The gas-phase molecular structure and quadratic force field of bis(dimethylamino)hydroborane, [(CH 3 ) 2 N] 2 BH, determined by electron diffraction and MO-calculations

Østby, Kari-Anne; Fjeldberg, Torgny; Gundersen, Grete

doi:10.1016/s0022-2860(01)00558-0

Cited by 6 publications

(9 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The calculated structure of the bisborylamine HN(BMe 2 ) 2 is in fact very similar to that previously obtained for the corresponding bisaminoborane HB(NMe 2 ) 2 . Structure optimization of the latter also led to an equilibrium structure of C 2 symmetry, the coordination geometry of the central B atom is planar by symmetry, and the sum of the three valence angles at each N is equal to 360.0°.…”

Section: Resultssupporting

confidence: 79%

“…All DFT calculations were carried out using the GAUSSIAN-94/98 program systems with standard 6-311++G** basis sets for all atoms , and with the B3PW91 functional that incorporates the exchange functional of Becke 30 and the local and nonlocal correlation functionals of Vosko, Wilk, and Nusair and of Perdew and Wang, respectively. , Each structure optimization was followed by calculation of the Hessian matrix to ensure that a minimum (or saddle point) on the potential energy surface had been reached. The Hessian matrices of HN(BMe 2 ) 2 , MeN(BMe 2 ) 2 , and MeB(NMe 2 ) 2 were transferred to the program ASYM40 and transformed to scaled symmetrized force fields as described in refs and . Diagonal C−H stretch force constants were multiplied by 0.900; all other diagonal force constants, by 0.943.…”

Section: Computational and Experimental Sectionmentioning

confidence: 99%

“…A microwave study of the simplest bisaminoborane, HB(NH 2 ) 2 , has shown that this molecule too is planar with C 2 v symmetry: The planarity of the molecule in conjunction with the short N−B bond distances suggests that the electron lone pairs of both N atoms are delocalized over the NBN frame, resulting in a 3c,4e π-bonding system. Studies of methyl-substituted derivatives such as MeB(NMe 2 ) 2 , by low-temperature XR, and more recently HB(NMe 2 ) 2 by GED and DFT calculations have yielded similar structures, except that the two dimethylamino groups in each compound are twisted in an disrotatory manner out of the N 2 B plane, the twist angles varying from about 10° to about 30°. A low-temperature X-ray study of MeB(NHMe) 2 yielded much smaller twist angles of about 5°; the magnitude of the twist may, however, be influenced by a network of intermolecular hydrogen bonds in the crystalline phase …”

Section: Introductionmentioning

confidence: 95%

See 2 more Smart Citations

Two-Center, Three-Center, and Four-Center Dative π-Bonding Systems in Boron−Nitrogen Compounds Studied by Density Functional Theory Calculations: The Molecular Structures of Bis(dimethylboryl)amine, Bis(dimethylboryl)methylamine and Bis(dimethylamino)methylborane Determined by Gas Electron Diffraction

et al. 2005

Self Cite

View full text Add to dashboard Cite

The nature of the two-center, two-electron (2c,2e) dative π-bonding system in aminoboranes has been explored by optimizing the equilibrium structures of R 2 NBR′ 2 (R, R′ ) H or Me) by DFT calculations at the B3PW91/6-311++G** level. The π-bond rupture energies were determined by optimizing models in which the relative orientation of the R 2 N and BR′ 2 fragments was fixed in such a manner that the lone-pair atomic orbital on N was orthogonal to the vacant 2p-orbital on the B atom. Similar calculations were carried out on the (3c,2e) dative π-bonding systems of bisborylamines, RN(BR′ 2 ) 2 ; the (3c,4e) π-system of bisaminoboranes, RB(NR′ 2 ) 2 ; the trigonal (4c,2e) π-bonding systems of trisborylamines, N(BR 2 ) 3 , and the (4c,6e) π-systems of trisaminoboranes, B(NR 2 ) 3 . The structures of HN(BMe 2 ) 2 , MeN-(BMe 2 ) 2 , and MeB(NMe 2 ) 2 determined by gas electron diffraction were in good agreement with those determined by calculations. The mean N-B π-bond rupture energies, 〈D π 〉, in the prototypical compounds H 2 NBH 2 , HN(BH 2 ) 2 , HB(NH 2 ) 2 , N(BH 2 ) 3 , and B(NH 2 ) 3 were found to depend not on the number of π-electrons, but on the number of centers. The mean π-bond rupture energies of the prototypical 2c, 3c, and 4c compounds were found to vary in the order 4.0:3.0:2.0. When H atoms at an acceptor atom (B) are replaced by more electron releasing methyl groups, 〈D π 〉 is significantly reduced due to a synergetic combination of destabilizing inductive effects and steric strain. When H atoms at the donor atom (N) are replaced by Me groups, the effect on 〈D π 〉 is determined by the balance of stabilizing inductive and destabilizing steric effects. The N-B bond distances in the 14 molecules tend to decrease with increasing mean π-bond rupture energy. Linear correlation analysis yields R(N-B) ) 149.3 pm -(0.075 pm mol kJ -1 ) 〈D π 〉 and a correlation coefficient of F ) 0.97.

