All-or-none switching of photon upconversion in self-assembled organogel systems

2017 ◽  
Vol 196 ◽  
pp. 305-316 ◽  
Author(s):  
Pengfei Duan ◽  
Deepak Asthana ◽  
Takuya Nakashima ◽  
Tsuyoshi Kawai ◽  
Nobuhiro Yanai ◽  
...  
Keyword(s):  
Self Assembly ◽  
Room Temperature ◽  
Stimuli Responsive ◽  
Molecular Systems ◽  
Controlled Assembly ◽  
Outstanding Problem ◽  
Self Assembling ◽  
New Strategy ◽  
Donor Acceptor

Aggregation-induced photon upconversion (iPUC) based on a triplet–triplet annihilation (TTA) process is successfully developed via controlled self-assembly of donor–acceptor pairs in organogel nanoassemblies. Although segregation of donor from acceptor assemblies has been an outstanding problem in TTA-based UC and iPUC, we resolved this issue by modifying both the triplet donor and aggregation induced emission (AIE)-type acceptor with glutamate-based self-assembling moieties. These donors and acceptors co-assemble to form organogels without segregation. Interestingly, these donor–acceptor binary gels show upconversion at room temperature but the upconversion phenomena were lost upon dissolution of the gels on heating. The observed changes in TTA-UC emission were thermally reversible, reflecting the controlled assembly/disassembly of the binary molecular systems. The observed on/off ratio of UC emission was much higher than that of the aggregation-induced fluorescence of the acceptor, which highlights the important role of iPUC, i.e., multi-exciton TTA for photoluminescence switching. This work bridges iPUC and supramolecular chemistry and provides a new strategy for designing stimuli-responsive upconversion systems.

Sticky ends in a self-assembling ABA triblock copolymer: the role of ureas in stimuli-responsive hydrogels

2019 ◽  
Vol 4 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Ryan T. Shafranek ◽  
Joel D. Leger ◽  
Song Zhang ◽  
Munira Khalil ◽  
Xiaodan Gu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Viscoelastic Properties ◽  
Triblock Copolymer ◽  
Thermal Response ◽  
Stimuli Responsive ◽  
Self Assembling ◽  
Polymeric Hydrogels ◽  
Aba Triblock Copolymer ◽  
Responsive Hydrogels

Directed self-assembly in polymeric hydrogels allows tunability of thermal response and viscoelastic properties.

scholarly journals Carbocycle-Based Organogelators: Influence of Chirality and Structural Features on Their Supramolecular Arrangements and Properties

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 54
Author(s):  
Rosa M. Ortuño
Keyword(s):  
Smart Materials ◽  
Self Assembly ◽  
Rational Design ◽  
Structural Features ◽  
Stimuli Responsive ◽  
Polycyclic Compounds ◽  
Relative Configuration ◽  
Responsive Materials ◽  
Self Assembling ◽  
Donor Acceptor

The rational design and engineer of organogel-based smart materials and stimuli-responsive materials with tuned properties requires the control of the non-covalent forces driving the hierarchical self-assembly. Chirality, as well as cis/trans relative configuration, also plays a crucial role promoting the morphology and characteristics of the aggregates. Cycloalkane derivatives can provide chiral chemical platforms allowing the incorporation of functional groups and hydrophobic structural units able for a convenient molecular stacking leading to gels. Restriction of the conformational freedom imposed by the ring strain is also a contributing issue that can be modulated by the inclusion of flexible segments. In addition, donor/acceptor moieties can also be incorporated favoring the interactions with light or with charged species. This review offers a perspective on the abilities and properties of carbocycle-based organogelators starting from simple cycloalkane derivatives, which were the key to establish the basis for an effective self-assembling, to sophisticated polycyclic compounds with manifold properties and applications.

Directive Effect of Chain Length in Modulating Peptide Nano-assemblies

2020 ◽  
Vol 27 (9) ◽  
pp. 923-929
Author(s):  
Gaurav Pandey ◽  
Prem Prakash Das ◽  
Vibin Ramakrishnan
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Light Scattering ◽  
Chain Length ◽  
Self Assembly ◽  
The Self ◽  
Ionic Charge ◽  
Self Assembling ◽  
Biophysical Techniques

Background: RADA-4 (Ac-RADARADARADARADA-NH2) is the most extensively studied and marketed self-assembling peptide, forming hydrogel, used to create defined threedimensional microenvironments for cell culture applications. Objectives: In this work, we use various biophysical techniques to investigate the length dependency of RADA aggregation and assembly. Methods: We synthesized a series of RADA-N peptides, N ranging from 1 to 4, resulting in four peptides having 4, 8, 12, and 16 amino acids in their sequence. Through a combination of various biophysical methods including thioflavin T fluorescence assay, static right angle light scattering assay, Dynamic Light Scattering (DLS), electron microscopy, CD, and IR spectroscopy, we have examined the role of chain-length on the self-assembly of RADA peptide. Results: Our observations show that the aggregation of ionic, charge-complementary RADA motifcontaining peptides is length-dependent, with N less than 3 are not forming spontaneous selfassemblies. Conclusion: The six biophysical experiments discussed in this paper validate the significance of chain-length on the epitaxial growth of RADA peptide self-assembly.

