scholarly journals A Novel Calix[4]Crown-Based 1,3,4-Oxadiazole as a Fluorescent Chemosensor for Copper(II) Ion Detection

2021 ◽  
Vol 9 ◽  
Author(s):  
Chun Sun ◽  
Siyi Du ◽  
Tianze Zhang ◽  
Jie Han
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Earth Metal ◽  
Transition Metal Ions ◽  
Fluorescent Chemosensor ◽  
Acetonitrile Solution ◽  
Electron Transfer Mechanism ◽  
Alkaline Earth Metal Ions ◽  
Photo Induced Electron Transfer ◽  
Metal Ion Exchange

The synthesis and characterization of a novel florescent chemosensor 1 with two different types of cationic binding sites have been reported in this work, which is a calix[4]crown derivative in 1,3-alternate conformation bearing two 2-phenyl-5-(4-dimethylaminopyenyl)-1,3,4-oxadiazole units. The recognition behaviors of 1 in dichloromethane/acetonitrile solution to alkali metal ions (Na+ and K+), alkaline earth metal ions (Mg2+ and Ca2+), and transition metal ions (Co2+, Ni2+, Zn2+, Cd2+, Cu2+, Mn2+, and Ag+) have been investigated by UV-Vis and fluorescence spectra. The fluorescence of 1 might be quenched selectively by Cu2+ due to the photo-induced electron transfer mechanism, and the quenched emission from 1 could be partly revived by the addition of Ca2+ or Mg2+; thus, the receptor 1 might be worked as an on–off switchable fluorescent chemosensor triggered by metal ion exchange.

X-Ray Crystal Structure, Acid - Base Properties and Complexation Characteristics of a Methylenephosphonate Derivative of 1,4,7,10-Tetraazacyclododecane

2009 ◽  
Vol 62 (12) ◽  
pp. 1583 ◽  
Author(s):  
Ute Kreher ◽  
Milton T. W. Hearn ◽  
Leone Spiccia
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Dissociation Constants ◽  
Earth Metal ◽  
Intramolecular Hydrogen Bonding ◽  
Transition Metal Ions ◽  
Acid Base ◽  
Complex Formation Constants ◽  
X Ray ◽  
Alkaline Earth Metal Ions

The X-ray crystal structures of 1,4,7-tris(methylenephosphonate)-1,4,7,10-tetraazacyclododecane (DO3P·3.5H2O) and 1,7-bis(methylenephosphonate)-1,4,7,10-tetraazacyclododecane dihydrochloride trihydrate (DO2P·2HCl·3H2O) reveal that two nitrogen atoms in the trans-annular positions are protonated. The macrocyclic ring adopts a (3,3,3,3)-B conformation stabilized by intramolecular hydrogen bonding involving oxygen atoms from the phosphonate groups and the protonated amines. The acid–base dissociation constants of DO3P and metal complex formation constants (for Ca2+, Mg2+, Zn2+, Fe3+) were determined using potentiometric measurements. The first two protonations of DO3P occur at quite high pH and, consequently, were determined by NMR measurements. The stability constants indicate that DO3P forms more stable complexes with the transition metal ions Zn2+ and Fe3+ (log K [ML] = 21.23(4) and 22.74(5) respectively) than with the alkaline earth metal ions Ca2+ and Mg2+ (log K [ML] = 10.96(6) and 8.72(6) respectively). For Fe3+, Ca2+ and Mg2+, the data support the formation of dinuclear species, presumably through the coordination of an additional metal ion to the phosphonate groups.

scholarly journals Electrochemical Studies for Cation Recognition with Diazo-Coupled Calix[4]arenes

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Bongsu Kim ◽  
Tae Hyun Kim
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Transition Metal Ions ◽  
Ester Group ◽  
Divalent Metal Ions ◽  
Alkaline Earth Metal Ions ◽  
Cation Recognition

The electrochemical properties of diazophenylcalix[4]arenes bearingortho-carboxyl group (o-CAC) andortho-ester group (o-EAC), respectively, in the presence of various metal ions were investigated by voltammetry in CH3CN.o-CAC ando-EAC showed voltammetric changes toward divalent metal ions and no significant changes with monovalent alkali metal ions. However,o-CAC preferentially binds with alkaline earth and transition metal ions, whereas no significant changes in voltammetric signals are observed ino-EAC with alkaline earth metal ions.o-EAC only binds with other transition metal ions. This can be explained on metal ion complexation-induced release of proton from the azophenol to the quinone-hydrazone tautomer followed by internal complexation of the metal ion with aid of nitrogen atoms andortho-carbonyl groups in the diazophenylazocalix[4]arenes.

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.

A simple fluorescent chemosensor for alkaline-earth metal ions

2000 ◽  
Vol 136 (1-2) ◽  
pp. 49-52 ◽  
Author(s):  
Luca Prodi ◽  
Roberto Ballardini ◽  
Maria Teresa Gandolfi ◽  
Roberta Roversi
Keyword(s):  
Metal Ions ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Fluorescent Chemosensor ◽  
Alkaline Earth Metal ◽  
Alkaline Earth Metal Ions

Effects of alkaline earth metal ions on the growth of Calothrix strain RC3, a natural isolate from Rock Creek, British Columbia

1998 ◽  
Vol 44 (2) ◽  
pp. 128-139 ◽  
Author(s):  
Susanne Douglas
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Alkaline Earth ◽  
Cell Envelope ◽  
Earth Metal ◽  
Outer Membrane Vesicles ◽  
Natural Environments ◽  
Filamentous Cyanobacterium ◽  
Photosynthetic Membrane ◽  
Alkaline Earth Metal Ions

Calothrix is a filamentous cyanobacterium that has a single terminal heterocyst and a tapering morphology. It exists in two forms: mature filaments as described and motile hormogonia, which have a distinct morphology and serve as a dispersal mechanism for the organism. These cyanobacteria are common inhabitants of freshwater environments, where they are subjected to a variety of fluctuating conditions, including levels of dissolved metal ions. The present study represented an initial investigation of the effects of increasing metal ion concentrations on Calothrix as assessed ultrastructurally by transmission electron microscopy and through alterations observable by light microscopy and growth studies. Exposure of filaments to various levels of the alkaline earth cations Ca2+, Mg2+, Sr2+, and Ba2+ led to various changes in structure, indicating effects on the organism's physiology. These included perturbation of cell envelope layers, such that the formation of outer membrane vesicles was enhanced, alteration to the patterns and abundance of sheath material formed, alteration of thylakoid (photosynthetic) membrane structure, and inhibition of hormogonium formation and release. It was interesting to note that even cations that are not typically thought of as toxic (Ca2+ and Mg2+) could have profound effects on the cells to the extent of inhibiting growth at the maximum levels used in this study (5 mM), which are below these often found in natural environments. These results give an indication that the presence of metal ions in natural environments can have an important influence on the structural and growth characteristics of commonly found cyanobacteria to the extent of making them appear, on a macroscopic basis, as different organisms entirely. This puts a note of caution on future field observations and interpretations of the effects of pollutants on natural microbial communities.Key words: cyanobacteria, metals, ultrastructure.

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