The C5‐substituent effects on the formic acid‐assisted tautomerization of protonated cytosine: A lower isomerization barrier and potential biological importance

2021 ◽  
Author(s):  
Lingxia Jin ◽  
Mengdan Lv ◽  
Shengnan Shi ◽  
Jiufu Lu ◽  
Qin Wang ◽  
...  
Keyword(s):  
Formic Acid ◽  
Substituent Effects ◽  
Biological Importance ◽  
Protonated Cytosine

Formic acid catalyzed isomerization of protonated cytosine: a lower barrier reaction for tautomer production of potential biological importance

2017 ◽  
Vol 19 (21) ◽  
pp. 13515-13523 ◽  
Author(s):  
Lingxia Jin ◽  
Mengdan Lv ◽  
Mengting Zhao ◽  
Rui Wang ◽  
Caibin Zhao ◽  
...  
Keyword(s):  
Formic Acid ◽  
Unimolecular Reaction ◽  
Small Reduction ◽  
Biological Importance ◽  
Acid Catalyzed ◽  
Protonated Cytosine

Isomerization barrier for isolated unimolecular reaction is quite high, and its probability may be very small. Reduction of isomerization barrier is over 36 kJ mol−1 in going from H2O to HCOOH⋯H2O group catalysts.

scholarly journals Correction: Formic acid catalyzed isomerization of protonated cytosine: a lower barrier reaction for tautomer production of potential biological importance

2017 ◽  
Vol 19 (48) ◽  
pp. 32741-32741
Author(s):  
Lingxia Jin ◽  
Mengdan Lv ◽  
Mengting Zhao ◽  
Rui Wang ◽  
Caibin Zhao ◽  
...  
Keyword(s):  
Formic Acid ◽  
Chem Phys ◽  
Biological Importance ◽  
Acid Catalyzed ◽  
Protonated Cytosine ◽  
Phys Chem Chem Phys

Correction for ‘Formic acid catalyzed isomerization of protonated cytosine: a lower barrier reaction for tautomer production of potential biological importance’ by Lingxia Jin et al., Phys. Chem. Chem. Phys., 2017, 19, 13515–13523.

Structure and Conformation of Photosynthetic Pigments and Related Compounds 9 On the Structure and Macrocycle Conformation of Two Copper(II) Rhodochlorin Derivatives and Two Related Rhodoporphyrins

1995 ◽  
Vol 50 (6) ◽  
pp. 969-981 ◽  
Author(s):  
Mathias O. Senge ◽  
Karin Ruhlandt-Senge ◽  
Shwn-Ji H. Lee ◽  
Kevin M. Smith
Keyword(s):  
Crystal Structure ◽  
Acetic Acid ◽  
Formic Acid ◽  
Photosynthetic Pigments ◽  
Dimethyl Ester ◽  
Substituent Effects ◽  
Crystal Data ◽  
Free Base ◽  
The Mean ◽  
Related Compounds

Crystal structure analyses of (rhodochlorinato-15-acetic trimethyl ester)copper(II) 3 and (31, 32-didehydro-rhodochlorinato-15-formic acid trimethyl ester)copper(II) 4 reveal intriguing multiple macrocycle conformations of the metallochlorins in the crystal. The observed conformations range from almost planar macrocycles to distorted macrocycles with individual atoms being displaced up to 0.72 Å from the mean plane. The nonplanar macrocycles show a S4-ruffled macrocycie distortion with significant distortions for the meso-carbons and tilting of the Cb- Cb axes. A comparison with the related free base porphyrins rhodoporphyrin-15- acetic acid trimethyl ester 5 and rhodoporphyrin dimethyl ester 6 shows that the conformational distortion is due to the mixing of metal and substituent effects, hydroporphyrin character, and packing forces. Crystal data: 3, monoclinic, P21, a = 12.096(4) Å, b - 14.307(4) Å, c = 22.343(9) Å , β = 104.94(4)°, Z = 4 (2 indep. mol.), R = 0.069 for 8141 reflections with I > 2.0σ(I); 4, triclinic, P 1, a = 10.528(3) Å . b - 10.646(4) Å, c = 34.026(13) Å, α = 89.81(4)°, β = 88.72(3)°, γ = 60.38(2)°, Z = 4 (4 indep. mol.). R = 0.073 for 9446 reflections with I > 2.5σ(I); 5, triclinic, P 1̄, a = 9.591(2) Å, b = 12.959(4) Å, c = 13.453(4) Å, α = 105.86(2)°, β = 92.67(2)°, γ = 96.12(2)°, Z = 2, R = 0.060 for 4990 reflections with I > 2.5 σ(I); 6, triclinic, P 1̄, a = 8.908(4) Å, b = 12.895(5) Å, c = 13.482(6) Å , α = 102.74(3)°, β = 90.38(4)°, γ = 91.84(3)°, Z = 2, R = 0.089 for 3369 reflections with I > 2.0σ(I).

