Star-shaped conjugated compounds forming nematic discotic systems

被引:76
作者
Meier, H [1 ]
Lehmann, M [1 ]
Holst, HC [1 ]
Schwöppe, D [1 ]
机构
[1] Johannes Gutenberg Univ Mainz, Inst Organ Chem, D-55099 Mainz, Germany
关键词
condensation; liquid crystals; photoreactivity;
D O I
10.1016/j.tet.2004.06.012
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Star-shaped compounds, having a benzene (9a,b) or a 1,3,5-triazine (11a,b) core and stilbenoid arms were prepared. Hexyloxy chains, attached in the middle of the arms, provide nematic discotic phases N-D, which are unusual for such systems. The position of the sidechains prevents the micro-segregation, which is valid for star-shaped discs of columnar phases. The stilbenoid character of 9a,b and 11a,b guarantees a high light sensitivity. Apart from the statistical CC bond formation by irradiation in solution or in the LC phases, a topochemically controlled chemo-, regio- and stereoselective photocyclodimerization 11a-->12 was found in the crystalline state. The structure determination of 12 is based on different two-dimensional NMR techniques (COSY, NOESY, HMQC, HMBC). (C) 2004 Elsevier Ltd. All rights reserved.
引用
收藏
页码:6881 / 6888
页数:8
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