Transition metal borylene complexes: boron analogues of classical organometallic systems

Vidović, Dragoslav; Pierce, Glesni A.; Aldridge, Simon

doi:10.1039/b816042b

Cited by 143 publications

(78 citation statements)

References 140 publications

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“…In the case of 3, the π donor abilities of the N i Pr 2 substituent would be expected to lie between those of the σ-bound mesityl and η 5 -bound Cp* substituents, and consistent with this, the Fe -B bond length (1.835(3) Å) is also intermediate between the distances measured for [Cp*Fe(CO) 2 (BMes)] + and [CpFe(CO) 2 (BCp*)] + . In addition, a DFT calculated breakdown of the covalent bonding density for the Fe -B bond in 3 gives a 69:31 σ:π ratio, as compared to 62:38 and 86:14 for the BMes and BCp* systems, respectively [1]. Thus, the FeB bond in 3 is probably best described as intermediate in nature between the Fischer carbene type double bond found in [Cp*Fe(CO) 2 (BMes)] + and the single bond found in [CpFe(CO) 2 (BCp*)] + .…”

Section: Discussionmentioning

confidence: 99%

“…Complexes containing bonds between transition metals and Group 13 elements have been extensively exploited during the last decade [1][2][3][4][5][6][7]. Examples of these complexes include boryl (L n MBX 2 ) [2,4,5] and borylene (L n MBX) [1][2][3] compounds featuring a variety of substituents, X, as well as systems containing the heavier Group 13 elements as donors [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…Examples of these complexes include boryl (L n MBX 2 ) [2,4,5] and borylene (L n MBX) [1][2][3] compounds featuring a variety of substituents, X, as well as systems containing the heavier Group 13 elements as donors [6,7]. Very recent additions to this family of compounds are transition metal complexes containing the simple Group 13 monohalides as ligands.…”

Section: Introductionmentioning

confidence: 99%

“…For example, simple variation of the boron-bound substituent in such systems has been shown to produce dramatic changes in the ironboron bond order (e.g. from a Fischer carbene-like double bond in [Cp*Fe(CO) 2 (BMes)] + to a simple donor/acceptor linkage in [CpFe(CO) 2 (BCp*)] + ) [1,[11][12][13]. With the aim of further contributing to the understanding of bonding and electronic structure in these compounds, we report the synthesis and structural characterization of diisopropylamino-substituted terminal borylene complexes of iron and ruthenium viz.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and structural characterization of terminal (diisopropylamino)borylene complexes of group 8 metals

Vidović¹,

Pierce²,

Coombs³

et al. 2010

Main Group Chemistry

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The syntheses and first structural characterization of terminal (diisopropylamino)borylene complexes are reported. The 11 B NMR chemical shifts for these novel systems (δB 93.8 and 90.2 for [Cp'Fe(CO)2(BN i Pr2)][BAr f 4 ], 3, and [CpRu(CO)2(BN i Pr2)][BAr f 4 ], 4, respectively) are ca. 40 ppm downfield of those measured for the boryl precursor complexes, consistent with observations for related trimethylsilyl and cyclohexylamino substituted compounds. Structurally, the linearity of the M -B -N fragment in each case and the marked shortening of the M -B bonds (cf. the single bonds found in boryl complexes CpFe(CO)2(BN i Pr2)Cl, 1b, and CpRu(CO)2(BN i Pr2)Cl, 2) reflect the fact that the M -B bond order in borylene systems 3 and 4 is between one and two.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Synthesis and structural characterization of terminal (diisopropylamino)borylene complexes of group 8 metals

Vidović¹,

Pierce²,

Coombs³

et al. 2010

Main Group Chemistry

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“…[14] Dies lässt darauf schließen, dass die Desymmetrisierung der reduzierten B 2 -Einheit Borylenähnliche Reaktivitätzur Folge hat. [17] Während die Reduktion von Aminoboranen und Diaminodiboranen zu diversen B-B-Bindungsknüpfungen geführt hat, [16m, 18] haben sich die Isolierung und der Abfang von Diaminodiborenen als schwierig erwiesen. In der ersten Gruppe befinden sich Borylene,bei denen das freie Elektronenpaar p-Charakter hat und durch p-Akzeptorliganden, wie cyclische Alkyl(amino)carbene (CAACs), CO,I sonitrile und andere Borylene,stabilisiert wird (Abbildung 1; C und D).…”

