General route to the half-open ruthenium metallocenes C5Me5Ru(pentadienyl) and C5Me5Ru(diene)Cl. X-ray structures of an optically active half-open metallocene and of a dimetallic ruthenabenzene complex

Bosch, H. William; Hung, Hans Ulrich; Nietlispach, Daniel; Salzer, Albrecht

doi:10.1021/om00042a025

Cited by 82 publications

(61 citation statements)

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“…The dihedral angle between this plane and the C1/Ru/C5 plane is 29.3°. The tilt angle is even larger than that in the coordinated ruthenabenzene [(C 5 H 5 )Ru(μ‐C 7 H 9 )Ru(C 5 Me 5 )(CH 3 CN)]PF 6 (27.2°) 12a. It is not very clear why the metallabenzene ring of 5 deviates significantly from planarity, whereas that of the closely related ruthenabenzene 2 is essentially planar.…”

Section: Methodsmentioning

confidence: 92%

Synthesis and Characterization of Stable Ruthenabenzenes

Zhang

Xia

et al. 2006

Angew Chem Int Ed

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Transition-metal-containing metallabenzenes [1][2][3] are an interesting class of compounds because they exhibit chemical properties of both organometallic compounds [1] and aromatic organic compounds. [1,4] The first stable transition-metal-containing metallabenzenes were reported in 1982 by Roper et al. [5] Since then a number of stable metallabenzenes have been successfully isolated and characterized. Most of the wellcharacterized stable metallabenzenes are those with a transition metal atom from the third transition series, especially osmium, [4][5][6][7] iridium, [2a-d, g-h, 8] and platinum. [2e, 9] In contrast, well-characterized metallabenzenes with a metal atom from the first or the second transition series are still very rare, although such species was predicted theoretically as early as 1979.[10] Although coordinated metallabenzenes with metal atoms from the first [11] and the second [12,13] transition series and 1,3-dimetallabenzenes [14] of Nb and Ta were isolated and well characterized, free metallabenzenes with a metal atom from the first or the second transition series have been isolated rarely. The ruthenabenzene [CpRu{C(Ph)CHCHC-(Ph)C(OEt)}(CO)] (Cp = cyclopentadienyl), and related ruthenaphenoxide and ruthenaphenanthrene oxide reported by Jones and co-workers represent rare examples (and the only reported examples, to the best our knowledge) of spectroscopically characterized metallabenzenes with a metal from the second transition series.[15a] However, these species are thermally unstable at ambient temperature. Other metallabenzenes such as ferrobenzene, [16a] ruthenaphenanthrene, [15a] ruthenaphenol, [15b] and chromobenzene [16b] have been proposed as reactive intermediates, but no direct observation of such species have been made. Herein we report the isolation and characterization of thermally stable ruthenabenzenes.We recently reported a convenient method for the preparation of osmabenzenes starting from the reactions of [OsCl 2 (PPh 3 ) 3 ] with HC CCH(OH)C CH. [7] We found that the method can also be used to prepare ruthenabenzenes. Treatment of [RuCl 2 (PPh 3 ) 3 ] (1) [17] with HC CCH(OH)C CH, PPh 3 , and Bu 4 NCl in THF produced cationic ruthenabenzene 2, which was isolated as a green solid in 55 % yield (Scheme 1). Interestingly, 2 can even be obtained from the one-pot reaction of RuCl 3 , PPh 3 , and HCCCH(OH)CCH in CHCl 3 , although the yield is lower.Complex 2 was characterized by solution NMR spectroscopy and elemental analysis. The 31 P{ 1 H} NMR spectrum in CDCl 3 showed two singlets at d = 18.2 and 8.1 ppm (CPPh 3 and RuPPh 3 , respectively). The presence of the metallacycle is clearly indicated by the 1 H and 13 C NMR data. In particular, the 1 H NMR spectrum in CDCl 3 showed the characteristic signal for RuCH at d = 17.5 ppm and for g-CH at d = 8.2 ppm. The 1 H NMR chemical shift for RuCH (d = 17.5 ppm) is significantly downfield relative to that for the vinyl complex [Ru{CH = CH(C 6 H 4 -p-OMe)}Cl(CO)(PPh 3 ) 2 ] (d = 8.13 ppm), [18] but is close to those for ruthenium...

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Section: Methodsmentioning

confidence: 92%

Synthesis and Characterization of Stable Ruthenabenzenes

Zhang

Xia

et al. 2006

Angew Chem Int Ed

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“…This route has enabled examples of first, second and third row metal-coordinated metallabenzenes to be prepared, including Fe, [197] Ni, [198] Mo [199,200] and Ru derivatives. [201][202][203][204][205][206][207] In contrast, "free" metallabenzenes involving first-row transition metals are currently unknown. Presumably,t he h 6 -coordinated metal groups have as ignificant stabilizing effect on the metallabenzenes.T he structural and spectroscopicp roperties exhibited by the h 6 -coordinated metallabenzenes are very similart o those of free metallabenzenes strongly suggesting aromatic characteri sr etained.…”

Section: Metal-coordinated Metallabenzenesmentioning

confidence: 99%

Recent Advances in Metallaaromatic Chemistry

Frogley

Wright

2017

Chemistry A European J

146

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Metallaaromatics can be broadly defined as aromatic compounds in which one of the ring atoms is a transition metal. The metallabenzenes are one important class of these compounds that has undergone extensive study recently. Closely related species such as fused-ring metallabenzenes, heterometallabenzenes, π-coordinated metallabenzenes and metallabenzynes have also attracted considerable attention. Although many metallaaromatics can be considered as metalla-analogues of classic organic aromatic compounds, this is not always the case. Recent seminal studies have shown that metallapentalenes and metallapentalynes, which are metalla-analogues of the anti-aromatic compounds pentalene and pentalyne, are in fact aromatic and highly stable. Very unusual spiro-metallaaromatic compounds have also recently been isolated. In this concepts article, key features of all these intriguing metallaaromatic compounds are discussed with reference to the structural, spectroscopic, reactivity and theoretical studies that have been undertaken. These compounds continue to generate much interest, not only because of the contributions they make to fundamental chemical understanding, but also because of the promise of possible practical applications.

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“…[1,2] Diese Reaktion kann entsprechend der Wade-Regeln als die Ergänzung eines arachno-zu einem nido-Cluster betrachtet werden. Die dabei Schema 1. gebildeten Metallabenzole (Ersatz von CH gegen ein isolobales Metallfragment) gehören zu den sehr seltenen, aber auch interessantesten Metallacyclen der Übergangsmetalle.…”

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“…Die Ru-C-Bindungen im Ring sind etwas länger als die in anderen Ruthenabenzolen. [1,4] Auch die M-C-Bindung zu den äquatorialen Carbonylgruppen ist signifikant länger als die zum axialen Liganden. Es ist plausibel, daû die trans-Anordnung von Carbonyl-und Pentadienylylidenligand zu einer gegenseitigen Bindungsschwächung führt.…”

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