The reactions of laser-ablated B atoms with acetonitrile in 4 K solid neon have been investigated by matrixisolation infrared spectra, and new products have been identified by 10 B, D, and 13 C isotopic substitutions and quantum chemical calculations. The side-on complex B-η 2 -(NC)-CH 3 was observed during deposition and isomerized to NCBCH 3 , CNBCH 3 , and CNB(H)�CH 2 , respectively, through C−C bond breakage and hydrogen transfer. For diboron reaction with acetonitrile, the Nend-on complex BBNCCH 3 was formed on deposition, which rearranged to HBNC(B)�CH 2 and HBNBC�CH 2 by λ > 220 nm irradiation. In this reaction pathway, the C�N triple bond was completely cleaved. The final diboron product HBNBC�CH 2 was much more stable than the precursors by 152.0 kcal mol −1 at the CCSD(T)-Full/cc-pVTZ//B3LYP/aug-cc-pVTZ level of theory.

Reactions of laser-ablated B and Al atoms with BF3 have been explored in the 4 K excess neon through the matrix isolation infrared spectrum, isotopic substitutions and quantum chemical calculations. The inserted complexes F2BMF (M = B, Al) were identified by anti-symmetric and symmetric stretching modes of F-B-F, and the F-11B-F stretch modes are at 1336.9 and 1202.4 cm−1 for F211B11BF and at 1281.5 and 1180.8 cm−1 for F211BAlF. The CASSCF analysis, EDA-NOCV calculation and the theory of atoms-in-molecules (AIM) are applied to investigate the bonding characters of F2BBF and F2BAlF molecules. The bonding difference between boron and aluminum complexes reveals interesting chemistries, and the FB species stabilization by a main group atom was first observed in this article.

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.