scholarly journals Monosulfonated Azo Dyes: A Crystallographic Study of the Molecular Structures of the Free Acid, Anionic and Dianionic Forms

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 662
Author(s):  
Alan R. Kennedy ◽  
Linda K. Conway ◽  
Jennifer B. A. Kirkhouse ◽  
Karen M. McCarney ◽  
Olivier Puissegur ◽  
...  
Keyword(s):  
Azo Dyes ◽  
Free Acid ◽  
Molecular Structures ◽  
Acid Anion ◽  
Single Crystal Diffraction ◽  
Resonance Effects ◽  
Crystallographic Study ◽  
Electron Donation ◽  
Salt Forms ◽  
Resonance Electron

Crystallographic studies of monosulfonated azo dyes have concentrated on the salt forms that contain the azo anion. Here we present a study that compares the structures of these anions with protonated free acid forms and with doubly deprotonated dianion forms. To this end, the new single crystal diffraction structures of 13 systematically related free acid forms of monosulfonated azo dyes are presented, together with three new structures of doubly deprotonated forms and two new structures of Na salt forms of azo anions. No structures of dideprotonated monosulfonated azo dyes have previously been reported and this paper also reports the first crystal structure of an azo dye with a hydronium cation. The geometries of the free acid, anion and dianion forms are compared to literature equivalents. It is shown that protonation of the azo bond gives predictable bond lengthening and shortening, which is of a greater magnitude than similar effects caused by azo-hydrazone tautomerisation, or the smaller again effects caused by the resonance electron donation from O or N based substituents. The dianion containing structures have twisted dianion geometries that can be understood based on the resonance effects of the phenoxide groups and upon the needs to bond to a relatively high number of metal cations.

scholarly journals Mixed Ca/Sr salt forms of salicylic acid: tuning structure and aqueous solubility

2018 ◽  
Vol 74 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Pamela Allan ◽  
Jean-Baptiste Arlin ◽  
Alan R. Kennedy ◽  
Aiden Walls
Keyword(s):  
Salicylic Acid ◽  
Coordination Polymer ◽  
Single Crystal ◽  
Structural Feature ◽  
Structural Changes ◽  
Aqueous Solubility ◽  
Single Crystal Diffraction ◽  
One Dimensional ◽  
The One ◽  
Salt Forms

Ten isostructural single-crystal diffraction studies of mixed cation Ca/Sr salt forms of the salicylate anion are presented, namely catena-poly[[diaquacalcium(II)/strontium(II)]-bis(μ2-2-hydroxybenzoato)], [Ca1–x Sr x (C7H5O3)2(H2O)2] n , where x = 0, 0.041, 0.083, 0.165, 0.306, 0.529, 0.632, 0.789, 0.835 and 1. The structure of an isostructural Sr/Ba species, namely catena-poly[[diaquastrontium(II)/barium(II)]-bis(μ2-2-hydroxybenzoato)], [Sr0.729Ba0.271(C7H5O3)2(H2O)2], is also described. The Ca/Sr structures form a series where, with increasing Sr content, the unit cell expands in both the crystallographic a and c directions (by 1.80 and 3.18%, respectively), but contracts slightly in the b direction (−0.31%). The largest percentage structural expansion lies parallel to the direction of propagation of the one-dimensional coordination polymer that is the primary structural feature. This structural expansion is thus associated with increased M—O distances. Aqueous solubility measurements show that solubility generally increases with increasing Sr content. Thus, tuning the composition of these mixed counter-ion salt forms leads to systematic structural changes and allows solubility to be tuned to values between those for the pure Ca and Sr species.

