Nonlinear Optics of Organic Molecules and Polymers

Nalwa, Hari Singh

doi:10.1117/1.601490

Cited by 852 publications

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“…Thus, the functionalized PPy described here can be a good option to specifically conjugate NGF under relatively simple and mild conditions. One obstacle is that pyrrole derivatives, particularly N-substituted pyrrole derivatives, hinder the structural planarity of p-electron conjugation in PPy, which results in a severe decrease in conductivity (Nalwa 1997;Skotheim et al 1998;Lee et al 2006;Guimard et al 2007). This drastic drop in conductivity of pyrrole derivatives can be mitigated to some extent by synthesizing copolymers of pristine pyrrole and pyrrole derivatives that exhibit a reasonable conductivity and significant reactive functional groups (i.e.…”

Section: Discussionmentioning

confidence: 99%

Neuroactive conducting scaffolds: nerve growth factor conjugation on active ester-functionalized polypyrrole

Lee

Schmidt

2008

J. R. Soc. Interface.

101

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Electrically conductive and biologically active scaffolds are desirable for enhancing adhesion, proliferation and differentiation of a number of cell types such as neurons. Hence, the incorporation of neuroactive molecules into electroconductive polymers via a specific and stable method is essential for neuronal tissue engineering applications. Traditional conjugation approaches dramatically impair conductivities and/or stabilities of the scaffolds and ligands. In this study, we developed copolymers (PPy-NSE) of N-hydroxyl succinimidyl ester pyrrole and regular pyrrole, which can be immobilized with nerve growth factor (NGF) without significantly hindering electroconductivity. The presence of active ester groups was confirmed using reflectance infrared spectroscopy and X-ray photoelectron spectroscopy (XPS) from the copolymers prepared from different monomer compositions. We selected PPy-NSE 50 (polymerized from a 50 : 50 monomer ratio of pyrrole : pyrrole-NSE) for further modification with NGF because this copolymer retains good conductivity (approx. 8 S cm K1 ) and presents active ester groups for NGF immobilization. We tethered NGF on the PPy-NSE 50 surface, and found that PC12 cells extended neurites similarly to cells cultured in NGF-containing medium. XPS and enzyme-linked immunosorbent assay confirmed that NGF immobilized via the active ester on the PPy-NSE 50 film was stable for up to 5 days in phosphate-buffered saline solution. Also, application of an external electrical potential to NGF-immobilized PPy films did not cause a significant release of NGF nor reduce their neurotrophic activity. This novel scaffold, providing electroconductive and neurotrophic activities, has potential for neural applications, such as tissue engineering scaffolds and biosensors.

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Section: Discussionmentioning

confidence: 99%

Neuroactive conducting scaffolds: nerve growth factor conjugation on active ester-functionalized polypyrrole

Lee

Schmidt

2008

J. R. Soc. Interface.

101

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“…The solid was dissolved in a small amount of CHCl 3 and reprecipitated from a large amount of MeOH three times to obtain polymer P1 in the form of the brown powder (73.3 mg, 0.16 mmol, 16%). Target polymers P1-P4 were synthesized by polymerization of 4 and comonomers M1-M4 by the modified Suzuki-Miyaura coupling reaction [68][69][70] in the presence of a catalytic amount of Pd(OAc) 2 and a bulky phosphine ligand, 2-dicyclohexylphosphino-2¢,6¢-dimethoxybiphenyl (S-Phos), with K 3 PO 4 in THF/H 2 O at reflux temperature for 48 h, as shown in Scheme 2. Cyclic oligomers 63,64 were not detected under this reaction condition because of the steric hindrance of pinacolborane moieties.…”

Section: Oxidative Coupling Polymerizationmentioning

confidence: 99%

“…Such conjugated polymers have attracted considerable attention because of their good processability and their readily tunable electronic and optical properties. [1][2][3] Recently, a new type of conjugated polymer that exhibits through-space interactions of pelectron systems has been developed. Poly(dibenzofulvene)s, 4-11 7,7-diarylnorbornane-containing conjugated polymers, 12,13 cyclophanecontaining polymers and face-to-face ferrocene polymers [36][37][38] have been synthesized, and their optical and electrochemical properties have been studied in detail.…”

