scholarly journals Multiple Optical Features In Binary-Transition-Metal Borate Glasses

2021 ◽  
Author(s):  
Moukhtar A. Hassan ◽  
M. A. Ashoush ◽  
F. M. Ebrahim ◽  
M. M. EL Hady ◽  
F. Ahmad ◽  
...  
Keyword(s):  
Transition Metal ◽  
Borate Glasses ◽  
Optical Transitions ◽  
Structural Modifications ◽  
Spin Resonance ◽  
Infrared Spectral ◽  
Opposite Behavior ◽  
Racah Parameters ◽  
Cr Concentration ◽  
Metal Borate

Abstract Glasses doped with transition metal (TM) ions exhibit rich optical transitions spanning the entire ultraviolet, visible, and infrared spectral regimes. Here we utilize the melt-quenching techniques to synthesis binary-TM-doped borate glasses of composition xCuO-(75-x)B2O3-24.7Li2O-0.3Cr2O3, with x = 0, 0.2, 1.0 and 2.0 mol %. We identify several optical transitions from Cr3+, Cr6+, and Cu2+ ions, the latter manifests at longer wavelengths and gains higher intensity with Cu additives. Despite Cr concentration being fixed, the Cr6+ peaks are quenched and Cr3+ signals are barely attenuated. This behavior rules out possible phase separation and suggests non-trivial interplay between the two TM ions and ligand, as supported by probing their oxidation states from electron spin resonance. The crystal field and Racah parameters followed an opposite behavior, while the optical band gap is reduced upon doping. These changes are correlated with structural modifications introduced by Cu additives, where we anticipate homogenous and preferential proximity of Cu-Cr ions within the network.

FTIR SPECTRAL ANALYSIS ON HEAVY METAL BORATE GLASSES

2006 ◽  
Vol 20 (10) ◽  
pp. 533-538 ◽  
Author(s):  
B. KARTHIKEYAN
Keyword(s):  
Heavy Metal ◽  
Spectral Analysis ◽  
Structural Analysis ◽  
Transition Metal ◽  
Metal Ion ◽  
Ion Concentration ◽  
Borate Glasses ◽  
Melt Quenching ◽  
Ftir Spectral Analysis ◽  
Metal Borate

Inorganic heavy metal borate glasses were prepared through the melt quenching technique. Two sets of glasses were prepared, the compositions are (wt.%) 35 Bi 2 O 3+(50-x) B 2 O 3+15 Na 2 O +x PbO , where x=0, 10, 20, 30 and 35 MO +30 Na 2 O +35 B 2 O 3 ( MO = Bi 2 O 3, PbO , ZnO ). The FTIR structural analysis was made. These glasses have different borate groups and it mainly depends on the modifier/metal ion concentration. The influence of heavy metal and transition metal ion on the borate network were also identified.

scholarly journals Optical Transitions from Hexavalent Chromium in Lithium-Borate Glasses

2021 ◽  
Author(s):  
Dhia-Aldin Slibi ◽  
Moukhtar Hassan ◽  
Zakaria M. Abd El-Fattah ◽  
M. Atallah ◽  
M. A. El-Sherbiny ◽  
...  
Keyword(s):  
Optical Band Gap ◽  
Oxidation States ◽  
Resonance Spectroscopy ◽  
Borate Glasses ◽  
Optical Transitions ◽  
Melt Quenching ◽  
Glass Color ◽  
Spin Resonance ◽  
Optical Applications ◽  
Cr Doping

Abstract The melt-quenching technique was used to prepare a series of chromium-doped borate glasses with the composition xCr2O3 - (70-x) B2O3- 30 Li2O- (x = 0, 0.1, 0.2, 0.3 and 0.5 mol %). The low-doping level here employed allowed to unambiguously identify well-defined near-edge Cr6+ optical transitions, and to precisely determine the optical band gap of the borate glass host. Additional Cr3+ transitions were observed in the visible regime, rendering a strong modulation of the glass color, from colorless to dark greenish, with Cr content. Both Cr6+(after the charge transfer transformation into Cr5+) and Cr3+oxidation states and their variations with Cr doping were identified from electron spin resonance spectroscopy. All samples exhibit similar vibrational spectra dominated by BO3 and BO4 structural units, with the development of weak Cr6+ vibration with Cr doping. The present study provides structurally similar but optically active and tunable glass hosts suitable for various optical applications.

scholarly journals Multiple optical features in binary-transition-metal borate glasses

2021 ◽  
Vol 53 (8) ◽  
Author(s):  
Moukhtar A. Hassan ◽  
M. A. Ashoush ◽  
F. M. Ebrahim ◽  
M. M. EL-Hady ◽  
F. Ahmad ◽  
...  
Keyword(s):  
Transition Metal ◽  
Borate Glasses ◽  
Metal Borate

scholarly journals Ru(II)-Dppz Derivatives and Their Interactions with DNA: Thirty Years and Counting

2021 ◽  
Vol 11 (7) ◽  
pp. 3038
Author(s):  
Maria Letizia Di Pietro ◽  
Giuseppina La Ganga ◽  
Francesco Nastasi ◽  
Fausto Puntoriero
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Small Molecules ◽  
Transition Metal Complexes ◽  
Mechanism Of Action ◽  
Spectroscopic Techniques ◽  
Biological Applications ◽  
Ancillary Ligands ◽  
Structural Modifications ◽  
Over Time

Transition metal complexes with dppz-type ligands (dppz = dipyrido[3,2-a:2′,3′-c]phenazine) are extensively studied and attract a considerable amount of attention, becoming, from the very beginning and increasingly over time, a powerful tool for investigating the structure of the DNA helix. In particular, [Ru(bpy)2(dppz)]2+ and [Ru(phen)2(dppz)]2+ and their derivatives were extensively investigated as DNA light-switches. The purpose of this mini-review, which is not and could not be exhaustive, was to first introduce DNA and its importance at a biological level and research in the field of small molecules that are capable of interacting with it, in all its forms. A brief overview is given of the results obtained on the Ru-dppz complexes that bind to DNA. The mechanism of the light-switch active in this type of species is also briefly introduced along with its effects on structural modifications on both the dppz ligand and the ancillary ligands. Finally, a brief mention is made of biological applications and the developments obtained due to new spectroscopic techniques, both for understanding the mechanism of action and for cellular imaging applications.

Electron resonance studies of transition metal oxyions, I. Experimental results for the manganate, hypomanganate and ferrate ions

1960 ◽  
Vol 254 (1276) ◽  
pp. 101-110 ◽  
Keyword(s):  
Electron Spin Resonance ◽  
Transition Metal ◽  
Single Crystals ◽  
Molecular Orbital ◽  
Electron Spin ◽  
Potassium Chromate ◽  
Tetrahedral Structure ◽  
Spin Hamiltonians ◽  
Spin Resonance ◽  
Qualitative Nature

Detailed electron spin resonance studies of single crystals of potassium chromate containing manganate and ferrate ions and of potassium orthovanadate containing hypom anganate ions are described and the appropriate spin Hamiltonians are determined. The results confirm the tetrahedral structure of these ions and the assignation of spin S = 1 to ferrate and hypomanganate. A discussion of the qualitative nature of the results shows that the unpaired electrons in these ions occupy a doubly degenerate molecular orbital.

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