PNacPNacE: (E = Ga, In, Tl) - monomeric group 13 metal(I) heterocycles stabilized by a sterically demanding bis(iminophosphoranyl)methanide

The salt metathesis reaction of the sterically demanding bis(iminophosphoranyl)methanide alkali metal complexes LM (L-=HC(Ph(2)PvNDip)(2)(-), Dip=2,6-(Pr2C6H3)-Pr-i; M =Li, Na, K) with "GaI", InBr or TlBr afforded the monomeric group 13 metal(I) complexes LE:, E = Ga (1), In (2) and Tl (3) in moderate yields, and small quantities of LGaI2 4 in the case of Ga, respectively. The molecular structures of LE: 1-3 from X-ray single crystal diffraction show them to contain puckered six-membered rings with N, N'-chelating methanide ligands and two-coordinated metal(I) centres. Reduction reactions of LAlI2 5, prepared by iodination of LAlMe2, were not successful and no aluminium(I) congener could be prepared so far. DFT studies on LE:, E =Al-Tl, were carried out and support the formulation as an anionic, N, N'-chelating methanide ligand coordinating to group 13 metal(I) cations. The HOMOs of the molecules for E = Al-In show a dominant contribution from a metal-based lone pair that is high in s-character.