Synthesis, Structure and Luminescence Properties of Four Novel Terbium2‐Fluorobenzoate Complexes

Four new complexes [Tb(2‐FBA) 3 · (2‐HFBA) · H 2 O] 2 ( 1 ), {[Tb(2‐FBA) 3 · (4,4'‐bpy) · H 2 O] 3 } n ( 2 ), [Tb(2‐FBA) 3 · (2,2'‐bpy)] 2 ( 3 ), and [Tb(2‐FBA) 3 · phen · CH 3 CH 2 OH] 2 · [Tb(2‐FBA) 3 · phen] 2 ( 4 ) (2‐HFBA: 2‐fluorobenzoic acid; 4,4'‐bpy: 4,4'‐bipyridine; 2,2'‐bpy: 2,2'‐bipyridine; phen: 1,10‐phenanthroline) have been synthesized and characterized by X‐ray diffraction analysis. Complex 1 is a dimeric molecule with a one‐dimensional supramolecular structure formed by hydrogen bonds. Complex 2 is an infinite one‐dimensional polymer chain formed by bridging carboxylato groups; its 2D framework structure is formed by hydrogen bonds. The structure of complex 3 contains three independent binuclear molecules in the asymmetric unit. In two of them, two Tb 3+ ions are held together by four 2‐FBA groups, with two of them in a bidentate‐bridging mode and the other two in a chelating‐bridging mode. In the third, two Tb 3+ ions are held together by four 2‐FBA groups, all of which are in the bidentate‐bridging mode. One 2‐FBA group and one 2,2'‐bpy chelate to one Tb 3+ ion, resulting in coordination numbers of the central terbium ion of nine and eight, respectively. The structure of complex 4 contains two nonequivalent binuclear molecules in the asymmetric unit — [Tb(2‐FBA) 3 · phen · CH 3 CH 2 OH] 2 and [Tb(2‐FBA) 3 · phen] 2 . In the former, the Tb 3+ ion is surrounded by eight atoms, five O atoms from five 2‐FBA groups, one O atom from one ethanol molecule and two N atoms from phen, and the 2‐FBA groups act in monodentate and bridging coordination modes. In the latter, the Tb 3+ ion is coordinated by nine atoms, seven O atoms from five 2‐FBA groups and two N atoms of phen, and the 2‐FBA groups link the Tb 3+ ion in chelating, bridging, and chelating‐bridging coordination modes. Complexes 1 , 3 , and 4 emit a bright green light under UV light in the solid state. There are four emission peaks in the luminescence spectra at 488, 543, 584, and 618 nm, corresponding to the 5 D 4 → 7 F 6 , 5 D 4 → 7 F 5 , 5 D 4 → 7 F 4 , and 5 D 4 → 7 F 3 transitions, respectively, of the Tb 3+ ion. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)