Polycyclic Aromatic Hydrocarbons in the Nanometer Range

Schlicke, Benedikt; Schlüter, A. Dieter; Hauser, P. J.; Heinze, Jügen

doi:10.1002/anie.199719961

Cited by 31 publications

(25 citation statements)

References 17 publications

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“…[4t, 15] To shine additional light on the optoelectronic and redox properties, we carried out DFT calculations (B3LYP-6-311 + g(2d,p)-Chloroform/B3LYP-6-31G(d,p)) that reveal a set of quasidegenerate HOMO orbitals and a set of quasidegenerate LUMO orbitals in all NRs (Table S3). The near degeneracy increases with increasing lengths (4,8 3f). TD-DFT reveals that the α band of the electronic absorption spectra corresponds in all cases to the transitions between the HOMO-1/HOMO and all the quasidegenerate LUMO orbitals (Table Whereas the ρ band shows a major contribution from the lowest quasidegenerate HOMO (HOMO-4, HOMO-8 and S4).…”

Section: Methodsmentioning

confidence: 97%

Doubling the Length of the Longest Pyrene‐Pyrazinoquinoxaline Molecular Nanoribbons

2022

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Molecular nanoribbons are a class of atomically‐precise nanomaterials for a broad range of applications. An iterative approach that allows doubling the length of the longest pyrene‐pyrazinoquinoxaline molecular nanoribbons is described. The largest nanoribbon obtained through this approach—with a 60 linearly‐fused ring backbone (14.9 nm) and a 324‐atoms core (C276N48)—shows an extremely high molar absorptivity (values up to 1 198 074 M−1 cm−1) that also endows it with a high molar fluorescence brightness (8700 M−1 cm−1).

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Section: Methodsmentioning

confidence: 97%

Doubling the Length of the Longest Pyrene‐Pyrazinoquinoxaline Molecular Nanoribbons

2022

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“…This is a result of the properties of biphenyl and pterphenyl of being n/p doped 96 and reacting with other AHs such as naphthalene. 97,98 In the latter case, the reaction results in two compounds, one having formed additional pentagonal rings 97 and another of the type biphenyl-doped naphthalene. 98 The occurrence of such interactions explains the similarity of SERS spectra (1 and 3) in Fig.…”

Section: Mechanico-chemical Interaction Of Swnts With Different Host mentioning

confidence: 99%

Surface‐enhanced Raman scattering studies on chemically transformed carbon nanotube thin films

Lefrant

Baltog

Baibarac

2005

J Raman Spectroscopy

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We review our experimental data obtained by Raman spectroscopy on single-walled carbon nanotubes (SWNTs) using surface-enhanced Raman scattering (SERS). We focused on the study of the dependence of the SERS spectra of SWNTs on both the rough metallic substrate type and the film thickness. In particular, we show that degradation of the nanotubes, mainly metallic, occurs for very thin films with the formation of graphitic, fullerene-like or amorphous carbon particles. We show also that SWNTs reacting with H 2 SO 4 form a salt of the hydrogensulfate type similar to that resulting from graphite-H 2 SO 4 interaction. SWNTs exhibit a complicated spectroelectrochemical behavior in aqueous and non-aqueous H 2 SO 4 solutions that depends also on the sweep potential range. We demonstrate that the oxidation-reduction processes have a quasi-reversible or irreversible character. Finally, SERS studies on compressed SWNTs in different host matrices, inorganic and organic, reveal nanotube breaking and that tube fragments may react or not with the host matrix used.

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“…Above data suggest that SWNTs compressed in biphenyl and p-terphenyl are covalent and/or ionic functionalized, too. This occurs as a consequence of the biphenyl and p-terphenyl properties to be n/p doped 23 and to react with other AHs such as naphthalene. 23,24 In the latter case, two compounds may result: one having formed additional pentagonal rings 23 and another appearing as a biphenyl-doped naphthalene.…”

Section: Sers Measurements On Compressed Swntsmentioning

confidence: 97%

“…This occurs as a consequence of the biphenyl and p-terphenyl properties to be n/p doped 23 and to react with other AHs such as naphthalene. 23,24 In the latter case, two compounds may result: one having formed additional pentagonal rings 23 and another appearing as a biphenyl-doped naphthalene. 24 The occurrence of such interactions explains the similarity of SERS spectra (1 and 3) from Fig.…”

Section: Sers Measurements On Compressed Swntsmentioning

confidence: 97%

Mechanico-chemical interaction of SWNTs with different host matrices evidenced by SERS spectroscopy

et al. 2005

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Surface enhanced Raman scattering (SERS) with 676.4 and 1064 nm excitations was used to investigate single-walled carbon nanotubes (SWNTs) compressed non-hydrostatically at 0.58 GPa, alone and dispersed into chemical reactive and non-reactive (SiO 2 and Al 2 O 3 ) host matrices. As reactive host matrices, we used inorganic compounds (KI and Ag microparticles) and aromatic hydrocarbons (biphenyl, naphthalene, p-terphenyl, phenantrene). SERS spectra indicate that by compression, SWNTs break in fragments of different size, which in turn can react or not with the host matrix. Various mechanico-chemical reactions take place. In inorganic matrices such as KI and Ag, donor-acceptor complexes are formed. Regardless of aromatic hydrocarbons type used as organic matrices, i.e. with isolated or condensed phenyl rings, a non-covalent functionalization of SWNTs is produced. Using aromatic hydrocarbons with isolated phenyl rings like biphenyl or p-terphenyl, an ionic and covalent functionalization of SWNT fragments is demonstrated by the appearance of new Raman bands at 1160 and 1458 cm -1 , the latter being associated with the Ag(2) pentagonal pinch mode observed regularly in Raman spectra of C 60 fullerenes. The signature for the appearance of short fragments of carbon nanotubes, behaving as closed-shell fullerenes, is observed also in photoluminescence spectra carried out on SWNTs compressed in biphenyl and p-terphenyl matrix. Additional proofs are found by transmission electron microscopy (TEM) investigations.

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Polycyclic Aromatic Hydrocarbons in the Nanometer Range

Cited by 31 publications

References 17 publications

Doubling the Length of the Longest Pyrene‐Pyrazinoquinoxaline Molecular Nanoribbons

Doubling the Length of the Longest Pyrene‐Pyrazinoquinoxaline Molecular Nanoribbons

Surface‐enhanced Raman scattering studies on chemically transformed carbon nanotube thin films

Mechanico-chemical interaction of SWNTs with different host matrices evidenced by SERS spectroscopy

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