Mechanistic aspects of diazaquinone chemiluminescence

1984 ◽  
Vol 37 (5) ◽  
pp. 1001 ◽  
Author(s):  
DB Paul
Keyword(s):  
Hydrogen Peroxide ◽  
Complex Formation ◽  
Dicarboxylic Acid ◽  
Potassium Hydroxide ◽  
Dicarboxylic Acids ◽  
Aqueous Alkali ◽  
Nitrogen Bases ◽  
Organic Bases ◽  
Hydroperoxide Anion

Twelve cyclic hydrazides of aromatic and heterocyclic o-dicarboxylic acids were converted into diazaquinones by treatment with t-butyl hypochlorite. Chemiluminescence was produced from all diazaquinones on treatment with HO2- derived from hydrogen peroxide and potassium hydroxide. Diazaquinones derived from pyridine and pyrazine o-dicarboxylic acid hydrazides afforded chemiluminescence with hydrogen peroxide alone. Such nitrogen bases and N-oxides increase the nucleophilicity of hydrogen peroxide by complex formation and this effect was also exemplified by observation of chemiluminescence from phthalazine-1,4-diones, hydrogen peroxide and either pyridine or pyridine N-oxide. Highly reactive diazaquinones emit light with aqueous alkali and oxygen. No chemiluminescence was produced with organic bases and oxygen which suggests the involvement of a different mechanism compared with the hydroperoxide anion case.

IR and 13C, 17O, and 119Sn NMR spectra of some bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids

1991 ◽  
Vol 56 (9) ◽  
pp. 1908-1915 ◽  
Author(s):  
Jaroslav Holeček ◽  
Antonín Lyčka ◽  
Milan Nádvorník ◽  
Karel Handlíř
Keyword(s):  
Infrared Spectroscopy ◽  
Nmr Spectroscopy ◽  
Dicarboxylic Acid ◽  
Nmr Spectra ◽  
Dicarboxylic Acids ◽  
119Sn Nmr ◽  
Carboxylic Groups ◽  
Cyclic Oligomers ◽  
The Media ◽  
Oxygen Atoms

Infrared spectroscopy and multinuclear (13C, 17O, and 119Sn NMR spectroscopy have been used to study the structure of bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids (1-C4H9)2. Sn(X(COO)2), where X = (CH2)n (n = 0-8), CH=CH (cis and trans) and C6H4 (ortho and para).The crystalline compounds are formed by linear or cyclic oligomers or polymers whose basic building units represent a grouping composed of the central tin atom substituted by two 1-butyl groups and coordinated with both oxygen atoms of two anisobidentate carboxylic groups derived from different molecules of a dicarboxylic acid. The environment of the tin atom has a shape of a trapezoidal bipyramid. When dissolvet in non-coordinating solvents, the compounds retain the oligomeric character with unchanged structure of environment of the central tin atom. In the media of coordinating solvents the bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids form complexes whose central hexacoordinated tin atom binds two molecules of the solvent trough their donor atoms. Carboxylic groups form monodenate linkages in these complexes.

A review of lignin hydrogen peroxide oxidation chemistry with emphasis on aromatic aldehydes and acids

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajinkya More ◽  
Thomas Elder ◽  
Zhihua Jiang
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidative Degradation ◽  
Reaction Medium ◽  
Dicarboxylic Acids ◽  
Aromatic Aldehydes ◽  
Product Distribution ◽  
Reaction Conditions ◽  
Alkaline Conditions ◽  
The Stability ◽  
Oxidation Chemistry

Abstract This review discusses the main factors that govern the oxidation processes of lignins into aromatic aldehydes and acids using hydrogen peroxide. Aromatic aldehydes and acids are produced in the oxidative degradation of lignin whereas mono and dicarboxylic acids are the main products. The stability of hydrogen peroxide under the reaction conditions is an important factor that needs to be addressed for selectively improving the yield of aromatic aldehydes. Hydrogen peroxide in the presence of heavy metal ions readily decomposes, leading to minor degradation of lignin. This degradation results in quinones which are highly reactive towards peroxide. Under these reaction conditions, the pH of the reaction medium defines the reaction mechanism and the product distribution. Under acidic conditions, hydrogen peroxide reacts electrophilically with electron rich aromatic and olefinic structures at comparatively higher temperatures. In contrast, under alkaline conditions it reacts nucleophilically with electron deficient carbonyl and conjugated carbonyl structures in lignin. The reaction pattern in the oxidation of lignin usually involves cleavage of the aromatic ring, the aliphatic side chain or other linkages which will be discussed in this review.

