Yellow-Emitting, Pseudo-Octahedral Zinc Complexes of Benzannulated N^N^O Pincer-Type Ligands

Lozada, Issiah B.; Braun, Jason D.; Williams, J.A. Gareth; Herbert, David E.

Abstract

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.

Citation

Lozada, I. B., Braun, J. D., Williams, J. G., & Herbert, D. E. (2022). Yellow-Emitting, Pseudo-Octahedral Zinc Complexes of Benzannulated N^N^O Pincer-Type Ligands. Inorganic Chemistry, 61(44), 17568-17578. https://doi.org/10.1021/acs.inorgchem.2c02585

• Journal Article Type: Article
• Acceptance Date: Oct 12, 2022
• Online Publication Date: Oct 27, 2022
• Publication Date: Nov 7, 2022
• Deposit Date: Oct 31, 2022
• Publicly Available Date: Oct 28, 2023
• Journal: Inorganic Chemistry
• Print ISSN: 0020-1669
• Electronic ISSN: 1520-510X
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 61
• Issue: 44
• Pages: 17568-17578
• DOI: https://doi.org/10.1021/acs.inorgchem.2c02585
• Public URL: https://durham-repository.worktribe.com/output/1187516