160061-05-2Relevant academic research and scientific papers
Self-assembly of taper- and wedge-shaped maleimide derivatives: Synthesis and structure-property relationship
Vinayakumara,Kumar, Sandeep,Prasad, S. Krishna,Adhikari, Airody Vasudeva
, p. 765 - 772 (2019)
Herein, we describe design and synthesis of five new amphiphilic systems, viz. 10b-c and 11a-c composed of maleimide at the focal point and alkoxy phenyl ring at the periphery. Their self-assembling behaviour was examined systematically by varying the length of hydrophobic part and aromatic core segment. Evidently, on increasing the aromatic core length, maleimide based amphiphiles relatively emerge as two distinct molecular structures, i.e. wedge- and tapered-shaped. The mesomorphic studies of the two series reveal that, tapered-shaped maleimide derivatives assemble into a smectic A phase with an interesting phasmidic arrangement, whereas the wedge-shaped molecules exclusively form a prospective supramolecular hexagonal columnar mesophase through the intermolecular hydrogen-bonding via maleimide head group. These self-assembled materials could demonstrate high-sensitivity towards various external stimuli.
Supramolecular columnar self-assembly of wedge-shaped rhodanine based dyes: Synthesis and optoelectronic properties
Vinayakumara,Kumar, Sandeep,Adhikari, Airody Vasudeva
, p. 215 - 222 (2018/11/20)
The development of small π-conjugated functional organic molecules capable of forming supramolecular columnar self-assembly, is a rapidly growing area of material research. In this context, the present work describes the design and synthesis of a new seri
Effect of regioisomerism on the self-assembly, photophysical and gelation behavior of aroylhydrazone based polycatenars: Synthesis and characterization
Kanth, Priyanka,Singh, Hemant Kumar,Kumar, Vijay,Singh, Sachin Kumar,Rao, D.S. Shankar,Prasad, S. Krishna,Singh, Bachcha
, (2019/07/02)
In this paper we report five series of aroylhydrazone based polycatenars differing from each other in number and position of alkoxy chains on one end of the core; keeping other end the same. A systematic variation in the structures was carried out to understand the effect of position and chain length on the mesophase behavior. In the case of single alkoxy chain at 4-position, there is a transition from Smectic C to Smectic A mesophase during cooling and Smectic A to Smectic C transition in heating cycle in all the homologues except n = 6 & n = 8. In the case of two alkoxy chains at 3-, 5-positions, the compounds are non-mesogenic in nature. On changing the position of alkoxy chains from 3-, 5-positions to 3-, 4-positions, intermolecular forces weaken and these compounds become liquid crystalline and show columnar rectangular mesophase resulting from the effect of regioisomerism. Moving on to the series with three alkoxy chains, it was observed that 2-, 3-, 4-trialkoxy substituted compounds exhibit columnar rectangular mesophase except lower chain length (n = 6 & 8) while 3-, 4-, 5-trialkoxy substituted aroylhydrazones show columnar rectangular mesophase; except n = 10 which shows columnar oblique mesophase. Thus it was established that on increasing density of alkoxy chains around one terminal, mesophase changes from smectic to columnar mesophase. Temperature dependent Raman studies confirm the presence of intermolecular hydrogen bonding. Further, effect of substitution pattern did not show much influence on the photophysical properties of the mesogenic series in solid and solution state. However, the non-mesogenic series showed a different absorption and emission transition from the mesogenic series in solid and solution state. Solid state fluorescence studies show almost similar emission maxima in all the series. However, it was also noticed that non-mesogenic series show maximum red shifted emission maxima in solid state as compared to that of solution. All the series showed good gelation properties with less than 1% CGC (wt%) suggesting the strong ability of molecules to form gel. These H-bonded liquid-crystalline gels have immense potential for applications in emissive displays.
s-Triazine-Based Functional Discotic Liquid Crystals: Synthesis, Mesomorphism and Photoluminescence
Veerabhadraswamy, B. N.,Dambal, Hashambi K.,Rao, D. S. Shankar,Yelamaggad, C. V.
