Self-Assembly of Organocatalysts: Fine-Tuning Organocatalytic Reactions.

ChemInform ◽  
2007 ◽  
Vol 38 (18) ◽  
Author(s):  
Matthew L. Clarke ◽  
Jose A. Fuentes
Keyword(s):  
Self Assembly ◽  
Fine Tuning ◽  
Organocatalytic Reactions

Self-Assembly of Organocatalysts: Fine-Tuning Organocatalytic Reactions

2007 ◽  
Vol 119 (6) ◽  
pp. 948-951 ◽  
Author(s):  
Matthew L. Clarke ◽  
José A. Fuentes
Keyword(s):  
Self Assembly ◽  
Fine Tuning ◽  
Organocatalytic Reactions

Investigation of Au SAMs Photoclick Derivatization by PM-IRRAS

2019 ◽  
Author(s):  
Mark Workentin ◽  
François Lagugné-Labarthet ◽  
Sidney Legge
Keyword(s):  
Cell Adhesion ◽  
Self Assembly ◽  
Materials Science ◽  
Fibroblast Cell ◽  
Fine Tuning ◽  
Chemical System ◽  
Infrared Reflection ◽  
Assembled Monolayers ◽  
One Step ◽  
High Degree

In this work we present a clean one-step process for modifying headgroups of self-assembled monolayers (SAMs) on gold using photo-enabled click chemistry. A thiolated, cyclopropenone-caged strained alkyne precursor was first functionalized onto a flat gold substrate through self-assembly. Exposure of the cyclopropenone SAM to UV-A light initiated the efficient photochemical decarbonylation of the cyclopropenone moiety, revealing the strained alkyne capable of undergoing the interfacial strain-promoted alkyne-azide cycloaddition (SPAAC). Irradiated SAMs were derivatized with a series of model azides with varied hydrophobicity to demonstrate the generality of this chemical system for the modification and fine-tuning of the surface chemistry on gold substrates. SAMs were characterized at each step with polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) to confirm successful functionalization and reactivity. Furthermore, to showcase the compatibility of this approach with biochemical applications, cyclopropenone SAMs were irradiated and modified with azide-bearing cell adhesion peptides to promote human fibroblast cell adhesion, then imaged by live cell fluorescence microscopy. Thus, the “photoclick” methodology reported here represents an improved, versatile, catalyst-free protocol that allows for a high degree of control over the modification of material surfaces, with applicability in materials science as well as biochemistry.<br>

scholarly journals Kinetic Constraints in the Specific Interaction between Phosphorylated Ubiquitin and Proteasomal Shuttle Factors

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1008
Author(s):  
Ling-Yun Qin ◽  
Zhou Gong ◽  
Kan Liu ◽  
Xu Dong ◽  
Chun Tang
Keyword(s):  
Exchange Rate ◽  
Self Assembly ◽  
Solution Structure ◽  
Specific Interaction ◽  
Dissociation Rate ◽  
Fine Tuning ◽  
Binding Mechanism ◽  
Kinetics Analysis ◽  
Kinetic Constraint ◽  
Thermodynamic Basis

Ubiquitin (Ub) specifically interacts with the Ub-associating domain (UBA) in a proteasomal shuttle factor, while the latter is involved in either proteasomal targeting or self-assembly coacervation. PINK1 phosphorylates Ub at S65 and makes Ub alternate between C-terminally relaxed (pUbRL) and retracted conformations (pUbRT). Using NMR spectroscopy, we show that pUbRL but not pUbRT preferentially interacts with the UBA from two proteasomal shuttle factors Ubqln2 and Rad23A. Yet discriminatorily, Ubqln2-UBA binds to pUb more tightly than Rad23A does and selectively enriches pUbRL upon complex formation. Further, we determine the solution structure of the complex between Ubqln2-UBA and pUbRL and uncover the thermodynamic basis for the stronger interaction. NMR kinetics analysis at different timescales further suggests an indued-fit binding mechanism for pUb-UBA interaction. Notably, at a relatively low saturation level, the dissociation rate of the UBA-pUbRL complex is comparable with the exchange rate between pUbRL and pUbRT. Thus, a kinetic constraint would dictate the interaction between Ub and UBA, thus fine-tuning the functional state of the proteasomal shuttle factors.

