Glycolaldehyde Monomer and Oligomer Equilibria in Aqueous Solution: Comparing Computational Chemistry and NMR Data

2013 ◽  
Vol 117 (14) ◽  
pp. 2997-3008 ◽  
Author(s):  
Jeremy Kua ◽  
Melissa M. Galloway ◽  
Katherine D. Millage ◽  
Joseph E. Avila ◽  
David O. De Haan
Keyword(s):  
Aqueous Solution ◽  
Computational Chemistry ◽  
Nmr Data ◽  
Equilibria In Aqueous Solution

Schiff base equilibria. II. Beryllium complexes of N-n-butylsalicylideneimine and the hydrolysis of the Be2+ ion

1965 ◽  
Vol 18 (5) ◽  
pp. 651 ◽  
Author(s):  
RW Green ◽  
PW Alexander
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Complex Formation ◽  
Distribution Coefficient ◽  
Dilute Aqueous Solution ◽  
The Stability ◽  
Ph Range ◽  
Hydrolysis Of ◽  
Beryllium Complexes ◽  
Equilibria In Aqueous Solution

The Schiff base, N-n-butylsalicylideneimine, extracts more than 99.8% beryllium into toluene from dilute aqueous solution. The distribution of beryllium has been studied in the pH range 5-13 and is discussed in terms of the several complex equilibria in aqueous solution. The stability constants of the complexes formed between beryllium and the Schiff base are log β1 11.1 and log β2 20.4, and the distribution coefficient of the bis complex is 550. Over most of the pH range, hydrolysis of the Be2+ ion competes with complex formation and provides a means of measuring the hydrolysis constants. They are for the reactions: Be(H2O)42+ ↔ 2H+ + Be(H2O)2(OH)2, log*β2 - 13.65; Be(H2O)42+ ↔ 3H+ + Be(H2O)(OH)3-, log*β3 -24.11.

scholarly journals DP4-Assisted Structure Elucidation of Isodemethylchodatin, a New Norlichexanthone Derivative Meager in H-Atoms, from the Lichen Parmotrema tsavoense

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1527 ◽  
Author(s):  
Thuc-Huy Duong ◽  
Mehdi A. Beniddir ◽  
Joël Boustie ◽  
Kim-Phi-Phung Nguyen ◽  
Warinthorn Chavasiri ◽  
...  
Keyword(s):  
Computational Chemistry ◽  
13C Nmr ◽  
Structure Elucidation ◽  
Methoxy Group ◽  
Chemical Shifts ◽  
13C Nmr Chemical Shifts ◽  
Nmr Data ◽  
Phytochemical Investigation ◽  
Integrated Interpretation ◽  
Foliose Lichen

A phytochemical investigation of the foliose lichen Parmotrema tsavoense (Krog and Swinscow) Krog and Swinscow (Parmeliaceae) resulted in the isolation of a new trichlorinated xanthone, isodemethylchodatin. The structure elucidation of this new norlichexanthone derivative proved tricky owing to proton deficiency, and to the lack of NMR data of closely related analogues. The structure of this compound was determined based on an integrated interpretation of 13C-NMR chemical shifts, MS spectra, and DP4-based computational chemistry was also performed to provide an independent and unambiguous validation of the determined structure. Isodemethylchodatin represents the first chlorinated lichexanthone/norlichexanthone derivative bearing a methoxy group at C-5.

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