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Azo dyes are known as structurally diverse class of organic compounds bearing one or more azo groups (–N=N–) as a bridge between organic residues of which at least one is an aromatic moiety. This group of synthetic dyes is obtained easily by the reaction of diazo coupling with high yield. The importance of azo dyes is reflected in the fact that they account for 60 % of the total number of the dye structures known to be manufactured and used in the coloration of textiles, leather, plastics and cosmetics. Aside from their traditional usage, azo dyes are known for their therapeutic properties and wide range of applications in biomedicine and pharmaceutical industry. Hereby, the present study aims to investigate the relationship between the chemical structure and pharmacological activity of four azo pyridone dyes taking into account the tautomeric form of dyes. The relationship was determined empirically using appropriate software packages as well as in vitro using the 2, 2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method. The results of in silico prediction suggested that all investigated compounds possess good oral bioavailability, while the results of the ABTS assay indicate poor to excellent antioxidant activity depending on the substituent in the phenyl ring. Considering the broad applications of arylazo pyridone dyes, as well as the fact that their relative importance may increase in the future, results obtained in this study serve as a basis for further investigations., Azo boje predstavljaju strukturno najraznovrsniju klasu organskih jedinjenja koja sadrže jednu ili više azo grupa (–N=N–) koje premošćavaju dva organska motiva od kojih je bar jedan aromatičan. Ova grupa sintetskih boja dobija se jednostavnom sintezom koja uključuje reakciju diazo-kuplovanja u visokom prinosu. Da su azo boje od neprocenjivog značaja u različitim granama industrije gde se primenjuju za nijansiranje tekstila, kože, plastike i kozmetičkih proizvoda, govori i činjenica da su zastupljene sa preko 60%. Pored tradicionalne primene, azo boje su poznate i po sve većoj upotrebu u biomedicini i farmaceutskoj industriji. Na osnovu navedeneg, cilj ovog rada je da se detaljnije ispita veza između hemijske strukture četiri azo piridonske boje i njihove farmakološke aktivnosti uzimajući u obzir tautomerni oblik boje. Ova veza određena je empirijski korišćenjem odgovarajućih softverskih paketa kao i in vitro određivanjem njihove antioksidativne aktivnosti primenom ABTS metode. Rezultati in silico predikcije pokazuju da sva ispitivana jedinjenja poseduju dobru oralnu bioraspoloživost i nisku do odličnu antioksidativnu aktivnost u zavisnosti od spupsptituenta u fenilnom jezgru. Uzimajući u obzir širok spektar primene arilazo piridonskih boja kao i činjenicu da će njihov značaj konstantno rasti, rezultati ostvareni u ovom radu predstavljaju interesantnu osnovu za buduća istraživanja.

Ferrocene derivatives are known as antioxidants, antiparasitic, antitumor, antiviral, antibacterial and antifungal agents. In addition to applications in medicinal chemistry and drug design, ferrocene derivatives are of exceptional importance in synthetic organic chemistry, especially in catalytic asymmetric transformations. They are also used in electrochemistry and polymer chemistry, as additives in fuels, as chemosensors in agrochemistry and biosensors of glucose and active components in molecular electronics. To design new antioxidant agents, five ferrocenyl chalcones were synthesized, and fully characterized by melting points, FT-IR, 1H and 13C NMR spectroscopic methods. The synthesized chalcones differ in the nature and the position of the substituent attached to the phenyl group in position 1 of the linear unsaturated carbonyl system. The potential antioxidant activity of the synthesized compounds was evaluated using the ABTS (2,2'-azinobis-(3- ethylbenzothiazoline-6-sulfonic acid) method and IC50 values of the most effective compounds were further determined., Derivati ferocena su poznati antioksidansi, antiparazitici, antitumorni, antivirusni, antibakterijski i antifungalni agensi. Pored primene u medicinskoj hemiji, derivati ferocena su od izuzetnog značaja u sintetičkoj organskoj hemiji, naročito u katalizovanim asimetričnim sintezama. Primenjuju se i u elektrohemiji i hemiji polimera, kao aditivi u gorivima, kao hemosenzori u agrohemiji i biosenzori glukoze i aktivnih komponenata u molekularnoj elektronici. U cilju dizajniranja novih antioksidativnih agenasa, u ovom radu, sintetisano je pet ferocenilhalkona koji su u potpunosti strukturno okarakterisani određivanjem temperature toplenja, FT-IR, 1H i 13C NMR spektroskopskim metodama. Sintetisani halkoni međusobno se razlikuju prema vrsti i položaju supstituenta na fenil-grupi u položaju 1 linearnog nezasićenog karbonilnog sistema. Potencijalna antioksidativna aktivnost ovih jedinjenja procenjena je primenom ABTS (2,2'-azinobis-(3-etilbenzotiazolin-6- sulfonska kiselina) metode i određivanjem IC50 vrednosti najefikasnijih jedinjenja.

