Gespannte Metallocenophane und ähnliche metallorganische Ringe mit π‐Kohlenwasserstoffliganden und Übergangsmetallzentren

Herbert, David E.; Mayer, Ulrich F. J.; Manners, Ian

doi:10.1002/ange.200604409

Cited by 79 publications

(35 citation statements)

References 228 publications

(198 reference statements)

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“…Toluene, hexane, and diethyl ether were dried by distillation over potassium or sodium/potassium alloy. [1], [1]Disilamolybdenocenophane was synthesized according to literature procedures. [5] NMR spectra were recorded by using a Bruker Avance 500 spectrometer operating at 500.…”

Section: Wwwchemeurjorg Experimental Sectionmentioning

confidence: 99%

“…Treatment of 1,1,2,2-tetramethyl[2]disilamolybdenocenophanedihydride under photolytic conditions led to reductive elimination of hydrogen and a facile oxidative addition of the Si À Si moiety to the molybdenum center (Scheme 1). Thus, two-fold bridged [1], [1]disilametallocenophane 1 was obtained, which contributes an unprecedented structural motif to the class of ansa-complexes. [5] Herein, we report on detailed density functional theory (DFT) studies that reveal the electronic structure of the title compound and additionally on the first results of the unusual reactivity of two-fold bridged ansa-complex 1 towards polar and nonpolar unsaturated organic substrates.…”

Section: Introductionmentioning

confidence: 96%

“…[1] Therefore, [1]-and [2]metallocenophanes are a focus of research due to their unique structure and reactivity pattern. Up to now, metallocenophanes have been extensively investigated with regard to ligand exchange reactions at the metal center and to haptotropic shifts of the cyclopentadienyl ligands.…”

Section: Introductionmentioning

confidence: 99%

“…[1f -h, 2] Furthermore, the chemical properties of the bridging moiety have been extensively studied, particularly the insertion of late transition metal fragments into the EÀC ipso bond of [1]metallocenophanes, which is considered to be the key step in transition-metal-catalyzed ROP.…”

Section: Introductionmentioning

confidence: 99%

“…The HOMOÀ1 and HOMOÀ2 are symmetrical and unsymmetrical linear combinations, respectively, of the Mo À Si Keywords: ansa-complexes · density functional calculations · molybdenum · silicon Abstract: The electronic structure of the two-fold bridged [1], [1]disilamolybdenocenophane has been analyzed by means of density functional theory. As predicted, the relatively high charge at the metal center and, in particular, the highly strained geometry determine a noticeable reactivity towards unsaturated organic substrates.…”

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confidence: 99%

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Electronic Structure and Reactivity of a [1],[1]Disilamolybdenocenophane

Arnold¹,

Braunschweig²,

Gross³

et al. 2010

Chemistry A European J

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The electronic structure of the two-fold bridged [1],[1]disilamolybdenocenophane has been analyzed by means of density functional theory. As predicted, the relatively high charge at the metal center and, in particular, the highly strained geometry determine a noticeable reactivity towards unsaturated organic substrates. Thus, treatment with the nonpolar reagents 2-butyne and azobenzene leads to side-on coordination of the substrate to the metal center, whereas the reaction with polar tert-butylisonitrile gives a highly unusual structural motif in the form of an ansa-carbene.

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Section: Wwwchemeurjorg Experimental Sectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Electronic Structure and Reactivity of a [1],[1]Disilamolybdenocenophane

Arnold¹,

Braunschweig²,

Gross³

et al. 2010

Chemistry A European J

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Organometallic Macrocycles and Cyclic Polymers by the Bipyridine‐Initiated Photolytic Ring Opening of a Silicon‐Bridged [1]Ferrocenophane

2007

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Im Kreis herum: Cyclische Ferrocenylsilan‐Oligomere (siehe Strukturbild) und ‐Polymere wurden durch die photolytische Ringöffnung eines siliciumverbrückten [1]Ferrocenophans in Gegenwart eines Bipyridin‐Initiators erhalten. Der Anteil von cyclischen Oligomeren und cyclischem Polymer kann über die Reaktionstemperatur gesteuert werden, gleiches gilt auch für das Molekulargewicht des cyclischen Polymers.

