Design, synthesis, structural characterization, non-linear optical and computational studies of some 3t-butyl-2r,6c-diarylpiperidin-4-on-1-ium picrates

•thermal stabilities ranging from decomposition temperatures of 187 to 169°C.•the doublet at 2.76 ppm is attributed to H-5e at C-5 in the piperidone ring.•CH3CH2OH show two peaks, one encircling 230 nm, it may be due to π-π* transition.•C-O bond distance characteristic values of 1.239(4) and∼1.261 Å by XRD and B3LYP.•picric acid into 3t-butyl-2r and 6c-diarylpiperidin-4 and analyze their NLO properties.