Aryl azo pyridone dyes belong to a very important class of organic compounds. World annual production of synthetic dyes is over 60 % based on the azo derivatives. They are mostly used as coloring agents for textiles, paper, leather, rubber, polymer, and many other materials. With the development of high technology, these structures also found their application as components of lasers and nonlinear optical systems, LCD (liquid crystal display) screens, and thermal printers. Lately, increasing attention has been directed to the biological activity of azo compounds. It has been proven that they have anti-tumor, anti-inflammatory, anti-oxidant, anti-microbial, and antituberculosis activity, while certain derivatives are used for therapeutic purposes. Aryl azo dyes are widely used due to their excellent physicochemical properties (primarily high value of the molar extinction coefficient and great resistance to light and wet processing) and the fact that can be obtained in a simple method of diazotization and coupling. In this paper, three new dyes of 6-hydroxy-5-(hydroxy substituted phenylazo)-4-methyl-2-oxo-1,2-dihydropyridine-3- carbonitriles were synthesized by a diazo coupling reaction starting from aminophenols (2-, 3- and 4-substituted) and 6-hydroxy-4-methyl-2-oxo-1,2-dihydropyridine-3-carbonitrile as coupling components. The obtained dyes were characterized by melting point, IR, NMR, and UV-Vis spectroscopy. Given the fact that the structure of the molecule and interactions obtained with the surrounding medium can affect its activity, the possibility of azo hydrazo tautomerism has been studied, as the influence of the position of the substituent present (orto-, meta- and para position). In addition, the effect of the solvent used was determined by applying a solvatochromic model using the LSER method (linear solvation energy relationship). Obtaining information about the inter- and intramolecular relationships that newly synthesized compounds can achieve may be o

The reduction of water pollution represents one of the priority topics of the EU’s goal to achieve climate neutrality by 2050. Herby textile industry is focused on developments in numerous environmental and social issues, including high emissions, high water and/or energy consumption and heavy pollution [1]. Coloured effluents from this industry disposed into natural ecosystems are responsible for about 20% of global clean water pollution [2]. The European Union aims to reduce textile waste and increase the life cycle and recycling of textiles as part of the plan to achieve a circular economy by 2050 by sustainable products and empowering consumers to participate in the green transition [2]. One of the main research topics connecting textile industry and waste water reduction is found in synthesis of eco-friendly dyes which are superior to their natural analogues due to the excellent dyeing capabilities and colour fastness properties. Among these, azo pyridine dyes gained attention for the simplicity of their preparation, good colour fastness, high tinctorial strength, thermal and optical stability [3]. Traditionally, applied as disperse dyes, they have low water solubility and are used for colouring mostly synthetic fibres. Recent findings showed that the introduction of the pyridinium ring into pyridone molecule resulted in enhanced water solubility of the dyes and improved affinity towards various natural and synthetic fibres, especially wool and cellulose diacetate fibres [4]. For the purpose of addressing environmental issues in the textile industry, in this work, two pyridinium-based azo pyridone dyes with improved solubility and affinity towards different fibres, are used for dyeing wool fabric. The results show that the same dyebath can be efficiently used multiple times, therefore reducing waste in the water while securing the optimizing dying. The obtained fabrics from different cycles are further characterized by K/S values while the residue of the dye in

A convenient and efficient approach toward the synthesis of six 3-(4-substituted benzyl)-6,7-benzo-1,3-diazaspiro[4.5]decane-2,4-diones (1‒6) by Bucherer-Bergs reaction and further alkylation at position 3 of the hydantoin ring is reported. Further, their chemical structure was confirmed by melting points, elemental analysis, FT-IR, NMR and UV–Vis spectroscopic methods. To gain an insight into interactions which the investigated spirohydantoins establish with their environment, their absorption spectra were recorded in selected solvents of different polarity and the solvent effects on the UV-Vis absorption band positions, intensity and shape, were discussed. Substiuent effects on the solvatochromism of compounds 1−6 were analyzed using the Hammett's equation. Considering the broad applications of hydantoin derivatives, as well as the fact that their relative importance may increase in the future, results obtained in this study serve as a basis for further investigations.

The reduction of water pollution represents one of the priority topics of the EU’s goal to achieve climate neutrality by 2050. Considering this, the concept of reusing the same dyebath for multiple dyeing cycles is proposed. For this purpose, two pyridinium-based azo pyridone dyes with improved solubility and affinity towards different fibers, are used for dyeing wool fabric. It is demonstrated that the dye concentration in wastewater could be reduced up to four times by recirculation of the same dyebath 5 times. The dyed fabrics obtained in each cycle are further characterized regarding color strength (K/S) and ultraviolet protection factor (UPF), while their antioxidant potential is evaluated by ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) test. The results revealed that the proposed concept could be used for obtaining multifunctional wool fabrics by following the principles of sustainable development of reducing the effluent load in wastewater.

