pH-Specific Synthesis of a Dinuclear Vanadium(V)−Peroxo−Citrate Complex in Aqueous Solutions:  pH-Dependent Linkage, Spectroscopic and Structural Correlations with Other Aqueous Vanadium(V)−Peroxo−Citrate and Non-Peroxo Species

2004 ◽  
Vol 43 (9) ◽  
pp. 2895-2905 ◽  
Author(s):  
M. Kaliva ◽  
C. P. Raptopoulou ◽  
A. Terzis ◽  
A. Salifoglou
Keyword(s):  
Aqueous Solutions ◽  
Citrate Complex ◽  
Ph Dependent ◽  
Specific Synthesis

Vanadium(IV)−Citrate Complex Interconversions in Aqueous Solutions. A pH-Dependent Synthetic, Structural, Spectroscopic, and Magnetic Study

2001 ◽  
Vol 40 (23) ◽  
pp. 5772-5779 ◽  
Author(s):  
M. Tsaramyrsi ◽  
M. Kaliva ◽  
A. Salifoglou ◽  
C. P. Raptopoulou ◽  
A. Terzis ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Magnetic Study ◽  
Citrate Complex ◽  
Ph Dependent

scholarly journals Circular Dichroism of Chromopeptides from Phycocyanin

1983 ◽  
Vol 38 (11-12) ◽  
pp. 951-959 ◽  
Author(s):  
C. Schamagl ◽  
E. Köst-Reyes ◽  
S. Schneider ◽  
H.-P. Köst ◽  
H. Scheer
Keyword(s):  
Circular Dichroism ◽  
Aqueous Solutions ◽  
Optical Activity ◽  
Ph Dependence ◽  
Acidic Ph ◽  
Sign Reversal ◽  
Aqueous Buffer ◽  
Ph Dependent ◽  
Circular Dichroïsm

The circular dichroism of bilipeptides from Spirulina geitleri phycocyanin is strongly solvent and pH dependent. Maximum optical activity has been observed in aqueous solutions containing urea (8 ᴍ). In aqueous buffer, a sign reversal occurred upon the change from neutral to acidic pH; in methanolic solutions shows the optical activity a strong pH dependence both with respect to sign and magnitude. These findings have been rationalized by the presence of chrom ophorepeptide interactions, which are minimized in the presence of urea. M olecular orbital calculations indicate that the observed sign reversal is not necessarily due to a reversal of the chirality of the entire chromophore, but may also result from more localized conform ational changes

11B and 10B NMR Investigations in Aqueous Solutions

1986 ◽  
Vol 41 (5) ◽  
pp. 737-742 ◽  
Author(s):  
R. Balz ◽  
U. Brändle ◽  
E. Kämmerer ◽  
D. Köhnlein ◽  
O. Lutz ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Isotope Effect ◽  
Chemical Shifts ◽  
Relaxation Mechanism ◽  
Magnetic Shielding ◽  
Solvent Isotope Effect ◽  
Weighted Averages ◽  
Dilute Aqueous Solutions ◽  
Ph Dependent ◽  
Solvent Isotope

11B NMR chemical shifts and linewidths have been measured in very dilute aqueous solutions of boric acid and borates. The results can be explained bv taking pH dependent weighted averages over the species B(OH)3 and B(OH)4−. The11B−10B primary isotope effect on the magnetic shielding is smaller then 3 · 10-8. The H2O - D2O solvent isotope effect on T1 has been established for 11B and 10B in the species mentioned, and from the ratios of T1 the quadrupolar origin of the relaxation mechanism has been inferred.

Structural diversity of a series of coordination polymers built from 5-substituted isophthalic acid with or without a methyl-functionalized N-donor ligand

CrystEngComm ◽  
2016 ◽  
Vol 18 (8) ◽  
pp. 1363-1375 ◽  
Author(s):  
De-Yun Ma ◽  
Liang Qin ◽  
Jia-Mei Lei ◽  
Yun-Qiu Liang ◽  
Wei-Jie Lin ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Coordination Polymers ◽  
Structural Diversity ◽  
Luminescent Properties ◽  
Isophthalic Acid ◽  
Donor Ligand ◽  
Zinc Cadmium ◽  
Ph Dependent

Nine new zinc/cadmium-based CPs derived from X-H2BDC (X = H, Br, NO2 and CH3) and methyl-functionalized dmbpy ligands have been prepared. Their luminescent properties and the pH-dependent stabilities in aqueous solutions were investigated.

Insight into the degradation of a manganese(III)-citrate complex in aqueous solutions

2011 ◽  
Vol 65 (3) ◽  
Author(s):  
Adrian Topolski
Keyword(s):  
Aqueous Solutions ◽  
Reaction Rate ◽  
Electron Transfer Process ◽  
Ph Profile ◽  
Reduction Potentials ◽  
Citrate Complex ◽  
Basic Solutions ◽  
Ph Range ◽  
Kinetics Of ◽  
Insight Into

AbstractKinetics of the electron transfer process between citrates and manganese(III) ions has been studied in acidic aqueous solutions. Acidification of the reaction mixture increased the reaction rate. The reaction is dependent on pH because there are two main protolytic forms of the Mn(III)-citrate complex in the studied pH range (4.5–6.5). Reduction potentials of Mn(III)/Mn(II) system in acidic and basic solutions as well as protolytic equilibria play a crucial role in understanding the pH profile of the studied system. The rate constants for Mn(III)citH and Mn(III)citH2+ species degradation processes are presented (citH3− and citH22− are trivalent and divalent anions of citric acid, citH4, respectively). Protolytic constant (expressed as pK′a) for Mn(III)citH protonation is estimated and discussed.

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