Humic Substances - Excited States, Quenching by Metal Ions, and Photosensitized Degradation of Chlorophenols

1997 ◽  
Vol 62 (8) ◽  
pp. 1159-1168 ◽  
Author(s):  
Kamil Lang ◽  
Dana M. Wagnerová ◽  
Šárka Klementová ◽  
Pavel Kubát
Keyword(s):  
Metal Ions ◽  
Humic Substances ◽  
Excited States ◽  
Fluorescence Spectra ◽  
Natural Waters ◽  
Static Quenching ◽  
Kinetic Spectroscopy ◽  
Laser Kinetic Spectroscopy ◽  
Photochemical Properties

Alteration of photochemical properties of humic substances (HS) by the addition of metals abundant in natural waters has been investigated. Excited HS states have been characterized by fluorescence spectra and by laser kinetic spectroscopy. The effect of Cu2+, Fe2+, and Mn2+ has been explained in terms of static quenching of the HS excited states. In agreement with this, the metal ions were found to inhibit HS sensitized photooxidative degradation of chlorophenols.

Synthesis and Photochemical Properties of Re(I) Tricarbonyl Complexes Bound to Thione and Thiazole-2-ylidene Ligands

2020 ◽  
Author(s):  
Matthew Stout ◽  
Brian Skelton ◽  
Alexandre N. Sobolev ◽  
Paolo Raiteri ◽  
Massimiliano Massi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Ligand Exchange ◽  
Ligand Substitution ◽  
Bidentate Ligand ◽  
The Other ◽  
Ligand Exchange Reaction ◽  
Multiple Products ◽  
Ligand Charge Transfer ◽  
Photochemical Properties

<p>Three Re(I) tricarbonyl complexes, with general formulation Re(N^L)(CO)<sub>3</sub>X (where N^L is a bidentate ligand containing a pyridine functionalized in the position 2 with a thione or a thiazol-2-ylidene group and X is either chloro or bromo) were synthesized and their reactivity explored in terms of solvent-dependent ligand substitution, both in the ground and excited states. When dissolved in acetonitrile, the complexes bound to the thione ligand underwent ligand exchange with the solvent resulting in the formation of Re(NCMe)<sub>2</sub>(CO)<sub>3</sub>X. The exchange was found to be reversible, and the starting complex was reformed upon removal of the solvent. On the other hand, the complexes appeared inert in dichloromethane or acetone. Conversely, the complex bound to the thiazole-2-ylidene ligand did not display any ligand exchange reaction in the dark, but underwent photoactivated ligand substitution when excited to its lowest metal-to-ligand charge transfer manifold. Photolysis of this complex in acetonitrile generated multiple products, including Re(I) tricarbonyl and dicarbonyl solvato-complexes as well as free thiazole-2-ylidene ligand.</p>

A phthalocyanine-based fluorescent sensor for Zn2+ ion

2013 ◽  
Vol 17 (01n02) ◽  
pp. 99-103 ◽  
Author(s):  
Hui He ◽  
Jian-Yong Liu ◽  
Dennis K.P. Ng
Keyword(s):  
Metal Ions ◽  
Spectral Properties ◽  
Fluorescence Spectra ◽  
Near Infrared ◽  
Fluorescent Sensor ◽  
High Sensitivity ◽  
Absorption And Fluorescence Spectra

This paper describes the preparation and spectral properties of a near-infrared fluorophore in which two bis(2-picolyl)amino moieties are axially linked to a silicon(IV) phthalocyanine core. The effects of various metal ions on its absorption and fluorescence spectra have been examined. The results indicate that this compound shows a high sensitivity and moderate selectivity toward Zn2+ ion.

scholarly journals Erratum to: Theoretical Study of the Electronic Excited States and Fluorescence Spectra of Squaraine in Solution

2014 ◽  
Vol 43 (9-10) ◽  
pp. 1644-1644
Author(s):  
Hitoshi Ozawa ◽  
Kazunori Yashiro ◽  
Takuma Yamamoto ◽  
Satoshi Yabushita
Keyword(s):  
Excited States ◽  
Fluorescence Spectra ◽  
Theoretical Study ◽  
Electronic Excited States

Rates of Reaction of Dissolved Oxygen With Scavengers in Sweet and Sour Brines

CORROSION ◽  
1969 ◽  
Vol 25 (10) ◽  
pp. 397-404 ◽  
Author(s):  
E. S. SNAVELY ◽  
F. E. BLOUNT
Keyword(s):  
Transition Metal ◽  
Dissolved Oxygen ◽  
Metal Ions ◽  
Induction Period ◽  
Natural Waters ◽  
Reaction Rate ◽  
Transition Metal Ions ◽  
Zero Order ◽  
Laboratory Apparatus ◽  
High Ph

Abstract Rates of reaction of dissolved oxygen with H2S were measured in a laboratory apparatus using a polarographic type instrument for the measurement of oxygen concentrations. Results show that oxidation occurs only at high pH in the absence of catalytic species. The reaction is catalyzed by transition metal ions in the order Ni++&gt;Co ++&gt;Mn++&gt;Cu++&gt;Fe++. In all cases, the reaction rate increases with pH and is at first complex but becomes zero-order with respect to oxygen after a brief induction period. Some natural waters contain sufficient catalysts that additional amounts are not required for scavenging O2 with SO2 or Na2SO3. Sour waters cannot be scavenged with SO2 or Na2SO3 because of ineffectiveness of catalysts.

OXIDATION OF HUMIC SUBSTANCES PRIOR TO THE DETECTION OF PCBs AND PAHs IN NATURAL WATERS BY FLUOROMETRY ON SOLID SORBENT

2005 ◽  
Vol 25 (5) ◽  
pp. 407-419 ◽  
Author(s):  
L. Belfatmi ◽  
S. Ait Lyazidi ◽  
M. Lamotte ◽  
Ph. Fornier de Violet
Keyword(s):  
Humic Substances ◽  
Natural Waters ◽  
Solid Sorbent

Complexation of Dissolved Organic Matter with Trace Metal Ions in Natural Waters

2012 ◽  
pp. 769-849 ◽  
Author(s):  
Khan M. G. Mostofa ◽  
Cong-qiang Liu ◽  
Xinbin Feng ◽  
Takahito Yoshioka ◽  
Davide Vione ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Trace Metal ◽  
Metal Ions ◽  
Natural Waters ◽  
Trace Metal Ions

The effect of the cobalt and manganese central metal ions on the nonlinear optical properties of tetra(4-propargyloxyphenoxy)phthalocyanines

2018 ◽  
Vol 42 (12) ◽  
pp. 9857-9864 ◽  
Author(s):  
D. Mwanza ◽  
M. Louzada ◽  
J. Britton ◽  
E. Sekhosana ◽  
S. Khene ◽  
...  
Keyword(s):  
Optical Properties ◽  
Metal Ions ◽  
Excited States ◽  
Nonlinear Optical ◽  
Nonlinear Optical Properties ◽  
Central Metal ◽  
Optical Limiters ◽  
Paramagnetic Complexes

The phthalocyanines were investigated as optical limiters. The paramagnetic complexes were not effective owing to quenching of the excited states.

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