- Synthesis and study of new rod-like mesogens containing 2-aminothiophene unit
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We present a synthesis and mesomorphic properties of a new series of rod-like mesogens. All the compounds possess a substituted 2-aminothiophene unit as a main element in the structure attached to a stilbene moiety with a terminal alkyloxy chain (OR1, OR2 where R 1=CnH2n+1, R2=CmH 2m+1; n, m ranging from 6 to 12). The synthesis of alkyloxybiphenyl substituted 2-aminothiophenes was carried out by the Gewald reaction and the appropriate reaction conditions were investigated. The liquid-crystalline properties were studied via polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction. These materials exhibit nematic and/or smectic A phases. The influence of structural changes (variation in alkyloxy chain length and symmetry of the molecule) on mesogenic behaviour is discussed. Evaluation of UV-vis, fluorescent and electrochemical properties are also included.
- Puterová, Zita,Romiszewski, Jerzy,Mieczkowski, Jozef,Gorecka, Ewa
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experimental part
p. 8172 - 8180
(2012/09/22)
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- Process for preparing 2,3-dihydro-1,3-dialkyl-2,3-dialkyl perimidines and N,N-'-dialkyl-1,8-naphthalene diamines
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Processes for preparing 2,3-dihydro-1,3-dialkyl-2,2-dialkyl perimidines and N,N'-dialkyl-1,8-naphthalene diamines are disclosed. The 2,3-dihydro-1,3-dialkyl-2,2-dialkyl perimidines are prepared by alkylating 2,3-dihydro-2,2-dialkyl perimidines with an alkylating agent in a water miscible organic solvent at room temperature to 80° C. in the presence of water and an inorganic base. N,N'-dialkyl-1,8-naphthalene diamines are prepared by hydrolyzing the 2,3-dihydro-1,3-dialkyl-2,2-dialkyl perimidines with strong aqueous acid in an aqueous organic solvent and removing a ketone by-product and the aqueous organic solvent by codistillation.
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- SYNTHESIS OF 4-ALKOXY-4'-CYANOBIPHENYLS
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A preparative method was developed for the synthesis of liquid crystals of the 4-alkoxy-4'-cyanobiphenyl group.It involves the nitration of 4-cyanobiphenyl to 4-nitro-4'-cyanobiphenyl, reduction of the latter, diazotization of the obtained 4-amino-4'-cyanobiphenyl, and alkylation of the 4-hydroxy-4'-cyanobiphenyl formed during decomposition of the diazonium salt.
- Ruolene, Yu. I.,Adomenas, P. V.,Adomenene, O. K.,Denis, G. I.
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p. 1192 - 1195
(2007/10/02)
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