Near-IR luminescent lanthanide complexes with 1, 8-diaminoanthraquinone-based chromophoric ligands. Issue 15 (14th March 2016)

• Record Type: Journal Article
• Authors: Stacey, Oliver J.; Ward, Benjamin D.; Amoroso, Angelo J.; Pope, Simon J. A.
• Is Part Of: Dalton transactions. Volume 45:Issue 15(2016)
• Page Start: 6674
• Page End: 6681
• Publication Date: 2016-03-14
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c5dt04351d
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : 1, 8-Anthraquinone derivatives can act as low energy, visible light sensitizers for near-IR emitting lanthanides. Abstract : Three new chromophoric anthraquinone-based multidentate ligands have been synthesised in a step-wise manner from 1, 8-dichloroanthraquinone. The ligands each comprise two dipicolyl amine units and react with trivalent lanthanide ions to form monometallic complexes of the form [Ln(L)](OTf)3 as indicated by MS studies and elemental analyses. Supporting DFT studies show that the monometallic species are highly favoured (>1000 kJ mol −1 ) over the formation of a 2 : 2 dimetallic congener. Both ligands and complexes absorb light efficiently ( ε ∼ 10 4 M −1 cm −1 ) in the visible part of the spectrum, with λ abs ca. 535–550 nm through an intramolecular charge transfer (ICT) transition localised on the substituted anthraquinone unit. In all cases the complexes show a fluorescence band at ca. 675 nm due to the ICT emitting state. The corresponding Nd(iii ), Yb(iii ) and Er(iii ) complexes also reveal sensitised near-IR emission characteristic of each ion following excitation of the ICT visible absorption band at 535 nm.