Preparation and optical features of samarium(III) complexes introducing bidentate fluorinate and secondary ligands Archana Chauhan 1 and Ritu Langyan 1, * 1 Department of Chemistry, Kurukshetra University, Kurukshetra, Haryana 136119, India Received: 4 July 2020 Accepted: 18 October 2020 Ó Springer Science+Business Media, LLC, part of Springer Nature 2020 ABSTRACT The syntheses of five luminescent samarium(III) complexes based on 6-Fluoro-4- oxo-4H-1-benzopyran-3-carboxaldehyde (L) and bidentate ancillary ligands were reported. The bidentate ancillary ligands were 1, 10-phenanthroline, 2, 2 0 - bipyridine, neocuproine, and bathophenanthroline. The complexes were char- acterized by employing elemental analysis, UV, FTIR, ESI–MS ? spectrometry, TGA, FESEM, and PXRD. The luminescence properties of complexes in solution and powder state have been discussed to investigate optical characterization. The complexes display characteristic luminescence peaks of samarium(III) ion at * 566, 600, and 647 nm. Different coordination environments around samarium(III) ion in dimethyl sulfoxide solution and powder state result in different emission colors: bright orange and red color with intense peaks at * 600 nm and * 647 nm. The luminescent quantum yield, decay time, CCT, and CIE coordinates were considered. The replacement of aqua ligands by the bidentate subsidiary ligands from the parent complex enriched emission properties, thermal stability, decay time, and quantum yields. Interesting optical properties of complexes in the orange-red spectral region might be useful in electronic devices, bio-assays, and liquid lasers. 1 Introduction Abundant research on organo-lanthanide complexes has been done to date. The seven f orbitals of lan- thanides are responsible for peculiar optical features such as line-like spectral bands, longer luminescence lifetime of the excited state, high purity of visible- region color, and high quantum yield [1–3]. These interesting properties make them attractive materials in imaging, photonics, sensing, and coordination science [4, 5]. Among the lanthanide series, more importance is given to red and green luminescent trivalent europium and terbium ions [6–8]. Although the weaker luminescence intensity of trivalent samarium ion limits its research in material and optical science, researchers are still developing new samarium(III)-based luminescent compounds with Address correspondence to E-mail: ritu.langyan@gmail.com https://doi.org/10.1007/s10854-020-04711-x J Mater Sci: Mater Electron