Stabilization of a π double bond between two boron atoms

Jouany, Claude; Barthelat, Jean‐Claude; Daudey, J. P.

doi:10.1016/0009-2614(87)87297-4

Cited by 36 publications

(15 citation statements)

References 20 publications

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“…28 On the B 2 H 2 system the first publication appeared more than 30 years ago by Dill et al,29 who at the unrestricted Hartree-Fock level predicted a linear geometry ͑HBBH͒ with a ground state of 3 ⌺ g − symmetry and a 1 ⌬ state 25 ͑UHF/STO-3G͒ or 34 ͑UHF/ 6-31G * ͒ kcal/ mol higher. Through CI+ MP2 / DZ+ P calculations Jouany et al 30 calculated the HB-BH dissociation energy with respect to the BH͑X 1 ⌺ + ͒ fragments, D e = 107 kcal/ mol. They also reported the location of the first two excited states, 1 ⌬ g and 1 ⌺ g + , 16.6 and 26.3 kcal/ mol higher.…”

Section: Introductionmentioning

confidence: 99%

Ab initio investigation of the electronic structure and bonding of BH, BH−, and HBBH molecules

Miliordos

Mavridis

2008

The Journal of Chemical Physics

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By correlating all electrons and employing core-tuned correlation consistent basis sets of quintuple-zeta quality, we applied multireference and coupled-cluster methods to study 32 electronic states of the diatomic BH molecule, two bound states of BH(-), and three states of the linear HBBH molecule. We have constructed full potential energy curves and profiles, reporting binding energies, geometries, spectroscopic parameters, dipole moments, and energy separations, whereas our numerical results are in excellent agreement with available experimental numbers. We are trying as well to interpret the binding modes of a large number of the examined states. 18 states of BH are of Rydberg character, with the BH(-) anion revealing similar structural characteristics to the isoelectronic CH species. The first three states of HBBH X 3Sigma g (-), a 1Delta g, and b 1Sigma g + diabatically correlate to two a 3Pi BH fragments, they are similar to the states b 3Sigma g (-), B 1Delta g, and B' 1Sigma g + of the isoelectronic molecule C2, however, their ordering follows that of the first three states of the O2 molecule.

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Section: Introductionmentioning

confidence: 99%

Ab initio investigation of the electronic structure and bonding of BH, BH−, and HBBH molecules

Miliordos

Mavridis

2008

The Journal of Chemical Physics

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“…The B±B bond lengths are 160.1(7) and 155.8(9) pm, respectively; these values speak for some double bond character, as judged from the calculated bond lengths of 165.3± 167.9 pm (single bond) and 149.8±151.5 pm (double bond; depending on the electronic state) of the hypothetical molecules H 2 B±BH 2 (D 2d ) [31] and HB=BH [32] as the standards. Bond angles C±B±B of 177.7(3)/182.3(3)°(oxirane) and 176.0(4)/172.3(5)°( aziridine) tend more or less to linearity.…”

Section: Addition Of Sitbu 2 To 1 Amentioning

confidence: 99%

Reactions at the B-B Bond of Tri-tert-butylazadiboriridine NB2R3: Ring Extensions

