Hydrogen bonding to divalent sulfur

2008 ◽  
Vol 10 (28) ◽  
pp. 4113 ◽  
Author(s):  
Daryl L. Howard ◽  
Henrik G. Kjaergaard
1997 ◽  
Vol 53 (4) ◽  
pp. 696-701 ◽  
Author(s):  
F. H. Allen ◽  
C. M. Bird ◽  
R. S. Rowland ◽  
P. R. Raithby

The hydrogen-bond acceptor ability of divalent sulfur in Y—S—Z systems, Y, Z= C, N, O or S, and the donor ability of thiol S—H have been studied using crystallographic data retrieved from the Cambridge Structural Database. Of 1811 Y—S—Z substructures that co-occur with N—H or O—H donors, only 86 (4.75%) form S...H—N,O bonds within S...H < 2.9 Å. In dialkylthioethers, the frequency of S...H bond formation is 6.24%, but drops below 3% when the alkyl groups are successively replaced by Csp 2 centres. This parallels an increasing \delta-positivity of S as calculated using ab initio methods. A similar frequency trend is observed for O...H—N,O bond formation by analogous oxyethers. Mean intermolecular >S...H distances for O—H [2.67 (3) Å] and N—H [2.75 (2) Å] donors (with H positions normalized to neutron values) are ca 0.25 Å longer than in C=S...H—N,O systems, indicative of very weak hydrogen bonding to >S. Intramolecular >S...H are slightly more frequent (8.56%), with S...H slightly shorter than for the intermolecular case. In contrast, 26 (70.3%) out of 37 S—H donors that co-occur with suitable acceptors form X...H—S bonds. The C=O...H—S system is predominant with a mean O...H distance of 2.34 (4) Å, considerably longer (weaker) than in C=O...H—O systems.


2000 ◽  
Vol 98 (3) ◽  
pp. 125-134 ◽  
Author(s):  
T. Weitkamp, J. Neuefeind, H. E. Fisch

1968 ◽  
Vol 65 ◽  
pp. 1587-1589 ◽  
Author(s):  
Bithika Ghosh ◽  
Sadhan Basu
Keyword(s):  

10.1002/jcc.2 ◽  
1996 ◽  
Vol 17 (16) ◽  
pp. 1804-1819 ◽  
Author(s):  
Attila Kov�cs ◽  
Istv�n Kolossv�ry ◽  
G�bor I. Csonka ◽  
Istv�n Hargittai

2017 ◽  
Vol 5 (4) ◽  
pp. 26-32 ◽  
Author(s):  
Azaria Robiana ◽  
M. Yashin Nahar ◽  
Hamidah Harahap

Glycerin residue is waste oleochemical industry that still contain glycerin. To produce quality and maximum quantity of glycerin, then research the effect of pH acidification using phosphoric acid. Glycerin analysis includes the analysis of pH, Fatty Acid and Ester (FAE), and analysis of the levels of glycerin. The maximum yield obtained at pH acidification 2 is grading 91,60% glycerin and Fatty Acid and Ester (FAE) 3,63 meq/100 g. Glycerin obtained is used as a plasticizer in the manufacture of bioplastics. Manufacture of bioplastics using the method of pouring a solution with varying concentrations of starch banana weevil (5% w/v and 7% w/v), variations of the addition of glycerin (1 ml, 3 ml, 5 ml and 7 ml), and a variety of gelatinization temperature (60°C, 70°C, and 80°C). Analysis of bioplastics include FTIR testing, tensile strength that is supported by SEM analysis. The results obtained in the analysis of FTIR does not form a new cluster on bioplastics starch banana weevil, but only a shift in the recharge area only, it is due to the addition of O-H groups originating from water molecules that enter the polysaccharide through a mechanism gelatinitation that generates interaction hydrogen bonding strengthened. The maximum tensile strength of bioplastics produced at a concentration of starch 7% w/v, 1 ml glycerine and gelatinization temperature of 80°C is 3,430 MPa. While the tensile strength bioplastic decreased with increasing glycerin which can be shown from the results of SEM where there is a crack, indentations and lumps of starch insoluble.


1963 ◽  
Vol 119 (3-4) ◽  
pp. 252-256 ◽  
Author(s):  
Brahama D. Sharma ◽  
Richard E. Marsh ◽  
Jerry Donohue
Keyword(s):  

Author(s):  
Z. Cheng ◽  
Y. Cheng ◽  
L. Guo ◽  
D. Xu

AbstractThe crystal structure of the title compound D(H)LAP with chemical formula (D


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