Group†6 Hexacarbonyls as Ligands for the Silver Cation: Syntheses, Characterization, and Analysis of the Bonding Compared with the Isoelectronic Group†5 Hexacarbonylates.

The syntheses of the two novel complexes [Ag{Mo/W(CO)(6) }(2) ](+) [F-{Al(OR(F) )(3) }(2) ](-) (R(F) =C(CF(3) )(3) ) are reported along with their structural and spectroscopic characterization. The X-ray structure shows that three carbonyl ligands from each M(CO)(6) fragment bend towards the silver atom within binding Ag-C distance range. DFT calculations of the free cations [Ag{M(CO)(6) }(2) ](+) (M=Cr, Mo, W) in the electronic singlet state give equilibrium structures with C(2) symmetry with two bridging carbonyl groups from each hexacarbonyl ligand. Similar structures with C(2) symmetry (M=Nb) and D(2) symmetry (M=V, Ta) are calculated for the isoelectronic group†5 anions [Ag{M(CO)(6) }(2) ](-) (M=V, Nb, Ta). The electronic structure of the cations is analyzed with the QTAIM and EDA-NOCV methods, which provide detailed information about the nature of the chemical bonds between Ag(+) and the {M(CO)(6) }(2) (q) (q = -2, M = V, Nb, Ta; q = 0, M = Cr, Mo, W) ligands.