Efficient Functionalization of Carbon Nanotubes with Porphyrin Dendrons via Click Chemistry

Abstract

The attempt to decorate carbon nanotubes with organic molecules as a powerful means to form new functional materials has attracted broad attention in the scientific community. Here, we report the functionalization of single-walled carbon nanotubes (SWNTs) with zinc porphyrins (ZnP) using very mild conditions to afford a series of SWNTs-ZnP (1 and 2) electron donor-acceptor conjugates. Owing to the presence of either one or two ZnP, introduced via "click chemistry", different absorption cross sections were realized. Important in this context is that the covalent linkages between SWNT and ZnP were corroborated by monitoring the diagnostic signature of the nitrogen atoms as part of the formed triazole ring by X-ray photoelectron spectroscopy (XPS). The resulting SWNTs-ZnP 1 and 2 were fully characterized. This characterization was complemented by a full-fledged investigation of their electrochemical and photophysical properties. In particular, appreciably strong electronic coupling between the photo- and electroactive constituents (i.e., SWNT and ZnP) led to rapid excited-state deactivation of ZnP via charge transfer to the nanotubes. Here, the different absorption cross sections throughout the visible part of the solar spectrum turned out to be valuable in enhancing the overall light-harvesting features. Upon photoexcitation, for both SWNTs-ZnP 1 and 2, radical ion pair states (i.e., reduced SWNT and oxidized ZnP) are formed. The charge-separated states decay to regenerate the singlet ground state with lifetimes of 820 and 200 ps for 1 and 2, respectively.

The effect of gold nanoparticles on the impedance of microcapsules visualized by scanning photo-induced impedance microscopy

“…The absence of Cu 2p3/2 emission at ~933 eV indicated that there is no residual copper on the surface. A high-resolution scan of the N 1s region (Figure 4b) was fitted to two peaks at 400.5 eV and 402.2 eV, which were assigned to N-N=N and N-N=N, respectively [27,30] …”

Luminescence of Polyethylene Glycol Coated CdSeTe/ZnS and InP/ZnS Nanoparticles in the Presence of Copper Cations

“…This reaction has therefore been successfully used for the surface functionalization of gold, [11,12] silica, [13] and magnetic nanoparticles, [14,15] as well as carbon nanotubes. [16] The use of click chemistry for quantum dot (QD) functionalization could be very promising for the development of bioconjugates dedicated to in vivo applications. Alkyne-azide ligation usually requires copper(I) catalysis.…”

Supramolecular Approach to Decorate Multi-Walled Carbon Nanotubes with Negatively Charged Iron(II) Complexes

“…1 Decoration of CNTs with coordination compounds can be achieved by covalent bonding using different reactions, leading to functionalization with, e.g., porphyrins, 2,3 phthalocyanines, 4,5 bipyridine, 6 terpyridine, 7,8 and catechol 9 complexes. Chemical modification of CNT surface is frequently performed by fluorination or by strong oxidizing agents, so that polar functional groups can be created to allow dispersion in solvents and subsequent bond formation with anchoring groups.…”

“…[28][29][30] As reported by Rouse,31 poly(4-vinylpyridine) (P4VP) performs well the role of bridge between CNT and solvent and hence is able to disperse them in alcoholic medium. P4VP was used by Vos and co-workers 32 to obtain stable suspensions of SWCNT or multi-walled carbon nanotube (MWCNT) with P4VP-based metallopolymers containing [M(bpy) 2 Cl]Cl, where M is Ru 2+ or Os 2+ and bpy is 2,2'-bipyridine. They show that the electronic and electrochemical properties of redox metallopolymers do not change after addition of CNT, thus letting to CNT the role of improving the mechanical properties of the material.…”