摘要:
Improved liquid crystalline materials may be prepared by doping liquid crystalline materials with chiral, uncharged metal compounds of formula [(P1—Y1—A1—Y2—M1—Y3—)nL]2Me or [(P1—Y1—A1—Y2—M1—Y3—)nL]Me(L′(—Y6—M2—Y5—A2—Y4—P2)n′)m. Groups P1 and P2 may be, independently, hydrogen, C1-C12-alkyl groups, polymerizable groups, or radicals containing a polymerizable group. Y1 to Y6 may be, independently, single chemical bonds, ether groups, thio groups, carbonyl groups, acid groups, etc. Groups A1 and A2 are spacers having from 1 to 30 carbon atoms, and M1 and M2 are mesogenic groups. Me may be a transition metal from the fourth, fifth or sixth period of the periodic table, except for technetium, silver, cadmium, gold, mercury, or any of the lanthanoids, or Me may be a main group element from group 14 (IUPAC system), except for carbon and lead. L is a tridentate ligand, and L′ is an organic group having up to 12 carbon atoms.