NIR-CPL from chiral complexes of lanthanides and d-metals

Near-infrared circularly polarised luminescence (NIR-CPL) has many interesting and potential applications ranging from CPL microscopy to the telecommunication industry. In recent years, a surge of visible-emissive CPL systems has occurred, due to the increased popularity of CPL as a spectroscopic technique and greater accessibility to CPL instrumentation. Despite the increased interest, few reports on complexes which emit in the NIR are available, and mostly limited to lanthanide and Cr(III) complexes due to their large pseudo-Stokes shift and magnetic dipole (MD) allowed, electric dipole (ED) forbidden nature. In the following, we aim to give an overview of the recent technological improvements, which allow NIR-CPL to be measured, and describe the chiroptical properties of metal complexes which achieve this feat.