Additions and Corrections - Interactant Structure and Complex Stability for Complexes of Theophylline with Cinnamate Esters and Related Compounds in Aqueous Solution

1969 ◽  
Vol 91 (20) ◽  
pp. 5697-5697
Author(s):  
Kenneth Connors ◽  
Martin Infeld ◽  
Berry Kline
Keyword(s):  
Aqueous Solution ◽  
Complex Stability ◽  
Related Compounds

Pairwise Gibbs Energies of Interaction InvolvingN-Alkyl-2-pyrrolidinones and Related Compounds in Aqueous Solution Obtained from Kinetic Medium Effects

2000 ◽  
Vol 65 (2) ◽  
pp. 411-418 ◽  
Author(s):  
Joke J. Apperloo ◽  
Lisette Streefland ◽  
Jan B. F. N. Engberts ◽  
Michael J. Blandamer
Keyword(s):  
Aqueous Solution ◽  
Medium Effects ◽  
Gibbs Energies ◽  
Related Compounds

Host-Guest Complexation of Aromatic Carboxylic Acids and their Conjugate Bases by β-Cyclodextrins Monosubstituted at C 6 by Linear and Cyclic Alkyl Triamines in Aqueous Solution

1999 ◽  
Vol 52 (12) ◽  
pp. 1157 ◽  
Author(s):  
Suzanna D. Kean ◽  
Bruce L. May ◽  
Philip Clements ◽  
Christopher J. Easton ◽  
Stephen F. Lincoln
Keyword(s):  
Aqueous Solution ◽  
Carboxylic Acid ◽  
Complex Stability ◽  
Guest Complex ◽  
Acid Complex ◽  
K Value ◽  
Host Guest Complex ◽  
Ph Range ◽  
Conjugate Bases ◽  
Significant Factors

A pH titrimetric study of the complexation of the guests benzoic acid, 4-methylbenzoic acid and (R)- and (S)-2-phenylpropanoic acids and their conjugate bases by the host 6A-[2-(2-aminoethylamino)ethylamino]-, 6A-[3-(3-aminopropylamino)propylamino]-, 6A-(1,4,7-triazacyclononan-1-yl)-, and 6A-(1,5,9-triazacyclododecan-1-yl)-6A-deoxy-β-cyclodextrins (βCDdien, βCDdipn, βCDtacn and βCDtacdo, respectively) is reported. Over the pH range 3.0–11.0, 49 host–guest complexes were detected. Their stability constants (K) range from 220±50 dm3 mol–1 for the βCDdienH22+ ·benzoate– complex to 48000±11000 dm3 mol–1 for the βCDdipnH22+·(S)-2-phenylpropanoic acid complex at 298.2 K and I = 0.10 mol dm–3 (NaClO4). The latter K value is among the highest reported for a complex of a simple carboxylic acid with a substituted β-cyclodextrin. The charge, hydrophobicity and stereochemistry of both host and guest appear to be significant factors in the variation of host–guest complex stability. 1H ROESY n.m.r. studies of some of the complexes formed are also reported.

DETERMINATION OF GLYCEROL AND RELATED COMPOUNDS IN FERMENTATION SOLUTIONS BY PARTITION CHROMATOGRAPHY

1950 ◽  
Vol 28b (9) ◽  
pp. 535-540 ◽  
Author(s):  
A. C. Neish
Keyword(s):  
Aqueous Solution ◽  
Periodate Oxidation ◽  
Colorimetric Determination ◽  
Partition Chromatography ◽  
Sugar Alcohols ◽  
Modified Technique ◽  
Silica Column ◽  
To Receive ◽  
Related Compounds

A modified technique is described for applying partition chromatography, using a silica column, to the separation of simple organic compounds which are difficult to extract from water. An aqueous solution is pipetted directly on a Celite–water column the upper 15% of which has been left dry to receive it. Acetoin, 2, 3-butanediol, 1, 2-propanediol, ethanediol, glycerol, and erythritol can be separated from each other and from sugars and sugar alcohols containing five or more carbon atoms if the column is properly developed by ethyl acetate and benzene–butanol mixtures. After separation the compounds can be estimated by a rapid colorimetric determination of the acetaldehyde or formaldehyde formed by periodate oxidation. The recoveries are quantitative, thus making it possible to determine 1 to 2 mgm. of glycerol or 2, 3-butanediol within an error of ± 3% even when they are mixed with larger amounts of closely related compounds which cause interference in the usual methods.

The Fine Structure of Cytosine

1962 ◽  
Vol 15 (4) ◽  
pp. 851 ◽  
Author(s):  
DJ Brown ◽  
M Lyall
Keyword(s):  
Aqueous Solution ◽  
Nuclear Magnetic Resonance ◽  
Fine Structure ◽  
Magnetic Resonance ◽  
Nuclear Magnetic Resonance Spectrum ◽  
Tautomeric Form ◽  
Resonance Spectrum ◽  
Ionization Constants ◽  
Recent Formulation ◽  
Related Compounds

The ionization constants and ultraviolet spectra of cytosine, of its appropriately methylated derivatives, and of related compounds are used to indicate that its pre- dominant tautomeric form in aqueous solution is 4-amino-1,2-dihydro-2-oxopyrimidine. This is in sharp contrast to its recent formulation as a zwitterion on the grounds of its nuclear magnetic resonance spectrum.

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