scholarly journals New Mixed Ligand Cobalt(II), Nickel(II) and Copper(II) Complexes of 2,2'-Bipyridine-3,3'-Dicarboxylic acid (bpdc) with 2-Mercapto-5-Phenyl-1,3,4-Oxadiazole (phozSH) and Their Antioxidant activity

2020 ◽  
Vol 36 (05) ◽  
pp. 834-842
Author(s):  
Rezan Ali Saleh ◽  
Hikmat Ali Mohammad ◽  
Salim Najm Aldin Saber
Keyword(s):  
Antioxidant Activity ◽  
Metal Ions ◽  
Dicarboxylic Acid ◽  
Potassium Hydroxide ◽  
Electronic Spectroscopy ◽  
Conductivity Measurement ◽  
Mixed Ligand ◽  
Methanol Solution ◽  
Dpph Method ◽  
Colored Complexes

The mixing of one mole of 2,2'-bipyridine-3,3'-dicarboxylic acid (bpdc) with two mole of potassium hydroxide (KOH) in methanol were refluxed for (half hour), followed by addition of one mole methanol solution of MCl2.nH2O (where M=Co, Ni or Cu). The mixture was refluxed for (2 hours) to give colored complexes of the metal ions of [M(bpdc)(H2O)4]. The [M(bpdc)(H2O)4] were reacted with one mole of 2-Mercapto-5-phenyl-1,3,4-oxadiazole (phozSH) producing the colored mixed ligand complexes with general formula [M(bpdc)(phozSH)(H2O)3] in which the metal ions coordinated to the ligand through O-atoms of carboxyl group in (bpdc) and N-atom of (phozSH) ligand. The ligands and complexes are well identified by using Furrier transform infrared spectroscopy, 1H-NMR, 13C-NMR, Electronic spectroscopy, CHNS analysis, Melting point, conductivity measurement. The Antioxidant activity were screened for all the complexes by the use of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method.

scholarly journals Pharmacological activity of new imidazole-4,5-dicarboxylic acid derivatives in dopaminergic transmission suppression ttests in mice and rats

2020 ◽  
Vol 6 (4) ◽  
pp. 51-57
Author(s):  
Ekaterina E. Yakovleva ◽  
Eugeny R. Bychkov ◽  
Maria M. Brusina ◽  
Levon B. Piotrovsky ◽  
Petr D. Shabanov
Keyword(s):  
Locomotor Activity ◽  
Dicarboxylic Acid ◽  
Open Field ◽  
Field Test ◽  
Open Field Test ◽  
Dicarboxylic Acids ◽  
Dopaminergic Transmission ◽  
Dose Dependent ◽  
Derivatives Of ◽  
Experimental Improvement

Objective: To study the antiparkinsonian activity of new 1,2-substituted imidazole-4,5-dicarboxylic acids in dopaminergic transmission suppression tests in mice and rats. Materials and methods: On a model of reserpine extrapyramidal disorders, the derivatives of imidazole-dicarboxylic acids (IEM2258, IEM2248, IEM2247) were injected into the lateral brain ventricles of the mice 30 minutes after injecting reserpine at the doses of 0.1–0.5 mmol. Locomotor activity was analyzed in the Open-field test 2 hours later. In the catalepsy model, the studied agents were injected, using a pre-implanted cannula, with a simultaneous intraperitoneal injection of haloperidol. The severity of catalepsy was assessed with the Morpurgo method. Amantadine was used as a comparator drug in all the tests. Results: It was shown that IEM2258 significantly increased the main indicators of locomotor activity in the Open-field test at all the studied doses. The value of the antiparkinsonian effect of IEM2258 at doses of 0.4–0.5 mmol significantly exceeded that of amantadine. The antiparkinsonian effect of IEM2247 was maximally expressed and was significantly different from those in the control and comparator group at doses of 0.2 and 0.3 mmol. For all the experimental groups, a significant decrease in the manifestations of catalepsy in comparison with control indexes was determined. Discussion: The results made it possible to suggest the involvement of imidazole-4,5-dicarboxylic acids derivatives in the process of experimental improvement of dopaminergic neuromodulation and efficiency in animals. Conclusion: The data showed a significant dose-dependent antiparkinsonian activity of new imidazole-4,5-dicarboxylic acid derivatives, which makes it promising to develop these agents and to further search for effective and safe antiparkinsonian drugs in this pharmacological class. Graphical abstract

scholarly journals Two-dimensional metal-organic frameworks containing linear dicarboxylates

