Near-Infrared Dichroism of a Mesogenic Transition Metal Complex and Its Solubility in Nematic Hosts,

摘要

A transition metal complex possessing the nematic phase, bis (p-n-butylstyryl-1,2-dithiolato) nickel, was synthesized and its optical properties and solubility in the nematic hosts K15 and MBBA were investigated. The metal complex displayed a high solubility in both host materials and a strong near-infrared absorption band centered at 860 nm. A blocking extinction of greater than OD = 3 was obtained with a 100 micrometer pathlength of a 0.5% wt/wt mixture of the nematic metal complex in K15, suggesting its usefulness for passive blocking of near-infrared radiation. A 24 micrometer thick, homogeneously aligned guest-host cell containing a 1% wt/wt/ mixture of the metal complex in K15 possessed a contrast ratio of nearly 5:1 and a blocking extinction of OD = 3.5 at 860 nm, demonstrating for the first time the existence of near-infrared dichroism in this class of materials. The solubility and blocking extinction of the mesogenic metal complex in K15 was considerably superior to the non-mesogenic near IR laser dye bis (dimethylaminodithiobenzil) nickel in the same host. An interaction of the nematic metal complex in mixtures with MBBA which resulted in the creation of a new absorption band at 1050 nm was also observed. Keywords: Laser dyes, Liquid crystal devices, Dichroic dyes, Electrooptics, Reprints. (aw)