Elucidation of the Adsorption Distribution of Cationic Porphyrin on the Inorganic Surface by Energy Transfer as a Molecular Ruler

Abstract

The adsorption distribution of porphyrin dye on the inorganic surface was examined by the use of Förster resonance energy transfer (FRET). Because the efficiency of FRET depends on the distance between energy donor and acceptor, FRET could be used as a spectroscopic molecular ruler to estimate the adsorption distribution of dyes on the inorganic surface. Saponite and cationic porphyrin were used as an anionic inorganic nanosheet and an adsorbing dye (an energy acceptor) on the clay surface. The edge of saponite was modified by pyrene that is an energy donor, through silane coupling. From the estimation of FRET efficiency, the adsorption distribution of cationic porphyrin is turned out to be biased to the center of the nanosheet surface. The factor to determine such adsorption distribution of cationic porphyrin was discussed based on the electrostatic interactions between anionic nanosheet and cationic porphyrin.

Heuristics from Modeling of Spectral Overlap in Förster Resonance Energy Transfer (FRET)

“…Transfer of excited-state energy from one chromophore to another chromophore constitutes a widespread molecular process. For cases where the distance between the donor chromophore and the acceptor chromophore is sufficiently large that the electronic (i.e., absorption, fluorescence) spectra are essentially unaltered, the energy-transfer process is accurately described as a Förster process. − Förster energy transfer entails the through-space coupling of the transition dipole moments of the respective donor and acceptor. , Förster energy transfer − is rich in scope, − undergirding diverse processes ranging from photosynthetic antenna function to myriad biological assays. Nearly 20 descriptive names have been employed, of which Förster resonance energy transfer (FRET) may be the most popular across the life sciences.…”

Materials Nanoarchitectonics Using 2D Layered Materials: Recent Developments in the Intercalation Process

“…The ordering of exfoliated nanosheets was also investigated via liquid crystal formation and hybridization with hydrogels, as well as using extra‐stimuli, showing unique structures (textures) and functions different to those of intercalation compounds. Combined with the progress made in layered materials syntheses (e.g., size and composition) and characterization techniques, materials design using layered inorganic solids will be more versatile and reliable for the realization of practical systems.…”

Mixed-Metal-Atom Markers Enable Simultaneous Imaging of Spatial Distribution in Two-Dimensional Heterogeneous Molecular Assembly by Scanning Transmission Electron Microscopy

“…Therefore, identifying the relative arrangement of heterogeneous molecules in an assembly is crucial for a detailed understanding of the functions and chemical reactions occurring in the assembly (see the common distribution models in Figure S1 in the Supporting Information). ,, Herein, we demonstrate the first direct observation of a well-mixed spatial molecular distribution of two types of porphyrin complexes with Pt and Pd atom markers on relatively thick monolayer clay mineral nanosheet strongly anchored via multiple electrostatic interactions.…”

“…While dyes generally tend to exhibit a segregation structure on solid surfaces, a uniform spatial distribution was observed owing to the strong host−guest interaction caused by multiple electrostatic interaction. 15,16 In addition, the approximation of the dye structure (Pt-and Pd-TMPyP) might contribute to the realization of a uniform structure.…”

“…A Pt/Pd ratio of approximately 1:1 was observed in every region of the image, for example, 6 × 6 nm 2 , including ∼15 molecules, indicating that the two types of molecules were in a well-mixed distribution without phase separation. While dyes generally tend to exhibit a segregation structure on solid surfaces, a uniform spatial distribution was observed owing to the strong host–guest interaction caused by multiple electrostatic interaction. , In addition, the approximation of the dye structure (Pt- and Pd-TMPyP) might contribute to the realization of a uniform structure.…”