The self-assembly behaviour of a library of tetra-amidated porphyrin molecules decorated with a variety of solubilizing wedges is investigated as dilute solutions in methylcyclohexane. Small changes in the solubilising wedge of the porphyrins resulted in different aggregated states, as evidenced by CD and UV/Vis absorption spectroscopy. The porphyrins form co-facially stacked H-aggregates, slip-stacked J-aggregates or a mixture of both. Detailed thermodynamic and kinetic analysis showed that in all cases the formation of J-aggregates proceeds via an isodesmic mechanism whereas H-aggregates are formed via a cooperative mechanism. It is shown that these aggregates assemble in a parallel pathway, in which both compete for the monomer, compared to a sequential pathway, in which one of the aggregates interconverts into the other. Interestingly, kinetic analysis of porphyrins that only form H-aggregates in thermodynamic equilibrium revealed that the competing pathway towards J-aggregates is operational in these systems as well. Our findings show that the balance between H- and J-aggregates depends on remarkably small changes in the architecture of the solubilising wedges.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/chem.201605872 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Competing Hexagonal and Square Lattices on a Spherical Surface.
Nano Lett
January 2025
School of Physics and Key Laboratory of Functional Polymer Materials of Ministry of Education, Nankai University, and Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300071, China.
The structural properties of packed soft-core particles provide a platform to understand the cross-pollinated physical concepts in solid-state and soft-matter physics. Confined on a spherical surface, the traditional differential geometry also dictates the overall defect properties in otherwise regular crystal lattices. Using molecular dynamics simulation of the Hertzian model as a tool, we report here the emergence of new types of disclination patterns: domain and counter-domain defects, when hexagonal and square patterns coexist.
View Article and Find Full Text PDFMagnetic Nanoactuator-Protein Fiber Coated Hydrogel Dressing for Well-Balanced Skin Wound Healing and Tissue Regeneration.
ACS Nano
January 2025
State Key Laboratory of Cardiology and Medical Innovation Center, Shanghai East Hospital, The Institute for Biomedical Engineering & Nano Science, School of Medicine, Tongji University, Shanghai 200092, P. R. China.
Despite significant progress in skin wound healing, it is still a challenge to construct multifunctional bioactive dressings based on a highly aligned protein fiber coated hydrogel matrix for antifibrosis skin wound regeneration that is indistinguishable to native skin. In this study, a "dual-wheel-driven" strategy is adopted to modify the surface of methacrylated gelatin (GelMA) hydrogel with highly aligned magnetic nanocomposites-protein fiber assemblies (MPF) consisting of photothermal responsive antibacteria superparamagnetic nanocomposites-fibrinogen (Fg) complexes as the building blocks. Whole-phase healing properties of the modified hydrogel dressing, GelMA-MPF (GMPF), stem from the integration of Fg protein with RGD peptide activity decorated on the surface of the antibacterial magnetic nanoactuator, facilitating facile and reproducible dressing preparation by self-assembly and involving biochemical, morphological, and biophysical cues.
View Article and Find Full Text PDFProgramming scheduled self-assembly of circadian materials.
Nat Commun
January 2025
Department of Physics and Biophysics, University of San Diego, San Diego, CA, USA.
Active biological molecules present a powerful, yet largely untapped, opportunity to impart autonomous regulation of materials. Because these systems can function robustly to regulate when and where chemical reactions occur, they have the ability to bring complex, life-like behavior to synthetic materials. Here, we achieve this design feat by using functionalized circadian clock proteins, KaiB and KaiC, to engineer time-dependent crosslinking of colloids.
View Article and Find Full Text PDFAn aperiodic chiral tiling by topological molecular self-assembly.
Nat Commun
January 2025
Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.
Studying the self-assembly of chiral molecules in two dimensions offers insights into the fundamentals of crystallization. Using scanning tunneling microscopy, we examine an uncommon aggregation of polyaromatic chiral molecules on a silver surface. Dense packing is achieved through a chiral triangular tiling of triads, with N and N ± 1 molecules at the edges.
View Article and Find Full Text PDFInterfacial mechanisms, environmental influences, and applications of polysaccharide-based emulsions: A review.
Int J Biol Macromol
December 2024
College of Food Science and Technology, Bohai University, Jinzhou 121013, China.
To develop stable polysaccharide-based emulsions, many studies have focused on the interfacial behavior of adsorbed polysaccharides. This review first discussed the mechanism of polysaccharides self-assembly at the oil-water interface. It can be concluded that polysaccharides can form a thick and strong interfacial membrane that stabilizes emulsions through steric hindrance and electrostatic interactions.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!