scholarly journals Room-temperature surface-assisted reactivity of a melanin precursor: silver metal–organic coordination versus covalent dimerization on gold

Nanoscale ◽  
2018 ◽  
Vol 10 (35) ◽  
pp. 16721-16729 ◽  
Author(s):  
F. De Marchi ◽  
G. Galeotti ◽  
M. Simenas ◽  
E. E. Tornau ◽  
A. Pezzella ◽  
...  

The surface drives the self-assembly of a catechol–indole molecule, triggering metal–organic coordination on silver and dimerization on gold at room temperature.

2015 ◽  
Vol 68 (2) ◽  
pp. 322 ◽  
Author(s):  
Wenlong Liu ◽  
Mengqiang Wu ◽  
Xueying Wang ◽  
Wei Wang ◽  
Dayu Liu ◽  
...  

Using a hydrothermal synthesis, the self-assembly of MnII ions and 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene with two dicarboxylate ligands, 2-nitrobenzene-1,4-dicarboxylic acid (2-H2ata) and 5-methylbenzene-1,3-dicarboxylic acid (5-CH3-H2ip) constructed two interesting coordination polymers: [Mn(2-ata)(bimb)]n (1) and {[Mn(5-CH3-ip)(bimb)1.5]·2H2O}n (2), where bimb refers to 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene. Their structures were determined by single-crystal X-ray diffraction, elemental analysis, and infrared spectroscopy. Complex 1 exhibits a 2-fold interpenetrated pcu net. Complex 2 shows an unusual polycatenated 2D+2D→3D framework. In addition, the solid-state photoluminescent properties of 1 and 2 were investigated at room temperature.


Nanoscale ◽  
2019 ◽  
Vol 11 (15) ◽  
pp. 7347-7357 ◽  
Author(s):  
Lei Wang ◽  
Zhennan Huang ◽  
Bo Wang ◽  
Hao Luo ◽  
Meng Cheng ◽  
...  

Titanium-based metal–organic frameworks have been used as an in situ etching template for the self-assembly of graphene oxide to construct NaTi2(PO4)3-rGO composite.


2021 ◽  
Author(s):  
Marc Lehr ◽  
Tobias Paschelke ◽  
Victoria Bendt ◽  
Andre Petersen ◽  
Lorenz Pietsch ◽  
...  

<div> <p>Bipyridine- and benzimidazole-based ligands for the self-assembly of Co<sub>4</sub>L<sub>6</sub> cages were synthesised in short reaction times and high isolated yields directly from aryl halide precursors using a copper-free one-pot Sonogashira-type coupling. This one-pot method circumvents the often time-consuming and challenging ligand synthesis for the preparation and application of cages.</p> </div> <br>


2020 ◽  
Author(s):  
Yuyang Miao ◽  
Shibo Lv ◽  
Daoyuan Zheng ◽  
Yuhan Liu ◽  
Dapeng Liu ◽  
...  

Abstract Porphyrin-based metal coordination polymers (MCPs) have attracted numerous attention due to their great promise application in phototherapy including photodynamic therapy (PDT) and photothermal therapy (PTT). However, the detailed self-assembly process of porphyrin-based MCPs still remains poorly understood. This work provides a detailed study of the self-assembly process of MCPs constructed by Mn2+ and TCPP (TCPP: 4,4′,4′′,4′′′-(Porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid)) in aqueous solution. Unlike traditional nucleation and growth mechanism, we discover that there is a metastable metal-organic intermediate which is kinetically favored in the self-assembly process. And the metastable metal-organic intermediate nanotape structures could convert into thermodynamically favored nanosheets through disassembling into monomers followed by reassembling process. Moreover, the two structurally different assemblies exhibit distinct photophysical performances. The intermediate Mn-TCPP aggregates show good light-induced singlet oxygen 1O2 generation for PDT while the thermodynamic favored stable Mn-TCPP aggregates exhibit good photothermal conversion ability as photothermal agents (PTAs). This study could facilitate controlling self-assembly pathway to fabricate complex MCPs with desirable applications.


