Visible and near-infrared emitting heterotrimetallic lanthanide-aluminum-sodium 12-metallacrown-4 compounds: discrete monomers and dimers

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 51; no. 15; pp. 5989 - 5996
• Main Authors: Eliseeva, Svetlana V, Travis, Jordan R, Nagy, Sarah G, Smihosky, Alyssa M, Foley, Collin M, Kauffman, Abigail C, Zaleski, Curtis M, Petoud, Stéphane
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 12.04.2022
• Subjects: Aluminum; Analytical chemistry; Benzoates; Chemical Sciences; Coordination chemistry; Cristallography; Dimers; Erbium; Gallium; Inorganic chemistry; Luminescence; Material chemistry; Molecular structure; Monomers; Near infrared radiation; Optical properties; Physics; Sodium; Solid state; Ytterbium
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d1dt04277g

The luminescence properties of two types of heterotrimetallic aluminum-lanthanide-sodium 12-metallacrown-4 compounds are presented here, LnNa(ben) 4 [12-MC Al(III)N(shi) -4] ( LnAl 4 Na ) and {LnNa[12-MC Al(III)N(shi) -4]} 2 (iph) 4 ( Ln 2 Al 8 Na 2 ), where Ln = Gd III , Tb III , Er III , and Yb III , MC is metallacrown, ben − is benzoate, shi 3− is salicylhydroximate, and iph 2− is isophthalate. The aluminum-lanthanide-sodium metallacrowns formed with benzoate are discrete monomers while, upon replacement of the benzoate with the dicarboxylate isophthalate, two individual metallacrowns can be joined to form a dimer. In the solid state, the terbium version of each structure type displays emission in the visible region, and the erbium and ytterbium complexes emit in the near-infrared. The luminescence lifetimes ( τ obs ) and quantum yields have been collected under ligand excitation ( Q L Ln ) for both LnAl 4 Na monomers and Ln 2 Al 8 Na 2 dimers. Several of these values tend to be shorter (luminescence lifetimes) and smaller (quantum yields) than the corresponding values recorded for the structurally similar gallium-lanthanide monomer and dimer 12-MC-4 molecules. However, the quantum yield value recorded for the visible emitting Tb 2 Al 8 Na 2 dimer, 43.9%, is the highest value observed in the solid state to date for a Tb III based metallacrown. The terbium-aluminum metallacrowns (MC), TbAl 4 Na (left image & capillary) and Tb 2 Al 8 Na 2 (right image & capillary) emit green light. Tb 2 Al 8 Na 2 has a quantum yield value of 43.9%, the highest value observed in the solid state to date for a Tb III MC.