Luckert¹,

Eversheim²,

Englert³

et al. 2001

Z. anorg. allg. Chem.

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The OCO carboxylate unit of pivalic acid adds to the B±B bond of the azadiboriridine NB 2 R 3 (1 a, R = tBu) to give the chiral heterocyclohexadiene 2 a; the enantiomers of 2 a are transformed into one another by a [1,3] sigmatropic hydride transfer along the B±N±B ring fragment. The azadiboracyclopentanes 3 a±e are formed from 1 a and the alkenes ethene, propene, isobutene, (trimethylsilyl)ethene, and 2,3-dimethyl-1-butene. Only one double bond of cyclopentadiene and 1,3-butadiene reacts in the same way to give 3 f, g, respectively, and both of the double bonds of 1,3-butadiene react with an excess of 1 a to give 3 h, which is obtained in a 9 : 1 mixture of racemate and meso-isomer; the meso-isomer crystallizes in the space group P2 1 /n. The corresponding diazadiboracyclopentane 3 i and the triazadiboracyclopentane 3 j are formed from 1 a and N-phenyl benzaldimine or azobenzene, respectively. Ethyne and 1 a give either the azadiboracyclopentene 4 a (1 : 1) or the diazatetraborabicyclo-[3.3.0]octane 3 k (1 : 2). The phosphaalkyne PºC±tBu and 1 a analogously yield the heterocyclopentene 4 c. The insertion of SitBu 2 into 1 a to give the azasiladiboracyclobutane 5 a is achieved by applying Li powder and tBu 2 SiCl 2 . The hitherto unknown azadiboriridines BN 2 R 2 R' (R = tBu; R' = 1-iPr, 2-Mes, 2-CMe 2 Et: 1 b±d) were synthesized by the chloroboration of the iminoboranes RBºNiPr and RBºNR with RBCl 2 , MesBCl 2 , and (EtMe 2 C)BCl 2 , respectively, and subsequent dechlorination of the isolated and characterized diborylamines Cl±BR±NiPr±BR±Cl (6 a), Cl±BR±NR± BMes±Cl (6 b), and Cl±BR±NR±B(CMe 2 Et)±Cl (6 c), respectively, with lithium (Mes = mesityl).The azadiboriridine 1 b dimerizes to give the diaza-nido-hexaborane 7 a, whereas 1 c and 1 d are storable at room temperature. The product 1 c crystallizes as a racemate in the space group P2 1 /c; its ring geometry differs from that of the known N-mesityl isomer.Reaktionen an der B±B-Bindung von Tri-tert-butylazadiboriridin NB 2 R 3 : Ringererweiterungen Inhaltsu È bersicht. Die OCO-Carboxylateinheit der Privalinsa È ure addiert sich an die B±B-Bindung des Azadiboriridins NB 2 R 3 (1 a, R = tBu) unter Bildung des chiralen Heterocyclohexadiens 2 a; die Enantiomeren von 2 a gehen durch [1,3]-sigmatropen Hydridtransfer entlang dem B±N±B-Ringfragment ineinander u È ber. Die Azaboracyclopentane 3 a±e entstehen aus 1 a und den Alkenen Ethen, Propen, Isobuten, (Trimethylsilyl)ethen bzw. 2,3-Dimethyl-1-buten. Je eine Doppelbindung von Cyclopentadien und 1,3-Butadien ergibt mit 1 a die Azadiboracyclopentane 3 f, g, und beide Doppelbindungen von 1,3-Butadien reagieren mit 1 a im Verha È ltnis 1 : 2 zu 3 h ab, das als 9 : 1-Mischung aus Racemat und mesoForm anfa È llt; das meso-Isomer kristallisiert in der Raumgruppe P2 1 /n. N-Phenylbenzaldimin und Azobenzol bilden mit 1 a das Diazadiboracyclopentan 3 i bzw. das Triazadiboracyclopentan 3 j. Die 1 : 1-Reaktion von 1 a und Ethin erbringt das Azadiboracyclopenten 4 a und die 2 : 1-Reaktion das Diazatetraborabicyclo[3.3.0]octan 3 ...

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“…Recently we have found that the investigation on the monomer and T-shaped X-H…π hydrogen-bonded complex involving the BB multiplebond has always been of the interesting topic, accompanied by the unusual "phenomenon" [11][12][13]. For example, the electron-deficient BB bond in LBBL shows the double-bond and triple-bond characteristic with the single-electron donating/withdrawing (L = −H, -CN, -F, etc.)…”

Section: Introductionmentioning

confidence: 97%

“…substituent, respectively [11,12,14], as is just opposite to the electron-rich CC bond in LCCL [15][16][17][18][19]. Knight and Jouany et al have found the valence molecular orbitals of HBBH were (2σ g ) 2 (2σ u ) 2 (3σ g ) 2 (1π u ) 2 where the two paired electrons occupied degenerate boron 2p bonding orbitals, indicating that HBBH contained one B-B π bonding orbital [10,11]. Papakondylis et al examined the OCBBCO and NNBBNN molecules using the coupledcluster methodology and large correlation consistent basis sets.…”

Section: Introductionmentioning

confidence: 99%

A (U)MP2(full) and (U)CCSD(T) theoretical investigation into the substituent effects on the intermolecular T-shaped F–H…π interactions between HF and LBBL (L = −H, ∶CO, :NN, –Cl, –CN and –NC)

et al. 2011

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The substituent effects on the intermolecular T-shaped F-H...π interactions are investigated between HF and LBBL (L = -H, : CO, :NN, -Cl, -CN and -NC) using the (U)MP2(full) and (U)CCSD(T) methods with the 6-311++G(2 d,p) basis set. The B ≡ B triple-bond contraction is found in the complexes with lone-pair-electron donors while the B = B double-bond is lengthened in the systems with the single-electron substituents upon complexation. The T-shaped F-H...π interaction energies follow the order of ClB = BCl...HF>HB = BH...HF>NNB ≡ BNN...HF>OCB ≡ BCO...HF>CNB = BNC...HF>NCB = BCN...HF. The electron-donating substituents : CO and :NN increases electron density of the B ≡ B triple bond by the delocalization interaction E ((2)) π ((CO/NN) → Lp(B)) while the electron-withdrawing substituents -CN and -NC decrease electron density of the B = B double bond by means of the π-π conjugative effect. The analyses of the APT atomic charge, "truncated" model, natural bond orbital (NBO), atoms in molecules (AIM) and electron density shifts reveal the nature of the substituent effect and explain the origin of the B ≡ B bond contraction.

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Stabilization of a π double bond between two boron atoms

Cited by 36 publications

References 20 publications

Ab initio investigation of the electronic structure and bonding of BH, BH−, and HBBH molecules

Ab initio investigation of the electronic structure and bonding of BH, BH−, and HBBH molecules

Reactions at the B-B Bond of Tri-tert-butylazadiboriridine NB2R3: Ring Extensions

A (U)MP2(full) and (U)CCSD(T) theoretical investigation into the substituent effects on the intermolecular T-shaped F–H…π interactions between HF and LBBL (L = −H, ∶CO, :NN, –Cl, –CN and –NC)

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