Xanthendiones (1,8-dioxooctahydroxanthenes) are a special class of oxygenincorporating tricyclic compounds bearing as a basic feature a pyran nucleus fused on either side with cyclohex-2-enone rings. They are often found as a structural motif in natural products with a wide range of biological activities, such as: antioxidant, antimicrobial, trypanocidal, antiinflammatory, antiproliferative and anticancer. A convenient and efficient approach toward the synthesis of seven aromatically substituted xanthendiones 1‒7 and one structurally-related xanthenone 8 through condensation of dimedone and the appropriate aromatic aldehyde is reported. The relationship between the chemical structure and pharmacological activity was determined empirically using appropriate software packages and in vitro using the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method. The results of the ABTS assay indicate that five compounds possess the ability to scavenge the ABTS•+ radical cation. Based on the comparison of the IC50 values, the activity of the compounds was found to be as follows: 6 > 1 > 7 > 2 > 8.

A convenient and efficient approach toward the synthesis of seven aromatically substituted xanthendiones 1‒7 and one structurally-related xanthenone 8 through condensation of dimedone and the appropriate aromatic aldehyde is reported. Further, their chemical structure was confirmed by melting points, elemental analysis, FT-IR, 1H-, 13C-NMR and UV–Vis spectroscopic methods. The relationship between the chemical structure and pharmacological activity was determined empirically using appropriate software packages and in vitro using the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method. The results of in silico prediction suggested that all investigated compounds possess good oral bioavailability. The results of the ABTS assay indicate that five compounds possess the ability to scavenge the ABTS•+ radical cation. Based on the comparison of the IC50 values, the activity of the compounds was found to be as follows: 6 > 1 > 7 > 2 > 8. The effects of solvent dipolarity/polarizability and solute solvent–hydrogen-bonding interactions on the shifts of the absorption maxima were rationalized by means of the linear solvation energy relationship concepts proposed by Kamlet–Taft and Catalán.

A convenient and efficient approach toward the synthesis of seven aromatically substituted xanthendiones 1‒7 and one structurally-related xanthenone 8 through condensation of dimedone and the appropriate aromatic aldehyde is reported. Further, their chemical structure was confirmed by melting points, elemental analysis, FT-IR, 1H-, 13C-NMR and UV–Vis spectroscopic methods. The relationship between the chemical structure and pharmacological activity was determined empirically using appropriate software packages and in vitro using the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) method. The results of in silico prediction suggested that all investigated compounds possess good oral bioavailability. The results of the ABTS assay indicate that five compounds possess the ability to scavenge the ABTS•+ radical cation. Based on the comparison of the IC50 values, the activity of the compounds was found to be as follows: 6 > 1 > 7 > 2 > 8. The effects of solvent dipolarity/polarizability and solute solvent–hydrogen-bonding interactions on the shifts of the absorption maxima were rationalized by means of the linear solvation energy relationship concepts proposed by Kamlet–Taft and Catalán., U ovom radu, predstavljena je jednostavna metoda u dva koraka za sintezu sedam derivata ksantendiona i jednog derivata ksantenona koji sadrže različite aromatične supstituente, polazeći od dimedona i odgovarajućih aromatičnih aldehida. Karakterizacija sintetisanih jedinjenja izvršena je određivanjem temperature topljenja, kao i primenom elementalne analize, FT-IR, 1 H-NMR i 13C-NMR spektroskopskih metoda. Veza između hemijske strukture ovih jedinjenja i njihove farmakološke aktivnosti uspostavljena je empirijski korišćenjem odgovarajućih softverskih paketa (za predikckciju farmakološke aktivnosti) i in vitro određivanjem njihove antioksidativne aktivnosti primenom ABTS metode. Rezultati ABTS metode pokazuju da od celokupne serije testiranih jedinjenja, pet jedinjenja pokazuje značajnu antioksidativnu aktivnost. Na osnovu međusobnog poređenja IC50 vrednosti ispitivanih jedinjenja pokazano je da njihova antioksidativna aktivnost opada u sledećem nizu: 6 > 1 > 7 > 2 > 8. Jedinjenje 6 je najaktivnije u analiziranoj seriji i ima IC50 vrednost približne vrednosti kao askorbinska kiselina. Rezultati solvatohromnih jednačina koje su razvili Kamlet (Kamlet), Taft (Taft) i Katalan (Catalán), ukazuju da položaj apsorpcionih maksimuma proučavanih jedinjenja zavisi od prirode (polarnosti i kiselo-baznih svojstava) upotrebljenih rastvarača. Sa visokim vrednostima antioksidativne aktivnosti i dobrom oralnom bioraspoloživošću, derivati ksantendiona i ksantenona sa aromatičnim supstituentima, predstavljaju dobru polaznu osnovu za sintezu novih farmakološki aktivnih jedinjenja i bolje razumevanje uticaja strukture na farmakološku aktivnost.

