Towards cationic gallium derivatives: Metallacycles from the reactions of organogallium compounds with tetraorganodichalcogenoimidodiphosphinates and a new N-(diphenylthiophosphinyl)thioureato ligand

The organometallic complexes of general formulae [Me₂Ga{η ²-E,E′-[R₂P(E)NP(E′)R′₂]}] [R = R′ = Ph, E = E′ = O (1); R = R′ = Ph, E = E′ = S (2); R = R′ = Ph, E = E′ = Se (3); R = R′ = Ph, E = O, E′ = S (4); R = Me, R′ = Ph, E = S, E′ = O (5)] and [Me ₂Ga{η²-S,S′-[Ph₂P(S)NC(S)(C ₉H₁₀N)]}] (6) were obtained by facile methane elimination reactions from GaMe₃ and the acidic ligands L¹H [(XPPh₂)₂NH (X = O, S, Se)1 (OPPh₂)(SPPh ₂)NH, and (OPMe₂)(SPPh₂)NH] and L²H [Ph₂P(S)NHC(S)(C₉H₁₀N)] in toluene. Replacement of one phosphorus atom by a carbon atom in the ligand skeleton of L ¹H gave the new ligand L²H, which, upon reaction with GaMe₃, gave compound 6, which shows no significant structural differences with respect to 1-5. Therefore, L²H does not induce partial planarity in the six-membered ring, indicating the necessity for replacing both phosphorus atoms of the ligand by carbon atoms, as in the β-diketonate-type derivatives, in order to impose ring planarity. Thus, despite originating from a variety of ligands with differing donor atoms and substituents at the phosphorus atoms, all complexes show little structural differences.