Adipic-1′,6′-bis(4-halogenpheny1 hydrazine) has been synthesized in ice bath with adipic chloride and 4-bromophenyl hydrazine made by ourselves.At the same time,adipic-1′,6′-bis(4-halogenpheny1 hydrazine) is synth...Adipic-1′,6′-bis(4-halogenpheny1 hydrazine) has been synthesized in ice bath with adipic chloride and 4-bromophenyl hydrazine made by ourselves.At the same time,adipic-1′,6′-bis(4-halogenpheny1 hydrazine) is synthesized firstly with oxidation system NaBrO3/H2SO4.The products are confirmed by elemental analysis,IR and 1HNMR.The yields of adipic-1′,6′-bis(4-halogenpheny1 hydrazine) is 83-92%.展开更多
2,2′-Dichlorohydrazobenzene(DHB) was prepared in two steps. o-Chloronitrobenzene( OCNB) was at first reduced to 2,2′-dichloroazoxybenzene(DOB) in aqueous medium using 2,3-dichloro-1,4-naphthaquinone(OCNQ) as catalys...2,2′-Dichlorohydrazobenzene(DHB) was prepared in two steps. o-Chloronitrobenzene( OCNB) was at first reduced to 2,2′-dichloroazoxybenzene(DOB) in aqueous medium using 2,3-dichloro-1,4-naphthaquinone(OCNQ) as catalyst with yield of 99.4%, mp 53～56 ℃; DOB was then reduced by formaldehyde to give DHB in aqueous alkaline methanol with yield of 76%, 49% higher than reported, mp 82～83.5 ℃. DHB could be rearranged to 3,3′-dichlorobenzidine in strong acidic medium with yield 91.8%, mp 132～ 134 ℃.展开更多
Liquid crystalline of a new carbosilane dendrimer of the second generation(D2) containing thirty-six 4-nitroazobenzene groups in its periphery was characterized by means of polarizing optical micrograph, DSC and WAXD....Liquid crystalline of a new carbosilane dendrimer of the second generation(D2) containing thirty-six 4-nitroazobenzene groups in its periphery was characterized by means of polarizing optical micrograph, DSC and WAXD. Mesogenic compound M5 exhibits threaded, schlieren and inversion lines texture of the nematic phase on the cooling from isotropic phase to solidified temperature. Dendrimer D2 shows the focal conic fan-shaped texture of the smectic A phase on the heating course from 69 to 187 ℃ and on the cooling course from 183 to 64 ℃. After cooling, the smectic E(S E) phase with a texture of the focal conic fan-shape with stripes and concentric arcs appears from smectic A(S A) phase. Phase behavior of dendrimer D2 in liquid crystalline state was K69S A187I182S A57S E47K. The isotropic-smectic A transition enthalpy, smectic A-smectic E transition enthalpy and isotropic-smectic A transition entropy were 1.8, 4.5 and 4.0 J/(K·mol), respectively, and were in agreement with or close to those of small molecular liquid crystal.展开更多
文摘Adipic-1′,6′-bis(4-halogenpheny1 hydrazine) has been synthesized in ice bath with adipic chloride and 4-bromophenyl hydrazine made by ourselves.At the same time,adipic-1′,6′-bis(4-halogenpheny1 hydrazine) is synthesized firstly with oxidation system NaBrO3/H2SO4.The products are confirmed by elemental analysis,IR and 1HNMR.The yields of adipic-1′,6′-bis(4-halogenpheny1 hydrazine) is 83-92%.
文摘2,2′-Dichlorohydrazobenzene(DHB) was prepared in two steps. o-Chloronitrobenzene( OCNB) was at first reduced to 2,2′-dichloroazoxybenzene(DOB) in aqueous medium using 2,3-dichloro-1,4-naphthaquinone(OCNQ) as catalyst with yield of 99.4%, mp 53～56 ℃; DOB was then reduced by formaldehyde to give DHB in aqueous alkaline methanol with yield of 76%, 49% higher than reported, mp 82～83.5 ℃. DHB could be rearranged to 3,3′-dichlorobenzidine in strong acidic medium with yield 91.8%, mp 132～ 134 ℃.
文摘Liquid crystalline of a new carbosilane dendrimer of the second generation(D2) containing thirty-six 4-nitroazobenzene groups in its periphery was characterized by means of polarizing optical micrograph, DSC and WAXD. Mesogenic compound M5 exhibits threaded, schlieren and inversion lines texture of the nematic phase on the cooling from isotropic phase to solidified temperature. Dendrimer D2 shows the focal conic fan-shaped texture of the smectic A phase on the heating course from 69 to 187 ℃ and on the cooling course from 183 to 64 ℃. After cooling, the smectic E(S E) phase with a texture of the focal conic fan-shape with stripes and concentric arcs appears from smectic A(S A) phase. Phase behavior of dendrimer D2 in liquid crystalline state was K69S A187I182S A57S E47K. The isotropic-smectic A transition enthalpy, smectic A-smectic E transition enthalpy and isotropic-smectic A transition entropy were 1.8, 4.5 and 4.0 J/(K·mol), respectively, and were in agreement with or close to those of small molecular liquid crystal.
