Intense 1400-1600 nm circularly polarised luminescence from homo- and heteroleptic chiral erbium complexes

Efficient near-infrared circularly polarised luminescence (CPL) between 1400 and 1600 nm of four enantiomer pairs of homo- and heteroleptic complexes has been successfully measured. Utilising inexpensive optics and a commercial fluorimeter, discrimination of the left and right circularly polarised components was achieved, yielding remarkably high dissymmetry values in emission (g(lum)). Most notably, homoleptic complexes CsEr(hfbc)(4) (hfbc = 3-heptafluorobutylyrylcamphorate) and [TMG-H+](3)Er(BINOLate)(3) (TMG = 1,1,3,3-tetramethylguanidine; BINOLate = 1,1 '-bi-2-naphtholate) show maximal |g(lum)| values of 0.83 (at 1510 nm) and 0.29 (at 1545 nm) respectively, with the former complex possessing the strongest CPL within the NIR to date.