Complex Pathways Drive Pluripotent Fmoc-Leucine Self-Assemblies.

Nature uses complex self-assembly pathways to access distinct functional non-equilibrium self-assemblies. This remarkable ability to steer same set of biomolecules into different self-assembly states is done by avoiding thermodynamic pit. In synthetic systems, on demand control over 'Pathway Complexity' to access self-assemblies different from equilibrium structures remains challenging.

Stabilization of a Photoradiated Naphthalene Diimide-Based Organic Radical Anion Inside a Peptide-Based Gel Matrix with an Improvement of Optoelectronic Properties.

An amino acid-conjugated naphthalene diimide (NDI)-based highly red fluorescent radical anion has been found in a water medium under the photoradiated condition. This molecule has failed to form the radical anion in the monomeric state; however, the J aggregation in the aqueous medium has ensured the formation of radical anion in the ambient condition after the irradiation of both sunlight and UV light exposure. Electron paramagnetic resonance (EPR) studies clearly suggest the formation of radical anions.

Carbon Dot as Visible-Light Photoredox Catalysts for a Myriad of Organic Transformations.

Metal-free catalysts for various organic transformations are of high demand now. In this study, we present a new carbon dot as an efficient metal-free nanophotocatalyst for carrying out a series of organic bond formation reactions. Using a single photocatalyst carbon dot, Csp-Csp, Csp-B, Csp-S, Csp-Se, and C-P bond formation reactions were performed with a high yield of the corresponding products.

Yellow-Emitting Carbon Dots for Selective Fluorescence Imaging of Lipid Droplets in Living Cells.

This study shows a one-pot preparation of carbon dots by a solvothermal method in ethylene glycol. The carbon dots show yellow-colored fluorescence emission in water. The carbon dots showed distinct preference to be present in the hydrophobic environment which was evident from their efficient transfer from aqueous phase to organic phase.

Solvent-Directed Transformation of the Self-assembly and Optical Property of a Peptide-Appended Core-Substituted Naphthelenediimide and Selective Detection of Nitrite Ions in an Aqueous Medium.

This study vividly displays the different self-assembling behavior and consequent tuning of the fluorescence property of a peptide-appended core-substituted naphthalenediimide (N1) in the aliphatic hydrocarbon solvents (-hexane/-decane/methyl cyclohexane) and in an aqueous medium within micelles. The N1 is highly fluorescent in the monomeric state and self-aggregates in a hydrocarbon solvent, exhibiting "H-type" or "face-to-face" stacking as indicated by a blue shift of absorption maxima in the UV-vis spectrum. In the H-aggregated state, the fluorescence emission of N1 changes to green from the yellow emission obtained in the monomeric state.

Tuning of the optoelectronic properties of peptide-appended core-substituted naphthalenediimides: the role of self-assembly of two positional isomers.

This study demonstrates how the self-assembly pattern of two different and isomeric peptide-appended core-substituted naphthalenediimides (NDIs) affects the modulation of their optoelectronic properties. Two isomeric peptide-attached NDIs were synthesized, purified and characterized. Interchanging the position of attachment of the peptide units and the alkyl chains in the NDI has altered the respective self-assembling patterns of these isomeric molecules in the aggregated states.

The aging effect on the enhancement of thermal stability, mechanical stiffness and fluorescence properties of histidine-appended naphthalenediimide based two-component hydrogels.

A histidine attached naphthalenediimide (NDI)-containing amphiphilic molecule (NDIP) self-assembles into nanotubes in aqueous solution at pH 6.6 as revealed by high-resolution transmission electron microscopy studies. This histidine-appended NDI forms a two-component hydrogel in the presence of tartaric acid at a molar ratio of 1 : 2.

A Self-Assembled Peptide-Appended Naphthalene Diimide: A Fluorescent Switch for Sensing Acid and Base Vapors.

A histidine-containing bola-amphiphilic molecule (NDIP) containing a peptide-appended naphthalenediimide (NDI) forms fluorescent hydrogels in phosphate buffer and organogels with benzenoid solvents. These gels were characterized by several spectroscopic and microscopic techniques including FT-IR, HR-TEM, powder X-ray diffraction and small-angle X-ray scattering, UV-Vis and fluorescence studies. The gelator molecule exhibits no significant fluorescence in the xerogel state, while it shows a significant fluorescence (bright cyan) in the presence of volatile organic/inorganic acid vapors; this cyan color vanishes in presence of base (ammonia vapors).

Assembly of amino acid containing naphthalene diimide-based molecules: the role of intervening amide groups in self-assembly, gelation, optical and semiconducting properties.

Two naphthalene diimide containing molecules, one with a covalently linked peptide (P1) and the other with a covalently attached amino acid residue and a diamine moiety (P2), have been chosen in such a way that the number of intervening amide groups and the centrally located imide moieties are the same, and their molecular formulae are also identical. However, the positions of the amide groups are different in these two molecules and this can dictate a different behaviour in molecular assembly and gelation processes for each of the individual NDI-appended peptide (P1) and pseudo-peptide (P2). The molecule P1 with an attached peptide moiety and the intervening -CO-NH groups forms an organogel in a mixture of chloroform-methylcyclohexane at a very rapid rate and the mechanical strength of the gel is quite high, whereas the molecule P2, containing the amino acid and diamide moieties, and with the intervening -NH-CO groups forms an organogel in a relatively much slower rate in chloroform-methylcyclohexane mixture.

Amino-Acid-Based Metallo-Hydrogel That Acts Like an Esterase.

A histidine-based amphiphile containing a C14 fatty acyl chain, N- histidyl N'-myristry ethyl amine (, 14.7 mM) forms hydrogels in the presence of Fe (within the range 1.47 to 4.

Carbon nanodot-induced gelation of a histidine-based amphiphile: application as a fluorescent ink, and modulation of gel stiffness.

This is a unique example of fluorescent carbon dot-induced hydrogelation of an amino acid-based amphiphile. The carbon dot-to-amphiphile ratio dictates the gel stiffness. Moreover, this hydrogel can be used as a prominent fluorescent ink and the dried gel shows a remarkable, unusual green fluorescence in the solid state.

Amphiphilic Peptide-Based Supramolecular, Noncytotoxic, Stimuli-Responsive Hydrogels with Antibacterial Activity.

A series of peptides with a long fatty acyl chain covalently attached to the C-terminal part and a free amine (-NH) group at the N-terminus have been designed so that these molecules can be assembled in aqueous medium by using various noncovalent interactions. Five different peptide amphiphiles with a general chemical formula [HN-(CH)CONH-Phe-CONHC (n = 1-5, C = dodecylamine)] have been synthesized, characterized, and examined for self-assembly and hydrogelation. All of these molecules [P1 (n = 1), P2 (n = 2), P3 (n = 3), P4 (n = 4), P5 (n = 5)] form thermoresponsive hydrogels in water (pH 6.