Wide commercial application of azo pyridone dyes rests on the cost-effectiveness of their preparation and almost innumerable possibilities for the synthesis by combining various diazo and coupling pyridone components that enable tuning of targeted properties. The great significance of these dyes in the last few decades is due to their outstanding properties, such as vivid colors and good color fastness properties. Azo pyridone dyes are also applicable in different coloration related processes such as inkjet printing and liquid crystal displays. On the other hand, they are recognized as valuable compounds in biological studies, as they possess antioxidant, antimicrobial and antiproliferative properties. In this work, three novel 6-hydroxy-4-methyl-1-pyridinium-2-pyridone based dyes bearing three bioactive heterocyclic rings in their structures are synthesized, wherein thiazole based anilines (2-aminothiazole, 2-aminobenzothiazole, 6-methoxy-2-aminobenzothiazole) are used as diazo components. The compounds are characterized by melting points, NMR and FTIR spectroscopy. The solvatochromic properties are investigated in solvents of different properties. Furthermore, the antioxidant capacities of the compounds are evaluated by ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) assay, while antimicrobial activity is determined by broth microdilution method against five bacterial strains (S. aureus, E. faecalis, B. subtilis, E. coli and K. pneumoniae) and one fungal strain (C. albicans)., Široka komercijalna upotreba piridonskih azo boja zasniva se na njihovoj relativno jeftinoj i jednostavnoj pripremi, kao i činjenici da se veliki broj kuplujućih i diazo komponenti mogu međusobno kombinovati kako bi se dobile boje odgovarajućih svojstava. Veliki značaj ovih boja poslednjih nekoliko decenija, ogleda se u njihovim istaknutim svojstvima kao što su živopisna obojenja i dobra postojanost. Ove boje, takođe, nalaze primenu u ink-džet štampi i LCD ekranima. Sa druge strane, ove boje predstavljaju značajna jedinjenja u biološkim studijama, jer poseduju antioksidativnu, antimikrobnu i antiproliferativnu aktivnost. U ovom radu, sintetisane su tri boje koje u svojoj strukturi obuhvataju tri bioakativna heterociklična jezgra, pri čemu je kao kuplujuća komponenta korišćen 6-hidroksi-4-metil-1-piridinijum-2-piridon, a kao diazo komponente anilini na bazi tiazola (2-aminotiazol, 2-aminobenzotiazol i 6-metoksi-2-aminobenzotiazol). Jedinjenja su okarakterisana temperaturom topljenja, NMR i FTIR spektroskopijama. Solvatohromna svojstva su ispitana u rastvaračima različitih svojstava. Antioksidativna aktivnost jedinjenja ispitana je ABTS (2,2'-azino-bis-3-etilbenzotiazolin-6-sulfonat) testom, dok je minimalna inhibitorna koncentracija ispitana primenom mikrodilucione metode u bujonu prema 5 bakterijskih sojeva (S. aureus, E. faecalis, B. subtilis, E. coli i K. pneumoniae), kao i prema oportunističkoj gljivici C. albicans.

In this work, the electrooxidation ability of nine pyridones was evaluated using cyclic(CV) and square-wave voltammetry (SWV) in Britton–Robinson (BR) aqueous buffer solutions on aglassy carbon electrode (GC). The dependence of electrochemical activity on pyridone structure waselucidated by means of experimentally obtained spectra and quantum chemical calculations. Firstly, itwas shown that electrochemical activity is determined by the –OH group as a substituent in position6 of the pyridone ring. By coupling the experimentally obtained UV-Vis spectra and DFT calculations,the most stable forms, both protonated and deprotonated, were defined. The calculated values areconsistent with the electrochemical behavior observed, indicating that the deprotonated anionic formwas the most electrochemically active. Moreover, the impact of the substituent in position 3 of thepyridone scaffold was discussed

In this work, the electrooxidation ability of nine pyridones was evaluated using cyclic (CV) and square-wave voltammetry (SWV) in Britton–Robinson (BR) aqueous buffer solutions on a glassy carbon electrode (GC). The dependence of electrochemical activity on pyridone structure was elucidated by means of experimentally obtained spectra and quantum chemical calculations. Firstly, it was shown that electrochemical activity is determined by the –OH group as a substituent in position 6 of the pyridone ring. By coupling the experimentally obtained UV-Vis spectra and DFT calculations, the most stable forms, both protonated and deprotonated, were defined. The calculated values are consistent with the electrochemical behavior observed, indicating that the deprotonated anionic form was the most electrochemically active. Moreover, the impact of the substituent in position 3 of the pyridone scaffold was discussed

Two azo dye ligands, bearing different substituents (chlorine atom or methoxy group) in the para-position of the phenyl ring, were employed for the synthesis of two Cu(II) chelates. Full structural affirmation of complexes was assessed. X-ray diffraction measurements revealed that the coordination geometry for Cu atoms in both complexes is square-pyramidal with a ligand:metal ratio of 2:1 where dyes behave as monobasic bidentate ligands. Thermogravimetric analyses of the complexes and their starting dyes were performed to study their thermal stabilities and decomposition behavior confirming the thermal stability of both dyes and complexes. Antioxidative activity of the complexes has been assigned and compared with their parent ligands revealing that the presence of the electron–donor, methoxy group, in the phenyl ring, in both dye and complex, is responsible for the activity (IC50 values of 1.54 for the dye and 1.30 mM for the complex). It should be stated that the complexation of the methoxy-substituted dye leads to enhanced antioxidative activity concurrent to a standard antioxidant molecule of ascorbic acid, making this molecule a promising antioxidant agent. Docking study with vascular endothelial growth factor receptor 2 and Aurora kinase A proteins indicate that complexes exhibit higher binding affinities to proteins than the starting ligand dyes. The most promising structure exhibiting the best docking potential toward both proteins is the complex-bearing methoxy group. The presented results represent a promising start for further investigations of these compounds as potential therapeutic candidates for the treatment of various types of cancer.

