Structure elucidation by Sparkle/RM1, and solution behavior of lanthanideIII complexes: NMR, 4f‒4f absorption spectra and Photoluminescent properties

•Ground state geometry of [Ln(hfaa)3(L)n] (L = phen or H2O; n =1–2) were determined.•Geometry of the complexes is very close to triangular dodecahedron (D2d symmetry).•Complexes are stable in coordinating and non‒coordinating solvents.•Solvents show impact on band shape and oscillator strength of hypersensitive transitions.•Photophysical properties are superior in non‒coordinating solvents.