Preliminary communication: Magnetic-field-induced Freedericksz transition of a planar aligned liquid crystal doped with porphyrinatozinc(II): influence of the substituent of the porphyrin ring

The magnetic-field-induced Freedericksz transition of a planar aligned nematic liquid crystal doped with 1.0 wt % of a diamagnetic porphyrinatozinc(II) has been studied. It was observed that 5CB doped with 1.0 wt % of derivatives of Zn(II)TPP-5,10,15,20-tetraphenyl-porphyrinatozinc(II) - which have different substituents in one phenyl ring display sharp Freedericksz transition curves and dramatically decrease the critical magnetic field compared with pure 5CB.