Synthesis and Characterization of Rhenabenzenes

Poon, Ka Chun; Liu, Liangxian; Guo, Tongxun; Li, Juan; Sung, Herman H. Y.; Williams, Ian D.; Lin, Zhenyang; Jia, Guochen

doi:10.1002/ange.200907014

Cited by 55 publications

(24 citation statements)

References 61 publications

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“…[8] Since the report of the first isolated metallabenzene in 1982, [9] a variety of stable metallabenzenes have been synthesized in recent years. [7,10] However, research on the functions and applications of these species remains undeveloped. Highly stable and soluble ruthenabenzenes can be obtained from the onepot reaction of RuCl 3 , PPh 3 , and HC CCH(OH)C CH.…”

Section: Introductionmentioning

confidence: 99%

pH‐Switchable Inversion of the Metal‐Centered Chirality of Metallabenzenes: Opposite Stereodynamics in Reactions of Ruthenabenzene with L‐ and D‐Cysteine

Lin

Zhang

et al. 2011

Chemistry A European J

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We report herein the first study on the chemical interaction between metallabenzenes and bioactive molecules. Due to its unique stereoelectronic activities, a phenanthroline-derived ruthenabenzene [Ru{CHC(PPh(3))CHC(PPh(3))CH}Cl(C(12)H(8)N(2))(PPh(3))]Cl(2) (1) selectively binds cysteine in aqueous solution at physiological pH and then undergoes a dynamic inversion of configuration at the Ru center. The structure of the L-cysteine-binding product of 1 has been determined by means of X-ray diffraction. The replacement of the L-cysteine with the D form results in an inverted stereodynamic effect. Furthermore, the inversion process of the Ru-centered configuration could be conveniently controlled by a simple pH adjustment. This is attributed to the significant influence of a special intramolecular electrostatic interaction on the dynamic epimerization process of the cysteine-binding product.

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Section: Introductionmentioning

confidence: 99%

pH‐Switchable Inversion of the Metal‐Centered Chirality of Metallabenzenes: Opposite Stereodynamics in Reactions of Ruthenabenzene with L‐ and D‐Cysteine

Lin

Zhang

et al. 2011

Chemistry A European J

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“…[12] Many interesting chemical properties of metallabenzenes have also been discovered. For example, it has been demonstrated that metallabenzenes can undergo electrophilic substitution reactions, [2a, 5d] cycloaddition reactions, [8d, 9c] nucleophilic addition reactions, [13] and nucleophilic aromatic substitution of hydrogen.…”

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confidence: 97%

Conversion of Metallabenzynes into Carbene Complexes

et al. 2011

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The chemistry of transition metal-containing metallabenzenes has attracted considerable attention.[1] Previous studies have led to the isolation and characterization of a number of stable metallabenzenes, especially those of osmium, [2][3][4] iridium, [5][6][7][8] platinum, [9] ruthenium, [10,11] and rhenium. [12] Many interesting chemical properties of metallabenzenes have also been discovered. For example, it has been demonstrated that metallabenzenes can undergo electrophilic substitution reactions, [2a, 5d] cycloaddition reactions, [8d, 9c] nucleophilic addition reactions, [13] and nucleophilic aromatic substitution of hydrogen. [14] Another common reactivity of metallabenzenes is that they can undergo migratory insertion reactions to give cyclopentadienyl complexes. The transformation has been demonstrated with well-characterized metallabenzenes [2e, 6b,-d,e, 10b] as well as a spectroscopically characterized ruthenabenzene, [15] and it has been proposed as a key step in the formation of cyclopentadienyl complexes.[1]Compounds closely related to metallabenzenes are metallabenzynes.[16] Compared with the chemistry of metallabenzenes, that of metallabenzynes is much less developed, which is partly due to the lack of convenient methods to synthesize such compounds.[17] Structurally, metallabenzynes are similar to metallabenzenes in that both have a delocalized structure. Thus it might be expected that metallabenzynes should have properties similar to those of metallabenzenes. Indeed, previous studies have demonstrated that metallabenzynes, like metallabenzenes, can also undergo electrophilic substitution reactions [18] and nucleophilic addition reactions.[17c] As formation of cyclopentadienyl complexes from metallabenzenes by migratory insertion reactions is well-known, one might expect that metallabenzynes could also undergo migratory insertion reactions to give carbene complexes. However, such reactions have not been previously observed. Herein, we present a reliable method to prepare osmabenzynes along with the first examples of conversion of metallabenzynes into carbene complexes.We recently observed that reaction of zinc with the osmium vinyl carbyne complex [OsCl 3 { C À CH = C(2-ClC 6 H 4 ) 2 }(PPh 3 ) 2 ] produced a osmanaphthalyne complex. [19] The reaction was proposed to proceed through a 16e fourcoordinate square planar osmium carbyne complex, which undergoes an oxidative addition reaction involving a CÀCl bond. Inspired by the observation, we envisioned that reactions of zinc with carbyne complexes of the type [OsCl 3 { C À CH = CR À CR' = CClR''}(PPh 3 ) 2 ] might lead to the formation of new osmabenzynes.To test this hypothesis, we first prepared the meridional osmium carbyne complex 1 and then treated it with zinc in THF at room temperature. An in situ 31 P NMR study showed that osmabenzyne 2 with substituents on the C3 and C5 positions was produced as the major phosphorus-containing product (Scheme 1), which can be isolated in 62 % yield after column chromatography.The osmabenzyne 2 has bee...

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“…The maximum deviation from the least-squares plane through Re1 and C1-C5 is 0.028 for C1. The C1-C2, C2-C3, C3-C4, and C4-C5 bond lengths are 1.310(11), 1.337(11), 1.426 (12), and 1.350 (14) , respectively. The Re-C1 bond length of 1.933 (7) is within the range of those reported for typical Re=CHR(carbene) bonds (1.850-2.143 ), [16,17] and shorter than those reported for typical Re-C(vinyl) bonds (1.996-2.305 ).…”

mentioning

confidence: 99%

“…[1] Previous studies have led to the isolation and characterization of an impressive number of stable metallabenzenes, especially those of osmium, [2][3][4] iridium, [5][6][7][8] platinum, [9] ruthenium, [10,11] and rhenium. [12] Metallabenzynes, [13] which are organometallic compounds derived from formal replacement of a carbon atom or a CÀH group in benzyne with an isolobal transition metal fragment, are closely related to metallabenzenes. At first sight, one might expect that metallabenzynes may be too unstable to be isolated, because organic compounds with a C C bond in the six-membered ring, for example, benzyne and cyclohexyne, are thermally highly unstable because of ring strain.…”

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confidence: 99%