Barium Dibenzopentalenide as a Main‐Group Metal η8 Complex: Facile Synthesis from 1,4‐Dilithio‐1,3‐butadienes and Ba[N(SiMe3)2]2, Structural Characterization, and Reaction Chemistry

Li, Heng; Wei, Baosheng; Xu, Ling; Zhang, Wen‐Xiong; Xi, Zhenfeng

doi:10.1002/anie.201305254

Cited by 49 publications

(23 citation statements)

References 71 publications

(20 reference statements)

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“…We have reported the facile synthesis of dibenzopentalene dianion from 1,4-dilithio-1,3-butadienes and Ba[N(SiMe 3 ) 2 ] 2 (ref. 34). With this result in hand, we envisioned a novel approach from 1,4-diiodo-1,3butadienes to perfluoro-p-extended pentalenes through C-F bond cleavage [35][36][37] .…”

Section: Resultsmentioning

confidence: 99%

Intramolecular C–F and C–H bond cleavage promoted by butadienyl heavy Grignard reagents

Wang

Wei

et al. 2014

Nat Commun

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Organomagnesium compounds (Grignard reagents) are among the most useful organometallic reagents and have greatly accelerated the advancement of synthetic chemistry and related sciences. Nevertheless, heavy Grignard reagents based on the metals calcium, strontium or barium are not widely used, mainly due to their rather inert heavy alkaline-earth metals and extremely high reactivity of their corresponding Grignard-type reagents. Here we report the generation and reaction chemistry of butadienyl heavy Grignard reagents whose extremely high reactivity is successfully tamed. Facile synthesis of perfluoro-π-extended pentalene and naphthalene derivatives is realized by the in situ generated heavy Grignard reagents via intramolecular C-F/C-H bond cleavage. These obtained perfluorodibenzopentalene and perfluorodinaphthopentalene derivatives show low-lying LUMO levels, with one being the lowest value so far among all pentalene derivatives. Our results set an exciting example for the meaningful synthetic application of heavy Grignard reagents.

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Section: Resultsmentioning

confidence: 99%

Intramolecular C–F and C–H bond cleavage promoted by butadienyl heavy Grignard reagents

Wang

Wei

et al. 2014

Nat Commun

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“…The number of structurally characterized 1,4-dilithio-1,3-butadienes is limited. Some examples are reported, [74][75][76][77][78][79][80][81] including three monomeric species [74][75][76] (all featuring three or four donor sites) and as olvent-free trimer. [77] Dimeric aggregates with a donor-site/Li ratio 1i nclude the parent [(PhC) 4 Li 2 (THF) 2 ] 2 with one THF donor at each Li ion, [80] and two derivatives with two donors, justaso bserved for [2·Et 2 O] 2 .…”

Section: Resultsmentioning

confidence: 99%

Electronic Push–Pull Modulation by Peripheral Substituents in Pentaaryl Boroles

Heitkemper

Sindlinger

2019

Chemistry A European J

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Establishing access to a bulky tetraaryl dilithiobutadiene (Ph*C)4Li2 (Ph*=3,5‐tBu2(C6H3)) allowed for the synthesis of five‐membered heterocycles with incorporated main‐group elements. Along with an amino borole, a set of substituted pentaaryl boroles (Ph*C)4BAr has been synthesized. The examination of their absorption spectra and computational studies by means of DFT granted insight into the influence of peripheral substituents on the electronic features of the parent pentaphenyl borole (PhC)4BPh. Introduction of the more electron‐rich Ph* residue at the carbon atoms increases the HOMO energy, redshifting the visible π/π*‐absorption bands compared with the parent pentaphenyl borole. The influence on the frontier orbitals of three different boron‐bound aryls with electronically modulating substituents in the remote 3,5‐positions Ar=3,5‐R2‐C6H3 (R=Me, H, CF3) was studied. The substituents were found to increase (+I effect, Me) or decrease (−I effect, CF3) the LUMO energy, thus directly affecting the visible absorption spectra. This represents the first study on HOMO–LUMO‐gap adjustments by a combined push–pull approach of a substituted pentaphenylborole.

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“…[32] Attempts have been madet os tudy the direct reactions of variousa lkaline earthm etals (Mg, Ca, Sr, and Ba) with 1,3-butadiene derivatives. [33][34][35][36] However the reported products were the complexes with p electrons donated from the hydrocarbon ligand to the exocyclic metal atoms (Mg, Ca, Sr,a nd Ba). That is, those compounds do not fall in the category of metallacycles discussed above.…”

Section: Introductionmentioning

confidence: 99%

“…For the main‐group metal elements, with small electronegativity values, it is more challenging to synthesize analogous cyclic compounds, although Grignard reagents, containing the alkaline‐earth metal magnesium, have of course been used for over one hundred years . Attempts have been made to study the direct reactions of various alkaline earth metals (Mg, Ca, Sr, and Ba) with 1,3‐butadiene derivatives . However the reported products were the complexes with π electrons donated from the hydrocarbon ligand to the exocyclic metal atoms (Mg, Ca, Sr, and Ba).…”

Section: Introductionmentioning

confidence: 99%

The Recently Synthesized Dimagnesiabutadiene and the Analogous Dimetalla‐Beryllium, ‐Calcium, ‐Strontium, and ‐Barium Compounds

Feng

Xie

et al. 2016

Chemistry A European J

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The 2014 synthesis of the remarkable dimagnesium compound Mg [C (CH ) (Si(CH ) ) ](C H ) (C H O) may point the way to a new chapter in alkaline earth organometallic chemistry. Accordingly, we have studied the known Mg compound and the analogous Be, Ca, Sr, and Ba structures. Although most of our theoretical predictions come from density functional methods, the latter have been benchmarked using coupled cluster theory including single, double, and perturbative triplet excitations, CCSD(T) using cc-pVTZ basis sets. Among our most important predictions are the energies for dissociation to the butadiene plus the RM-MR [R=(C H ) (C H O) ; M=Be, Mg, Ca, Si, and Ba] entities. The most reliable predictions for the dissociation energies are 99-104 (Be), 85-93 (Mg), 90-99 (Ca), 83-92 (Sr), and 83-94 (Ba) kcal mol . Thus, there is reason to anticipate that the four unknown compounds should be achievable synthetically. The predicted metal-metal distances (not single bonds) are 2.89 Å (Mg⋅⋅⋅Mg), 3.46 Å (Ca⋅⋅⋅Ca), 3.75 Å (Sr⋅⋅⋅Sr), and 4.04 Å (Ba⋅⋅⋅Ba). The separated RM-MR compounds have longer M-M distances but genuine metal-metal single bonds. This perhaps counter intuitive result is due to the presence of the bridging carbons in the alkaline earth butadiene compounds. All five compounds incorporate metal-carbon ionic interactions.

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Barium Dibenzopentalenide as a Main‐Group Metal η⁸ Complex: Facile Synthesis from 1,4‐Dilithio‐1,3‐butadienes and Ba[N(SiMe₃)₂]₂, Structural Characterization, and Reaction Chemistry

Cited by 49 publications

References 71 publications

Intramolecular C–F and C–H bond cleavage promoted by butadienyl heavy Grignard reagents

Intramolecular C–F and C–H bond cleavage promoted by butadienyl heavy Grignard reagents

Electronic Push–Pull Modulation by Peripheral Substituents in Pentaaryl Boroles

The Recently Synthesized Dimagnesiabutadiene and the Analogous Dimetalla‐Beryllium, ‐Calcium, ‐Strontium, and ‐Barium Compounds

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