102020-55-3Relevant academic research and scientific papers
Tweaking a BODIPY Spherical Self-Assembly to 2D Supramolecular Polymers Facilitates Excited-State Cascade Energy Transfer
Das, Gourab,Cherumukkil, Sandeep,Padmakumar, Akhil,Banakar, Vijay B.,Praveen, Vakayil K.,Ajayaghosh, Ayyappanpillai
, p. 7851 - 7859 (2021)
Excited state properties such as emission, exciton transport, electron transfer, etc., are strongly dependent on the shape, size and molecular arrangement of chromophore based supramolecular architectures. Herein, we demonstrate creation and control of distinct supramolecular energy landscapes for the reversible control of the excited-state emission processes through cascade energy transfer in chromophore assemblies, facilitated by an unprecedented solvent effect. In methylcyclohexane, a tailor-made Y-shaped BODIPY derivative self-assembles to form an unusual spherical architecture of 400–1200 nm size, which exhibits a single emission at 540 nm upon 475 nm excitation through a normal excitation deactivation process. However, in n-decane, the same BODIPY derivative forms two-dimensional supramolecular sheets, exhibiting multiple emission peaks at 540, 610, 650, 725 and 790 nm with 475 nm excitation due to cascade energy transfer. Further control on the morphology and excitation energy transfer is possible with variable solvent composition and ultrasound stimulation, resulting in enhanced near-infrared emission with an overall pseudo Stokes shift of 7105 cm?1.
Fluorescent columnar bis(boron difluoride) complexes derived from tetraketonates
Chen, Ya-Wen,Lin, Yen-Chun,Kuo, Hsiu-Ming,Lai, Chung K.
, p. 5465 - 5477 (2017/07/10)
Three new series of bis-(boron difluoride) complexes 1a-c derived from substituted tetraketonates 2a-c are reported, and their mesomorphic and optical properties have been investigated. Two single crystals of mesogenic ligand 2a (n = 6) and nonmesogenic d
Self-assembly of hekates-tris(N -salicylideneaniline)s into columnar structures: Synthesis and characterization
Achalkumar, Ammathnadu S.,Hiremath, Uma S.,Rao, D. S. Shankar,Prasad, S. Krishna,Yelamaggad, Channabasaveshwar V.
, p. 527 - 544 (2013/03/13)
Two series of new, photoluminescent star-shaped discotic liquid crystals, recently termed as "hekates", derived from tris(N-salicylideneaniline) s (TSANs), were synthesized by the facile threefold condensation of 3,4-bis(alkoxy)phenyl 4-aminobenzoates/3,4,5-tris(alkoxy) phenyl 4-aminobenzoates with 1,3,5-triformylphloroglucinol and characterized. These two series of discotics with six and nine peripheral n-alkoxy tails were especially designed and accomplished to understand the relation between mesomorphic/photophysical properties and molecular structure. Proton NMR spectral analysis revealed their existence as an inseparable mixture of two keto-enamine tautomeric forms featuring C3h and Cs rotational symmetries. A systematic study into the thermotropic liquid crystal behavior using polarizing optical microscopy, differential scanning calorimetry, and X-ray scattering confirmed the presence of columnar (Col) phase in vast majority of the TSANs prepared. The two-dimensional (2D) lattices of these fluid columnar phases were found to be characteristic of hexagonal Col (Col h), rectangular Col (Colr), or oblique Col (Col ob) phases depending on the number/length of the peripheral flexible chains. The stabilization of the Colob phase, a less commonly found fluid columnar structure, and the first of its kind in TSAN systems, implies very intensive intermolecular (face-to-face) interactions among the TSAN cores within the column. The photophysical properties were investigated both in solution and the columnar states by UV-vis absorption and photoluminescence; markedly, the solution state emits light in the blue region. The light-emitting ability of the Col phase is particularly significant given the possibility that, in such cores, the protons and electrons interact with each other through the H-bonding environment.
