scholarly journals Synthesis and Photocontrolled Supramolecular Self-Assembly of Azobenzene-Functionalized Perylene Bisimide Derivatives

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1143 ◽  
Author(s):  
Ling ◽  
Cheng ◽  
Miao ◽  
Zhang ◽  
Zhang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Alkyl Chain ◽  
Supramolecular Assembly ◽  
Proton Nuclear Magnetic Resonance ◽  
Ionization Time ◽  
Perylene Bisimide ◽  
Flight Mass Spectrometry ◽  
Chain Lengths ◽  
Tetracarboxylic Dianhydride ◽  
Photoisomerization Process

Azobenzene (Azo) units were successfully introduced into perylene bisimide (PBI) structures in order to realize the photocontrolling of the morphology of the supramolecular assembly of PBI by a photoisomerization process. A total of three Azo-functionalized perylene bisimide derivatives (PBI1, PBI2, and PBI3) with different alkyl chain lengths were designed and synthesized by imidization of 3,4,9,10-perylene tetracarboxylic dianhydride with the corresponding amines. The structures of these compounds were characterized by proton nuclear magnetic resonance (1H NMR) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The photoisomerization behaviors of Azo units in PBIs were investigated using ultraviolet-visible (UV-VIS) absorption spectroscopy, which were obviously effected by solvents and the alkyl chain length. Furthermore, the photoisomerization of Azo units has the obviously regulatory effect on the morphology of supramolecular assembly of PBIs, especially for the medium-length alkyl chain-linked Azo-functionalized PBI derivative (PBI2). This research realized the photocontrolling of the morphology of the supramolecular assembly of PBI derivatives by photoisomerization of Azo units.

scholarly journals Locating Methyl-Etherified and Methyl-Esterified Uronic Acids in the Plant Cell Wall Pectic Polysaccharide Rhamnogalacturonan II

2020 ◽  
Vol 25 (4) ◽  
pp. 329-344
Author(s):  
Malcolm A. O’Neill ◽  
Ian Black ◽  
Breeanna Urbanowicz ◽  
Vivek Bharadwaj ◽  
Mike Crowley ◽  
...  
Keyword(s):  
Plant Species ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Pectic Polysaccharide ◽  
Ionization Time ◽  
Methyl Esterification ◽  
Flight Mass Spectrometry ◽  
Borate Ester ◽  
Rhamnogalacturonan Ii

Rhamnogalacturonan II (RG-II) is a structurally complex pectic polysaccharide that exists as a borate ester cross-linked dimer in the cell walls of all vascular plants. The glycosyl sequence of RG-II is largely conserved, but there is evidence that galacturonic acid (GalA) methyl etherification and glucuronic acid (GlcA) methyl esterification vary in the A sidechain across plant species. Methyl esterification of the galacturonan backbone has also been reported but not confirmed. Here we describe a new procedure, utilizing aq. sodium borodeuteride (NaBD4)-reduced RG-II, to identify the methyl esterification status of backbone GalAs. Our data suggest that up to two different GalAs are esterified in the RG-II backbone. We also adapted a procedure based on methanolysis and NaBD4 reduction to identify 3-, 4-, and 3,4- O-methyl GalA in RG-II. These data, together with matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry (MALDI-TOF) MS analysis of sidechain A generated from selected RG-IIs and their NaBD4-reduced counterparts, suggest that methyl etherification of the β-linked GalA and methyl esterification of the GlcA are widespread. Nevertheless, the extent of these modifications varies between plant species. Our analysis of the sidechain B glycoforms in RG-II from different dicots and nonpoalean monocots suggests that this sidechain has a minimum structure of an O-acetylated hexasaccharide (Ara-[MeFuc]-Gal-AceA-Rha-Api-). To complement these studies, we provide further evidence showing that dimer formation and stability in vitro is cation and borate dependent. Taken together, our data further refine the primary sequence and sequence variation of RG-II and provide additional insight into dimer stability and factors controlling dimer self-assembly.

scholarly journals Self-Assembly of [3]Catenane and [4]Catenane Based on Neutral Organometallic Scaffolds

2021 ◽  
Vol 9 ◽  
Author(s):  
Gui-Yuan Wu ◽  
Hong-Juan Zhu ◽  
Fang-Fang Pan ◽  
Xiao-Wei Sheng ◽  
Ming-Rui Zhang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Theoretical Calculations ◽  
Tubular Structures ◽  
Interlocked Molecules ◽  
Ionization Time ◽  
X Ray ◽  
Flight Mass Spectrometry ◽  
Oxygen Coordination ◽  
Organometallic Scaffolds ◽  
Tof Ms

Transition metal-mediated templating and self-assembly have shown great potential to construct mechanically interlocked molecules. Herein, we describe the formation of the bimetallic [3]catenane and [4]catenane based on neutral organometallic scaffolds via the orthogonality of platinum-to-oxygen coordination-driven self-assembly and copper(I) template–directed strategy of a [2]pseudorotaxane. The structures of these bimetallic [3]catenane and [4]catenane were characterized by multinuclear NMR {1H and 31P} spectroscopy, electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS), and PM6 semiempirical molecular orbital theoretical calculations. In addition, single-crystal X-ray analyses of the [3]catenane revealed two asymmetric [2]pseudorotaxane units inside the metallacycle. It was discovered that tubular structures were formed through the stacking of individual [3]catenane molecules driven by the strong π–π interactions.

Superhydrophobic surface formation and modulation in a biphenyltetracarboxylic dianhydride derivative self-assembly system via changing alkyl chain lengths

RSC Advances ◽  
2015 ◽  
Vol 5 (60) ◽  
pp. 48500-48505 ◽  
Author(s):  
Xinhua Cao ◽  
Aiping Gao ◽  
Haiting Lv ◽  
Haichuang Lan ◽  
Qiuli Cheng ◽  
...  
Keyword(s):  
Self Assembly ◽  
Superhydrophobic Surface ◽  
Alkyl Chain ◽  
Assembly System ◽  
Lotus Effect ◽  
Surface Formation ◽  
Low Weight ◽  
Biphenyltetracarboxylic Dianhydride ◽  
Chain Lengths

A Superhydrophobic surface with lotus effect was formed via low weight molecule self-assembly.

Synthesis and Self-assembly of Amphiphilic Hetero-arm Molecular Brushes

2011 ◽  
Vol 64 (8) ◽  
pp. 1100 ◽  
Author(s):  
Waled Hadasha ◽  
Mpho Mothunya ◽  
Niels Akeroyd ◽  
Bert Klumperman
Keyword(s):  
Self Assembly ◽  
Ring Opening ◽  
Alkyl Chain ◽  
Ring Closure ◽  
Molecular Brushes ◽  
Alkyl Amines ◽  
Ring Opening Reaction ◽  
Grafting From ◽  
Chain Lengths

We report the synthesis of amphiphilic hetero-arm molecular brushes (AMBs), which were prepared by a combination of ‘grafting from’ and ‘grafting onto’ methodologies. First, styrene-terminated polyethylene glycol macromonomer (VB-PEG12, ∼666 g mol–1) was copolymerized with maleic anhydride (MAnh) to yield a polymer containing hydrophilic PEG chains and reactive (MAnh) groups. Subsequently, the reactive MAnh units in the obtained polymer were modified via a ring-opening reaction using primary alkyl amines, with different alkyl chain lengths, as the nucleophile. In situ ring closure yielded the styrene–maleimide-based AMB. The amphiphilic character of the AMBs was used for their self-assembly in different solvents. The effect of the ratio in hydrophilic to hydrophobic graft length on the morphology of the assemblies was studied using scanning electron microscopy.

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