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Strained Metallocenophanes with Late Transition Metals in the Bridge: Syntheses and Structures of Nickel‐ and Platinum‐Bridged [1]Ferrocenophanes

et al. 2008

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Until recently, few classes of strained rings containing transition elements had been explored, but these interesting species are now attracting substantial attention.[1] In particular, strained metallocenophanes (1) and related species containing p-hydrocarbon ligands (e.g. 2-5) [2] have been the focus of recent investigations due to the fascinating questions that surround their electronic structures, bonding, and reactivity. Furthermore, the ability of these compounds to yield functional metallopolymers by ring-opening polymerisation (ROP) has provided an extra impetus to the field. [3] The nature of the transannular bridge, ER x , in such species is of pivotal importance as the size and geometric preferences of the bridging element directly influence the strain present. Moreover, in the ring-opened polymers 6 the metal-metal interactions are modulated by the spacer unit.[4] To date, most work in the area of strained metallorings has involved [1]ferrocenophanes (e.g. 1, M = Fe) containing bridging nonmetallic main group elements E such as Si, P, and more recently S and B.[2a] The incorporation of main group metals (Sn, [5] Al, [2c, 6] and Ga [2c, 7] ) and early d-block metals (Ti, Zr, and Hf) [8] has also been successful. However, to date no transition metals other than the aforementioned Group 4 d 0 tetrahedral centers have been successfully introduced into the bridge. Herein, we report examples of [1]ferrocenophanes with the Group 10 metals Ni and Pt in the bridge, which leads to strained, unexpectedly electron-rich species containing square-planar d 8 centers. The scarcity of metal-bridged [1]ferrocenophanes is at first sight somewhat surprising, given that the main synthetic route to these molecules would appear applicable to any element for which a dichloride is available.[2a] We have found, however, that reaction of many transition-metal dihalides with dilithioferrocene-tmeda complex (tmeda = N,N,N',N'-tetramethylethylenediamine) results in reduction of the metal center. For instance, treatment of Li 2 [Fe(h 5 -C 5 H 4 ) 2 ]·tmeda (7) [9] with trans-[NiCl 2 (PMe 3 ) 2 ], [10] in hexane at À20 8C, only leads to the precipitation of metallic nickel. In striking contrast, the analogous reaction of 7 with trans-[NiCl 2 -(PnBu 3 ) 2 ] (8, Scheme 1) [11] resulted in a cloudy, dark red solution with a single new product detected by 31 P{ 1 H} NMR spectroscopy (d = 13.5 ppm, ca. 20 % conversion). Work-up afforded a dark red crystalline solid in modest yield (11 %) that was subsequently characterized as the first nickel-bridged [1]ferrocenophane [{Fe(h 5 -C 5 H 4 ) 2 }Ni(PnBu 3 ) 2 ] (9). [12] It is of interest that the Ni II component readily undergoes a trans-tocis isomerisation during the reaction and that no product containing the original trans configuration was observed.Compound 9 was fully characterized by 1 H, 13 C{ 1 H}, and 31 P{ 1 H} NMR spectroscopy. It is noteworthy that all three spectra displayed resonances at predictable chemical shifts and as such were consistent with the incorporation of a diam...

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Gespannte Metallocenophane und ähnliche metallorganische Ringe mit π‐Kohlenwasserstoffliganden und Übergangsmetallzentren

Cited by 79 publications

References 228 publications

Electronic Structure and Reactivity of a [1],[1]Disilamolybdenocenophane

Electronic Structure and Reactivity of a [1],[1]Disilamolybdenocenophane

Organometallic Macrocycles and Cyclic Polymers by the Bipyridine‐Initiated Photolytic Ring Opening of a Silicon‐Bridged [1]Ferrocenophane

Strained Metallocenophanes with Late Transition Metals in the Bridge: Syntheses and Structures of Nickel‐ and Platinum‐Bridged [1]Ferrocenophanes

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