scholarly journals The Fluorescence Quenching of Zinc Porphyrins with the ω-[4-(4-Pyridyl)pyridinio]alkyl Group

1989 ◽  
Vol 62 (10) ◽  
pp. 3069-3074 ◽  
Author(s):  
Kohshin Takahashi ◽  
Tetsuo Terashima ◽  
Teruhisa Komura ◽  
Hiroto Imanaga
2004 ◽  
Vol 111 (2) ◽  
pp. 105-113 ◽  
Author(s):  
Justyna Mrozek ◽  
Alicja Rzeska ◽  
Katarzyna Guzow ◽  
Jerzy Karolczak ◽  
Wiesław Wiczk

2009 ◽  
Vol 79-82 ◽  
pp. 1703-1706 ◽  
Author(s):  
Pei Hua Zhu ◽  
Cheng Zhu ◽  
Yang Fang Zhao ◽  
Qin Wei ◽  
Yan Li Chen

Three new zinc porphyrins ( [5,15-bisferrocenyl-porphyrinato]-zinc(II)(4), [5,15-bisferrocenyl-10,20-bis(4-nitro-phenyl)-porphyrinato]-zinc(II)(5), and [5,10,15,20- tetraferrocenyl-porphyrinato]-zinc(II) (6)) with ferrocenyl units at the meso-positions of porphyrin ring have been prepared and characterized. Towards further understanding the fluorescence quenching and recovery of ferrocene-porphyrins, the fluorescence spectra of these compounds was detailedly studied.


2020 ◽  
Author(s):  
Shubham Deolka ◽  
Orestes Rivada Wheelaghan ◽  
Sandra Aristizábal ◽  
Robert Fayzullin ◽  
Shrinwantu Pal ◽  
...  

We report selective formation of heterobimetallic PtII/CuI complexes that demonstrate how facile bond activation processes can be achieved by altering reactivity of common organoplatinum compounds through their interaction with another metal center. The interaction of the Cu center with Pt center and with a Pt-bound alkyl group increases the stability of PtMe2 towards undesired rollover cyclometalation. The presence of the CuI center also enables facile transmetalation from electron-deficient tetraarylborate [B(ArF)4]- anion and mild C-H bond cleavage of a terminal alkyne, which was not observed in the absence of an electrophilic Cu center. The DFT study indicates that the role of Cu center acts as a binding site for alkyne substrate, while activating its terminal C-H bond.


2012 ◽  
Vol 29 (4) ◽  
pp. 440
Author(s):  
Yaqiong WANG ◽  
Shaopu LIU ◽  
Zhongfang LIU ◽  
Xiaoli HU

2016 ◽  
Vol 26 (1) ◽  
pp. 1-7 ◽  
Author(s):  
A.N. Kapitonov ◽  
G.N. Alexandrov ◽  
F.D. Vasileva ◽  
S.A. Smagulova ◽  
V.B. Timofeev ◽  
...  

2019 ◽  
Vol 15 (5) ◽  
pp. 486-495 ◽  
Author(s):  
Li-Xin Peng ◽  
Xue-Hui Liu ◽  
Bo Lu ◽  
Si-Ming Liao ◽  
Feng Zhou ◽  
...  

Background:The polysialic acid (polySia) is a unique carbohydrate polymer produced on the surface Of Neuronal Cell Adhesion Molecule (NCAM) in a number of cancer cells, and strongly correlates with the migration and invasion of tumor cells and with aggressive, metastatic disease and poor clinical prognosis in the clinic. Its synthesis is catalyzed by two polysialyltransferases (polySTs), ST8SiaIV (PST) and ST8SiaII (STX). Selective inhibition of polySTs, therefore, presents a therapeutic opportunity to inhibit tumor invasion and metastasis due to NCAM polysialylation. Heparin has been found to be effective in inhibiting the ST8Sia IV activity, but no clear molecular rationale. It has been found that polysialyltransferase domain (PSTD) in polyST plays a significant role in influencing polyST activity, and thus it is critical for NCAM polysialylation based on the previous studies.Objective:To determine whether the three different types of heparin (unfractionated hepain (UFH), low molecular heparin (LMWH) and heparin tetrasaccharide (DP4)) is bound to the PSTD; and if so, what are the critical residues of the PSTD for these binding complexes?Methods:Fluorescence quenching analysis, the Circular Dichroism (CD) spectroscopy, and NMR spectroscopy were used to determine and analyze interactions of PSTD-UFH, PSTD-LMWH, and PSTD-DP4.Results:The fluorescence quenching analysis indicates that the PSTD-UFH binding is the strongest and the PSTD-DP4 binding is the weakest among these three types of the binding; the CD spectra showed that mainly the PSTD-heparin interactions caused a reduction in signal intensity but not marked decrease in α-helix content; the NMR data of the PSTD-DP4 and the PSTDLMWH interactions showed that the different types of heparin shared 12 common binding sites at N247, V251, R252, T253, S257, R265, Y267, W268, L269, V273, I275, and K276, which were mainly distributed in the long α-helix of the PSTD and the short 3-residue loop of the C-terminal PSTD. In addition, three residues K246, K250 and A254 were bound to the LMWH, but not to DP4. This suggests that the PSTD-LMWH binding is stronger than the PSTD-DP4 binding, and the LMWH is a more effective inhibitor than DP4.Conclusion:The findings in the present study demonstrate that PSTD domain is a potential target of heparin and may provide new insights into the molecular rationale of heparin-inhibiting NCAM polysialylation.


2020 ◽  
Vol 16 ◽  
Author(s):  
Pan Zhang ◽  
Shun-Sheng Zhao ◽  
JiaJia Wang ◽  
Xiang Rong Liu

Background: In recent years, environmental pollution and heavy metal pollution caused by rapid urbanization and industrialization have become increasingly serious. Among them, mercury (II) ion (Hg2+) is one of the highly toxic heavy metal ions, and its pollution comes from various natural resources and human activities. Therefore, people attach great importance to the development of analytical methods for effective analysis and sensitive detection of Hg2+ . Objective: Using grape skin as a green and environmental friendly carbon source, to synthesize fluorescent carbon dots, and try to apply them to the detect the concentration of Hg2+ in water. Method: Using "Hutai No. 8" grape skin as carbon source, fluorescent carbon dots were synthesized by one-step hydrothermal method. Structure and fluorescent properties of the carbon dots were tested using TEM, XPS, XRD and other characterization instruments, and their utilization on detection of mercury ions in the actual water samples was explored. Results: The CDs had a particle size of about 4.8 nm and a spherical shape. There are N-H, C-N, C=O and other functional groups on the surface. It was found that Hg2+ has obvious fluorescence quenching effect on CDs, and thus CDs fluorescence quenching method to detect the concentration Hg2+ was established, and the detection limit is 3.7 μM, which could be applied to test the concentration of Hg2+ in water samples. Conclusion: Using grape skin as carbon source, fluorescent carbon dots were successfully synthesized by hydrothermal method. Carbon dots were used to detect mercury ions in water, and a method for detecting mercury ions in actual water samples was established.


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