2006 ◽  
Vol 62 (5) ◽  
pp. 808-814 ◽  
Author(s):  
Samuel M. Hawxwell ◽  
Harry Adams ◽  
Lee Brammer
Keyword(s):  
Dicarboxylic Acid ◽  
Solvothermal Synthesis ◽  
Interplanar Spacing ◽  
Metal Organic Frameworks ◽  
Dicarboxylic Acids ◽  
Two Dimensional ◽  
Secondary Building Units ◽  
Metal Organic ◽  
Gas Molecules ◽  
Solvent Molecules

The solvothermal synthesis of four two-dimensional metal-organic frameworks containing linear dicarboxylic acids as ligands for ZnII centres is described. Zn(BDC)(DMF) [(1) where BDC = benzene-1,4-dicarboxylic acid; DMF = N,N-dimethylformamide] adopts a common paddlewheel motif leading to a 44 grid network, whereas Zn3(BDC)3(EtOH)2 (2), Zn3(BDC)3(H2O)2·4DMF (3) and Zn3(BPDC)3(DMF)2·4DMF (4) each form networks with the relatively uncommon 36 topology based upon Zn3(O2CR)6 secondary building units. All contain coordinated solvent molecules, namely DMF [(1) and (4)], ethanol (2) or H2O (3). Comparison of structures (2) and (3) illustrates a clay-like flexibility in interplanar spacing which sheds light on the ability of the Zn3(BDC)3 framework to undergo desolvation and uptake of small solvent and gas molecules.

scholarly journals Engineering energetically efficient transport of dicarboxylic acids in yeast Saccharomyces cerevisiae

2019 ◽  
Vol 116 (39) ◽  
pp. 19415-19420 ◽  
Author(s):  
Behrooz Darbani ◽  
Vratislav Stovicek ◽  
Steven Axel van der Hoek ◽  
Irina Borodina
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dicarboxylic Acid ◽  
Acid Production ◽  
Dicarboxylic Acids ◽  
Scale Production ◽  
Protein Motif ◽  
Yeast Saccharomyces Cerevisiae ◽  
Organic Acid Production ◽  
Cell Factories ◽  
Voltage Dependent

Biobased C4-dicarboxylic acids are attractive sustainable precursors for polymers and other materials. Commercial scale production of these acids at high titers requires efficient secretion by cell factories. In this study, we characterized 7 dicarboxylic acid transporters in Xenopus oocytes and in Saccharomyces cerevisiae engineered for dicarboxylic acid production. Among the tested transporters, the Mae1(p) from Schizosaccharomyces pombe had the highest activity toward succinic, malic, and fumaric acids and resulted in 3-, 8-, and 5-fold titer increases, respectively, in S. cerevisiae, while not affecting growth, which was in contrast to the tested transporters from the tellurite-resistance/dicarboxylate transporter (TDT) family or the Na+ coupled divalent anion–sodium symporter family. Similar to SpMae1(p), its homolog in Aspergillus carbonarius, AcDct(p), increased the malate titer 12-fold without affecting the growth. Phylogenetic and protein motif analyses mapped SpMae1(p) and AcDct(p) into the voltage-dependent slow-anion channel transporter (SLAC1) clade of transporters, which also include plant Slac1(p) transporters involved in stomata closure. The conserved phenylalanine residue F329 closing the transport pore of SpMae1(p) is essential for the transporter activity. The voltage-dependent SLAC1 transporters do not use proton or Na+ motive force and are, thus, less energetically expensive than the majority of other dicarboxylic acid transporters. Such transporters present a tremendous advantage for organic acid production via fermentation allowing a higher overall product yield.

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