Synthesis and characterisation of new tripodal lanthanide complexes and investigation of their optical and magnetic propertiesElectronic supplementary information (ESI) available: NMR, SEM-EDS, ESI-mass, PXRD, emission and FT-IR spectra and magnetic studies. CCDC 1515525-1515528. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7dt02556d

This paper presents the synthesis of a tripodal ligand (H 3 L) via the Schiff base condensation of N , N -diethylsalicylaldehyde and tris(2-aminoethyl)amine. The neutral complexes of type [EuL], [GdL] and [DyL] were synthesized and characterized by FT-IR, SEM-EDS, PXRD, single crystal X-ray diffraction, CHN analysis and high resolution ESI-MS. X-ray crystallographic studies demonstrated that the heptadentate ligand incorporating a cavity pre-organized by hydrogen bonding binds the Ln( iii ) ions to yield a face capped octahedral coordination geometry with three-fold symmetry. Photoluminescence studies show a typical Ln( iii ) absorption character for the three complexes, with [EuL] demonstrating considerably stronger lanthanide-based luminescence peaks, and a Eu( iii ) centered luminescence lifetime of 0.144 ± 0.01 ms. Temperature/field-dependent DC and temperature/frequency-dependent AC magnetic measurements carried out for the Dy( iii ) complex indicated obvious magnetic anisotropy and suggested slow relaxation behaviour with considerable quantum tunnelling of the magnetization contribution. The neutral complexes of type [EuL], [GdL] and [DyL] incorporating a heptadentate tripodal ligand were synthesized and their optical and magnetic properties have been investigated.