2)2OTf (13), Cp*(Me3P)2RuSi(NMe2)(OTf)2 (14), Cp*(Me3P)2RuSi(SMes)2OTf (18), and Cp*(Me3P)2RuSi(SMes)(Cl)OTf (19). By NMR spectroscopy, compound 8 in dichloromethane solution appears to possess a labile triflate group. Reactions of the triflates 8 and Cp*(Me3P)2RuSi(S-p-Tol)2OTf (10) with NaBPh4 provided the silylene complexes [Cp*(Me3P)2RuSi(SR)2][BPh4] (20, R = Et; 21, R = p-Tol). Similarly, the reaction of 6 with NaBPh4 gave [Cp*(Me3P)2RuSi(SCy)2][BPh4] (22), and the reaction of 4 with B(C6F5)3 produced [Cp*(Me3P)2RuSi(S-2-Naph)2][MeB(C6F5)3] (23). Silylene complexes 20−23 display characteristic 29Si NMR shifts in the region of δ 250−270. The non-heteroatom-stabilized silylene complexes [Cp*(Me3P)2RuSiR2][B(C6F5)4] (24, R = Me; 25, R = Ph), obtained via reactions of (Et2O)LiB(C6F5)4 with Cp*(Me3P)2RuSiR2OTf (11, R = Me; 12, R = Ph) exhibit 29Si NMR shifts around δ 300. The crystal structure of 24 revealed a Ru−Si distance of 2.238(2) Å, and the Cp*(centroid)−Ru−Si−Me dihedral angle is 34°. Compound 24 reacts quantitatively with 1 equiv of PMe3 or PPh3 in dichloromethane-d 2 to form the base-stabilized silylene complexes [Cp*(Me3P)2RuSiMe2(PR3)][B(C6F5)4] (28, R = Me; 29, R = Ph), identified by 1H and 31P NMR spectroscopy. These complexes are thermally labile and decompose with elimination of the dimethylsilylene fragment to give [Cp*(Me3P)2RuPR3][B(C6F5)4] (R = Me, Ph). The ylide CH2PPh3 reacts with 24 to form [Cp*(Me3P)2RuSiMe2CH2PPh3][B(C6F5)4] (32a), and the characterization of [Cp*(Me3P)2RuSiMe2CH2PPh3][OTf] (32b) by X-ray crystallography suggests that the complex is best viewed as a ruthenium silyl derivative with the positive charge localized on the “ylide” phosphorus atom. Reactions of 20 and 24 with hydrogen proceed slowly and result in relatively complex product mixtures that contain various ruthenium hydride species. The reaction involving 20 also produced HSi(SEt)3, perhaps via redistribution of initially formed H2Si(SEt)2. For the reaction of 24 with hydrogen, no H2SiMe2 was detected in the product mixture. The reaction of 20 with H3SiSiPh3 gave [Cp*(Me3P)2Ru(H)(SiH2SiPh3)][BPh4] (35) and HSi(SEt)3, and the corresponding reaction of H3SiMes in dichloromethane gave [Cp*(Me3P)2RuHCl][BPh4] (34), BPh3, and H2SiMes(SEt), among other products. By NMR spectroscopy, the intermediate [Cp*(Me3P)2Ru(H)(SiH2Mes)][BPh4] (36) was observed for the latter process. Compound 36, generated independently by reaction of [Cp*(Me3P)2Ru(NCMe)][BPh4] with H3SiMes, was shown to react with HSi(SEt)3 to give H2SiMes(SEt).

show abstract

Conversion of a (methoxymethyl)iridium(I) acetylene complex to a metallacyclobutene iridium(III) complex. Crystal and molecular structures of Ir(CH2OMe)(p-tol-C.tplbond.C-p-tol)(PMe3)3 and [cyclic] fac-Ir[CH2C(p-tol):C(p-tol)]Br(PMe3)3 (p-tol = p-tolyl)

Cited by 36 publications

References 5 publications

Kinetic Addition of Nucleophiles to η³-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes

Kinetic Addition of Nucleophiles to η³-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes

Chiral critical behavior of frustrated spin systems in two dimensions from five-loop renormalization-group expansions

Synthesis and Study of Ruthenium Silylene Complexes of the Type [(η⁵-C₅Me₅)(Me₃P)₂RuSiX₂]⁺(X = Thiolate, Me, and Ph)

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Conversion of a (methoxymethyl)iridium(I) acetylene complex to a metallacyclobutene iridium(III) complex. Crystal and molecular structures of Ir(CH2OMe)(p-tol-C.tplbond.C-p-tol)(PMe3)3 and [cyclic] fac-Ir[CH2C(p-tol):C(p-tol)]Br(PMe3)3 (p-tol = p-tolyl)

Cited by 36 publications

References 5 publications

Kinetic Addition of Nucleophiles to η3-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes

Kinetic Addition of Nucleophiles to η3-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes

Chiral critical behavior of frustrated spin systems in two dimensions from five-loop renormalization-group expansions

Synthesis and Study of Ruthenium Silylene Complexes of the Type [(η5-C5Me5)(Me3P)2RuSiX2]+(X = Thiolate, Me, and Ph)

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Kinetic Addition of Nucleophiles to η³-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes

Kinetic Addition of Nucleophiles to η³-Propargyl Rhenium Complexes Occurs at the Central Carbon to Produce Rhenacyclobutenes

Synthesis and Study of Ruthenium Silylene Complexes of the Type [(η⁵-C₅Me₅)(Me₃P)₂RuSiX₂]⁺(X = Thiolate, Me, and Ph)