Lozada Issiah B, Braun Jason D, Williams J A Gareth, Herbert David E
Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, ManitobaR3T 2N2, Canada.
Department of Chemistry, Durham University, DurhamDH1 3LE, U.K.
Inorg Chem. 2022 Nov 7;61(44):17568-17578. doi: 10.1021/acs.inorgchem.2c02585. Epub 2022 Oct 27.
A series of yellow-emitting, pseudo-octahedral Zn(II) complexes supported by monoanionic, tridentate acetylacetone-derived N^N^O ligands incorporating phenanthridine (benzo[]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 -heterocycle/amido-supported Zn(II) coordination compounds.
本文报道了一系列由单阴离子三齿乙酰丙酮衍生的含菲啶（苯并[h]喹啉）单元的N^N^O配体支撑的发黄光的伪八面体Zn(II)配合物。这些物种在溶液中发光较弱，但在室温下的固态以及77 K的冷冻玻璃态中表现出延长的毫秒级发光寿命，表明来自低能级三重激发态的磷光。激发光谱表明聚集在增强固态发射中起作用。与在流体溶液中不发光的四配位菲啶基酰胺支撑的四齿Zn(II)配合物不同，固态X射线晶体结构、溶液红外光谱和计算分析均表明中心去质子化的NH具有离域特征，这缓和了配体的酰胺特征。这种设计为开启由-杂环/酰胺支撑的Zn(II)配位化合物的长寿命发光提供了一种机制。
