Universität zu Köln, Fakultät für Mathematik und Naturwissenschaften, Department für Chemie, Institut für Anorganische Chemie, Greinstraße 6, 50939 Köln, Germany
Maren Krause
Universität zu Köln, Fakultät für Mathematik und Naturwissenschaften, Department für Chemie, Institut für Anorganische Chemie, Greinstraße 6, 50939 Köln, Germany
Rose Jordan
Universität zu Köln, Fakultät für Mathematik und Naturwissenschaften, Department für Chemie, Institut für Anorganische Chemie, Greinstraße 6, 50939 Köln, Germany
Iván Maisuls
Institut für Anorganische und Analytische Chemie, CiMIC, CeNTech, Westfälische Wilhelms-Universität Münster, Heisenbergstraße 11, 48149 Münster, Germany
Dana Brünink
Institut für Festkörpertheorie and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
Dominik Schwab
Institut für Festkörpertheorie and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
Nikos L. Doltsinis
Institut für Festkörpertheorie and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
Cristian A. Strassert
Institut für Anorganische und Analytische Chemie, CiMIC, CeNTech, Westfälische Wilhelms-Universität Münster, Heisenbergstraße 11, 48149 Münster, Germany
Axel Klein
Universität zu Köln, Fakultät für Mathematik und Naturwissenschaften, Department für Chemie, Institut für Anorganische Chemie, Greinstraße 6, 50939 Köln, Germany
In a series of Pt(II) complexes [Pt(dba)(L)] containing the very rigid, dianionic, bis-cyclometalating, tridentate C^N^C2− heterocyclic ligand dba2– (H2dba = dibenzo[c,h]acridine), the coligand (ancillary ligand) L = dmso, PPh3, CNtBu and Me2Imd (N,N’-dimethylimidazolydene) was varied in order to improve its luminescence properties. Beginning with the previously reported dmso complex, we synthesized the PPh3, CNtBu and Me2Imd derivatives and characterized them by elemental analysis, 1H (and 31P) NMR spectroscopy and MS. Cyclic voltammetry showed partially reversible reduction waves ranging between −1.89 and −2.10 V and increasing along the series Me2Imd 3 tBu. With irreversible oxidation waves ranging between 0.55 (L = Me2Imd) and 1.00 V (dmso), the electrochemical gaps range between 2.65 and 2.91 eV while increasing along the series Me2Imd tBu 3 ΦL ranged between 0.04 and 0.24, at 298 K, and between 0.80 and 0.90 at 77 K. The lifetimes τ at 298 K ranged between 60 and 14040 ns in Ar-purged solutions and increased from 17 to 43 µs at 77 K. The TD-DFT calculated emission spectra are in excellent agreement with the experimental findings. In terms of high ΦL and long τ, the dmso and PPh3 complexes outperform the CNtBu and Me2Imd derivatives. This is remarkable in view of the higher ligand strength of Me2Imd, compared with all other coligands, as concluded from the electrochemical data.
