Solvophobic control of core-substituted naphthalene diimide nanostructures
作者:Sheshanath V. Bhosale、Chintan Jani、Cecilia H. Lalander、Steven J. Langford
DOI:10.1039/b920015k
日期:——
The requirements for the self-assembly of 2,3-annulated core-substituted NDIs into discrete worm-like nanostructures are explored in MeOH-CHCl(3) solutions. AFM was used to visualize and characterize the structures formed at precise proportions of solvent mixes.
Ultrafast excited-state dynamics of strongly coupled porphyrin/core-substituted-naphthalenediimide dyads
作者:Natalie Banerji、Sheshanath V. Bhosale、Irina Petkova、Steven J. Langford、Eric Vauthey
DOI:10.1039/c0cp01544j
日期:——
The photophysics and excited-state dynamics of two dyads consisting of either a free-base or a zinc-tetraphenylporphyrin linked through a rigid bridge to a core-substituted naphthalenediimide (NDI) have been investigated by femtosecond-resolved spectroscopy. The absorption and fluorescence spectra differ substantially from those of the individual units, pointing to a substantial coupling and to a delocalisation of the excitation over the whole molecule, as confirmed by quantum chemistry calculations. A strong dependence of their excited-state dynamics on the solvent polarity has been observed. In toluene, the fluorescence quantum yield of the dyads is of the order of a few percent and the main decay channel of the emitting state is proposed as intersystem-crossing to the triplet state. However, in a medium polarity solvent like dichloromethane, the emitting state undergoes charge separation from the porphyrin to the NDI unit within 1–3 ps, and the ensuing charge-separated state recombines in about 10–20 ps. This solvent dependence can be explained by the weak driving force for charge separation in polar solvents and the large electronic coupling between the porphyrin and NDI moieties, making charge separation a solvent-controlled adiabatic process.
飞秒分辨光谱学研究了由自由碱或锌-四苯基卟啉通过刚性桥与核心取代的萘二亚胺(NDI)连接而成的两个二元体的光物理和激发态动力学。吸收光谱和荧光光谱与单个单元的光谱有很大不同,这表明整个分子中存在大量的耦合和激发扩散,量子化学计算也证实了这一点。据观察,它们的激发态动力学与溶剂的极性有很大关系。在甲苯中,二元化合物的荧光量子产率仅为百分之几,而发射态的主要衰变通道被认为是向三重态的系统间交叉。然而,在二氯甲烷等中等极性溶剂中,发射态会在 1-3 ps 内发生从卟啉到 NDI 单元的电荷分离,随后的电荷分离态会在大约 10-20 ps 内重新结合。这种溶剂依赖性可解释为极性溶剂中电荷分离的驱动力较弱,以及卟啉和 NDI 分子之间的电子耦合较大,使得电荷分离成为一个溶剂控制的绝热过程。
A Core-Substituted Naphthalene Diimide Fluoride Sensor
作者:Sheshanath V. Bhosale、Sidhanath V. Bhosale、Mohan B. Kalyankar、Steven J. Langford
DOI:10.1021/ol9022722
日期:2009.12.3
characterization of a highly fluorescent core-substitutednaphthalenediimidesensor (ϕ = 0.34) bearing a bis-sulfonamide group is described. The compound shows a unique selectivity and reactivity for the fluoride ion over other anions in CHCl3 by a two-stage deprotonation process leading to a colorimetric response. In DMSO solution, the sensor is shown to be highly selective for fluoride (Ka ∼ 106 M−1) over other
Synthesis and Photophysics of a Red-Light Absorbing Supramolecular Chromophore System
作者:Jeroen A. Rombouts、Janneke Ravensbergen、Raoul N. Frese、John T. M. Kennis、Andreas W. Ehlers、J. Chris Slootweg、Eelco Ruijter、Koop Lammertsma、Romano V. A. Orru
DOI:10.1002/chem.201402398
日期:2014.8.11
In search of supramolecular antenna systems for light‐harvesting applications, we report on a short and effective synthesis of a fused NDI–zinc–salphen‐based chromophore (salphen = bis‐salicylimide phenylene) and its photophysical properties. A supramolecular recognition motif is embedded into the chromophoric π‐system of this compound. The fused π‐chromophore behaves as one pigment, absorbs light
A Hybrid Solid-State NMR and Electron Microscopy Structure-Determination Protocol for Engineering Advanced<i>para</i>-Crystalline Optical Materials
作者:Brijith Thomas、Jeroen Rombouts、Gert T. Oostergetel、Karthick B. S. S. Gupta、Francesco Buda、Koop Lammertsma、Romano Orru、Huub J. M. de Groot
DOI:10.1002/chem.201700324
日期:2017.3.8
Starting from chiral building blocks with C2 molecular symmetry, the asymmetric unit was determined by MAS NMR spectroscopy, index low-resolution TEM diffraction data, and resolve reflection conditions, and for the first time the ability to determine the space group from reciprocal space data using this hybrid approach was shown. Transfer of molecular C2 symmetry into P2/c packing symmetry provided