A computational study to determine whether substituents make E13nitrogen (E13 = B, Al, Ga, In, and Tl) triple bonds synthetically accessible†
Abstract
This study theoretically determines the effect of substituents on the stability of the triple-bonded L–E13N–L (E13 = 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(SitBu3)2, SiiPrDis2, Tbt ( C6H2-2,4,6-{CH(SiMe3)2}3) and Ar* (C6H3-2,6-(C6H2-2,4,6-i-Pr3)2)) are used. Unlike other triply bonded L–E13P–L, L–E13As–L, L–E13Sb–L and L–E13Bi–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 E13N triple bond. Nevertheless, these theoretical observations using the natural bond orbital and the natural resonance theory show that the central E13N triple bond in these acetylene analogues must be weak, since these E13N compounds with various ligands do not have a real triple bond.