1. a Liquid Crystal Research Center and Department of Chemistry, division of Natural Science , Kon‐Kuk University 1 , Hwayang‐dong, Kwangjin‐gu, Seoul , 143–701 , Korea Phone: Fax: E-mail:
2. b Liquid Crystal Research Center and Department of Chemistry, division of Natural Science , Kon‐Kuk University 1 , Hwayang‐dong, Kwangjin‐gu, Seoul , 143–701 , Korea