Synthesis and mesomorphism of 1,1′-disubstitued ferrocene liquid crystals with a schiff's base bridge

To investigate the influence of alkyl chain on thermotropic and mesomorphic properties of 1,1'-disubstitued ferrocene derivatives, two series of ferrocene derivatives containing Schiffs base, 1,1'-C(8)H(17)FcC(6)H(4)COOC(6)H(4)CH=NC6H4OOCC6H4R1 (R-1 = H, OCnH2n+1, n = 2, 4, 6, 8) and 1,1'-C(8)H(17)FcC(6)H(4)COOC(6)H(4)CH=NC6H4N=NC6H4R2 (R-2= Br, Cl, CH3) have been synthesized and characterized by IR and H-1 NMR. Polarized optical microscopy (POM) and differential scanning calorimetry (DSC) results showed that all compounds exhibit nematic mesophase. The results show that the flexible alkyl chain connecting with ferrocene moiety could lower the melting points and clearing points, favor the formation of nematic mesophase.