U ovom radu prikazana je sinteza i karakterizacija 6-hidroksi-4-metil-3-(piridinijum-1-il)-2-piridona. Sintetisano jedinjenje dobijeno je u obliku dipol-jona. Spektrofotometrijskom titracijom u rastvoru etanola ispitan je uticaj pH vrijednosti na strukturu jedinjenja. Kako bi se detaljno opisala struktura derivata 2-piridona, eksperimentalno dobijene vrijednosti dobijenih apsorpcionih maksimuma upoređeni su sa kvantno-hemijskim proračunima optimizovanih geometrija i teorijskih UV-Vis spektara pri različitim pH vrijednostima., In this research, synthesis and characterization of 6-hydroxy-4-methyl-3-(pyridinium-1-yl)-2-pyridone was shown. Synthesized compound was achieved in the zwitterionic form. UV-Vis spectrophotometric titration was performed in order to examine the influence of pH values on the structure of the compound. For the purpose of detail characterization of 2-pyridone derivative, experimentally obtained results were compared to quantum-chemical calculations of optimized geometries and theoretical UV-Vis spectra of solution for different pH values.

The heterocyclic azo dyes represent significant synthetic organic colorants. In addition to their exceptional coloration properties, heterocyclic azo compounds exhibit antibacterial, antifungal, an-tiviral, antioxidant, anti-inflammatory and anticancer properties. The antimicrobial resistance is one of the major problems for global public health. Therefore, finding new organic structures with anti-microbial properties represents a challenging research field. In this study, antimicrobial screening of two Biginelli-based azo pyridone dyes has been carried out. The antimicrobial activity of synthe-tized dyes wasstudied against bacteria (Staphylococcus aureus, Escherichia coli) and yeast (Candida albicans), using agar diffusion method. The preliminary research results indicate the antimicrobial potential of the investigated compounds., Heterociklična azo jedinjenja predstavljaju značajnu klasnu organskih sintetskih boja. Pored njihovih izuzetnih svojstava za bojenje, heterociklična azo jedinjenja imaju i biološku aktivnost. Mnoge studije pokazuju da azo boje sa heterocikličnim fragmentima u strukturi mogu ispoljavati antibakterijska, antifungalna, antivirusna, antiinflamatorna i antikancerogena svojstva. Rezistencija mikroorganizama na postojeće antimikrobne agense predstavlja jedan od najvećih problema u svetskom zdravstvu. Zbog toga je razvijanje novih molekula sa antimikrobnim svojstvima kako značajno, tako i neophodno za globalno očuvanje zdravlja. U ovom radu, ispitivanje antimikrobne aktivnosti dve Biđineli-azo piridonske boje je urađeno pomoću metode difuzije na agarnoj podlozi. Antimikrobna svojstva su ispitana prema patogenim sojevima Staphylococcus aureus (Gram-pozitivna bakterija), Escherichia coli (Gram-negativna bakterija) i Candida albicans (oportunistički kvasac). Preliminarni rezultati istraživanja ukazali su na antimikrobni potencijal ispitivanih azo jedinjenja.

Considering a significant antioxidant activity of 6-hydroxy-6-methyl-2-pyridones, in this paper four series of arylazo pyridone dyes were subjected to antioxidant ABTS assay. Firstly, preliminary tests were conducted at concentration of 1 mg/ml in order to investigate the effects of different substituents on the dye activity. Based on the preliminary results, dyes with the highest activity were selected for further evaluation of IC50 values and these values were compared with IC50 value of ascorbic acid used as standard. It has been shown that five arylazo pyridone dyes exhibit more potent activity when compared to the ascorbic acid., Uzimajući u obzir značajnu antioksidativnu aktivnost 6-hidroksi-4-metil-2-piridona, u okviru ovog rada ispitana je antioksidativna aktivnost četiri serije arilazo piridonskih azo boja pomoću ABTS testa. U prvom delu su urađeni preliminari testovi aktivnosti pri koncentracij od 1 mg/ml kako bi se ispitao uticaj različitih supstituenata na antioksidativnu aktivnost. Na osnovu ovih rezultata izabrane su boje sa najvećom antioksidativnom aktivnošću, i u drugom delu je za njih određena IC50 vrednost i upoređena sa vrednošću askorbinske kiseline koja je korišćena kao standard. Rezultati su pokazali da pet boja imaju značajniju aktivnost od askorbinske kiseline.

