The use of 2,1,3-benzothiadiazole (BTD) as a structural element with advanced electronic properties for DNA hybrids is described. Bis(alkynyl)- and bis(carboxamide)-derived BTD units are shown to support duplex stability through interstrand stacking interactions. Placement of the BTD units opposite to a natural base, however, leads to considerable destabilization. The bis(alkynyl)-derived BTD W is
描述了 2,1,3-苯并噻二唑 (BTD) 作为具有先进电子特性的结构元件用于 DNA 杂交的用途。双(炔基)和双(甲酰胺)衍生的 BTD 单元显示出通过链间堆叠相互作用支持双链稳定性。然而,将 BTD 单元与自然基地相对放置会导致相当大的不稳定。双(炔基)衍生的 BTD W 具有很强的荧光性,并且观察到高达 0.20 的量子产率。其荧光行为强烈依赖于相邻的核碱基。天然碱的猝灭效应以 G >> A ≥ T ≥ C 的顺序降低,并且与通过光诱导电子转移进行的电荷分离 (ΔGCS) 的自由能非常相关,如 Rehm-Weller 方程计算的那样。
A Light-Driven Supramolecular Optical Switch
作者:Shin-nosuke Uno、Chikara Dohno、Holger Bittermann、Vladimir L. Malinovskii、Robert Häner、Kazuhiko Nakatani
DOI:10.1002/anie.200903251
日期:2009.9.21
Switched on: The fluorescence emission of a DNA‐based opticalswitch can be reversibly switched from blue to green using modulating light of different wavelengths (see picture). The device is based on the hybridization of two pyrene‐functionalized DNA strands in the presence of a photochromic azobenzene‐containing effector ligand. Hybridization occurs only with the cis‐configured ligand, and results
a reaction is essential for the development of efficient catalysts that enable direct access to chiral alcohols. We now report on the enantioselective hydration of α,β-unsaturatedketones, catalyzed by modular DNA-based hybrid catalysts, affording β-hydroxy ketones with up to 87% enantiomeric excess. Oligonucleotides containing an intrastrand bipyridine ligand were readily synthesized by a straightforward
Development of donor–acceptor modified DNA hairpins for the investigation of charge hopping kinetics in DNA
作者:Nicole Rahe、Cornelia Rinn、Thomas Carell
DOI:10.1039/b307395e
日期:——
Investigation of hole or excess electron hopping in DNA is mostly performed based on yield studies, in which an injector modified DNA duplex is irradiated to continuously inject either holes or electrons into the duplex. Observed is a chemical reaction of a âprobeâ molecule, which can be either one of the two purine bases or a different trap molecule positioned at various distances. The next step in the field will be the direct time resolution of the hole or electron transfer kinetics in DNA. Herein we describe the development of defined donorâDNAâacceptor systems, with properties that may allow time resolved electron and hole transfer studies in stably folded DNA structures.
We synthesized a three-way branched oligodeoxynucleotide (ODN) 30-mer using a new branch unit with acid-labile DMTr and oxidatively cleavable TrS groups as orthogonal protecting groups. The branched ODN was successfully synthesized using 5-[3,5-bis(trifluoromethyl)phenyl]-1H-tetrazole and (2R,8aS)-(+)-(camphorylsulfonyl)oxaziridine as the activator of phosphoramidite units and the oxidizing reagent,