Experimental and computational structural study of two hindered aminoanthraquinones in crystals and solutions

2000 ◽  
Vol 215 (9) ◽  
Author(s):  
A.V. Yatsenko ◽  
K.A. Paseshnichenko ◽  
S.I. Popov
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Electronic Spectra ◽  
Molecular Structures ◽  
Amino Group ◽  
Single Crystal Diffraction ◽  
Molecular Conformations ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Visible Spectra

The crystal and molecular structures of 2-methyl-1-methylamino-anthraquinone (I) and 1-methylphenylamino-anthraquinone (II) were studied by the X-ray single-crystal diffraction and the visible spectra of crystalline specimens and their solutions were recorded. The molecule I is closely planar, whereas in the molecule II the amino group is 58° rotated out of the plane of the anthraquinone skeleton. In both structures the molecules pack in stacks. The comparison of experimental and calculated (on the DFT and AM1 levels) molecular structures, together with the comparison of experimental and INDO/S-calculated electronic spectra, give the evidence that molecular conformations (especially for II) change upon transfer from the solid state to solutions, and the π-delocalisation throughout the whole molecule enhances in the solid state.

scholarly journals DFT Study and Antiparasitic Activity of Some Azo Dyes Containing Uracil

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Nevin Süleymanoğlu ◽  
Pınar Kubaşık ◽  
Şahin Direkel
Keyword(s):  
Molecular Modeling ◽  
Spectral Data ◽  
1H Nmr ◽  
Azo Dyes ◽  
Trichomonas Vaginalis ◽  
Molecular Structures ◽  
Antiparasitic Activity ◽  
Tautomeric Forms ◽  
First Time

In this study, for the first time, molecular modeling and antiparasitic activity studies were carried out on some azo dyes containing uracil, 6-amino-5-[(4-nitrophenyl) diazenyl] pyrimidine-2,4 (1H, 3H)-dione (dye I) and 6-amino-5-[(4-bromophenyl) diazenyl] pyrimidin-2,4 (1H, 3H)-dione (dye II), which were resynthesized using the same method in the literature and whose molecular structures were confirmed using FTIR and 1H-NMR methods. In molecular modeling study, all calculations were performed using DFT/B3LYP/6-311++G(d,p) method. The molecular structures of the possible tautomeric forms of dyes I and II were optimized, and their molecular total energies were calculated in the gas phase and DMSO solvent. IR and 1H-NMR spectral data of the possible tautomeric forms of dyes were obtained, and theoretical spectral data were compared with experimental ones. The evaluations show that, for both dyes, the spectral data of the imine-diketo-hydrazone form, which has the lowest energy and is hence determined to be the most stable form, are in agreement with the experimental ones. In antiparasitic activity study, dyes I and II were tested for the first time against parasites Leishmania infantum, Leishmania major, Leishmania tropica promastigotes, and Trichomonas vaginalis trophozoites. In vitro antileishmanial activities against Leishmania promastigotes were tested by microdilution broth assay with Alamar Blue in RPMI 1640 medium, and in vitro trichomonacidal activities against Trichomonas vaginalis parasite were tested using TYM medium. In tests, antileishmanial and trichomonacidal effects were determined by comparing the obtained minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) values with those obtained for standard drugs (amphotericin B and metronidazole, respectively).

A structural study of seven salt forms of sulfonated azo dyes containing nitrile functional groups

2013 ◽  
Vol 97 (1) ◽  
pp. 100-104 ◽  
Author(s):  
Catherine Astbury ◽  
Linda K. Conway ◽  
Cheska Gillespie ◽  
Kirsty Hodge ◽  
Elaine Innes ◽  
...  
Keyword(s):  
Functional Groups ◽  
Structural Study ◽  
Azo Dyes ◽  
Salt Forms ◽  
Sulfonated Azo Dyes

42 salt forms of tyramine: structural comparison and the occurrence of hydrate formation

2012 ◽  
Vol 68 (4) ◽  
pp. 453-464 ◽  
Author(s):  
Naomi E. B. Briggs ◽  
Alan R. Kennedy ◽  
Catriona A. Morrison
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Single Crystal ◽  
Hydrate Formation ◽  
Structural Comparison ◽  
Hydrogen Bond Donor ◽  
Single Crystal Diffraction ◽  
Hydrogen Bond Acceptor ◽  
First Time ◽  
Salt Forms

The single-crystal diffraction structures of 38 salt forms of the base tyramine (4-hydroxyphenethylamine) are reported for the first time. Together with literature examples, these structures are discussed with respect to cation conformation, cation packing, hydrogen bonding and hydrate formation. It is found that isostructural cation packing can occur even with structurally different anions, with different hydration states and with different hydrogen bonding. Hydrate formation is found to be more likely both (i) when there is an increase in the total number of potential hydrogen bond acceptor and donor atoms; and (ii) when the ratio of potential hydrogen bond donor to acceptor atoms is low.