Mesomorphism and luminescence properties of platinum(II) complexes with tris(alkoxy)phenyl-functionalized pyridyl pyrazolate chelates
Liao, Ching-Ting,Chen, Hsiu-Hui,Hsu, Hsiu-Fu,Poloek, Anurach,Yeh, Hsiu-Hsuan,Chi, Yun,Wang, Kang-Wei,Lai, Chin-Hung,Lee, Gene-Hsiang,Shih, Chun-Wei,Chou, Pi-Tai
experimental part, p. 546 - 556 (2011/03/21)
A series of new mesomorphic platinum(II) complexes 1-4 bearing pyridyl pyrazolate chelates are reported herein. In this approach, pyridyl azolate ligands have been strategically functionalized with tris(alkoxy)phenyl groups with various alkyl chain length
Molecular control of macroscopic cubic, columnar, and lamellar organizations in luminescent lanthanide-containing thermotropic liquid crystals
Terazzi, Emmanuel,Torelli, Stephane,Bernardinelli, Gerald,Rivera, Jean-Pierre,Benech, Jean-Marc,Bourgogne, Cyril,Donnio, Bertrand,Guillon, Daniel,Imbert, Daniel,Buenzli, Jean-Claude G.,Pinto, Andre,Jeannerat, Damien,Piguet, Claude
, p. 888 - 903 (2007/10/03)
The connection of lipophilic gallic acid derivatives at the 5,5′- or 6,6′-positions of the rigid 2,6-bis(1-ethyl-benzimidazol-2-yl)pyridine core provides two pro-mesogenic tridentate ligands L10 and L12, whose molecular shapes, anisometries, and directional intermolecular π-stacking can be tuned. X-ray diffraction data in the crystalline state, combined with solution 1H NMR measurements, show that complexation with trivalent lanthanides, Ln(III), produces the neutral hemi-disklike complexes [Ln(Li)(NO3)3] (i = 10, 12), which dimerize to give the rodlike bimetallic complexes [Ln2(Li)2(NO 3)6] at lower temperature. The relevant thermodynamic parameters for the latter process depend on the nature of the ligand, the size of the metal ion, and the strength of the intermolecular interactions involved in the condensed phase. These three-dimensional models obtained for the complexes in the crystals and in solution are eventually confronted with small-angle XRD profiles recorded in the intermediate thermotropic liquid crystalline phase, in which the rigidity of the packed polyaromatic cores is maintained, while the alkyl chains are molten. According to the specific geometries and nuclearities of the molecular complexes, three types of mesophases (lamellar, columnar, and cubic) can be induced, which provides a direct correlation between the microscopic arrangements and the macroscopic ordering in lanthanide-containing metallomesogens.
Depigmenting activity and low cytotoxicity of alkoxy benzoates or alkoxy cinnamte in cultured melanocytes
Kang, Hak Hee,Rho, Ho Sik,Hwang, Jae Sung,Oh, Seong-Geon
, p. 1085 - 1088 (2007/10/03)
To obtain effective and safe topical depigmenting agents, we synthesized hydroxybenzoates, alkoxybenzoates, and 3,4,5-trimethoxycinnamate containing a thymol moiety and screened then for high-level inhibitory activity against melanin synthesis in cultured melanocytes. Eight compounds were tested for their depigmenting effect and cytotoxicity using a murine melanocyte cell line. We found that 3,4,5-trialkoxybenzoates and 3,4,5-trimethoxycinnamate, synthesized by conjugating 3,4,5-trialkoxybenzoic acids and 3,4,5-trimethoxycinnmic acid with thymol, showed a potent depigmenting effect and low cytotoxicity. Compound 4h, 5-methyl-2-(methylethyl)phenyl (2E)-3-(3,4,5-trimethoxyphenyl)prop-2-enoate, showed the most potent depigmenting effect (IC50=10 μM) with low cytotoxicity (IC50=200 μM).
Metallomesogens by ligand design
Date, Richard W.,Iglesias, Eva Fernandez,Rowe, Kathryn E.,Elliott, James M.,Bruce, Duncan W.
, p. 1914 - 1931 (2007/10/03)
In this Perspective, some of the basic principles of ligand design will be described as they apply to the synthesis of metal complexes with liquid crystal properties. Liquid crystal properties of metal complexes are a delicate function of both ligand and metal and examples will be chosen to illustrate this statement. In particular, the effect of the metal complex moiety on the mesomorphism of a series of imine and diimine liquid crystals is described. The Royal Society of Chemistry 2003.
Coassembly of a hexagonal columnar liquid crystalline superlattice from polymer(s) coated with a three-cylindrical bundle supramolecular dendrimer
Percec, Virgil,Ahn, Cheol-H.,Bera, Tushar K.,Ungar, Goran,Yeardley, Duncan J.P.
, p. 1070 - 1083 (2007/10/03)
The synthesis and structural analysis of a polymer containing twin- dendritic benzamide side-groups (i.e. poly{N-[3,4-bis(n-dodecan-1-yloxy)- 5(1-methacryloyl-η-undecan-1-yloxy)phenyl]-3,4,5-tris(n-dodecan-1- yloxy)benzamide}) (19) are described. The disc
The synthesis and mesomorphism of di-, tetra- and hexa-catenar liquid crystals based on 2,2′-bipyridine
Rowe, Kathryn E.,Bruce, Duncan W.
, p. 331 - 341 (2007/10/03)
2,2′-Bipyridines are known to coordinate to a wide variety of metal centres. In this paper, liquid-crystalline two-chained (dicatenar), four-chained (tetracatenar) and six-chained (hexacatenar) bipyridines are synthesised and their mesomorphism is described. For the tetracatenar bipyridines, a full homologous series, from tetramethoxy to tetratetradecyloxy, was synthesised, and the phase diagram showed a classic progression from nematic and smectic C phases at short chain length, through a cubic phase to a columnar phase.