Crystallographic Studies and Physicochemical Properties of π-Electron Systems, Part 7 Refinement of the Crystal and Molecular Structure of p-N,N-Dimethylaminobenzoic Acid, Full ab initio STO-3G Optimization of its Molecular Geometry, and Empirical Analysis of Substituent Effects on the Geometry of Benzene Rings in p-Substituted Benzoic Acids

1987 ◽  
Vol 42 (7) ◽  
pp. 917-927 ◽  
Author(s):  
R. Anulewicz ◽  
G. Häfelinger ◽  
T. M. Krygowski ◽  
C. Regelmann ◽  
G. Ritter
Keyword(s):  
Molecular Structure ◽  
Benzoic Acid ◽  
Formic Acid ◽  
Crystal And Molecular Structure ◽  
Substituent Effects ◽  
Molecular Geometry ◽  
Benzoic Acids ◽  
Bond Lengths ◽  
Dimethylaminobenzoic Acid ◽  
Substituted Benzoic Acids

Abstract The crystal and molecular structure of N,N -dimethylaminobenzoic acid (DABA ) was redetermined by means of X-ray diffraction. Crystal data are: Mr = 165.2, triclinic, P1̄, a = 6.651(2) Å , b = 8.045(2) Å , c = 8.609(2) Å , α - 88.97(3)°, β = 94.72(3)°, γ = 113.76(3)°, V = 420.13 Å3, Z = 2, Dm = 1.28 g cm-1, Dx = 1.306 g cm-1; CuKα: λ = 1.54178 Å, μ = 6.74 cm -1, F(000) = 176.00, T - 293 K; R = 0.0684, Rw = 0.0780 for 1185 observed reflections. The DABA molecules are almost planar and form cyclic dimers exhibiting no orientational disorder with separation of oxygen atoms RO...O - 2.627(2) Å . The pattern of molecular geometry in DABA suggests a relatively strong through-resonance effect between the NMe2 and COOH groups and shows non-additivity of substituent effects on valence angles and bond lengths in the ring. Mesomeric equalization of CO bond lengths in the carboxylic groups of 10 well solved p-substituted benzoic acids is found to depend linearly on the RO...O distance in H-bridged dimers. Full abinitio STO -3G optimizations of molecular geometries for monomers of DABA , p-aminobenzoic acid, benzoic acid, and formic acid as well as for aniline and N,N -dimethylaniline show resonable agreement with experimental data. Changes of molecular geometries on formation of planar H-bridged dimers have been obtained from calculations for benzoic acid dimers, benzoic - formic acid complex, and formic acid dimers. The latter was also optimized using the 6 -31 G basis set.

The Biological Importance of Bile Salts

1979 ◽  
Vol 7 (6) ◽  
pp. 1323-1323
Author(s):  
H. DANIELSSON
Keyword(s):  
Bile Salts ◽  
Biological Importance

Substituent effects and solvents

1992 ◽  
Vol 89 ◽  
pp. 1567-1571
Author(s):  
O Pytela ◽  
M Ludwig
Keyword(s):  
Substituent Effects
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