scholarly journals Thermochromic aggregation-induced dual phosphorescence via temperature-dependent sp3-linked donor-acceptor electronic coupling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tao Wang ◽  
Zhubin Hu ◽  
Xiancheng Nie ◽  
Linkun Huang ◽  
Miao Hui ◽  
...  
Keyword(s):  
Excited State ◽  
Room Temperature ◽  
Electronic Coupling ◽  
Temperature Dependent ◽  
Molecular Systems ◽  
Donor And Acceptor ◽  
Theoretical Investigations ◽  
Donor Acceptor ◽  
And Control ◽  
Two Temperature

AbstractAggregation-induced emission (AIE) has proven to be a viable strategy to achieve highly efficient room temperature phosphorescence (RTP) in bulk by restricting molecular motions. Here, we show that by utilizing triphenylamine (TPA) as an electronic donor that connects to an acceptor via an sp3 linker, six TPA-based AIE-active RTP luminophores were obtained. Distinct dual phosphorescence bands emitting from largely localized donor and acceptor triplet emitting states could be recorded at lowered temperatures; at room temperature, only a merged RTP band is present. Theoretical investigations reveal that the two temperature-dependent phosphorescence bands both originate from local/global minima from the lowest triplet excited state (T1). The reported molecular construct serves as an intermediary case between a fully conjugated donor-acceptor system and a donor/acceptor binary mix, which may provide important clues on the design and control of high-freedom molecular systems with complex excited-state dynamics.

scholarly journals Self-assembly induced luminescence of Eu3+-complexes and application in bioimaging

2021 ◽  
Author(s):  
Ping-Ru Su ◽  
Tao Wang ◽  
Pan-Pan Zhou ◽  
Xiao-Xi Yang ◽  
Xiao-Xia Feng ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Rare Earth ◽  
Luminescence Intensity ◽  
Self Assembly ◽  
Room Temperature ◽  
Molecular Motion ◽  
Proof Of Concept ◽  
Room Temperature Phosphorescence ◽  
New Strategy ◽  
Size Controlled

Abstract Design and engineering of highly efficient emitting materials with assembly-induced luminescence, such as room temperature phosphorescence (RTP) and aggregation-induced emission (AIE), have stimulated extensive efforts. Here, we propose a new strategy to obtain size-controlled Eu3+-complex nanoparticles (Eu-NPs) with self-assembly induced luminescence (SAIL) characteristics without encapsulation or hybridization. Compared with previous RTP or AIE materials, the SAIL phenomena of increased luminescence intensity and lifetime in aqueous solution for the proposed Eu-NPs are due to the combined effect of self-assembly in confining the molecular motion and shielding the water quenching. As a proof of concept, we also show that this system can be further applied in bioimaging, temperature measurement and HClO sensing. The SAIL activity of the rare-earth (RE) system proposed here offers a further step forward on the roadmap for the development of RE light conversion systems and their integration in bioimaging and therapy applications.

Synthesis of 6-hydroxy-N-(6-methylpyridin-2-yl) naphthalene-2- carboxamide and its alkoxy analogues

2017 ◽  
Vol 1 (3) ◽  
Author(s):  
Braja G. Bag ◽  
Subrata Ghorai ◽  
Saikat K. Panja ◽  
Shaishab K. Dinda ◽  
Koushik Paul
Keyword(s):  
Self Assembly ◽  
Alkyl Chains ◽  
Replication Studies ◽  
Naphthoic Acid ◽  
New Strategy ◽  
Donor Acceptor ◽  
High Yields ◽  
Self Replication

6-hydroxy-N-(6-methylpyridin-2-yl)naphthalene-2- carboxamide and its alkoxy analogues bearing long alkyl chains have been synthesized using 6-hydroxy-2-naphthoic acid and 2-amino-6-picoline. The facile synthetic scheme reported here using conventional laboratory reagents opens up a new strategy for the generation of libraries of such compounds in high yields. The H-bond donor acceptor groups along with the reactive 2-naphthol moiety present in the target compounds make them useful for their use in self-assembly and self-replication studies.

scholarly journals Thermochromic AIE Dual Phosphorescence via Temperature-Dependent sp3-Linked Donor-Acceptor Electronic Coupling

