| 초록 |
We investigated the electrochemical and excited-state properties of 2,3-bis(2-pyridyl)pyrazine (dpp)-bridged bimetallic complexes, (L)2Ir-dpp-PtCl [1, L = 2-(4′,6′-difluorophenyl)pyridinato-N,C2 (dfppy); 2, L = 2-phenylpyridinato-N,C2 (ppy)] and [(L)2Ir]2(dpp) [3, L = dfppy; 4, L= ppy] compared to monometallic complexes, (L)2Ir-dpp (5, L = dfppy; 6, L = ppy) and dpp-PtCl (dpp-PtIICl2; 7). The structures of 1, 3, 5, and 6 showed that 1 and 3 have approximately coplanar structures of the dpp unit, while the non-coordinated pyridine ring of dpp in 5 and 6 is largely twisted with respect to the pyrazine ring. Their electrochemical and photophysical properties revealed that efficient electron-transfer processes predominated in the bimetallic systems regardless of the second metal participation. The TA study further confirmed that the planarity of the dpp had a direct correlation with the degree of nonradiative decay from the emissive iridium-based 3MLCT to the Ir d−d or Pt d−d state. |
