scholarly journals SYNTHESIS, ELECTRONIC STRUCTURE AND STUDY OF YTTERBIUM TETRAPHENYLPORPHYRIN COMPLEXES STABILITY BY PHOTOELECTRON SPECTROSCOPY AND THERMOGRAVIMETRY

Author(s):  
V. D. Rumyantseva ◽  
R. N. Mozhchil ◽  
V. S. Bozhko ◽  
S. I. Bozhko ◽  
A. P. Menushenkov ◽  
...  

Metalloorganic complexes of rare earth elements with porphyrins have attracted attention over the past years in view of potential applications as templates for biology, nanotechnology and medicine. For deeper understanding and studying of their properties the knowledge of electronic structure and bonding in these compounds is required and should be investigated essentially by a photoelectron spectroscopy. In present work the electronic structure and stability of tetrakis-porphyrins and its ytterbium complexes were studied experimentally by X-ray (XPS) photoemission spectroscopy. The X-ray photoemission data show the different atomic constituents in accordance with its states in molecules which can be related to the peaks of N1s, C1s, O1s, Yb4d appearing in the electronic spectra. In the tetraphenylporphyrin free base spectrum of the N1s state core levels there are two peaks of N1s which were assigned to sp3 and sp2 nitrogen respectively (pyrrol- and azastates). In Yb metalloporphyrin charge distribution is more uniform for N1s spectra and thus wide single peak of N1s states reflects small difference between pyrol- and aza-nitrogen. The analysis of Yb4d electronic states shows that spectra do not consist of the spin-orbit split doublet, but instead is composed of asymmetric peak with multiplet splitting. Divalent Yb has a filled 4f shell, i.e. a 4f14 configuration, and the 4d spectra shows the doublet with 3:2 ratio, while for trivalent Yb, 4f13, the 4d peaks consist of a multiplet. The spectrum analysis demonstrated the multiplet splitting of Yb 4d and trivalent state in Yb(acac)-5,10,15,20-tetrakis-porphyrins. The research of thermal stability of tetraphenylporphyrin, octabrominetetraphenylporphyrin, ytterbium acetylacetonate octabrominetetraphenylporphyrin by X-ray photoelectron spectroscopy and thermogravimetry measurements in the range of temperatures of 30-450°C (when heating in ultrahigh vacuum) has shown destruction of the octabrominetetraphenylporphyrin and ytterbium acetylacetonate octabrominetetraphenylporphyrin after warming up higher than 150ºС while free base porphyrines (tetraphenylporphyrines) have shown thermal stability under vacuum conditions.

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Tae Hyeong Kim ◽  
Hyeji Kim ◽  
Hyo Jun Jang ◽  
Nara Lee ◽  
Kwang Hyun Nam ◽  
...  

AbstractIn the study reported herein, silver-coated copper (Ag/Cu) powder was modified with alkanethiols featuring alkyl chains of different lengths, namely butyl, octyl, and dodecyl, to improve its thermal stability. The modification of the Ag/Cu powders with adsorbed alkanethiols was confirmed by scanning electron microscopy with energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Each powder was combined with an epoxy resin to prepare an electrically conductive film. The results confirmed that the thermal stability of the films containing alkanethiol-modified Ag/Cu powders is superior to that of the film containing untreated Ag/Cu powder. The longer the alkyl group in the alkanethiol-modified Ag/Cu powder, the higher the initial resistance of the corresponding electrically conductive film and the lower the increase in resistance induced by heat treatment.


2000 ◽  
Vol 447 (1-3) ◽  
pp. 112-116 ◽  
Author(s):  
I.N. Shabanova ◽  
V.I. Kormilets ◽  
L.D. Zagrebin ◽  
N.S. Terebova

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yan Ye ◽  
Da Yin ◽  
Bin Wang ◽  
Qingwen Zhang

We report the synthesis of three-dimensional Fe3O4/graphene aerogels (GAs) and their application for the removal of arsenic (As) ions from water. The morphology and properties of Fe3O4/GAs have been characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and superconducting quantum inference device. The 3D nanostructure shows that iron oxide nanoparticles are decorated on graphene with an interconnected network structure. It is found that Fe3O4/GAs own a capacity of As(V) ions adsorption up to 40.048 mg/g due to their remarkable 3D structure and existence of magnetic Fe3O4nanoparticles for separation. The adsorption isotherm matches well with the Langmuir model and kinetic analysis suggests that the adsorption process is pseudo-second-ordered. In addition to the excellent adsorption capability, Fe3O4/GAs can be easily and effectively separated from water, indicating potential applications in water treatment.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 992
Author(s):  
Song Chen ◽  
Yuanli He ◽  
Linna Zhong ◽  
Wenjia Xie ◽  
Yiyuan Xue ◽  
...  

The surface modification of titanium (Ti) can enhance the osseointegration and antibacterial properties of implants. In this study, we modified porous Ti discs with calcium phosphate (CaP) and different concentrations of Lactoferrin (LF) by biomimetic mineralization and examined their antibacterial effects and osteogenic bioactivity. Firstly, scanning electron microscopy (SEM), the fluorescent tracing method, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and the releasing kinetics of LF were utilized to characterize the modified Ti surface. Then, the antibacterial properties against S. sanguis and S. aureus were investigated. Finally, in vitro cytological examination was performed, including evaluations of cell adhesion, cell differentiation, extracellular matrix mineralization, and cytotoxicity. The results showed that the porous Ti discs were successfully modified with CaP and LF, and that the LF-M group (200 μg/mL LF in simulated body fluid) could mildly release LF under control. Further, the LF-M group could effectively inhibit the adhesion and proliferation of S. sanguis and S. aureus and enhance the osteogenic differentiation in vitro with a good biocompatibility. Consequently, LF-M-modified Ti may have potential applications in the field of dental implants to promote osseointegration and prevent the occurrence of peri-implantitis.


2019 ◽  
Vol 470 ◽  
pp. 607-612 ◽  
Author(s):  
Martin Magnuson ◽  
Grzegorz Greczynski ◽  
Fredrik Eriksson ◽  
Lars Hultman ◽  
Hans Högberg

1983 ◽  
Vol 27 (4) ◽  
pp. 2145-2178 ◽  
Author(s):  
John C. Fuggle ◽  
F. Ulrich Hillebrecht ◽  
R. Zeller ◽  
Zygmunt Zołnierek ◽  
Peter A. Bennett ◽  
...  

2006 ◽  
Vol 600 (18) ◽  
pp. 3749-3752 ◽  
Author(s):  
C. Biswas ◽  
S. Banik ◽  
A.K. Shukla ◽  
R.S. Dhaka ◽  
V. Ganesan ◽  
...  

1986 ◽  
Vol 34 (10) ◽  
pp. 6874-6879 ◽  
Author(s):  
M. G. Thube ◽  
S. K. Kulkarni ◽  
D. Huerta ◽  
Arun S. Nigavekar

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