Section: Introductionmentioning

confidence: 99%

Naphthalene-based oligothiophene-stacked polymers

Morisaki

Fernandes

Chujo

2010

Polym J

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We report the synthesis and properties of p-stacked polymers consisting of oligothiophene and naphthalene as the stacked p-system and the scaffold, respectively. The titled polymers were obtained by the Suzuki-Miyaura coupling reaction. Oligothiophene units were layered in proximity, B3.0 Å from each other. Contribution of the quinoidal structure of the oligothiophene units involving the naphthalene scaffolds in the excited state resulted in relatively high photoluminescence quantum efficiencies. The polymers have potential application to optoelectronic devices such as hole-transporting materials. Polymer Journal (2010) 42, 928-934; doi:10.1038/pj.2010.101; published online 27 October 2010Keywords: conjugated polymers; p-stacked polymers; oligothiophene; redox polymers; synthesis INTRODUCTIONCommon conjugated polymers generally consist of sp-and/or sp 2 -carbon frameworks, and p-electrons are delocalized throughout the polymer backbone. Such conjugated polymers have attracted considerable attention because of their good processability and their readily tunable electronic and optical properties. [1][2][3] Recently, a new type of conjugated polymer that exhibits through-space interactions of pelectron systems has been developed. Poly(dibenzofulvene)s, 4-11 7,7-diarylnorbornane-containing conjugated polymers, 12,13 cyclophanecontaining polymers and face-to-face ferrocene polymers [36][37][38] have been synthesized, and their optical and electrochemical properties have been studied in detail. Polymers with layered aromatic rings and p-electron systems have also been investigated; 39-53 for example, Chen et al. 53 recently reported the synthesis and formation of a twodimensional assembly of polymeric ladder phanes containing face-toface p-electron systems. These polymers have potential applications in optoelectronic devices and single-molecular devices such as singlemolecular wires.Cofacially aligned p-electron systems have an important role in biochemistry and material chemistry; DNA has face-to-face base pairs stacked in the double-stranded main chains, 54 and the performance of organic optoelectronic devices strongly depends on the arrangement of the p-electron systems. 55 We have recently reported the synthesis of aromatic-ring-layered polymers using xanthene compounds as scaffolds. [40][41][42][43][44][45][46][47] [2.2] Paracyclophane-layered polymers, which mimic multilayered cyclophanes, 56-59 exhibited fluorescence resonance energy transfer from the layered paracyclophanes to the end-capping groups. The use of xanthene as a scaffold enabled us to introduce various aromatic compounds, such as phenylenes, 44 carbazoles, 45 thiophenes 46 and anthracene, 47 into the polymers, with the distance between the layered aromatic units being B4.5 Å . Our next target is to construct layered and p-stacked aromatic systems in proximity, less than the sum of the van der Waals radius (3.40 Å ) of an sp 2 -carbon, in the polymer backbone.

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“…However, there have also been many investigations 47,48 into the science and development of organic nonlinear optical crystals and polymers due to their versatility and easy processability. Grote et al 24 succeeded in preparing a DNA-CTMA thin film (5 mm thick) containing 10% of the DR1 chromophore on an indium tin oxide-coated glass.…”

Section: Dna-based Nonlinear Optical Compositionsmentioning

confidence: 99%

Optical, electro-optic and optoelectronic properties of natural and chemically modified DNAs

Kwon

Choi

Jin

2012

Polym J

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This article reviews recent findings on the optical, electro-optic and optoelectronic properties of natural and modified DNAs. When the sodium (Na þ ) ions of DNA are replaced with long alkyl quaternary ammonium (Q þ ) ions, the resulting compositions (Q þ DNA À ) are organic-soluble, and thin films produced using these materials reveal many interesting optical and optoelectronic properties. These films tend to form well-structured supramolecular assemblies. In contrast, natural DNAs are water-soluble and hygroscopic. DNAs are strong absorbers of UV wavelengths in the region of 260 nm. The Q þ DNA À films are excellent dielectrics that can be utilized as insulating layers in organic thin film transistors. Chemical modification of the Q þ parts results in many interesting structures that can be used in a wide variety of optical and optoelectronic devices. This review specifically deals with the optical and fluorescence properties of, organic lasing composites, the nonlinear optical characteristics of, light-emitting diodes, and photovoltaic cells based on natural and modified DNAs.

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Nonlinear Optics of Organic Molecules and Polymers

Cited by 852 publications

References 0 publications

Neuroactive conducting scaffolds: nerve growth factor conjugation on active ester-functionalized polypyrrole

Neuroactive conducting scaffolds: nerve growth factor conjugation on active ester-functionalized polypyrrole

Naphthalene-based oligothiophene-stacked polymers

Optical, electro-optic and optoelectronic properties of natural and chemically modified DNAs

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