Bent-core 6-thioxoverdazyl: a comparison of mesogenic properties with the 6-oxo analogue

Abstract

Two bent-core verdazyl radicals, 2[16] and 3[16], containing 6-thioxo and 6-oxo groups, respectively, were prepared and their physical properties were compared. Analysis of binary mixtures with bent-core mesogen 1[12] gave virtual N-I ([TNI]) and N-Ire ([TNIre]) transition temperatures. Results indicate that the thioxo derivative 2[16] has greater stabilising effect on the nematic phase than the 6-oxo analogue 3[16], presumably due to the higher dipole moment of the core (1.90 D vrs 0.83 D) despite the less favourable conformational properties.