2-(1H-2-Benzimidazolyl)-6-(1-(arylimino)ethyl)pyridylnickel Complexes: Synthesis, Characterization, and Ethylene Oligomerization

2010 ◽  
Vol 63 (1) ◽  
pp. 109 ◽  
Author(s):  
Liwei Xiao ◽  
Min Zhang ◽  
Rong Gao ◽  
Xiaoping Cao ◽  
Wen-Hua Sun
Keyword(s):  
Spectroscopic Analysis ◽  
Nickel Complexes ◽  
Molecular Structures ◽  
Ethylene Oligomerization ◽  
Distorted Octahedral Geometry ◽  
Electronic Effects ◽  
Single Crystal Diffraction ◽  
Catalytic Activities ◽  
Distorted Octahedral ◽  
Ir Spectroscopic

A series of tridentate N,N,N-nickel complexes bearing 2-(1H-2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridines was synthesized and characterized by elemental and IR spectroscopic analysis. The molecular structures of representative complexes were determined by single-crystal diffraction, and these were found to have a six-coordinate distorted octahedral geometry around the Ni centre. On treatment with Et2AlCl, all nickel complexes exhibited good catalytic activities up to 106 g mol–1(Ni) h–1 for ethylene oligomerization with major dimerization. The steric and electronic effects on catalytic activities of metal complexes as well as the influence of various reaction parameters were carefully investigated.

scholarly journals Structure-Based Long-Term Biodegradation of the Azo Dye: Insights from the Bacterial Community Succession and Efficiency Comparison

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3017
Author(s):  
Chao Zhu ◽  
Zarak Mahmood ◽  
Muhammad Saboor Siddique ◽  
Heyou Wang ◽  
He Anqi ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Azo Dyes ◽  
Azo Dye ◽  
Community Dynamics ◽  
Molecular Structures ◽  
Methyl Red ◽  
Biological Degradation ◽  
Chemical Structures ◽  
Microbial Community Dynamics ◽  
Efficiency Comparison

In this study, microbial community dynamics were explored during biological degradation of azo dyes with different chemical structures. The effect of the different molecular structures of the azo dyes was also assessed against the simultaneous removal of color and the bacterial community. Winogradsky columns were inoculated with dewatered sludge and separately fed with six different azo dyes to conduct the sludge acclimatization process, and nine bacterial decolorizing strains were isolated and identified. The decolorization and biodegradation performances of the acclimated system and isolated strains were also determined. Results showed that the bacterial isolates involved in decolorization and the degradation of the azo dyes were mainly associated with the azo dye structure. After 24 h acclimatization at room temperature without specific illumination, immediate decolorization of methyl red (89%) and methyl orange (78%) was observed, due to their simple structure compared to tartrazine (73%). However, after 8 days of acclimatization, methyl red was easily decolorized up to 99%, and about 87% decolorization was observed for orange G (87%), due to its complex chemical structure. Higher degrees of degradation and decolorization were achieved with Pseudomonas geniculate strain Ka38 (Proteobacteria), Bacillus cereus strain 1FFF (Firmicutes) and Klebsiella variicola strain RVEV3 (Proteobacteria) with continuous shaking at 30 °C. The azo dyes with benzene rings were found to be easier to decolorize and degrade with similar microbial communities. Moreover, it seems that the chemical structures of the azo dyes, in a sense, drove the divergent succession of the bacterial community while reducing the diversity. This study gives a deep insight into the feasible structure-based artificial manipulation of bacterial communities and offers theoretical guidance for decolorizing azo dyes with mixed bacteria cultures.

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