| Autor: |
Lozada IB; Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, ManitobaR3T 2N2, Canada., Braun JD; Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, ManitobaR3T 2N2, Canada., Williams JAG; Department of Chemistry, Durham University, DurhamDH1 3LE, U.K., Herbert DE; Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, ManitobaR3T 2N2, Canada. |
| Abstrakt: |
A series of yellow-emitting, pseudo-octahedral Zn(II) complexes supported by monoanionic, tridentate acetylacetone-derived N^N - ^O ligands incorporating phenanthridine (benzo[ c ]quinoline) units is presented. These species emit weakly in solution but exhibit extended millisecond luminescence lifetimes in the solid state at room temperature, and in a frozen glass at 77 K, indicative of phosphorescence from low-lying triplet excited states. Excitation spectra indicate a role for aggregation in enhancing emission in the solid state. In contrast to four-coordinate phenanthridinyl amide-supported tetradentate Zn(II) complexes which are nonemissive in fluid solution, solid-state X-ray crystallographic structures, solution IR spectroscopy, and computational analysis all indicate a delocalized character for the central deprotonated NH which tempers the amido character of the ligand. This design provides a mechanism for "turning on" long-lived luminescence from N -heterocycle/amido-supported Zn(II) coordination compounds. |
