The microwave spectrum and structure of trimethylamine-monofluoroborane

Cassoux, P.; Kuczkowski, Robert L.; Fong, Gerald D.; Geanagel, Russell A.

doi:10.1016/0022-2860(78)87219-6

Cited by 11 publications

(2 citation statements)

References 17 publications

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“…For F 3 BN(CH 3 ) 3 , FBH 2 N(CH 3 ) 3 , and BF 4 − , a formally single bond, BF, has been proposed . For F 3 BN(CH 3 ) 3 and FBH 2 N(CH 3 ) 3 only the results obtained with the M062x are discussed.…”

Section: Resultsmentioning

confidence: 99%

The electronic structure of molecules with the BF and BCl bond in light of the topological analysis of electron localization function: Possibility of multiple bonds?

Mierzwa

Gordon

Berski

2018

Int J of Quantum Chemistry

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Topological analysis of electron localisation function (ELF) has been used to study the nature of the B X (X = F, Cl) bonds in 26 molecules. Twelve small molecules with formal B X, B X, and B X bonds and 14 organoboron molecules with the B Cl bond from the Cambridge Structural Database have been studied using CCSD, DFT(M062x) methods. As the V(B,F) basin population for the investigated molecules is smaller than 4 and 6e, the existence of B X, B X bonds is not confirmed. The results show higher polarity of B F bonds as compared to the B Cl bonds. Electronic structure of selected molecules has been discussed from the ELF-topological perspective. K E Y W O R D S B Cl, B F, chemical bond, double bond, electron localisation function, Lewis structure, QCT, quantum chemical topology, triple bond 1 | INTRODUCTION Nature of a localized, dicenter-two-electron (2c 2e) chemical bond, A-B, assumed to exist between a pair of atoms in a molecule, is one of the most important considerations of theoretical chemistry. Such bond can broadly be characterized as covalent or ionic. The concept of covalentbond is based on sharing electron densities, while ionic bond stems from electrostatic interactions. A contemporary paradigm, derived from quantum theory, states that chemical bonding can be described using the molecular orbital (MO) theory [1] or valence bond (VB) theory, [2] where covalent chemical bond between A and B is a consequence of atomic orbitals overlapping. Molecular orbitals, fully characterizing electronic structure of molecules are vectors in the Hilbert space. Notably, chemical bonding can also be described using the graph theory [3] or the information theory. [4] Another way of analyzing the nature of a chemical bond, developed in addition to the MO and VB theories, constitute of methods operating in a real (physical) space. They focus on topological properties of the scalar fields: electron density, ρ(r), [5] electron localisation function, ELF, η(r), [6,7] electron localisability indicator, ELI-D, [8] electrostatic potential, [9] and others. [10,11] All those methods have been gathered by Popelier [12] under the umbrella of quantum chemical topology (QCT).This article concentrates only on topological analysis of ELF from the whole range of the QCT, therefore, a nonexpert reader is encouraged to familiarize with the subject. [6,7,[13][14][15][16][17] In short, the two-center two-electron (2c 2e) covalent bond, A-B, is represented by an attractor (local maximum) of the η(r) field, V (A,B), found in the region of expected chemical bond. The attractor V(A,B) belongs to valence and disynaptic types. [13,18] Futher application of the gradient vector theory of dynamical systems enables calculation of its basin (localisation basin) for ELF, denoted also V (A,B). Projection of all points of η(r) field, defining attractor's basin in the electron density field, ρ(r) and integrating the electron density with respect to the localisation basin leads to the definition of its basin population, N. Further analysis includes d...

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Section: Resultsmentioning

confidence: 99%

The electronic structure of molecules with the BF and BCl bond in light of the topological analysis of electron localization function: Possibility of multiple bonds?

Mierzwa

Gordon

Berski

2018

Int J of Quantum Chemistry

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“…The prototypical fluoroborane, BH 2 F, has been detected using microwave spectroscopy [18], and using the experimental ground-state rotational constants and ab initio vibration-rotation coupling constants, an accurate geometry of H 2 BF has been determined [19]. In addition, by way of microwave spectroscopy, the adduct formed between the interaction of H 2 BF and trimethylamine has Molecules 2023, 28, 5707 2 of 17 also been investigated spectroscopically [20]. A particularly well-studied monofluoroborane, which is commercially available, is dimesitylboron fluoride (Mes 2 BF), for which a crystal structure has been obtained [21].…”

Section: Introductionmentioning

confidence: 99%

A Systematic Exploration of B–F Bond Dissociation Enthalpies of Fluoroborane-Type Molecules at the CCSD(T)/CBS Level

O'Reilly

Karton

2023

Molecules

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Fluoroborane-type molecules (R1R2B–F) are of interest in synthetic chemistry, but to date, apart from a handful of small species (such as H2BF, HBF2, and BF3), little is known concerning the effect of substituents in governing the strength of the B–F bonds of such species toward homolytic dissociation in the gas phase. In this study, we have calculated the bond dissociation enthalpies (BDEs) of thirty unique B–F bonds at the CCSD(T)/CBS level using the high-level W1w thermochemical protocol. The B–F bonds in all species considered are very strong, ranging from 545.9 kJ mol−1 in (H2B)2B–F to 729.2 kJ mol−1 HBF2. Nevertheless, these BDEs still vary over a wide range of 183.3 kJ mol−1. The structural properties that affect the BDEs are examined in detail, and the homolytic BDEs are rationalized based on molecule stabilization enthalpies and radical stabilization enthalpies. Since polar B–F bonds may represent a challenging test case for density functional theory (DFT) methods, we proceed to examine the performance of a wide range of DFT methods across the rungs of Jacob′s Ladder for their ability to compute B–F BDEs. We find that only a handful of DFT methods can reproduce the CCSD(T)/CBS BDEs with mean absolute deviations (MADs) below the threshold of chemical accuracy (i.e., with average deviations below 4.2 kJ mol−1). The only functionals capable of achieving this feat were (MADs given in parentheses): ωB97M-V (4.0), BMK (3.5), DSD-BLYP (3.8), and DSD-PBEB95 (1.8 kJ mol−1).

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2.5.2.5 Elements with two or three internal rotors

Demaison¹

Landolt-Börnstein - Group II Molecules and Radicals

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The microwave spectrum and structure of trimethylamine-monofluoroborane

Cited by 11 publications

References 17 publications

The electronic structure of molecules with the BF and BCl bond in light of the topological analysis of electron localization function: Possibility of multiple bonds?

The electronic structure of molecules with the BF and BCl bond in light of the topological analysis of electron localization function: Possibility of multiple bonds?

A Systematic Exploration of B–F Bond Dissociation Enthalpies of Fluoroborane-Type Molecules at the CCSD(T)/CBS Level

2.5.2.5 Elements with two or three internal rotors

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