2020 ◽  
Author(s):  
Tao Wang ◽  
Zhubin Hu ◽  
Xiancheng Nie ◽  
Linkun Huang ◽  
Hui Miao ◽  
...  
Keyword(s):  
Excited State ◽  
Room Temperature ◽  
Electronic Coupling ◽  
Triplet States ◽  
Molecular Motions ◽  
Temperature Dependent ◽  
Molecular Systems ◽  
Donor And Acceptor ◽  
Donor Acceptor ◽  
And Control

<p>Aggregation-induced emission (AIE) has proven to be a viable strategy to achieve highly efficient RTP in bulk by restricting molecular motions. Here we show that by utilizing triphenylamine (TPA) as an electronic donor which connects to an acceptor via an sp3 linker, six TPA-based AIE-active RTP luminophores were obtained. Both the TPA AIE-gen and the <i>sp</i><sup>3</sup>-linkage can suppress aggregation-caused quenching. Consequently, dual phosphorescence bands emitting from localized donor and acceptor triplet states, respectively, could be recorded at lowered temperatures; at room temperature, only a single RTP band corresponding to the lowest triplet state is present, presumably due to thermally assisted electronic coupling between the two states. The reported molecular construct serves as an “intermediary case” between a fully conjugated donor-acceptor system and a do-nor/acceptor binary mix, which may provide important clues on the design and control of molecular systems with complex excited-state dynamics.<br></p>

scholarly journals Multiscale Molecular Modelling of ATP-fueled Supramolecular Polymerisation and Depolymerisation

2020 ◽  
Author(s):  
Claudio Perego ◽  
Luca Pesce ◽  
Riccardo Capelli ◽  
Subi J. George ◽  
Giovanni M. Pavan
Keyword(s):  
Molecular Modelling ◽  
Self Assembly ◽  
Rational Design ◽  
Atp Hydrolysis ◽  
Grand Challenge ◽  
Molecular Systems ◽  
Artificial Materials ◽  
Profound Knowledge ◽  
General Aspects

Fuel-regulated self-assembly is a key principle by which Nature creates spatiotemporally controlled materials and dynamic molecular systems that are in continuous communication (molecular exchange) with the external environment. Designing artificial materials that self-assemble and disassemble via conversion/consumption of a chemical fuel is a grand challenge in supramolecular chemistry, which requires a profound knowledge of the factors governing these complex systems. Here we focus on recently reported metal-coordinated monomers that polymerise in the presence of ATP and depolymerise upon ATP hydrolysis, exploring their fuel-regulated self-assembly/disassembly via multiscale molecular modelling. We use all-atom simulations to assess the role of ATP in stabilising these monomers in assemblies, and we then build on a minimalistic model to investigate their fuel-driven polymerization and depolymerization on a higher scale. In this way, we elucidate general aspects of fuel-regulated self-assembly that are important toward the rational design of new types of bioinspired materials.

scholarly journals Unusual Enthalpy Driven Self Assembly at Room Temperature with Chitosan Amphiphiles

2019 ◽  
Vol 7 (1) ◽  
pp. 57-71 ◽  
Author(s):  
Uchechukwu Odunze ◽  
Fionn O'Brien ◽  
Lisa Godfrey ◽  
Andreas Schätzlein ◽  
Ijeoma Uchegbu
Keyword(s):  
Molecular Weight ◽  
Negative Correlation ◽  
Quaternary Ammonium ◽  
Self Assembly ◽  
Room Temperature ◽  
Isothermal Calorimetry ◽  
Relative Proportion ◽  
Polymer Molecular Weight ◽  
Self Assembling ◽  
Micellar Aggregates

Background: GCPQ (N-palmitoyl-N-monomethyl-N,N-dimethyl-N,N,N-trimethyl- 6-O-glycolchitosan) is a self-assembling polymer being investigated as a pharmaceutical nano-carrier. GCPQ nanoparticles shuttle drugs across biological barriers, improving drug performance. The exact chemistry of GCPQ is varied by the relative proportion of hydrophobic (N-palmitoyl) and hydrophilic (quaternary ammonium) groups and molecular weight. Objective: We hypothesised that the thermodynamics of self-assembly is controlled by the polymer molecular weight and hydrophobicity. Method: The thermodynamics of self-assembly was investigated using isothermal calorimetry. Results: GCPQs (Mw = 8-15 kDa) formed micellar aggregates at critical micellar concentrations of 1-2.4 µM at 25°C and micellisation was unusually enthalpy driven. There was a positive correlation between ΔHmic and mole% quaternary groups (Q): ΔHmic = 3.8 Q- 159 (r2 = 0.93) and a negative correlation between ΔHmic and molecular weight (Mw): ΔHmic = -13.5 Mw-26.3 (r2 = 0.99). Conclusion: These findings provide insights into the positive drivers of stable selfassemblies, namely hydrophobicity and molecular weight, as both hydrophobicity and molecular weight are associated with an increased enthalpy contribution to micellisation.

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