Liquid crystalline derivatives of bis(tricarbollide)Fe(II)

A series of Schiff bases 2n] with n = 4, 6, 8, 10, 12, and 18 was prepared by the condensation of 9,9'-diaminobis(tricarbollide)Fe(II) (1b) with appropriate 4-alkoxybenzaldehydes (3n]). Thermal analysis showed that they form nematic and smectic phases with clearing temperatures above 200 degrees C. Comparative studies of series 2n] and its organic analogs demonstrated that the effectiveness of bis(tricarbollide)Fe(II) in supporting liquid crystalline phases is between that of benzene and biphenyl for n < or = 18 and lower than that of benzene for n = infinity. The photophysical properties were investigated for the butoxy derivative 24] and modeled using ZINDO calculations.