title: Rethinking Sensitized Luminescence in Lanthanide Coordination Polymers and MOFs: Band Sensitization and Water Enhanced Eu Luminescence in [Ln(C15H9O5)3(H2O)3]n (Ln = Eu, Tb).
abstract: A coordination polymer [Ln(C15H9O9)3(H2O)3]n (1-Ln = Eu(III), Tb(III)) assembled from benzophenonedicarboxylate was synthesized and characterized. The organic component is shown to sensitize lanthanide-based emission in both compounds, with quantum yields of 36% (Eu) and 6% (Tb). Luminescence of lanthanide coordination polymers is currently described from a molecular approach. This methodology fails to explain the luminescence of this system. It was found that the band structure of the organic component rather than the molecular triplet state was able to explain the observed luminescence. Deuterated (Ln(C15H9O9)3(D2O)3) and dehydrated (Ln(C15H9O9)3) analogues were also studied. When bound H2O was replaced by D2O, lifetime and emission increased as expected. Upon dehydration, lifetimes increased again, but emission of 1-Eu unexpectedly decreased. This reduction is reasoned through an unprecedented enhancement effect of the compound's luminescence by the OH/OD oscillators in the organic-to-Eu(III) energy transfer process.
authors.affiliation: Department of Chemistry & Biochemistry, Florida Atlantic University , 777 Glades Road, Boca Raton, Florida 33431 United States.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Einkauf
authors.affiliation: Department of Chemistry & Biochemistry, Florida Atlantic University , 777 Glades Road, Boca Raton, Florida 33431 United States.
authors.forename: Tanya T
authors.initials: TT
authors.lastname: Kelley
authors.affiliation: Department of Chemistry, The College of New Jersey , 2000 Pennington Road, Ewing, New Jersey 08628, United States.
authors.forename: Benny C
authors.initials: BC
authors.lastname: Chan
authors.affiliation: Department of Chemistry & Biochemistry, Florida Atlantic University , 777 Glades Road, Boca Raton, Florida 33431 United States.
authors.forename: Daniel T
authors.initials: DT
authors.lastname: de Lill