Star‐Shaped Oligothiophenes with Unique Photophysical Properties and Nanostructured Polymorphs

Abstract

A considerable amount of research has been devoted to carbon nanotubes because of their unique electrical, mechanical, optical, and chemical properties. Here, in this report, we introduce a novel, simple ultraviolet initiated “graft from” polymerization method to synthesize PEGylated carbon nanotubes. This grafting procedure significantly enhanced nanotube aqueous dispersibility and long term stability in solution. Mass of grafted polymer chains was easily modulated by adjusting polymerization reaction time, and nanomaterials containing up to 80% polymer by weight were synthesized. Nanotube morphology was characterized by SEM, TEM before and after the functionalization. In addition, the covalent bonding of polymer chains to the nanotubes structure was elucidated by Raman, ATR‐FTIR, and XPS spectroscopy. © 2009 American Institute of Chemical Engineers AIChE J, 2010

Experimental and Theoretical Studies of Quadrupolar Oligothiophene‐Cored Chromophores Containing Dimesitylboryl Moieties as π‐Accepting End‐Groups: Syntheses, Structures, Fluorescence, and One‐ and Two‐Photon Absorption

“…Comparison of the TPA activity of our quadrupolar chromophores with related chromophores built from either BMes 2 8–13 or oligothiophene moieties15–20 reveals further information about structure–TPA relationships. We have collated in Table 5, to the best of our knowledge, available data for the best‐performing related TPA chromophores, including their TPA cross‐sections normalized by molecular weight, σ 2 /MW.…”

“…However, despite numerous studies of the structure–property relationship for TPA response over more than a decade,1 chromophores built from dimesitylboryl π‐accepting moieties are still relatively rare7–14 as are those containing oligothiophene moieties 8. 11, 14–20…”

“…Next, one‐photon absorption (OPA), emission, solvatochromism and TPA are discussed in sequence, aided by TD‐DFT calculations relevant for the ground state conformations and anterior few‐state modeling for the emission properties 21. Finally, the TPA activity of our quadrupolar chromophores is compared to that of related compounds built from either BMes 2 8–13 or oligothiophene moieties,15–20 allowing additional insight into structure‐TPA relationships.…”

Structure‐Dependent Electronic Nature of Star‐Shaped Oligothiophenes, Probed by Ensemble and Single‐Molecule Spectroscopy

“…[22] Samples for single-molecule spectroscopic measurements were prepared by spin-coating (2000 rpm) solutions of the star-shaped oligothiophenes ( 10 À10 m) in toluene (anhydrous, ! [22] Samples for single-molecule spectroscopic measurements were prepared by spin-coating (2000 rpm) solutions of the star-shaped oligothiophenes ( 10 À10 m) in toluene (anhydrous, !…”

Phenyl–Acetylene Bond Assembly: A Powerful Tool for the Construction of Nanoscale Architectures

“…Most syntheses can be classified as either following the principles of convergence or of divergence,41 in which the building blocks are either assembled together before attachment to a central unit (convergent) or assembled directly onto a core substituent (divergent). Narita et al42 employed the use of just such a change in disconnection in their convergent synthesis of star‐shaped oligothiophenes (Scheme ). Under the same coupling conditions – Pd(PPh 3 ) 4 , CuI and NEt 3 – but by changing which building block was the acceptor and which the donor, they were able to obtain their target star‐shaped compounds.…”