TY  - JOUR
A1  - Kar, Haridas
A1  - Gehrig, Dominik W.
A1  - Allampally, Naveen Kumar
A1  - Fernández, Gustavo
A1  - Laquai, Frédéric
A1  - Ghosh, Suhrit
T1  - Cooperative supramolecular polymerization of an amine-substituted naphthalene-diimide and its impact on excited state photophysical properties
JF  - Chemical Science
N2  - A donor-acceptor-donor (D-A-D) type naphthalene-diimide (NDI-H) chromophore exhibits highly cooperative J-aggregation leading to nanotubular self-assembly and gelation in n-decane, as demonstrated by UV/Vis, FT-IR, photoluminescence and microscopy studies. Analysis of temperature-dependent UV/Vis spectra using the nucleation-elongation model and FT-IR data reveals the molecular origin of the cooperative nature of the self-assembly. The supramolecular polymerization is initiated by H-bonding up to a degree of polymerization similar to 20-25, which in a subsequent elongation step promotes J-aggregation in orthogonal direction leading to possibly a sheet-like structure that eventually produces nanotubes. Time-resolved fluorescence and absorption measurements demonstrate that such a tubular assembly enables very effective delocalization of excited states resulting in a remarkably prolonged excited state lifetime.
KW  - nanotube
KW  - supramolecular polymerization
KW  - NDI-H
KW  - UV/Vis spectroscopy
KW  - FT-IR spectroscopy
KW  - transient absorption
KW  - nucleation-elongation model
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-191459
VL  - 7
IS  - 2
ER  - 
TY  - JOUR
A1  - Pratihar, Pampa
A1  - Ghosh, Suhrit
A1  - Stepanenko, Vladimir
A1  - Patwardhan, Sameer
A1  - Grozema, Ferdinand C.
A1  - Siebbeles, Laurens D. A.
A1  - Würthner, Frank
T1  - Self-assembly and semiconductivity of an oligothiophene supergelator
N2  - A bis(trialkoxybenzamide)-functionalized quaterthiophene derivative was synthesized and its self-assembly properties in solution were studied. In non-polar solvents such as cyclohexane, this quaterthiophene π-system formed fibril aggregates with an H-type molecular arrangement due to synergistic effect of hydrogen bonding and π-stacking. The self-assembled fibres were found to gelate numerous organic solvents of diverse polarity. The charge transport ability of such elongated fibres of quaterthiophene π-system was explored by the pulse radiolysis time resolved microwave conductivity (PR-TRMC) technique and moderate mobility values were obtained. Furthermore, initial AFM and UV-vis spectroscopic studies of a mixture of our electron-rich quaterthiophene derivative with the electron acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) revealed a nanoscale segregated assembly of the individual building blocks in the blend.
KW  - Organische Chemie
KW  - charge transport; hydrogen bonding; oligothiophene; organogel; self-assembly
Y1  - 2010
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-67817
ER  -