A computational study to determine whether substituents make E13?nitrogen (E13 = B, Al, Ga, In, and Tl) triple bonds synthetically accessible

This study theoretically determines the effect of substituents on the stability of the triple-bonded L-E-13?N-L (E-13 = B, Al, Ga, In, and Tl) compound using the M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, and B3LYP/LANL2DZ+dp levels of theory. Five small substituents (F, OH, H, CH3 and SiH3) and four large substituents (SiMe(SitBu(3))(2), SiiPrDis(2), Tbt (? C6H2-2,4,6-{CH(SiMe3)(2)}(3)) and Ar* (?C6H3-2,6-(C6H2-2,4,6-i-Pr-3)(2))) are used. Unlike other triply bonded L-E-13?P-L, L-E-13?As-L, L-E-13?Sb-L and L-E-13?Bi-L molecules that have been studied, the theoretical findings for this study show that both small (but electropositive) ligands and bulky substituents can effectively stabilize the central E-13?N triple bond. Nevertheless, these theoretical observations using the natural bond orbital and the natural resonance theory show that the central E-13?N triple bond in these acetylene analogues must be weak, since these E-13?N compounds with various ligands do not have a real triple bond.