title: Bionano donor-acceptor hybrids of porphyrin, ssDNA, and semiconductive single-wall carbon nanotubes for electron transfer via porphyrin excitation.
abstract: Photoinduced electron transfer in self-assemblies of porphyrins ion-paired with ssDNA wrapped around single-wall carbon nanotubes (SWCNTs) has been reported. To accomplish the three-component hybrids, two kinds of diameter-sorted semiconducting SWCNT(n,m)s of different diameter ((n,m) = (6,5) and (7,6)) and free-base or zinc porphyrin bearing peripheral positive charges ((TMPyP(+))M (tetrakis(4-N-methylpyridyl)porphyrin); M = Zn and H(2)) serving as light-absorbing photoactive materials are utilized. The donor-acceptor hybrids are held by ion-pairing between the negatively charged phosphate groups of ssDNA on the surface of the SWCNT and the positively charged at the ring periphery porphyrin macrocycle. The newly assembled bionano donor-acceptor hybrids have been characterized by transmission electron microscopy (TEM) and spectroscopic methods. Photoinduced electron transfer from the excited singlet porphyrin to the SWCNTs directly and/or via ssDNA as an electron mediator has been established by performing systematic studies involving the steady-state and time-resolved emission as well as the transient absorption studies. Higher charge-separation efficiency has been successfully demonstrated by the selection of the appropriate semiconductive SWCNTs with the right band gap, in addition to the aid of ssDNA as the electron mediator.
authors.affiliation: Contribution from the Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, USA. francis.dsouza@unt.edu
authors.forename: Francis
authors.initials: F
authors.lastname: D'Souza
authors.forename: Sushanta K
authors.initials: SK
authors.lastname: Das
authors.forename: Melvin E
authors.initials: ME
authors.lastname: Zandler
authors.forename: Atula S D
authors.initials: AS
authors.lastname: Sandanayaka
authors.forename: Osamu
authors.initials: O
authors.lastname: Ito
mesh_terms: D004247:DNA / Q000737:chemistry*; D004579:Electron Transport; D008665:Metalloporphyrins / Q000737:chemistry; D008958:Models, Molecular; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D011166:Porphyrins / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D008665:Metalloporphyrins; D037742:Nanotubes, Carbon; D011166:Porphyrins; C017802:zinc hematoporphyrin; C021096:tetra(4-N-methylpyridyl)porphine; D004247:DNA