Synthesis, structures, and emissive properties of platinum(II) complexes with a cyclometallating aryldiamine ligand.

A new series of square planar Pt(II) complexes with the mer-coordinating tridentate ligand, pip 2 NCN - (pip 2 NCNH = 1,3-bis(piperdylmethyl)benzene), has been prepared: Pt(pip 2 NCN)Cl (2), Pt(pip 2 NCN)Br (3), Pt(pip 2 NCN) (4), and [Pt(pip 2 NCN))(CH 3 N=C(CH3)2)][CF 3 SO 3 ] (5). The complexes have been fully characterized by 1 H NMR spectroscopy, elemental analysis, and UV-vis spectroscopy. The X-ray crystal structures of pip 2 NCNBr (1), 2, and 5 are reported. Compound 1: triclinic, P1, a = 10.081(1) A b = 10.153(2) A, c = 10.390(1) A, α = 66.05(1)°, β = 79.07(1)°, y = 64.51(1)°, V = 877.1(2) A 3 , Z = 2. Complex 2: triclinic, P1, a = 9.897(2) A, b = 10.191(2) A, c = 19.174(4) A, α = 75.09(3)°, β = 76.14(3)°, γ = 71.00(3)°, V = 1741.2(6) A 3 , Z = 4. Complex 5: triclinic, P1, a = 10.709(2) A, b = 11.2321(10) A, c = 12.447(2) A, α = 110.509(8)°, β = 112.417(10)°, γ = 91.066(9)°, V = 1276.1(3) A 3 , Z = 2. In 77 K 3:1 EtOH/MeOH glassy solution, these colorless complexes exhibit weak red-orange to red emissions originating from a lowest spin-forbidden ligand field excited state.