A quantum chemistry study: A new kind of boron nitrides

Abstract

At the B3LYP/6-311+G** and the BP86/6-311+G** levels of theory, BNN, H(3)BNN, NNBH(2)-BH(2)NN, (BNN)(2)H(2), NNBBNN, (BNN)(3) (+), (BNN)(4), (BNN)(4) (2+), (BNN)(4) (2-), B(4)(NN)(2), (BNN)(5) (-), (BNN)(6), (BNN)(7) (+), and (BNN)(8) (2+) are investigated. Neutral (BNN)(4) is aromatic with its triplet state but antiaromatic with its singlet state. (BNN)(4) dication favors D(2d) structure, while (BNN)(4) dianion favors a planar D(4h) structure. (BNN)(3) (+), (BNN)(4) (2-), (BNN)(5) (-), (BNN)(6), (BNN)(7) (+), (BNN)(7) (3-), (BNN)(8) (2+), and (BNN)(8) (2-) are all aromatic with planar monocyclic conformation, following the 4n + 2 rule. Moreover, according to the CASSCF and MRCI calculations, the planar B(4)(NN)(2) of D(2h) symmetry prefers to be a sigma-pi diradical in spite of open-shell singlet or triplet and is also aromatic. Akin to the sigma-pi back interaction in compounds containing transition metal, there exists the sigma-pi back interaction between boron and N(2) ligand among some species reported herein, which strengthens B(-)N bond but activates N-N bond, especially in (4)Sigma(-) BNN. The T-shaped structure lies lowest in energy among seven isomers of the (BNN)(2)H(2) dimer, and the parallel-displaced structure is favored between two isomers of the (BNN)(6) dimer.

Geometry, stability, and isomerization of B n N2 (n = 1−6) isomers

“…So far, many reports on small B x N y clusters[] have been investigated experimentally and theoretically. Experimentally, some small boron–nitrogen clusters including BN, B 2 N, BN 2 , B 3 N, BN 3 , and their anions have been investigated by photoelectron spectroscopy, pulsed laser evaporation, and electron spin resonance methods.…”

“…Then, BN, B 2 N, BN 2 , B 3 N, and BN 3 clusters were calculated by different methods. [] Some stable nonclassical geometries of boron‐containing compounds with planar tetracooordinate nitrogen atoms have been computationally designed based on density functional theory by Minkin and coworkers The structure and aromaticity of new BNs were investigated by different theoretical methods . The potential energy surface (PES) of NB 6 – suggested that the planar hexacoordinate nitrogen species NB 6 – is not stable .…”

“…Boron nitride (BN) materials have wide applications in industry because of their excellent mechanical, thermal, electrical properties, high-temperature stability, corrosion resistance, and oxidation resistance properties. [1][2][3] So far, many reports on small B x N y clusters [4][5][6][7][8][9][10][11][12][13][14][15][16] have been investigated experimentally and theoretically. Experimentally, some small boron-nitrogen clusters including BN, B 2 N, BN 2 , B 3 N, BN 3 , and their anions have been investigated by photoelectron spectroscopy, pulsed laser evaporation, and electron spin resonance methods.…”

“…[10][11][12][13] Some stable nonclassical geometries of boron-containing compounds with planar tetracooordinate nitrogen atoms have been computationally designed based on density functional theory by Minkin and coworkers [14] The structure and aromaticity of new BNs were investigated by different theoretical methods. [15] The potential energy surface (PES) of NB 6 suggested that the planar hexacoordinate nitrogen species NB 6 is not stable. [16] The structure and property of (BN) n (n ¼ 2À11) have been investigated theoretically, [17][18][19][20][21][22][23][24][25] among which researchers found the stability of cyclic B 3 N 3 isomer with D 3h symmetry is ascribed mainly to its aromaticity.…”

A quantum chemistry study on boron nitrides (BNN)2n and (BNN)2n2+ (n = 3–8)

“…Schleyer and coworkers 29–32 experimentally and/or theoretically investigated an extensive series of boron carbonyl compounds, including planar aromatic structures and three‐dimensional ones. In our previous work 33, we systematically studied a series of the corresponding planar aromatic boron nitrides containing BNN units and further investigated their dimerization. As a natural extension, we report herein a type of three‐dimensional boron nitride clusters formed by only aggregating BNN units.…”