Self-assembly of gold nanowire networks into gold foams: production, ultrastructure and applications

2017 ◽  
Vol 4 (6) ◽  
pp. 1033-1041 ◽  
Author(s):  
A. Jakhmola ◽  
M. Celentano ◽  
R. Vecchione ◽  
A. Manikas ◽  
E. Battista ◽  
...  
Keyword(s):  
Nanostructured Materials ◽  
Self Assembly ◽  
Fine Tuning ◽  
Gold Nanowire ◽  
Green Nanotechnology ◽  
Nanowire Networks

Fine-tuning the shape of nanostructured materials through easy and sustainable methods is a challenging task for green nanotechnology.

From supramolecular chemistry to nanotechnology: Assembly of 3D nanostructures

2009 ◽  
Vol 81 (12) ◽  
pp. 2225-2233 ◽  
Author(s):  
Xing Yi Ling ◽  
David N. Reinhoudt ◽  
Jurriaan Huskens
Keyword(s):  
Supramolecular Chemistry ◽  
Self Assembly ◽  
Supramolecular Assembly ◽  
Fine Tuning ◽  
Nanoparticle Assembly ◽  
Layer By Layer ◽  
Surface Binding ◽  
Free Standing ◽  
Functionalized Nanoparticles ◽  
Assembled Monolayers

Fabricating well-defined and stable nanoparticle crystals in a controlled fashion receives growing attention in nanotechnology. The order and packing symmetry within a nanoparticle crystal is of utmost importance for the development of materials with unique optical and electronic properties. To generate stable and ordered 3D nanoparticle structures, nanotechnology is combined with supramolecular chemistry to control the self-assembly of 2D and 3D receptor-functionalized nanoparticles. This review focuses on the use of molecular recognition chemistry to establish stable, ordered, and functional nanoparticle structures. The host–guest complexation of β-cyclodextrin (CD) and its guest molecules (e.g., adamantane and ferrocene) are applied to assist the nanoparticle assembly. Direct adsorption of supramolecular guest- and host-functionalized nanoparticles onto (patterned) CD self-assembled monolayers (SAMs) occurs via multivalent host–guest interactions and layer-by-layer (LbL) assembly. The reversibility and fine-tuning of the nanoparticle-surface binding strength in this supramolecular assembly scheme are the control parameters in the process. Furthermore, the supramolecular nanoparticle assembly has been integrated with top-down nanofabrication schemes to generate stable and ordered 3D nanoparticle structures, with controlled geometries and sizes, on surfaces, other interfaces, and as free-standing structures.

scholarly journals Synthesis and Applications of Porphyrin-Biomacromolecule Conjugates

2021 ◽  
Vol 9 ◽  
Author(s):  
Pravin Pathak ◽  
Mohammad Amin Zarandi ◽  
Xiao Zhou ◽  
Janarthanan Jayawickramarajah
Keyword(s):  
Nucleic Acid ◽  
Functional Groups ◽  
Self Assembly ◽  
De Novo ◽  
Solid Phase ◽  
Academic Research ◽  
Fine Tuning ◽  
Cancer Tissue ◽  
Site Specific ◽  
Synthetic Approaches