Heterociklična azo jedinjenja predstavljaju značajnu klasnu organskih sintetskih boja. Pored njihovih izuzetnih svojstava za bojenje, heterociklična azo jedinjenja imaju i biološku aktivnost. Mnoge studije pokazuju da azo boje sa heterocikličnim fragmentima u strukturi mogu ispoljavati antibakterijska, antifungalna, antivirusna, antiinflamatorna i antikancerogena svojstva. Rezistencija mikroorganizama na postojeće antimikrobne agense predstavlja jedan odnajvećih problema u svet-skom zdravstvu. Zbog toga je razvijanje novih molekula sa antimikrobnim svojstvima kako značajno, tako i neophodno za globalno očuvanje zdravlja. U ovom radu, ispitivanje antimikrobne aktivnosti dve Biđineli-azo piridonske boje je urađeno pomoću metode difuzije na agarnoj podlozi. Anti-mikrobna svojstva su ispitana prema patogenim sojevima Staphylococcus aureus (Gram-pozitivna bakterija), Escherichia coli (Gram-negativna bakterija) i Candida albicans (oportunistički kvasac). Preliminarni rezultati istraživanja ukazali su na antimikrobni potencijal ispitivanih azo jedinjenja., The heterocyclic azo dyes represent significant synthetic organic colorants. In addition to their exceptional coloration properties, heterocyclic azo compounds exhibit antibacterial, antifungal, an-tiviral, antioxidant, anti-inflammatory and anticancer properties. The antimicrobial resistance is one of the major problems for global public health. Therefore, finding new organic structures with anti-microbial properties represents a challenging research field. In this study, antimicrobial screening of two Biginelli-based azo pyridone dyes has been carried out. The antimicrobial activity of synthe-tized dyes wasstudied against bacteria (Staphylococcus aureus, Escherichia coli) and yeast (Candida albicans), using agar diffusion method. The preliminary research results indicate the antimicrobial potential of the investigated compounds

Herein, we report the synthesis and characterization of nine 6-hydroxy-4-methyl-3-pyridinium-2-pyridone based azo dyes, wherein, eight of them being novel. Used building blocks ensured water solubility of six dyes and made them adequate to be used for dyeing in an alkaline environment contrary to the traditional application of arylazo pyridone dyes. The peculiarity of the compounds arises as they exhibit zwitterion-hydrazone equilibrium and shift from neutral to cationic dyes. It is shown that the equilibrium strongly depends on the electronic effects of the p-substituent in the phenyl moiety, as well as, pH values of the solutions. The screening of the dyeing process (by using multifiber fabric) suggested that synthesized compounds are most eligible for dyeing wool and diacetate fabrics at a pH of 8.5. Furthermore, 100% wool and diacetate fabrics were dyed and used for the dyeing assessment. A comprehensive study between dye architectures and fiber dyeing was performed. The interplay of various interactions, responsible for the dye-fiber binding, has been proposed, bearing in mind both, dyes' and fibers' structures and pH dependency. Namely, dye-wool interactions are mostly based upon charge assisted hydrogen bonds, wherein these interactions are strengthened by C-H...pi contact when dyes are affixed to diacetate. The specific nature of the dye is affected by the electronic effect of the p-substituents of the phenyl moiety, upon which, a detailed study on fibers affinity towards zwitterionic and/or hydrazone forms has been outlined. Most of the dyed fabrics exhibit good to excellent ultraviolet protection, while dyed diacetate shows good washing fastness.

Two pyridone derivatives, bearing the pyridinium moiety (1), or dimethylpyridinium moiety (2), have been synthesized and their crystal structures have been determined. The compounds crystalize in hydrated zwitterionic forms with either two (1.2H(2)O) or four (2.4H(2)O) water molecules. The zwitteri-onic networks contain different types of water clusters, generated into channels, incorporating them into the network by sandwiching. The type of channel depends on the crystal lattice and the nature of non-covalent interactions established between zwitterions as well as the number of water molecules incorporated into the architecture. 1 affords tubes filled in with water channels formed by water tetramers, contrary to 2, which affords a layered network altering the zwitterionic layer and the layer formed by water tetramers and hexamers. A detailed study of intermolecular interactions of both crystal structures and a quantification of interaction energies has been performed using PIXEL lattice energy calculations, giving an insight to a quantitative evaluation of interactions through Coulombic, disperse, repulsion and polarization energies. The strongest pairwise, in both structures, is found to be a dipole-dipole interaction between oppositely charged heterocyclic rings. The differences in the crystal packings of these hydrates have been elucidated by the fingerplot analysis. The comparative studies between experimental and calculated (DFT) data of molecules 1.H2O and 2.4H(2)O for systems of different complexity are performed. Furthermore, correlations of experimental and calculated bond lengths and the simulation of compound solvation with the CPCM model are done.

