Green light-emitting electrochemical cells based on platinum(II) complexes with a carbazole-appended carbene ligand

Platinum(II) complexes bearing new carbazole-appended cyclometallated N-heterocyclic carbenes such as [Pt(Cbz-C boolean AND C*)CI(NCCH3)](3), [Pt(Cbz-C boolean AND C*)CI(PPh3)](4), [Pt(Cbz-C boolean AND C*)(PPh3)(py)]PF6 (py = pyridine, 5), [Pt(Cbz-C boolean AND C*)(P boolean AND N)]PF6 (P<^>N = 2-(2-(diphenylphosphino) ethyl) pyridine, 6), and [Pt(Cbz-C boolean AND C*)(PAP)]PF6(P boolean AND P)] 1,1-bis(diphenylphosphino)methane, dppm 7; 1,2-bis(diphenylphosphino)ethane, dppe, 8, 1,2-bis(diphenylphosphino) benzene, dppbz, 9) have been prepared using a stepwise procedure from 9-(4-bromophenyl)-9H-carbazole, imidazole, [{Pt(mu-cl)(eta(3)-2-Me-C3H4))(2)] and the corresponding ancillary ligands. They have been fully characterized. Also, single-crystal X-ray structures, theoretical calculations and photophysicaL studies have been performed. These compLexes have been employed as emitters in simple solutionprocessed Eight-emitting electrochemical cells (LECs). When driven under a puked current of 50 A m(-2), devices based on 7-9 exhibited green emission, a Luminance of 265 cd m(-2) and a current efficiency of 5.7 cd A(-1) (for the best performing emitter, 7). As far as we know, these are the first examples of greenemitting Pt(m)-based LECs.