, p. 2225 - 2237 (2016/08/27)
A new series of C3-symmetric, π-conjugated molecules was designed, synthesized and characterized. The materials were derived from electron-accepting s-triazine, appended covalently to electron-donating styrylbenzene arms, and were readily prepared in excellent yield with high purity by means of three-fold condensation of triphosphonate with n-alkoxybenzaldehydes under Horner–Wadsworth–Emmons reaction conditions. Examination of the phase transitional properties by several complementary techniques evidenced self-assembly into a hexagonal columnar phase, occurring over wide and reasonable thermal ranges. The photophysical properties were studied both in solution and in the fluid/frozen columnar states by UV/Vis absorption and photoluminescence spectroscopy. The emission spectra obtained as a function of the temperature rule out the breaking-up of larger columns and a non-radiative, thermally activated process. A study carried out on thin films of the glassy columnar state, which accounts for conserved fluorescence, defect-free orientation, and freezing ionic species, with the help of atomic force microscopy (AFM) images, suggested a homogeneous granular morphology comprising fibrillar structures. Dissimilarities in the surface morphology and birefringence of thin films of the solid and frozen columnar states were clearly shown by Raman spectroscopy. An electrochemical investigation revealed a LUMO energy of ?4.0 eV. Thus, the discotic motifs presented herein meet certain criteria of organic materials, which are essential for developing electronic devices.
Tuning the thermotropic properties of liquid crystalline p-substituted aroylhydrazones
Singh, Hemant Kumar,Singh, Sachin Kumar,Nandi, Rajib,Singh, Madan Kumar,Kumar, Vijay,Singh, Ranjan K.,Rao, D. S. Shankar,Prasad, S. Krishna,Singh, Bachcha
, p. 44274 - 44281 (2015/06/02)
The synthesis and mesomorphic properties of forty substituted aroylhydrazones with peripheral mono-, di- and tri- alkoxy chains derived from a p-amino aroylhydrazone core are described. The compounds with two side chains exhibited a smectic A phase, while the compounds with six soft alkoxy side chains at symmetrical positions formed a rectangular columnar mesophase. The structures of these mesophases were confirmed by differential scanning calorimetry (DSC) analysis, polarized optical microscopy (POM) and powder X-ray diffraction (XRD) studies. Raman studies with the help of density functional theory on some of the mesogenic members have been performed to understand the changes in the intermolecular interactions during phase transitions. A structure-property relationship has been deduced, and mesogenic properties are found to be dependent on the chain length, density and position of the alkoxy chains around the molecular core.
LIQUID PORPHYRIN DERIVATIVE AND METHOD FOR PRODUCING THE SAME
-
Page/Page column 24, (2010/12/17)
The present invention is to provide a liquid porphyrin derivative at 25 °C and at temperatures from 26 to 40 °C, and a method for producing the same. The liquid porphyrin derivative of the present invention is represented by the following formula (1): whe
Room temperature liquid porphyrins
Maruyama, Sumio,Sato, Kenta,Iwahashi, Hiroyuki
supporting information; experimental part, p. 714 - 716 (2011/01/09)
The syntheses of 5,10,15,20-tetrakis(3,4,5-trialkoxyphenyl)porphyrins, which exhibit fluid state behavior at room temperature, are reported. The thermal and rheological measurements indicate that they behave like liquid at 25 °C (298 K).
Porphyrin derivatives their use in photodynamic therapy and medical devices containing them
-
, (2008/06/13)
There is provided a compound of formula (I), wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, X, Y1, Y2, Y3, Z, M, A-B and C-D have meanings given in the description, which are useful in the treatment of medical conditions for which a photodynamic compound is indicated. Compositions, apparatus and methods of treatment of a medical condition for which a photodynamic compound is indicated are also disclosed.
Electroluminescent liquid crystals
Contoret, Adam,Eastwood, Amanda,Farrar, Simon,Kelly, Stephen M.,Nicholls, Edward,O'Neill, Mary,Richards, Gary,Wu, Catherine
, p. 271 - 278 (2007/10/03)
A new class of liquid crystals for use as transport layers and/or emission layers in organic light-emitting diodes has been prepared. Depending on the nature and number of the terminal substituents enatiotropic nematic, smectic and columnar phases are observed. Chain branching gives rise to materials with a low melting point. Several of these liquid crystals electroluminesce in the visible region. The charge transport properties of some of these materials have been evaluated.