2020 ◽  
Vol 98 (7) ◽  
pp. 379-385
Author(s):  
Carson O. Zellman ◽  
Danielle Vu ◽  
Vance E. Williams

Although the impact of individual functional groups on the self-assembly of columnar liquid crystal phases has been widely studied, the effect of varying multiple substituents has received much less attention. Herein, we report a series of dibenzo[a,c]phenazines containing an alcohol or ether adjacent to an electron-withdrawing ester or acid. With one exception, these difunctional mesogens form columnar phases. The phase behavior appeared to be dominated by the electron-withdrawing substituent; transition temperatures were similar to derivatives with these groups in isolation. In most instances, the addition of an electron-donating group ortho to an ester or acid suppressed the melting temperature and elevated the clearing temperature, leading to broader liquid crystal thermal ranges. This effect was more pronounced for derivatives functionalized with longer chain hexyloxy groups. These results suggest a potential strategy for controlling the phase ranges of columnar liquid crystals and achieving room temperature mesophases.


CrystEngComm ◽  
2020 ◽  
Vol 22 (15) ◽  
pp. 2649-2655 ◽  
Author(s):  
Yuanbin Zhang ◽  
Lingyao Wang ◽  
Jianbo Hu ◽  
Simon Duttwyler ◽  
Xili Cui ◽  
...  

A family of microporous boron cage pillared supramolecular metal–organic frameworks are synthesized with the self-assembly behavior controlled by solvents. Interpenetrated BSF-4 is potential for highly selective C2H2/C2H4 and C2H2/CO2 separation.


2021 ◽  
Author(s):  
Cui-Lian Liu ◽  
Eduard Bobylev ◽  
Brice Kauffmann ◽  
Koen Robeyns ◽  
Yann Garcia ◽  
...  

Non-covalent interactions play an essential role in the folding and self-assembly of large biological assemblies. These interactions are not only a driving force for the formation of large structures but also control conformation and com-plementary shapes of subcomponents that promote the diversity of structures and functions of the resulting assemblies. Understanding how non-covalent interactions direct self-assembly and the effect of conformation and complementary shapes on self-assembled structures will help design artificial supramolecular systems with extended components and functions. Herein, we develop a strategy for controlling more complex self-assembly with lower symmetry and flexible building blocks that combine endohedral non-covalent interactions with a dual curvature in the ligand backbone to give additional shape complementarity. A Diels-Alder reaction was used to break the symmetry of the diazaanthracene units of the ligands to give dual curvature ligands with different shapes and endohedral groups (L1-L3). The self-assembly studies of these ligands demonstrated that non-covalent interactions and shape complementary effectively control the self-assembly and enable the design of cages for supramolecular catalysis.


2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Braja Gopal Bag ◽  
Subhajit Das

A solution of oleanolic acid, a renewable nano-sized monohydroxy triterpenic acid in tetrahydrofuran, transformed into a gel instantly at room temperature on treatment with aqueous ammonia. Study of the self-assembly properties of ammonium oleanolate in water and aqueous solvent mixtures indicated that it self-assembles in the aqueous solvent mixtures forming gels in DMSO-water and DMF-water. Fibrillar networks with optical birefringence properties were observed by polarized optical microscopy. Scanning electron microscopy of the dried gel samples indicated fibrillar networks with fibers of nano to micrometer diameters. The thermodynamic parameters calculated from the gel to sol transition temperatures indicated the stability of the gels. A gel-gold nanoparticles hybrid material has also been prepared and characterized by HRTEM, EDX, SAED and surface Plasmon resonance studies.


2017 ◽  
Vol 139 (34) ◽  
pp. 12020-12026 ◽  
Author(s):  
Bo Qi ◽  
Xiangyang Guo ◽  
Yunyi Gao ◽  
Dong Li ◽  
Jiancheng Luo ◽  
...  
Keyword(s):  
The Self ◽  

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