A polymorphic lanthanide complex as selective Co2+ sensor and luminescent timer

A rarely reported polymorphic lanthanide complex is prepared by acetylacetone (acac) tuning method. Luminescence properties of 1 are studied. Interestingly, 1 is proved to be a multifunctional material. It is a highly selective and sensitive Co2+ sensor, among 24 species, only Co2+ quenching the Tb3+ centered luminescence. The possible sensing mechanism is the decomposition of 1 which induced by Co2+. The limit of detection (LOD) for sensing Co2+ is as low as 330 nM, which is lower than the standard of Chinese environmental protection department. Mechanism study confirmed the luminescence quenching can be ascribed to the decomposition of 1 which induced by Co2+. Further investigations find 1-Co2+ can be applied as tunable luminescent timer, by tuning the ratio of 1/Co2+. CIE coordinates of 1-Co2+ change regularly (has excellent linearity) from green to violet with the time increasing. (C) 2015 Elsevier B.V. All rights reserved.