Stabilization of two coordinate tetrylene by borylamide ligand

The aminoborane HN(BCy2)(C6H3-2,6-Me2) (Cy = cyclohexyl) was prepared and used for synthesis of two coordinate tetrylenes {E[N(BCy2) (C6H3-2,6-Me2)]2} (E = Sn (4), Pb (5)). Frontier orbitals analysis of 4 and 5 showed Sn/Pb lone pair associated with the HOMO and the LUMO with substantial p-orbital character located on metal atoms. Experimental and theoretical studies suggest that amidoborane -N(BCy2)(C6H3-2,6-Me2) may protect sufficiently the empty p orbital located on the central E atoms similarly to bulky amido ligands, but it deviates in the character of N-E bonds.186