Investigations on 1,5‐diaminoanthraquinone by laser excitation

Umadevi, M.; Ramakrishnan, V.

doi:10.1002/jrs.922

Cited by 15 publications

(10 citation statements)

References 39 publications

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“…The assignments of SERS spectra of a-PMMA film dip-coated on Ag substrate are listed in Table 1. [25][26][27] It can be found that the orientation of PMMA chains of a-PMMA film dip-coated on Ag substrate is different from that of the normal PMMA film due to the interfacial interaction between polymer and Ag metal. To get the qualitative information about the molecular orientation, we avoid the disturbance of the band distortions by comparing with the relative intensity of band in the same spectra.…”

Section: Results and Discussion A-pmma Nss Analysismentioning

confidence: 99%

SERS study on surface chain geometry of atactic poly (methyl methacrylate) film and nanosphere

Chen

Zhang

et al. 2013

J Raman Spectroscopy

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The surface chain geometry of atactic poly (methyl methacrylate) (a‐PMMA) film and nanosphere (NS) was revealed by surface‐enhanced Raman scattering (SERS) spectra. The Ag nanoparticles and nanoplates were prepared by electrochemical deposition and chemical synthesis for SERS substrates. The experimental results suggested that the molecular chain axis of a‐PMMA film adopted a trans‐conformation on bonding to Ag surface ascribed to the short‐range chemical (CHEM) effect according to the SERS selection rules. However, for the well‐coated monolayer of a‐PMMA NSs, the α‐CH3 in polymer chains stood vertically to the Ag surface due to the giant local electromagnetic effect, then the chain conformation presented in the interface between a‐PMMA NSs and Ag metal was adopted the opposite orientation compared with a‐PMMA film. The Raman enhancement of the Ag nanoparticles was more prominent than that of the Ag nanoplates due to the free energies of face‐centered cubic crystal faces in nanoparticles, but the single crystals with (111) plane of Ag nanoplates could improve the stability of SERS signals when the annealed temperature was above Tg of a‐PMMA NSs. The present work can provide some useful information of surface chain geometry and conformation of NSs for designing various materials with well‐defined structure via a‐PMMA NSs template. Copyright © 2013 John Wiley & Sons, Ltd.

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Section: Results and Discussion A-pmma Nss Analysismentioning

confidence: 99%

SERS study on surface chain geometry of atactic poly (methyl methacrylate) film and nanosphere

Chen

Zhang

et al. 2013

J Raman Spectroscopy

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“…The shape, position, and intensity of the excitation and emission spectra of the PDAA nanoparticles differ significantly from those of the DAA monomer. [29] In particular, the excitation and emission intensities of the PDAA nanoparticles in NMP, due to fluorescence reinforcement by polyaniline-like p-conjugated chains, are almost six times stronger than those of DAA monomer at the same concentration in NMP. This phenomenon reflects the fact that the molecular structure of PDAA nanoparticles is quite different from that of the DAA monomer.…”

Section: Bulk Electrical Conductivitymentioning

confidence: 99%

Productive Synthesis and Properties of Polydiaminoanthraquinone and Its Pure Self‐Stabilized Nanoparticles with Widely Adjustable Electroconductivity

Huang

2007

Chemistry A European J

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Wholly aromatic poly(1,5-diaminoanthraquinone) (PDAA) particles were productively synthesized for the first time by chemically oxidative polymerization of 1,5-diaminoanthraquinone (DAA) by using CrO3, K2Cr2O7, K2CrO4, or KMnO4 as oxidants in acidic DMF. The effects of the oxidant species, oxidant/DAA ratio, polymerization temperature, and medium on the polymerization yield, macromolecular structure, size, electroconductivity, solubility, solvatochromism, thermostability, photoluminescence, and silver-ion sorption of the PDAA particles were systematically studied by IR, UV/Vis, fluorescence, and solid-state 13C NMR spectroscopies, wide-angle X-ray diffraction, scanning and transmission electron microscopies, and laser particle-size, differential scanning calorimetry (DSC), and thermal gravimetric (TG) analyses. It seems that the DAA is oxidatively polymerized at the 1,4- and 5,8-positions. Surprisingly, the chemical oxidative polymerization of DAA with CrO3 at 0 degrees C in H2SO4/DMF in the absence of external stabilizer simply affords novel PDAA nanoparticles of around 30 nm in diameter with high purity, clean surfaces, inherent semiconductivity, and self-stability that can be ascribed to the presence of a large number of 1,4-benzoquinone units that are negatively charged on their macromolecular chains. The polymers exhibit a high thermal stability at temperatures below 400 degrees C. Two unique nanoeffects were found, namely the strongest silver-ion adsorbability and photoluminescence of the PDAA nanoparticles. This gives a facile and general route for the application of the versatilities of PDAA nanomaterials. The PDAA particles are good semiconductors with a widely adjustable conductivity that moves across seven orders of magnitude through simple HClO4 redoping or Ag+ sorption, as expected.

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“…The observed quantum yield reveals that the intermolecular hydrogen bond does not participate appreciably in the radiationless decay as in the case of anthraquinone derivatives. 15,19 In the case of polar aprotic solvents the observed quantum yield suggests that the dipole-dipole interaction in the excited state participates in the radiationless decay. The lower quantum yield in apolar solvents shows that dipole-induced dipole interaction increases the radiationless decay rate.…”

Section: 3-bis(chloromethyl)-14-naphthoquinone (2)mentioning

confidence: 99%

Spectral investigations on 2‐methyl‐3‐chloromethyl‐1,4‐naphthoquinone and 2,3‐bis(chloromethyl)‐1,4‐naphthoquinone under laser excitation

Umadevi

Vanelle

Terme

et al. 2003

J Raman Spectroscopy

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Solvent effects on 2-methyl-3-chloromethyl-1,4-naphthoquinone and 2,3-bis(chloromethyl)-1,4-naphthoquinone were investigated using optical absorption and fluorescence emission techniques and the orientation of 2-methyl-3-chloromethyl-1,4-naphthoquinone on a silver surface was studied by surfaceenhanced Raman scattering (SERS). The observed spectral shift and the bandwidth of the optical absorption spectrum reveal the changes in dipole moment and the solvent reorganization energy in the excited state. The observed fluorescence quantum yield influences the weak intermolecular hydrogen bond and the dipole-dipole interaction in the excited state. Fluorescence polarization measurements provide the faster rotational relaxation of 2-methyl-3-chloromethyl-1,4-naphthoquinone and 2,3-bis(chloromethyl)-1,4-naphthoquinone in the excited state. SERS studies suggest that the orientation of 2-methyl-3-chloromethyl-1,4-naphthoquinone on a silver surface is stand-on.

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Investigations on 1,5‐diaminoanthraquinone by laser excitation

Cited by 15 publications

References 39 publications

SERS study on surface chain geometry of atactic poly (methyl methacrylate) film and nanosphere

SERS study on surface chain geometry of atactic poly (methyl methacrylate) film and nanosphere

Productive Synthesis and Properties of Polydiaminoanthraquinone and Its Pure Self‐Stabilized Nanoparticles with Widely Adjustable Electroconductivity

Spectral investigations on 2‐methyl‐3‐chloromethyl‐1,4‐naphthoquinone and 2,3‐bis(chloromethyl)‐1,4‐naphthoquinone under laser excitation

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