Molecular structure–thermal behaviour relationship of dimers consisting of different terminal substituents and sulphur–sulphur linking group
摘要:
A new series of dimers 6-(4-oxybenzylidine-4'-substituted-aniline)hexyldisulphides containing various terminal substituents (CH3, C2H5, Cl and Br) have been synthesized. The correlation between the molecular structure and the properties of all the ultimate compounds has been made on the basis of their thermal behaviour. The dimers with CH3 and C2H5 substituents exhibit predominantly the monotropic N phase of which the C2H5-containing derivative possesses more stable nematogenic temperature range in comparison to its methyl-containing analogue. As for the member with Cl substituent, it exhibits enantiotropic N and monotropic smectic A phase. However, the dimer in which the Cl was substituted by Br exhibits purely enantiotropic smectic A phase. Upon cooling all of the final compounds show the transition from isotropic to mesophase prior to the change from mesophase to crystal except the member with Br substituent which displays mosaic B phase even at room temperature. An extensive study to further substantiate the relationship between the stability of the phase and associated transition temperatures due to different terminal substituent is also studied. This study reveals that the terminal Br increases the clearing temperature and polarizability which enhances the formation and stability of SmA and mosaic B phases. (C) 2014 Elsevier B.V. All rights reserved.
Non-symmetric chiral liquid crystal dimers. Preparation and characterisation of the (S)-(benzylidene-4′-substitutedaniline)-2″-methylbutyl-4‴-(4″″-phenyloxy)-benzoateoxy)hexanoates
作者:Guan-Yeow Yeap、Faridah Osman、Corrie T. Imrie
DOI:10.1016/j.molstruc.2016.01.007
日期:2016.5
described. The terminal substituents on the 4-benzylidene-4′-substituted fragment are H, Cl, Br, I, CH 3 and C 2 H 5 . All six dimers exhibit an enantiotropic chiral nematic phase. The relationship between the chiral nematic-isotropic transition temperature and the terminal substituent is discussed in terms of the size of the substituent and its effect of the molecularshape, and its ability to interact
摘要 描述了属于 ( S )-(benzylidene-4'-locatedaniline)-2"-methylbutyl-4‴-(4""-phenyloxy)benzoate-oxy)己酸酯家族的六种手性非对称二聚体的性质。 . 4-亚苄基-4'-取代片段上的末端取代基是H、Cl、Br、I、CH 3 和C 2 H 5 。所有六个二聚体都表现出对映手性向列相。手性向列-各向同性转变温度与末端取代基之间的关系根据取代基的大小及其对分子形状的影响,以及与它所连接的介晶基团相互作用的能力进行了讨论。C 2 H 5 取代的二聚体还显示出对映单层手性近晶C相,其形成归因于更长的烷基链引起的增强的分子不均匀性。
Molecular structure–thermal behaviour relationship of dimers consisting of different terminal substituents and sulphur–sulphur linking group
作者:Guan-Yeow Yeap、Faridah Osman、Wan Ahmad Kamil Mahmood、Daisuke Takeuchi
DOI:10.1016/j.molstruc.2014.03.071
日期:2014.9
A new series of dimers 6-(4-oxybenzylidine-4'-substituted-aniline)hexyldisulphides containing various terminal substituents (CH3, C2H5, Cl and Br) have been synthesized. The correlation between the molecular structure and the properties of all the ultimate compounds has been made on the basis of their thermal behaviour. The dimers with CH3 and C2H5 substituents exhibit predominantly the monotropic N phase of which the C2H5-containing derivative possesses more stable nematogenic temperature range in comparison to its methyl-containing analogue. As for the member with Cl substituent, it exhibits enantiotropic N and monotropic smectic A phase. However, the dimer in which the Cl was substituted by Br exhibits purely enantiotropic smectic A phase. Upon cooling all of the final compounds show the transition from isotropic to mesophase prior to the change from mesophase to crystal except the member with Br substituent which displays mosaic B phase even at room temperature. An extensive study to further substantiate the relationship between the stability of the phase and associated transition temperatures due to different terminal substituent is also studied. This study reveals that the terminal Br increases the clearing temperature and polarizability which enhances the formation and stability of SmA and mosaic B phases. (C) 2014 Elsevier B.V. All rights reserved.
Synthesis, crystal structures, quantum chemical studies and corrosion inhibition potentials of 4-(((4-ethylphenyl)imino)methyl)phenol and (E)-4-((naphthalen-2-ylimino) methyl) phenol Schiff bases
作者:Elias E. Elemike、Henry U. Nwankwo、Damian C. Onwudiwe、Eric C. Hosten
DOI:10.1016/j.molstruc.2017.06.104
日期:2017.11
Schiff base ligands, 4-(((4-ethylphenyl)imino)methyl)phenol (4EMP) and (E)-4-((naphthalen-2-ylimino) methyl) phenol (4NMP) were synthesized by the reaction of 4-hydroxybenzaldehyde with 4-ethylaniline, 4EMP, or naphthalene-2-amine, 4NMP. The compounds were characterized using NMR ( 1 H and 13 C), Fourier transform infra-red (FTIR) and mass spectroscopic techniques. The protonNMR identified the OH peaks