Complex with Linear B–B–B Skeleton Trapped in Dinitrogen Matrix: Matrix Infrared Spectra and Quantum Chemical Calculations

Abstract

The neutral (NN)–B–B–B–(N2) complex has been trapped in low-temperature dinitrogen matrix and identified by isotopic substitution and theoretical frequency calculations. The linear B–B–B skeleton is stabilized by two inequivalent N2, namely, one end-on and other side-on N2. The structure of linear B–B–B skeleton illustrates much difference from previously reported triangle configuration of B3 clusters. Frontier orbital analysis demonstrates that the σ orbital of end-on NN and the π-bonding orbital of side-on N2 acts as the donor orbital. π bonding character across B–B–B skeleton donates to the antibonding π* orbital of end-on NN and out of phase the B–B–B features π back-donation to antibonding π* orbital of side-on N2. The combination of strong σ-donating capacity coupled with a greater ability for accepting π-back-donation of the N2 ligand leads to the formation of (NN)–B–B–B–(N2) complex with linear B–B–B skeleton. In addition, complexes of (NN)­B­(NN), (NN)­BB­(NN), and (NN)­B4(NN) have been identified in our experiments.

Synthesis and characterization of azaborepin radicals in solid neon through boron-mediated C–N bond cleavage of pyridine

“…These shifts are mainly due to the N-B stretching mode, consistent with the previous observation of the N-B stretching band at 1266.2 cm À1 for the (NN)BB(NN) molecule. 44 The absorption band at 1247.8 cm À1 shows 3.0 cm À1 11 B isotopic shifts, 12.6 cm À1 15 N isotopic shifts, and 80.6 D isotopic shifts, suggesting its association with C-N stretching mixed C-H stretching modes. The absorption band at 664.1 cm À1 shows 0.4 cm À1 11 B isotopic shifts, 2.8 cm À1 15 N isotopic shifts, and 94.7 D isotopic shifts, and it can be attributed to the C-H bending mode.…”

Beryllium Dimer Reactions with Acetonitrile: Formation of Strong Be−Be Bonds

“…The experimental details in conjunction with matrix infrared spectroscopy investigation have been described previously [ 39 , 40 , 41 , 42 ]. Briefly, the Nd:YAG laser fundamental (1064 nm, 10 Hz repetition rate with 10 ns pulse width) was focused onto a rotating beryllium metal target (Alfa Aesar, Haverhill, MA, USA), and the ablated beryllium atoms were co-deposited with the gas mixture of neon and acetonitrile (Sinopharm Chemical Reagent Co., Ltd., Shanghai, China) onto a substrate (CsI) maintained at 4 K using a closed-cycle helium refrigerator (Sumitomo Heavy Industries Model RDK 205D, Tokyo, Japan) for normally 60 min.…”