With potential applications in materials and especially in light-responsive biomedicine that targets cancer tissue selectively, much research has focused on developing covalent conjugation techniques to tether porphyrinoid units to various biomacromolecules. This review details the key synthetic approaches that have been employed in the recent decades to conjugate porphyrinoids with oligonucleotides and peptides/proteins. In addition, we provide succinct discussions on the subsequent applications of such hybrid systems and also give a brief overview of the rapidly progressing field of porphyrin-antibody conjugates. Since nucleic acid and peptide systems vary in structure, connectivity, functional group availability and placement, as well as stability and solubility, tailored synthetic approaches are needed for conjugating to each of these biomacromolecule types. In terms of tethering to ONs, porphyrins are typically attached by employing bioorthogonal chemistry (e.g., using phosphoramidites) that drive solid-phase ON synthesis or by conducting post-synthesis modifications and subsequent reactions (such as amide couplings, hydrazide-carbonyl reactions, and click chemistry). In contrast, peptides and proteins are typically conjugated to porphyrinoids using their native functional groups, especially the thiol and amine side chains. However, bioorthogonal reactions (e.g., Staudinger ligations, and copper or strain promoted alkyne-azide cycloadditions) that utilize de novo introduced functional groups onto peptides/proteins have seen vigorous development, especially for site-specific peptide-porphyrin tethering. While the ON-porphyrin conjugates have largely been explored for programmed nanostructure self-assembly and artificial light-harvesting applications, there are some reports of ON-porphyrin systems targeting clinically translational applications (e.g., antimicrobial biomaterials and site-specific nucleic acid cleavage). Conjugates of porphyrins with proteinaceous moieties, on the other hand, have been predominantly used for therapeutic and diagnostic applications (especially in photodynamic therapy, photodynamic antimicrobial chemotherapy, and photothermal therapy). The advancement of the field of porphyrinoid-bioconjugation chemistry from basic academic research to more clinically targeted applications require continuous fine-tuning in terms of synthetic strategies and hence there will continue to be much exciting work on porphyrinoid-biomacromolecule conjugation.

Investigation of Au SAMs Photoclick Derivatization by PM-IRRAS

2019 ◽  
Author(s):  
Mark Workentin ◽  
François Lagugné-Labarthet ◽  
Sidney Legge
Keyword(s):  
Cell Adhesion ◽  
Self Assembly ◽  
Materials Science ◽  
Fibroblast Cell ◽  
Fine Tuning ◽  
Chemical System ◽  
Infrared Reflection ◽  
Assembled Monolayers ◽  
One Step ◽  
High Degree

In this work we present a clean one-step process for modifying headgroups of self-assembled monolayers (SAMs) on gold using photo-enabled click chemistry. A thiolated, cyclopropenone-caged strained alkyne precursor was first functionalized onto a flat gold substrate through self-assembly. Exposure of the cyclopropenone SAM to UV-A light initiated the efficient photochemical decarbonylation of the cyclopropenone moiety, revealing the strained alkyne capable of undergoing the interfacial strain-promoted alkyne-azide cycloaddition (SPAAC). Irradiated SAMs were derivatized with a series of model azides with varied hydrophobicity to demonstrate the generality of this chemical system for the modification and fine-tuning of the surface chemistry on gold substrates. SAMs were characterized at each step with polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) to confirm successful functionalization and reactivity. Furthermore, to showcase the compatibility of this approach with biochemical applications, cyclopropenone SAMs were irradiated and modified with azide-bearing cell adhesion peptides to promote human fibroblast cell adhesion, then imaged by live cell fluorescence microscopy. Thus, the “photoclick” methodology reported here represents an improved, versatile, catalyst-free protocol that allows for a high degree of control over the modification of material surfaces, with applicability in materials science as well as biochemistry.<br>

scholarly journals Two-dimensional self-assembly of benzotriazole on an inert substrate

Nanoscale ◽  
2016 ◽  
Vol 8 (17) ◽  
pp. 9167-9177 ◽  
Author(s):  
F. Grillo ◽  
J. A. Garrido Torres ◽  
M.-J. Treanor ◽  
C. R. Larrea ◽  
J. P. Götze ◽  
...  
Keyword(s):  
Self Assembly ◽  
Fine Tuning ◽  
Two Dimensional ◽  
Dimensional Control ◽  
Experimental Conditions ◽  
Inert Substrate

Fine tuning of experimental conditions allows dimensional control of benzotriazole species adsorbed on Au(111), revealing a subtle interplay between H-bonding, vdW inter-adsorbate and surface-adsorbate interactions, as highlighted both experimentally and theoretically.

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