Rapid Semi-Micro Potentiometric Titration of Ir(IV) with Hydrazine Sulphate

The relative basicity of fifteen methylethoxysilylalkylamines of the type (CH3)3-m(C2H5O)m.Si(CH2)nNH2 in acetone has been studied by potentiometric titration. For n 1 the basicity increases with increasing m, which is likely due to increasing electronic interaction of the oxygen of acetone with the silicon of silylalkylamines. The basicity of silylmethylamines (n = 1) changes nonsystematically, probably as a consequence of the competing action of opposite effects.

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Synthesis and properties of 5-phenoxyfurancarboxylic acids

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19800910 ◽

1980 ◽

Vol 45 (3) ◽

pp. 910-913 ◽

Cited By ~ 1

Author(s):

Viera Knoppová ◽

Anton Beňo ◽

Jaroslav Kováč

Keyword(s):

Transfer Coefficient ◽

Potentiometric Titration ◽

Transfer Effect ◽

Furan Series ◽

Oxygen Bridge

Furancarboxylic acids were prepared by oxidation with Ag2O of the corresponding 5-(X-phenoxy)-2-furaldehydes (X = 4-OCH3, 4-SCH3, 3-NHCOCH3, 4-Cl, 4-Br, 4-COOC2H5, 3-NO2, and 4-NO2. The appearing pKa values of the synthesized acids were determined by potentiometric titration. The transfer effect of the substituents through the oxygen bridge is discussed and the transfer coefficient is compared with π' values of other linking groups in the furan series.

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The Unusual Role of Pro in Cu(II) Binding by His2-Cyclopentapeptide

International Journal of Molecular Sciences ◽

10.3390/ijms22126628 ◽

2021 ◽

Vol 22 (12) ◽

pp. 6628

Author(s):

Aleksandra Pieniężna ◽

Aleksandra Kotynia ◽

Justyna Brasuń

Keyword(s):

Amino Acid ◽

Potentiometric Titration ◽

Amino Acid Residue ◽

Strong Impact ◽

Mononuclear Complexes ◽

Study Results ◽

Metal Ratio ◽

Ph Range ◽

L1 And L2

In this paper, we present findings from studying the interaction of copper(II) ions with the His2-cyclopentapeptide and the role of proline used for the purpose of potentiometric titration and UV-Vis, CD and EPR spectroscopic measurements. Experiments of two homodetic peptides differing by one amino acid residue were conducted for a ligand to metal ratio of 1:1 in the pH range 2.5–11.0. The presented studies reveal that peptides form only mononuclear complexes, and the CuH2L complex appears in the system first (for both L1 and L2). Study results show that the presence of Pro influences the structure of formed complexes and their stabilities and has a strong impact on the efficiency of copper(II) coordination.

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