Fig. S1 Optimized geometry forms of compound 1 without (1a, 1b, 1c) and with water molecules (1d ,1e, 1f). Table S1 Optimized geometry forms of compound 1·2H2O in comparison with experimental data. Fig. S2 Optimized geometry forms of compound 2 without (2a, 2b, 2c) and with water molecules (2d, 2e, 2f). Table S2 Optimized geometry forms of compound 2·4H2O in comparison with experimental data. Fig. S3 NBO charges of 1a and 1b forms of the compound 1. Table S3 NBO charge of 1a and 1b forms of the compound 1. Fig. S4 The structural segment of 1·2H2O containing water molecule W2. Fig. S5 The structural segment of 2·4H2O containing interlayer water molecule W4. Fig. S6 Hirshfeld surface analysis of 1 without (a) and with (b) zwitterion-water interactions included. Fig. S7 Hirshfeld surface analysis of 2 without (a) and with (b) zwitterion-water interactions included. Fig. S8 Comparable PES study of 1 and 2 with biphenyl. Fig S9. Optimized geometry forms affected by crystal network of compounds 1·2H2O and 2·4H2O. Table S4 Optimized geometry forms of compound 1·2H2O in comparison with experimental data. Table S5 Optimized geometry forms of compound 2·4H2O in comparison with experimental data.

Azo dyes are the most important group of organic synthetic dyes. High molar extinction coefficients, which characterize azo compounds, contribute to their wide use in traditional dyeing of various materials, as well as the increasing application in new technologies such as optical devices and solar cells. Numerous studies show that azo dyes based on heterocyclic molecules possess biological activity. Arylazo pyridone dyes belong to the class of disperse dyes, which exhibit antibacterial, antifungal, anticancer and antioxidant properties. In this work, three azo dyes were synthesized starting from 2-, 3- and 4-aminophenol and 3-cyano-6-hydroxy-4-methyl-1-propyl-2-pyridone. The structure of dyes was confirmed by ATR-FTIR, NMR and UV-Vis spectroscopy. The antioxidant activity of compounds was examined by the ABTS method. Physico-chemical descriptors and ADME parameters were determined in silico using SwissADME program., Azo boje su najznačajnija grupa organskih sintetskih boja. Visoki molarni ekstencioni koefici-jenti, koji karakterišu azo jedinjena, doprinose njihovoj širokoj upotrebi kako u tradicionalnom bo-jenju materijala, tako i sve većoj primeni u novijim tehnologijama kao što su optički materijali i solarne ćelije. Mnoga istraživanja pokazuju da azo boje dobijene iz heterocikličnih molekula imaju biološku aktivnost. Arilazo piridonske boje pripadaju klasi disperznih boja koje ispoljavaju antibak-terijsku, antifungalnu, antikancerogenu i antioksidativnu aktivnost. U ovom radu sintetisane su tri azo boje polazeći iz 2-, 3-i 4-aminofenola i 3-cijano-6-hidroksi-4-metil-1-propil-2-piridona. Struk-tura jedinjenja potvrđena je ATR-FTIR, NMR i UV-Vis podacima. Antioksidsativna aktivnost jedinje-nja ispitana je ABTS metodom. Fizičko-hemijski deskriptori i ADME parametari određeni su in silico pomoću SwissADME programa.

Budući da tekstilna industrija predstavlja jednu od glavnih grana industrije, razvoj globalne ekonomije je direktno povezan sa razvojem tekstilne industrije. Sa druge strane, razvoj novih boja je od ključnog značaja za samu tekstilnu industriju. Boje predstavljaju jednu od glavnih zagađujućih materija u otpadnim vodama što predstavlja ekološki problem. Azo boje se nerijetko koriste u industriji kao jedna od najvećih grupa sintetskih boja. Piridinski prsten pokazuje odlično vezivanje za vunu, dok sa druge strane hromofore azo boja daju odlično obojenje. U ovom radu, dvije boje su korišćene za bojenje vune, pri čemu je isti rastvor za bojenje korišćen više puta. Cilj ovog rada je da se smanji udio boja u otpadnoj vodi. Količina boje koja se vezela za vunu, tj. koja je ostala u rastvoru, praćena je UV-Vis spektroskopijom., Considering that the textile industry is an evergrowing industry and its growth directly contributes to economic growth, the interest in developement is strongly dependent with developing new colorants. On the other hand, colored effluent from the textile industry cause water pollution which has an acute effect on the enviorment. The reduction of dye waste and toxicity represents a global problem. As state-of-the art showed pyridine ring allows excellent sublimation fastness for dying wool fibers, wherein azo dyes show brilliant chromophoric strength. Herein, we present the wool dyed with two pyridone based azo dyes bearing pyridinium ring as a substituent. The aim of this work is to reduce the water waste by using the same dyebath for dying wool multiple times. The amount of the dye absorbed on the fabric is determined by the absorption spectra of the dye solution used in the dyebath, followed by the UV-Vis spectra. Therefore the principle of reusing the same dyebath multiple times were determined, wherein the concentration of the dye in the final product is reduced.

