Fluorescence Dynamics of Chlorophyll Trefoils in the Solid State Studied by Single-Molecule Fluorescence Spectroscopy

Abstract

We have comparatively investigated the single-molecule photophysical properties of two chlorophyll trefoils that feature distinctive electronic couplings induced by differences in linkage: one is an ethynyl-linked chlorophyll trefoil (1) in which relatively short and rigid linkage between the chromophores promotes effective electronic coupling, and the other is a phenyl−ethynyl-linked chlorophyll trefoil (2) in which the phenyl addition induces an orthogonal geometry impeding π-conjugation and provides a longer interchlorophyll distance reducing through-space interaction. By recording single-molecule fluorescence intensity trajectories and their corresponding lifetimes, we observed one-step photobleaching behaviors, less frequent on−off behaviors, a narrower fluorescence lifetime distribution, and higher photostability in 1 as compared with 2. These results indicate that the performance of molecular photosynthetic systems in the solid state is strongly associated with electronic couplings and, thus, give insight into the construction of well-functioning artificial photosynthetic systems.

Механизм Зависимости Флуоресцентных Свойств Тетраарилтетрацианопорфиразина И Его Производных От Вязкости

“…Подобные [21][22][23][24][25][26][27][28][29] и их сольватных комплексов [13]. Так, например, для порфиринов с искажением макроцикла по типу седла в толуоле при 273 K отмечалось уменьшение τ F почти в 20 раз [28].…”

Deactivation of Excited States in Nanostructures Containing Cu-Porphyrin Subunit

“…[4][5][6][7][8][9] Correspondingly, a significant interest of numerous scientific groups is devoted to the design and investigation of biomimetic models based on tetrapyrrole compounds that fold or self-assemble predictably in order to form multicomponent well-defined arrays with effective energy transfer and charge separation like in photosynthetic objects in vivo. [10][11][12][13][14][15][16][17][18][19][20][21][22] On the other hand, there are many promising self-organized systems or nanoassemblies (including even organic-inorganic counterparts) which offer exciting opportunities for the engineering and preparation of various man-made molecular nanodevices in the modern fields of molecular electronics (photoinduced molecular switches, photonic wires, solar cells, optoelectronic gates, information storage, etc.) and nanobiophotonics (nanoprobes for biomedical imaging, biosensing and photodynamic therapy of cancer, etc).…”

Ligand Exchange Dynamics and Temperature Effects upon Formation of Nanocomposites Based on Semiconductor CdSе/ZnS Quantum Dots and Porphyrins: Ensemble and Single Object Measurements

“…[10,11] In the organic world, the preparation of supramolecular architectures in which organic compounds present a high degree of order, which spans from the nanoscopic to the macroscopic level across multiple length scales, is highly desirable and represents a key issue within the fast-growing fields of nanoscience and nanotechnology. [12][13][14][15][16][17][18][19][20] In this respect, the interest in emerging organic nanostructures formed via the bottom-up approach (including those based on tetrapyrrolic macrocycles) is growing exponentially since they are not only good models for mimicking the primary photochemical processes in vivo but seem to be considered as promising building blocks for advanced multifunctional nanocomposites with potential applications in improved drug delivery systems, photodynamic therapy, nanovoltaic cells, optoelectronic memory, multimolecular architectures for information storage and highly efficient catalysts. [21][22][23][24][25][26] However, many fundamental issues still need to be in-depth investigated in order to have full understanding of mechanisms that drive the properties of organic nanocomposites.…”