Functional Single-Wall Carbon Nanotube NanohybridsAssociating SWNTs with Water-Soluble Enzyme Model Systems

Abstract

We succeeded in integrating single-wall carbon nanotubes (SWNTs), several water-soluble pyrene derivatives (pyrene(-)), which bear negatively charged ionic headgroups, and a series of water-soluble metalloporphyrins (MP(8+)) into functional nanohybrids through a combination of associative van der Waals and electrostatic interactions. The resulting SWNT/pyrene(-) and SWNT/pyrene(-)/MP(8+) were characterized by spectroscopic and microscopic means and were found to form stable nanohybrid structures in aqueous media. A crucial feature of our SWNT/pyrene(-) and SWNT/pyrene(-)/MP(8)(+) is that an efficient exfoliation of the initial bundles brings about isolated nanohybrid structures. When the nanohybrid systems are photoexcited with visible light, a rapid intrahybrid charge separation causes the reduction of the electron-accepting SWNT and, simultaneously, the oxidation of the electron-donating MP(8)(+). Transient absorption measurements confirm that the radical ion pairs are long-lived, with lifetimes in the microsecond range. Particularly beneficial are charge recombination dynamics that are located deep in the Marcus-inverted region. We include, for the first time, work devoted to exploring and testing FeP(8)(+) and CoP(8)(+) in donor-acceptor nanohybrids.

Hybrid materials of 1D and 2D carbon allotropes and synthetic π-systems

“…Due to their extended π-surfaces, polyaromatic molecules such as naphthalene, anthracene, pyrene, and perylene have been used extensively to prepare hybrid materials with CNTs [11][12][13][14][68][69][70][71] . Supramolecular systems of these molecules have been exploited in the preparation of hybrid materials with CNTs.…”

Mechanistic Studies on the Activation of NO by Iron and Cobalt Complexes

“…It seems that in acidic medium, water-exchange processes control the rate and mechanism of the nitrosylation reactions of all three diaqua iron(III) porphyrins in which the labilization of the Fe-OH 2 bond is determined by the electron-donating/withdrawing properties of the substituted porphyrin, which in turn depend on the anionic/cationic nature of the substituents, respectively. In order to better understand the influence of the porphyrin microenvironment in iron(III) porphyrin systems on the rate and mechanism of NO binding and release, as well as to establish the relationship between the structure of the prosthetic group and its reactivity toward NO in various hemoproteins in vivo, two new iron(III) porphyrin models, a highly negatively charged {(P [39,40] (see Figure 6). A detailed kinetic and mechanistic description of the reversible binding of NO to these complexes in aqueous solution at low and high pH has been presented recently.…”

“…In addition, depending on the nature of the axial ligands and porphyrin-ring substituents, the spin state of Figure 6. Structures of (a) a highly negatively charged (P 8-)Fe III (L) 2 [40] and (b) a highly positively charged (P 8+ )Fe III (L) 2 [39] iron(III) porphyrin model. the iron(III) in many iron(III) porphyrins can be described as admixed intermediate, in which varying ratios of S = 5/2 and S = 3/2 admixing were noted.…”

Improvement of the mechanical and electrical properties of waste rubber with carbon nanotubes

“…Traditionally, conductive fillers, such as carbon black, chopped carbon fiber, or metallic flakes are used. [1][2][3] Carbon nanotubes (CNTs), as self-assembling nanostructures, have attracted a great deal of attention as model systems for nanoscience and for various potential applications, including composite materials, battery electrode materials, field emitters, nanoelectronics, and nanoscale sensors. The interest in CNTs stems from their unique structure and properties, including their very small size (down to 0.42 nm in diameter); the possibility of CNTs to be metallic or semiconducting, depending on their geometrical structure; their exceptional properties of ballistic transport; their extremely high thermal conductivity and optical polarizability; and the possibilities of high structural perfection.…”