Differential reactivity of the inner and outer positions of Au25(SCH2CH2Ph)18 dimeric staples under place exchange conditions

2015 ◽  
Vol 51 (15) ◽  
pp. 3204-3207 ◽  
Author(s):  
Paolo Pengo ◽  
Cristian Bazzo ◽  
Mariangela Boccalon ◽  
Lucia Pasquato
Keyword(s):  
Exchange Reaction ◽  
Differential Reactivity ◽  
Site Selectivity ◽  
Place Exchange

The site selectivity of the place exchange reaction at the two inequivalent positions of the neutral Au25(SCH2CH2Ph)18 staples depends on the nature of the incoming thiol.

Radical Mechanism of a Place-Exchange Reaction of Au Nanoparticles

2005 ◽  
Vol 44 (24) ◽  
pp. 3720-3722 ◽  
Author(s):  
Petre Ionita ◽  
Bruce C. Gilbert ◽  
Victor Chechik
Keyword(s):  
Exchange Reaction ◽  
Au Nanoparticles ◽  
Radical Mechanism ◽  
Place Exchange

The Influence of Hydrophilic Decoration on X-ray Excited Luminescence Nanoparticles to Singlet Oxygen Production

NANO ◽  
2020 ◽  
Vol 15 (07) ◽  
pp. 2050092
Author(s):  
Xiaosheng Zhu ◽  
Yi Tian ◽  
Lei Dai ◽  
Qiaofeng Wang ◽  
Mei Shi ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Exchange Reaction ◽  
X Ray ◽  
Good Biocompatibility ◽  
Place Exchange ◽  
High Concentrations ◽  
Excited Luminescence ◽  
Tumor Inhibition Rate

(1) Background: Though X-ray excited photodynamic therapy (X-PDT) breakthrough the bottom neck of PDT application in deep tumor by overcoming light penetration depth limitation, the quantum yield of the hydrophilic X-PDT nanoparticles (NPs) still hampered its further application in vivo. Thus, establishing a proper hydrophilic decoration method which can maximally maintain the quantum yield of X-ray excited luminescent NPs is of urgent demand. (2) Methods: We synthesized NaGdF4: [Formula: see text] (NGF) as X-ray excited luminescent NPs and conducted hydrophilic decoration by two hydrophilic ligands, polyethylene glycol-NH2 (PEG) and cysteamine (Cy) via place exchange reaction, and coupled with photosensitizer (MC540) to form a X-PDT nanosystem. We also conducted experiments in vitro and in vivo to evaluate the efficacy of the X-PDT system. (3) Results: Both PEG and Cy decoration NPs presented excellent emission intensity, which could well excite the coupled photosensitizer MC540 to generate significant X-PDT efficacy under low-dose X-ray radiation. Especially for the NGF-Cy-MC540 treatment group, the cell viability reduced to [Formula: see text]% under 0.3[Formula: see text]Gy radiation and [Formula: see text]% under only 0.1[Formula: see text]Gy radiation, which is the lowest radiation dosage in the literature reports so far. In vivo experiment showed about 36% of tumor inhibition rate under 0.3[Formula: see text]Gy X-ray. Besides, no biotoxicity was observed in NGF groups even in high concentrations, demonstrating good biocompatibility. (4) Conclusions: The hydrophilic decoration method by Cy or PEG via place exchange reaction may pave a brand new way and strategy for X-PDT further clinical application.

scholarly journals Hydrogen Bonding: A Bottom-Up Approach for the Synthesis of Films Composed of Gold Nanoparticles

2008 ◽  
Vol 2 ◽  
pp. 115-128 ◽  
Author(s):  
Mariana Chirea ◽  
Carlos M. Pereira ◽  
Fernando Silva
Keyword(s):  
Gold Nanoparticles ◽  
Hydrogen Bonding ◽  
Exchange Reaction ◽  
Film Formation ◽  
Gold Clusters ◽  
Blue Color ◽  
Mercaptosuccinic Acid ◽  
First Case ◽  
Place Exchange ◽  
Film Synthesis

Citrate gold nanoparticles of 13.5 nm average diameters have been synthesized by Turkevich method and further functionalized by place exchange reaction using mercaptosuccinic acid (MSA), 1,4-benezenedimethanethiol (1,4BDMT) or mercaptoundecanoic acid (MUA) as the incoming ligands. In the first case, the functionalization of the gold clusters with MSA yielded solution of blue color and large aggregates on carbon grids. Moreover, after filtration and drying, any film formed by hydrogen bonding, could not be removed from the filter, being embedded into the filter texture. The second ligand used for the place exchange reaction, the 1,4BDMT, determined the change of the solution color from red to dark purple, and generation of a purple powder but no film formation. In the third case, the purification and drying of the MUA functionalized gold clusters yielded films of purple color with homogenous composition, robustness, soft topographies and remarkable optical properties which were dependent on their thicknesses. The Au-MUA NP films obtained are new, being generated by hydrogen bonding and having features which makes them very attractive for the fabrication of optoelectronic devices. The long alkyl chained thiol proved to be the adequate ligand for film synthesis.

EPR Study of a Place-Exchange Reaction on Au Nanoparticles:  Two Branches of a Disulfide Molecule Do Not Adsorb Adjacent to Each Other

2002 ◽  
Vol 124 (31) ◽  
pp. 9048-9049 ◽  
Author(s):  
Petre Ionita ◽  
Agneta Caragheorgheopol ◽  
Bruce C. Gilbert ◽  
Victor Chechik
Keyword(s):  
Exchange Reaction ◽  
Au Nanoparticles ◽  
Place Exchange

Mechanistic Study of a Place-Exchange Reaction of Au Nanoparticles with Spin-Labeled Disulfides

Langmuir ◽  
2004 ◽  
Vol 20 (26) ◽  
pp. 11536-11544 ◽  
Author(s):  
Petre Ionita ◽  
Agneta Caragheorgheopol ◽  
Bruce C. Gilbert ◽  
Victor Chechik
Keyword(s):  
Exchange Reaction ◽  
Au Nanoparticles ◽  
Mechanistic Study ◽  
Place Exchange

Radical Mechanism of a Place-Exchange Reaction of Au Nanoparticles

2005 ◽  
Vol 117 (24) ◽  
pp. 3786-3788 ◽  
Author(s):  
Petre Ionita ◽  
Bruce C. Gilbert ◽  
Victor Chechik
Keyword(s):  
Exchange Reaction ◽  
Au Nanoparticles ◽  
Radical Mechanism ◽  
Place Exchange

Chelation-assisted transition metal-catalysed C–H chalcogenylations

2020 ◽  
Vol 7 (8) ◽  
pp. 1022-1060 ◽  
Author(s):  
Wenbo Ma ◽  
Nikolaos Kaplaneris ◽  
Xinyue Fang ◽  
Linghui Gu ◽  
Ruhuai Mei ◽  
...  
Keyword(s):  
Transition Metal ◽  
Recent Advances ◽  
Site Selectivity ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

This review summarizes recent advances in C–S and C–Se formations via transition metal-catalyzed C–H functionalization utilizing directing groups to control the site-selectivity.

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