U ovom radu prikazane su sinteza i primena dve azo boje na bazi 6-hidroksi-4-metil-3-piridinijum2-piridona. Supstituisani piridon dobijen je Guareši-Torpeovom reakcijom kondenzacije, dok su azo boje sintetisane klasičnim postupkom diazo kuplovanja pri čemu su korišćena dva različito supstituisana anilina. Primenom FTIR, 1H i 13C NMR, UV-Vis i masene spektroskopije dobijena jedinjenja su okarakterisana. U zavisnosti od rastvarača i supstituenta, boje se nalaze u ravnoteži dva tautomerna oblika, hidrazonskog i cviterjonskog, za razliku od literaturnih analoga u kojima se navodi hidrazon-azo anjon ravnoteža. Specifična struktura dobijenih boja omogućava bolju rastvorljivost, pre svega u vodi. Primena se sastoji u bojenju vune pri ranije optimizovanim uslovima bojenja. U ovom radu na osnovu predloženog mehanizma vidi se da, pored očekivanih vodoničnih veza, jon-jon interakcije učestvuju u vezivanju boje za tkaninu. Komparativna studija antioksidativne aktivnosti boja i obojenih tkanina urađena je pomoću ABTS metode., Herein, we report the synthesis and application of two azo dyes based on 6-hydroxy-4-methyl-3- pyridinium-2-pyridone. The substituted pyridone was synthesized via Guareschi-Thorpe condensation, wherein dyes are obtained by the classical reaction of diazo coupling by using two diversely p-substituted anilines. The characterization of the synthesized compounds was carried out by FTIR, 1H and 13C NMR, UV-Vis and mass spectroscopy. These compounds exist in an equilibrium of two tautomeric forms in solution depending on the solvent as well as on the substituent and are water-soluble. It is worth mentioning that the hydrazone form of the dyes is in equilibrium with the zwitterion form of the dyes unlike the literature analogs existing in the anionic form. The application of the dyes consists of dying wool fiber at optimized conditions. The dying mechanism is suggested, wherein it revealed that these like dyes utilize ion-ion interactions next to expected hydrogen bonds. A comparative study on the antioxidant activity of the dyes and the dyestuff was conducted using ABTS assay.

Dyes bearing imino group along with azo one in the structure, present the class of azo-azomethine dyes. Azomethine compounds, known as Schiff bases, find application in biomedical research considering their potential antibacterial, antifungal, antimalaric, anticancer, antiinflammatory and antiviral activity. Furthermore, azo dyes are used in textile fiber dyeing, ink-jet and laser printers, LCDs, photovoltaic devices and metal complexes. With respects to the strong biological activity and a broad spectrum of potential application in industry, herein the microwave assisted synthesis and characterization of three new azo-azomethine dyes is presented. New azo-azomethine dyes were obtained by merging arylazo pyridone dye with different aniline cores resulting in azo-azomethine structure. In addition, tautomerism and solvatochromic properties of the dyes have been discussed., Organske sintetske boje koje u svojoj strukturi sadrže azo i imino grupu predstavljaju klasu azo-azometinskih jedinjenja. Azometinska jedinjenja, poznata kao Schiff-ove baze, imaju značajnu ulogu u biomedicinskim istraživanjima zbog potencijalne antibakterijske, antifungalne, antimalarijske, antikancerogene, antiinflamatorne i antivirusne aktivnosti. Azo-azometinske boje se mogu koristiti u industriji za bojenje tekstilnih vlakana, zatim u LCD ekranima, ink-džet i laserskim štampačima, fotonaponskim uređajima i metalnim kompleksima. U ovom radu prikazana je mikrotalasna sinteza i strukturna karakterizacija tri nove azo-azometinske boje, polazeći iz arilazo piridonske boje i različito supstituisanih anilina. Solvatohromna svojstva i tautomerija novih azo-azometinskih jedinjenja proučavani su u rastvaračima različitih svojstava.

Some of the recent research results dealing with the potential valorization of red mud emphasized long-term perspective of the new-class materials with the application in construction: so called geopolymers. This paper presents the investigation results of some of the red-mud-white-bauxite geopolymers performances. Geopolymerization is based on the heterogeneous chemical reaction, upon the atmospheric pressure and temperatures bellow 100°C between the solid alumosilicaterich materials and sodium silicate solution, which results in the creation of many alumosilicate oligomer components. Varieties in red mud content, as well as in white bauxite and metakaolinite content, solid to liquid ration within the raw mixture, affect the creation of different products from the prospective of their porosity and strength., Neki od skorijih istraživačkih rezultata vezanih za potencijalnu valorizaciju crvenog mulja pokazuju dugoročnije perspektive za primjenu kroz razvoj nove klase materijala za upotrebu u gradjevinskim konstrukcijama, tzv. geopolimera. U ovom radu su vršena ispitivanja karakteristika geopolimera na bazi sirovinske mješavine crvenog mulja i bijelog boksita. Proces geopolimerizacije se bazira na heterogenoj hemijskoj reakciji, koja se odvija na atmosferskom pritisku i temperaturi do 100°C između čvrstih materijala bogatih alumosilikatima i alkalnog rastvora natrijum-silikata, koja rezultira stvaranjem brojnih alumosilikatnih oligomernih komponenata, odnosno umreženom geopolimernom strukturom. Varijacijom sadržaja crvenog mulja, bijelog boksita, metakaolina, kao i odnosa čvrste i tečne faze, dobijeni su geopolimeri sa različitim nivoom pritisne čvrstoće i poroznosti.