scholarly journals Transition-Metal Ions in Nd-Doped Glasses: Spectra and Effects on Nd Fluorescence

1985 ◽  
Vol 61 ◽  
Author(s):  
S. E. Stokowski ◽  
D. Krashkevich
Keyword(s):  
Energy Transfer ◽  
Transition Metal ◽  
Fluorescence Quenching ◽  
Metal Ion ◽  
Impurity Content ◽  
Transition Metal Ions ◽  
Fluorescence Decay ◽  
Absorption Loss ◽  
Quenching Rate ◽  
Doped Glasses

ABSTRACTWe have measured transition-metal ion (Ti, V, Cr, Mn, Fe, Co, Ni, Cu) spectra and their effects on Nd fluorescence quenching in Nd-doped phosphate and silicate glasses. Our purpose was to determine the maximum allowable impurity content given particular limits on the absorption loss at 1053 nm and the Nd fluorescence quenching rate. To keep the absorption loss <0.1 m−1 the transition-metal impurity content should be kept below 0.5 ppmw. To keep the increase in the Nd fluorescence decay rate below 1%, the impurity content should be <3 ppmw. We have also found that the Nd quenching rates do not scale as predicted by the Forster- Dexter dipole-dipole energy transfer theory if we assume that the dominant variation with transition metal is the overlap integral of the Nd fluorescence spectrum and the transition-metal absorption. We suggest that phonon-assisted energy transfer to transition metals is effective in quenching Nd. We find that quenching rates increase 1.5 to 4 times as the Nd concentration increases from 0.5 to 10 × 1020 cm−2.

Pre-concentration and energy transfer enable the efficient luminescence sensing of transition metal ions by metal–organic frameworks

2015 ◽  
Vol 51 (95) ◽  
pp. 16996-16999 ◽  
Author(s):  
Xinping Lin ◽  
Yahui Hong ◽  
Chao Zhang ◽  
Ruiyun Huang ◽  
Cheng Wang ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Transition Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Metal Organic Frameworks ◽  
Transition Metal Ions ◽  
Transfer Energy ◽  
Metal Organic

The 2,2′-bipyridyl moieties in designer MOFs pre-concentrate metal ion analytes and transfer energy to lanthanide reporters for luminescence sensing.

scholarly journals Optical properties of selected 4d and 5d transition metal ion-doped glasses

RSC Advances ◽  
2017 ◽  
Vol 7 (42) ◽  
pp. 26411-26419 ◽  
Author(s):  
Hongli Wen ◽  
Bing-Ming Cheng ◽  
Peter A. Tanner
Keyword(s):  
Optical Properties ◽  
Charge Transfer ◽  
Transition Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Oxidation States ◽  
Transition Metal Ion ◽  
Doped Glasses

Charge transfer emission from transition metal ions in glasses and identification of their oxidation states.

Fluorescence energy transfer studies in a cross-linked polyurethane network

1995 ◽  
Vol 73 (11) ◽  
pp. 1823-1830 ◽  
Author(s):  
Jie Yang ◽  
Mitchell A. Winnik
Keyword(s):  
Energy Transfer ◽  
Fluorescence Quenching ◽  
Fluorescence Decay ◽  
Critical Distance ◽  
Nonradiative Energy Transfer ◽  
Fluorescence Energy Transfer ◽  
Distribution Analysis ◽  
Analysis Method ◽  
Acceptor Concentration ◽  
Fluorescence Energy

A series of cross-linked polyurethane samples, labeled with dyes suitable for fluorescence energy transfer experiments, were prepared (donor, phenanthrene; acceptor, anthracene). Fluorescence decay profiles for these samples were measured as a function of acceptor concentration. These decays obey Förster nonradiative energy transfer kinetics, with an energy transfer critical distance (R0) of 26.7 Å. Fluorescence intensities, calculated from the decays by integrating the decay profiles, also fit the Perrin model, with a quenching radius (Rs) of 25.6 Å. The fluorescence decay profiles were further examined with a distribution analysis method, which also revealed uniformly distributed donors and acceptors in the polymer matrices. Keywords: fluorescence quenching, fluorescence decay, phenanthrene, anthracene, polyurethane.

scholarly journals Density-Based Descriptors of Redox Reactions Involving Transition Metal Compounds as a Reality-Anchored Framework: A Perspective

