The reactivity of pyridine-imine and diamine ligands with dimethylplatinum(II) compounds

Article abstract of DOI:10.1016/0277-5387(95)00458-0

The reactions of [Pt₂Me₄(μ-SMe₂)₂] (1) with pyridine-imines 2-(CH= NCHRR′)C₅H₄N [R = H, R′ = 2-BrC₆H₄ (2a) ; R = H, R′ = 2,4-Cl₂C₆H₃ (2b) ; R = Me, R′ = C₆H₅ (2c)] or diamines Me₂N(CH₂)₂N(Me)CH₂R [R = 2-BrC₆H₄ (5d) ; R = C₆F₅ (5e) ; R = C₆H₅ (5f)] result in the formation of complexes [PtMe₂{2-(CH= NCHRR′)C₅H₄N}] (3) and [PtMe₂{Me₂N(CH₂)₂N(Me)CH ₂R}] (6), respectively, in which the ligand is coordinated through the two nitrogen atoms to platinum, but such reactions fail to produce metallation at the benzyl group. The reactivity of the more flexible diamines Me₂N(CH₂)₃N(Me)CH₂R [R = 2-BrC₆H₄ (5g) ; R = C₆F₅ (5h) ; R - C₆H₅ (5i)] was also tested in the presence of [Pt₂Me₄(μ-SMe₂)₂] (1). While 5h and 5i failed to react, activation of a C - Br bond to produce the platinum(IV) compound [PtMe₂Br{Me₂N(CH₂)₃N (Me)CH₂C₆H₄}] (7g), which contains a terdentate (C,N,N′) ligand, was achieved with 5g. Compounds 3 reacted readily with methyl iodide to afford platinum(IV) compounds [PtMeI2-(CH=NCHRR′)C₅H₄] (4).