A computational NQR study on the hydrogen-bonded lattice of cytosine-5-acetic acid

2008 ◽  
Vol 29 (5) ◽  
pp. 832-838 ◽  
Author(s):  
Mahmoud Mirzaei ◽  
Nasser L. Hadipour
Keyword(s):  
2005 ◽  
Vol 29 (11) ◽  
pp. 1390 ◽  
Author(s):  
Wei Wang ◽  
Shuling Gong ◽  
Yuanyin Chen ◽  
Jianpin Ma

1987 ◽  
Vol 40 (7) ◽  
pp. 1147 ◽  
Author(s):  
EJ Oreilly ◽  
G Smith ◽  
CHL Kennard ◽  
TCW Mak

The crystal structures of (2-formyl-6-methoxyphenoxy)acetic acid (1), diaquabis [(2-formyl-6-methoxyphenoxy) acetato ]zinc(11) (2), tetraaquabis [(2-chlorophenoxy) acetato ]zinc(11) (3), triaquabis [(2-chlorophenoxy) acetato ]cadmium(11) dihydrate (4) and lithium (2-chloro- phenoxy )acetate 1.5 hydrate (5) have been determined by X-ray diffraction. The acid (1) forms centrosymmetric hydrogen-bonded cyclic dimers [O…0, 2.677(6) �] which are non-planar. Complex (2) is six-coordinate with two waters [Zn- Ow , 1.997(2) �] and four oxygens from two asymmetric bidentate carboxyl groups [Zn-O, 2.073, 2.381(2) �] completing a skew trapezoidal bipyramidal stereochemistry. Complex (5) is also six-coordinate but is octahedral, with two trans-related unidentate carboxyl oxygens [mean Zn-O, 2.134(9) �] and four waters [mean Zn-O, 2.081(9) �]. The seven-coordinate complex (4) has crystallographic twofold rotational symmetry relating two :symmetric bidentate acid ligands [ Cd -O, 2.26, 2 48(:) �] and two waters [ Cd -O, 2.34(2) �] while the third water lies on this axis [ Cd -O, 2.27(2) �]. In contrast to the monomers (2)-(4), complex (5) is polymeric with tetrahedral lithium coordinated to one water and three carboxylate oxygens [mean Li-0, 1.95(1) �]. The essential conformation of the free acid is retained in complexes (2), (3) and (4) but in (5), it is considerably changed.


2014 ◽  
Vol 16 (41) ◽  
pp. 22458-22461 ◽  
Author(s):  
Jianping Wu

Gaussian analysis of Raman spectroscopy reveals three hydrogen bonding structures in the liquid acetic acid (AA): linear chains, cyclic dimers and dissociated monomers that effectively cooperate with hydrogen bonded stacks of linear AA or polymer chains.


1977 ◽  
Vol 31 (2) ◽  
pp. 110-115 ◽  
Author(s):  
P. F. Krause ◽  
J. E. Katon ◽  
J. M. Rogers ◽  
D. B. Phillips

The polarized infrared spectra of crystalline acetic acid and two of its deuterated derivatives, CH3COOD and CD3COOD, have been recorded from 400 to 4000 cm−1 at cryogenic temperatures. The spectroscopic results have been interpreted on the basis of a factor group analysis based on two structural models: a crystallographic cell composed of four interacting monomer units some of whose vibrational modes are highly perturbed by hydrogen bonding and a unit cell composed of two noninteracting acetic acid chains. The results are discussed in terms of possible interactions between the hydrogen-bonded acetic acid polymeric chains.


1995 ◽  
Vol 48 (4) ◽  
pp. 869 ◽  
Author(s):  
G Smith ◽  
EJ Oreilly ◽  
SA See ◽  
KA Byriel ◽  
CHL Kennard

The ring-substituted phenoxyacetic acid (2-benzoyl-5-methoxyphenoxy)acetic acid (HL) (3) and its complex adduct dimer (4) with sodium, [Na2(L)2(HL)2].2HL, have been synthesized and their structures determined by X-ray diffraction. The acid (3) does not have the usual cyclic hydrogen-bonded dimer association, but instead has three-centre intramolecular hydrogen bonding between the carboxyl proton and both the ether and keto oxygens [O---O, 2.602(3), 2.711(3) Ǻ respectively]. Each sodium in the centrosymmetric complex dimer (4) is seven-coordinate [Na-O, 2.313(5)-2.612(5) Ǻ], involving the 'inner' three oxygens of both a protonated and an ionic ligand molecule. In addition, one of these carboxyl oxygens forms a bridge to the inversion-related sodium, while the uncoordinated carboxyl oxygen is hydrogen-bonded to a protonated carboxy group [O---O, 2.464(8) Ǻ]. The molecules of the lattice acid have only one hydrogen-bonded association with the second uncoordinated carboxy group in the dimer [O---O, 2.513(7) Ǻ].


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