Self-adduct formation in the extraction of cobalt(II) chelates of certain 8-quinolinols

1979 ◽  
Vol 57 (5) ◽  
pp. 580-585 ◽  
Author(s):  
Arvind T. Rane ◽  
Kashinath S. Bhatki
Keyword(s):  
Aqueous Solution ◽  
Ambient Temperature ◽  
Equilibrium Distribution ◽  
Formation Constants ◽  
Distribution Coefficients ◽  
Adduct Formation ◽  
The Self ◽  
Reagent Concentration ◽  
Pyramidal Structure ◽  
Cobalt Chelates

Equilibrium distribution ratios have been determined for the extraction of cobalt(II) with 8-quinolinol and its 2-methyl-, 4-methyl-, 5-chloro-, and 5-nitro- analogues into chloroform as a function of pH and reagent concentration at ambient temperature. Except in the case of 2-methyl-8-quinolinol, which formed a simple 1:2 chelate, the extractable complexes were mono-adducts, that is, 1:2 chelates to which a third molecule of the reagent was coordinated. The overall formation constants of the cobalt chelates in aqueous solution were determined. A linear correlationship was observed between the formation constants, adduct formation constants, and the basicity of the reagent. This dependence could be used to predict, based on known data, the stabilities of not yet studied complexes of cobalt with this family of ligands. The distribution coefficients of the chelates and the chelate adducts are discussed in terms of structural influences. A penta-coordinate, square pyramidal structure has been proposed for the self-adducts of cobalt(II) with 8-quinolinols (except 2-methyl analogue).

scholarly journals Self-Assembled Nanomaterials Based on Complementary Sn(IV) and Zn(II)-Porphyrins, and Their Photocatalytic Degradation for Rhodamine B Dye

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3598
Author(s):  
Nirmal K. Shee ◽  
Hee-Joon Kim
Keyword(s):  
Aqueous Solution ◽  
Visible Light Irradiation ◽  
Rhodamine B ◽  
Self Assembly ◽  
The Self ◽  
Assembly Process ◽  
Absorption Bands ◽  
Ligand Coordination ◽  
Rhodamine B Dye ◽  
Metal Ligand

A series of porphyrin triads (1–6), based on the reaction of trans-dihydroxo-[5,15-bis(3-pyridyl)-10,20-bis(phenyl)porphyrinato]tin(IV) (SnP) with six different phenoxy Zn(II)-porphyrins (ZnLn), was synthesized. The cooperative metal–ligand coordination of 3-pyridyl nitrogens in the SnP with the phenoxy Zn(II)-porphyrins, followed by the self-assembly process, leads to the formation of nanostructures. The red-shifts and remarkable broadening of the absorption bands in the UV–vis spectra for the triads in CHCl3 indicate that nanoaggregates may be produced in the self-assembly process of these triads. The emission intensities of the triads were also significantly reduced due to the aggregation. Microscopic analyses of the nanostructures of the triads reveal differences due to the different substituents on the axial Zn(II)-porphyrin moieties. All these nanomaterials exhibited efficient photocatalytic performances in the degradation of rhodamine B (RhB) dye under visible light irradiation, and the degradation efficiencies of RhB in aqueous solution were observed to be 72~95% within 4 h. In addition, the efficiency of the catalyst was not impaired, showing excellent recyclability even after being applied for the degradation of RhB in up to five cycles.

Fluorescence of the Complexes of 2-Methylnaphthoate and 2-Hydroxypropyl-α-, -β-, and -γ-Cyclodextrins in Aqueous Solution

2002 ◽  
Vol 56 (12) ◽  
pp. 1579-1587 ◽  
Author(s):  
Antonio Di Marino ◽  
Franscisco Mendicuti
Keyword(s):  
Aqueous Solution ◽  
Fluorescence Anisotropy ◽  
Intensity Ratio ◽  
Driving Forces ◽  
Emission Spectra ◽  
Formation Constants ◽  
Dielectric Constants ◽  
Additional Information ◽  
Fluorescence Techniques ◽  
Naturally Occurring

Fluorescence techniques were employed to study the inclusion complexes of 2-methylnaphthoate (MN) with 2-hydroxypropyl-α-cyclodextrin (αHPCD), 2-hydroxypropyl-β-cyclodextrin (βHPCD), and 2-hydroxypropyl-γ-cyclodextrin (γHPCD). Emission spectra of MN show two vibronic bands whose intensity ratio R is very sensitive to the polarity of the medium. The stoichiometry and formation constants of these complexes were investigated by obtaining R as a function of the cyclodextrin (CD) concentration. Results showed identical stoichiometry (1/1) for the three MN/αHPCD, MN/β-HPCD, and MN/γHPCD complexes. Formation constants at 25 °C were 780 ± 15, 2700 ± 130, and 165 ± 10 M−1, respectively. ΔH0 and ΔS0 were obtained from linear van't Hoff plots. Results reveal that the complexation of MN with αHPCD is enthalpy driven. With βHPCD, both the entropy and enthalpy terms favor the process, whereas the formation of the complex with γHPCD is entropically governed. The extrapolation of R at infinite CD concentration allows us to estimate the effective dielectric constants of the inner CD cavities, which are around 50, but which differ from their counterparts, the naturally occurring α-, β-, and γ-CDs. Fluorescence anisotropy, quencher lifetimes, and average lifetimes can also give additional information about the structure and driving forces accompanying the formation of such complexes.

scholarly journals Distinctive features of the self-association of deoxyhexanucleotide 5'-d(GpCpApTpGpC) and its complexation with anthracycline antibiotic daunomycin in aqueous solution

2004 ◽  
Vol 20 (6) ◽  
pp. 479-492
Author(s):  
A. N. Veselkov ◽  
R. J. Eaton ◽  
V. I. Pahomov ◽  
O. V. Rogova ◽  
V. S. Volynkin ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
The Self ◽  
Anthracycline Antibiotic ◽  
Distinctive Features ◽  
Self Association

A self-healing and multi-responsive hydrogel based on biodegradable ferrocene-modified chitosan

RSC Advances ◽  
2014 ◽  
Vol 4 (98) ◽  
pp. 55133-55138 ◽  
Author(s):  
Ya-Kun Li ◽  
Cheng-Gong Guo ◽  
Liang Wang ◽  
Youqian Xu ◽  
Chen-yang Liu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
The Self ◽  
Self Healing ◽  
Modified Chitosan ◽  
Acid Aqueous Solution ◽  
External Stimuli

Here, we present a novel and facile method for constructing a self-healing hydrogel with multi-responses to external stimuli via the self-assemble of biodegradable ferrocene-modified chitosan (FcCS) in an acid aqueous solution.

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