Generation and Identification of the Linear OCBNO and OBNCO Molecules with 24 Valence Electrons

Abstract

Twos tructural isomersc ontaining five second-row element atoms with 24 valence electrons were generated and identified by matrix-isolationI Rs pectroscopya nd quantum chemical calculations. The OCBNO complex, which is produced by the reaction of boron atoms with mixtures of carbon monoxide and nitric oxide in solid neon, rearranges to the more stable OBNCO isomer on UV excitation.B onding analysisi ndicates that the OCBNO complex is best described by the bonding interactions between at riplet-state boron cation with an electron configuration of (2s) 0 (2p s) 0 (2p p) 2 and the CO/NO À ligandsi nt he triplet state forming two degenerate electron-sharing p bonds and two ligand-to-boron dative s bonds.

Linear BeNCO and OBeNC: kinetically stable neutral Be-bearing free molecules

“…81 The fact that the N–C–O antisymmetric stretching frequency of BeNCO is higher than that of HNCO can be easily rationalized by the ionic interaction between the Be + and NCO − ion fragments, that is, anionic hyperconjugation in the NCO − of BeNCO can strengthen the C–O bond, leading to an augmented stretching relative to that of HNCO. 82 Furthermore, the computed N–C–O antisymmetric stretching mode ( ν 7 ) of BeNCO is very close in wavenumber to that of the experimentally identified OBNCO (2331.1 cm −1 ), 83 but has a blueshift of 48 cm −1 relative to the experimentally observed value of 2287.5 cm −1 in NBeNCO. 84…”

Spectroscopic Identification of the Heterocumulenic Isocyanatoborane Radical HBNCO

“…The band position and isotopic shifts imply that it corresponds to a terminal NCO stretching vibration (ν 2 ) in configuration (II) (Scheme 1). It is close to the frequencies for the same modes in NBNCO (2317.4 cm −1 , Ne matrix), 21 OBNCO (2331.1 cm −1 , Ne matrix), 18 and F 2 BNCO (2333 cm −1 , gas phase) 19 but slightly higher than the frequencies in HNCO (2264.0 cm −1 , para-H 2 matrix) 32 and B(NCO) 2 (2259.7 cm −1 , Ne matrix). 21 The band at 1539.7 cm −1 shows large 15 N and 11 B isotope shifts of −27.6 and −9.6 cm −1 but a small 13 C isotopic shift of −2.6 cm −1 (Table 1).…”

“…Recently, novel small molecules containing covalently bonded pseudohalogens (e.g., HPCO, , H 2 BPCO, and H 2 PCN) have been the targets of experimental investigations due to their fundamental importance in main-group chemistry. Despite the challenges facing the facile polymerization of boron-containing pseudohalogen compounds at ambient conditions, significant progress has been made in the generation and characterization of species such as B­(NCO) 3 , Cl x B­(NCO) 3– x ( x = 1 and 2), , (CH 3 ) 2 BNCO, and OBNCO by using various spectroscopic techniques. However, free radicals containing a BNCO backbone are extremely rare.…”

Photoelectron velocity-map imaging spectroscopy of nickel carbide: examination of the low-lying electronic states

“…As demonstrated for a variety of chemical bonds, the smallest value for the associated orbital interaction Δ E orb is a useful criterion for the best description of the bonding situation, because it indicates that the least alteration in electronic energy is required during bond formation. 94–97 Table 4 shows the numerical results of the comparative EDA-NOCV calculations using several electron configurations (Ni: 3d 8 4s 2 , 3d 9 4s 1 , and 3d 10 4s 0 ; C: 2s 2 2p 2 ) for the interacting moieties. The lowest value for Δ E orb is found when the interacting fragments are the Ni atom in the electronic triplet state with the electronic configuration of 3d 9 4s 1 and the C atom also in the triplet state with one unpaired electron in the 2p π orbital and the other in the 2p σ orbital.…”