show abstract

Section: Resultssupporting

confidence: 79%

Section: Computational and Experimental Sectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

See 1 more Smart Citation

Two-Center, Three-Center, and Four-Center Dative π-Bonding Systems in Boron−Nitrogen Compounds Studied by Density Functional Theory Calculations: The Molecular Structures of Bis(dimethylboryl)amine, Bis(dimethylboryl)methylamine and Bis(dimethylamino)methylborane Determined by Gas Electron Diffraction

et al. 2005

Self Cite

View full text Add to dashboard Cite

show abstract

“…Structure refinements were carried out by least-squares calculations on the molecular intensities using the program PLSQ. 26 Non-refined vibrational amplitudes were fixed at calculated values. Corrections for thermal vibrations were neglected.…”

Section: Structure Refinementsmentioning

confidence: 99%

“…. Backgrounds were drawn as least-squares adjusted ninth-degree polynomials to the difference between the total experimental and calculated molecular intensities with the background program PBG 26.…”

mentioning

confidence: 99%

Dative σ- and π-bonding in boron–nitrogen compounds: molecular structures of (CH3)2NB(CH3)N(CH3)B(CH3)2 and [(CH3)2B]2NN(CH3)2 determined by gas electron diffraction and quantum chemical calculations

et al. 2005

Self Cite

View full text Add to dashboard Cite

The molecular structures of dimethylamino[(dimethylboryl)methylamino]methylborane, Me2NBMeNMeBMe2 (1) and 1,1-bis(dimethylboryl)-2,2-dimethylhydrazine, (Me2B)2NNMe2 (2) have been determined by gas electron diffraction (GED), density functional theory calculations at the B3PW91/6-311++G** level and ab initio calculations at the MP2/6-311++G** level. 1 adopts an open structure similar to that of the isoelectronic hydrocarbon molecule permethylbutadiene; the central B-N bond distance at 148.0/149.3(7) pm (MP2/GED) corresponds to a single covalent N--B bond distance, the two terminal distances, 140.9/140.5(4) pm and 141.8/141.3(4) pm, correspond to the distance between N and B atoms joined by a covalent sigma-bond and a dative pi-bond. A closed form where the establishment of a dative bond between the terminal N and B atoms has led to the formation of a four-membered ring also corresponds to a minimum on the potential energy surface, but the energy is calculated to be 14.3 kJ mol(-1) higher at the MP2 level. This structure is also incompatible with the GED data. 2 adopts a structure in which a dative sigma-bond between the dimethylamino N atom and one of the boron atoms has led to the formation of a three-membered N(2)B ring. The dative sigma-bond distance is 165.5/164.0(13) pm, the two other bond distances in the ring are N-B=150.6/148.9(9) pm corresponding to a covalent sigma-bond and N-N=145.1/145.4(3) pm. The terminal B--N distance 139.6/138.9(9) pm is consistent with a covalent sigma-bond augmented by a dative pi-bond. An open Y-shaped structure also corresponds to a minimum on the potential energy surface, but the energy is 18.7 kJ mol(-1) higher (MP2) and it is incompatible with the GED data.

show abstract

Coordination of a Phosphine‐Tethered Aminoborane to Group 10 Metals

Tiddens,

Kappé,

Smak

et al. 2024

Chemistry A European J

View full text Add to dashboard Cite

While π‐complexes of C=C bonds are ubiquitous in organometallic chemistry, analogous complexes of the isoelectronic but strongly polarized B=N double bond of aminoboranes are extremely scarce. To address this gap, a diphosphine‐aminoborane ligand (PhDPBAiPr) is introduced and its coordination with group 10 metals is investigated. The B=N bond does not coordinate to the metal in Pt(0) and Pd(II) complexes. In contrast, side‐on coordination of the B=N bond is observed in the Ni(0) complex [PhDPBAiPr]Ni(NCPh), and the X‐ray crystal structure reveals B—N bond elongation compared to the free ligand. The choice of co‐ligand strongly influences the presence or absence of side‐on coordination at Ni(0) as evidenced by NMR spectroscopy. While the B=N π‐complex is geometrically similar to C=C analogues, a bonding analysis reveals that the interaction of the B=N motif with the electron‐rich Ni(0) center is best described as 3c4e hyperbond, in which Ni and N are competing for the empty orbital on B.

show abstract

The gas-phase molecular structure and quadratic force field of bis(dimethylamino)hydroborane, [(CH 3 ) 2 N] 2 BH, determined by electron diffraction and MO-calculations

Cited by 6 publications

References 37 publications

Dative σ- and π-bonding in boron–nitrogen compounds: molecular structures of (CH3)2NB(CH3)N(CH3)B(CH3)2 and [(CH3)2B]2NN(CH3)2 determined by gas electron diffraction and quantum chemical calculations

Coordination of a Phosphine‐Tethered Aminoborane to Group 10 Metals

Contact Info

Product

Resources

About