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Bindungsstärkende Rückbindung in Aminoborylen‐stabilisierten Aminoborylenen: an der Grenze zwischen Borylenen und Diborenen

et al. 2019

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Einfach NHC-koordinierte (Aminoboryl)aminoborenium-Salzer eagieren mit Na 2 [Fe(CO) 4 ]z ud en ersten stabilen Koordinationskomplexen von Aminoborylen-stabilisierten Aminoborylenen, die außergewçhnliche s-Donor-Eigenschaften aufweisen. Bei photolytischer CO-Verdrängung vom Metallzentrum nimmt der Dibor-Ligand einen neuartigen h 3 -BBN-Koordinationsmodus ein, wobei eine bindungsstärkende Rückbindung vom Metallzentrum in das unbesetzte B-B-p-Orbital beobachtet wird.D iese Bindungssituation kann ebenfalls als Fe-Diaminodiboren-Komplex beschrieben werden. In einer verwandten Reduktion CAAC-stabilisierter Diamino(dihalogen)diborane mit KC 8 kçnnen die reduzierten Spezies mit Nukleophilen abgefangen und damit dreifach-koordinierte (Diaminoboryl)borylene gebildet werden, in denen beide Aminogruppen zum distalen Boratom migriert sind. Zusammengenommen illustrieren diese Reaktionen die isomere Flexibilität, die Aminogruppen diesem Dibor-System verleihen, wodurchs ich mehrere neue Reaktionswege erçffnen.

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Coordination and Activation of the BF Molecule

Vidović

Aldridge

2009

Angewandte Chemie

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Coordination to a transition-metal center offers a convenient synthetic approach applicable both to the labilization of kinetically inert molecules and to the trapping of highly reactive species. [1][2][3] Thus, the activation of the dinitrogen molecule (N 2 ) at a metal center-mimicking the capabilities of complex biological systems-illustrates the significant changes in electronic structure which occur on coordination. [2,4] The isoelectronic molecule carbon monoxide (CO), while more reactive in the "free" state, is a much-utilized ligand in organometallic chemistry, primarily owing to its ability to stabilize low-valent transition-metal centers. [5] Among this family of simple diatomic molecules, fluoroborylene (BF) offers a stark contrast to both N 2 and CO, being an exotic species known only at extreme temperatures or in high vacuum, and as yet eluding structural characterization as a ligand in a simple metal complex. [6] In part, the steady increase in lability along the series of diatomic molecules N 2 , CO, BF reflects the decreasing energy difference between the highest occupied and lowest unoccupied molecular orbitals (HOMO-LUMO gap) and increasing bond polarity. [7] Notwithstanding this, quantum chemical studies have predicted BF to form stronger bonds to transition-metal centers than either N 2 or CO, principally owing to improved s-donor capabilities. [7] Despite such thermodynamic advantages, the high BÀF bond polarity, and consequent electrophilicity at boron, are likely to render such complexes very labile. The borylene ligand is therefore typically found in conjunction with more sterically bulky or p-electron-releasing substituents (such as amino groups). [8] However, recent synthetic studies have demonstrated the viability of complexes containing bridging BX or terminal GaX ligands (X = heavier Group 17 element), [9,10] together with transitionmetal compounds containing the difluoroboryl (BF 2 ) unit, which might serve as precursors in the formation of BFcontaining complexes by either fluoride abstraction or metathesis processes (Scheme 1). [11] With this in mind, we set out to synthesize BF-containing transition-metal complexes, focusing initially on systems featuring a bridging coordination mode, given the reduced lability typical of bridging borylene complexes compared to their terminally coordinated ana-logues. [12] Herein we report the synthesis and structural characterization of the first such system, together with a comparative study (vs. CO) of its reactivity towards electrophiles.The reaction of BF 3 ·OEt 2 with Na[CpRu(CO) 2 ] (Cp = C 5 H 5 ) in diethyl ether is shown by 11 B NMR spectroscopy to result in the formation of the fluoroborylene complex [{CpRu(CO) 2 } 2 (m-BF)] (1) as the predominant boroncontaining product in greater than 90 % conversion (d B = 97.3 ppm, 1 J BF = 247 Hz). The presence of a small amount (less than 10 %) of a second product is also indicated by a triplet resonance ( 1 J BF = 169 Hz) at d B = 40.8 ppm; this species was subsequently shown to be the difluorobor...

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Transition metal borylene complexes: boron analogues of classical organometallic systems

Cited by 143 publications

References 140 publications

Synthesis and structural characterization of terminal (diisopropylamino)borylene complexes of group 8 metals

Synthesis and structural characterization of terminal (diisopropylamino)borylene complexes of group 8 metals

Bindungsstärkende Rückbindung in Aminoborylen‐stabilisierten Aminoborylenen: an der Grenze zwischen Borylenen und Diborenen

Coordination and Activation of the BF Molecule

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