A series of new lanthanide benzoates: Syntheses, crystal structures, and luminescent properties

A series of new luminescent lanthanide benzoates [Ln2(phen)2(bza)4(Ac)2] {Ln = Eu (1), Gd3+(2), Tb3+ (3), Dy3+(4), Tm3+(5); phen = 1,10-phenanthroline, Hbza = benzoic acid, Ac− = acetate)} and [Ln2(phen)2(bza)4(NO3)2] [Ln = Sm3+(6), Eu3+ (7), Tb3+ (8), Dy3+ (9), Tm3+ (10)] have been hydrothermally prepared by the usage of the π-conjugated phen ligands as chromophores. 1–5 exhibit binuclear [Ln2(phen)2(bza)4(Ac)2] moieties built up from two [Ln(phen)]3+ groups joined together by the bridging bza− and Ac− ligands, while 6–10 show another binuclear [Ln2(phen)2(bza)4(NO3)2] moieties constructed by two [Ln(phen)(NO3)]2+ groups linked together by the bridging bza− ligands. These compounds offer the rare examples of binuclear lanthanide benzoates decorated by phen chromophores. Luminescent and sensing properties of 1–10 were studied, revealing that europium (1 and 7) and terbium (3 and 8) benzoates can be used as a bifunctional luminescent probe for acetone and Fe3+ with high efficiency and selectivity.