Reactivity of cyclopalladated compounds derived from biphenyl-2-ylamine towards carbon monoxide, tbutyl isocyanide and alkynes

The reactivity of the dimeric cyclopalladated compounds derived from biphenyl-2-ylamine (μ-X)2[κ2-N2′,C1-1-Pd-2-{(2′-NH2C6H4)C6H4}]2 [X = OAc (1), X = Cl (2)] towards unsaturated organic molecules is reported. Compound 1 reacted with carbon monoxide and tbutyl isocyanide producing phenanthridin-6(5H )-one and N -tert -butylphenanthridin-6-amine in 63% and 88% yield, respectively. Compound 2 reacted separately with diphenylacetylene and 3-hexyne, affording the mononuclear organopalladium compounds [κ2-N2″,C1-η2-C2,C3- 1-Pd{(R–Cdouble bond; length as m-dashC–R)2-2′-(2″-NH2C6H4)C6H4}Cl] [R = Ph (5), R = Et (6)] in 50–60% yield, which derived from the insertion of two alkyne molecules into the C–Pd σ bonds of 2. The crystal structure of compounds 5 and 6 has been determined. Compound 5 crystallized in the monoclinic space group P 21/n with a = 13.3290(10) Å, b = 10.6610(10) Å and c = 22.3930(10) Å and β = 100.2690(10)°. Compound 6 crystallized in the triclinic space group View the MathML sourceP1¯ with a = 7.271(7) Å, b = 10.038(3) Å and c = 16.012(5) Å, and α = 106.79(3)°, β = 96.25(4)° and γ = 99.62(4)°. The crystal structures of 5 and 6 have short intermolecular Pd–Cl⋯H–N–Pd non-conventional hydrogen bonds, which associated the molecules in chains in the first case and in dimers in the second.