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5541
Author(s):  
Daniel Koch ◽  
Mohamed Chaker ◽  
Manabu Ihara ◽  
Sergei Manzhos
Keyword(s):  
Transition Metal ◽  
Metal Ion ◽  
Redox Reactions ◽  
Rational Design ◽  
Chemical Properties ◽  
Transition Metal Ions ◽  
Blind Spot ◽  
Transition Metal Compounds ◽  
Metal Compounds ◽  
Active Transition

Description of redox reactions is critically important for understanding and rational design of materials for electrochemical technologies, including metal-ion batteries, catalytic surfaces, or redox-flow cells. Most of these technologies utilize redox-active transition metal compounds due to their rich chemistry and their beneficial physical and chemical properties for these types of applications. A century since its introduction, the concept of formal oxidation states (FOS) is still widely used for rationalization of the mechanisms of redox reactions, but there exists a well-documented discrepancy between FOS and the electron density-derived charge states of transition metal ions in their bulk and molecular compounds. We summarize our findings and those of others which suggest that density-driven descriptors are, in certain cases, better suited to characterize the mechanism of redox reactions, especially when anion redox is involved, which is the blind spot of the FOS ansatz.

2,2î-Bipyridine Catalyzed Bleaching of Cotton Fibers with Peracetic Acid

1988 ◽  
Vol 58 (4) ◽  
pp. 198-210 ◽  
Author(s):  
James W. Rucker ◽  
David M. Cates
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Peracetic Acid ◽  
Metal Ion ◽  
Solution Treatment ◽  
Transition Metal Ions ◽  
Ferrous Ion ◽  
Cotton Fibers ◽  
Lauryl Sulfate ◽  
Ferrous Ions

Peracetic acid can be catalyzed to bleach cotton fibers at temperatures as low as 30°C by incorporating 2,2î-bipyridine in the bleach solution. Treatment of the fibers with HCl prior to bleaching reduces bleaching effectiveness by removing trace transition metal ions from the fibers. Sorption of individual ions (Cr+3 Mn+2, Fe+2, Fe+3 Co+2, Ni+2, Cu+2, and Zn+2) by HCl treated cotton fibers prior to bleaching indicates that the ferrous ion produces the greatest catalytic effect, and it is only effective when the metal ion is in the fiber as opposed to in solution. Ferrous ions in the fibers sorb 2,2î-bipyridine from solution to form the tris-2,2î-bipyridine ferrous ion complex that is associated with the fibers, and it is the trischelate associated with the fibers that catalyzes bleaching. The effects of pH, temperature, and concentrations of 2,2î-bipyridine, sodium lauryl sulfate, and transition metal ions (in the fibers and in solution) on bleaching effectiveness and peracetic acid decomposition have been studied, and a bleaching mechanism is proposed.

Energy transfer—room temperature phosphorescence for the optosensing of transition metal ions

2003 ◽  
Vol 486 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Juan Dı́az-Garcı́a ◽  
José M Costa-Fernández ◽  
Nerea Bordel ◽  
Rosario Pereiro ◽  
Alfredo Sanz-Medel
Keyword(s):  
Energy Transfer ◽  
Transition Metal ◽  
Metal Ions ◽  
Room Temperature ◽  
Transition Metal Ions ◽  
Room Temperature Phosphorescence

Intermediate-stage transition metal ion exchange in a zeolite X

1982 ◽  
Vol 35 (7) ◽  
pp. 1335 ◽  
Author(s):  
M Chatterjee ◽  
D Ganguli
Keyword(s):  
Ion Exchange ◽  
Transition Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Intermediate Stage ◽  
Transition Metal Ions ◽  
Zeolite X ◽  
Counter Ions ◽  
Metal Ion Exchange ◽  
Exchange Behaviour

The exchange behaviour of some divalent transition metal ions M2+ (Zn2+, Cu2+, Ni2+, Co2+, Mn2+) in a zeolite NaX (SiO2/Al2O3 2.75) was studied at intermediate stages before equilibrium. The equivalent counter ion supply in the solution, given by the equivalent ratio of the two counter ions 2M2+/Na+, was found to be critical in determining the saturation level of exchange. The series of relative abilities of exchange was very similar to the well known selectivity series at equilibrium. It is suggested that water exchange of the metal ions in solution could be one of the factors controlling the relative ease of ion exchange.

Site of transition metal ions in ion-exchanged metal-doped glasses

2008 ◽  
Vol 149 (2) ◽  
pp. 171-176 ◽  
Author(s):  
C. Maurizio ◽  
F. D’Acapito ◽  
C. Sada ◽  
E. Cattaruzza ◽  
F. Gonella ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Transition Metal Ions ◽  
Doped Glasses ◽  
Metal Doped
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