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Synthesis of pendant macrocycles by N-alkylation reactions on amine macrocycles
No full textCilj ovog diplomskog rada je sinteza pendantnih makrocikli kih spojeva reakcijama N-alkiliranja makrocikli kih amina. Makrocikli ka Schiffova baza, pripremljena iz dialdehida i diamina, reducirana je natrijevim borohidridom. Reducirani je oblik potom metiliran, a sredstva za metiliranje su bili metil-4-(bromometil)benzoat i metil bromoacetat. Tijek svake reakcije metilacije je pra en tankoslojnom kromatografijom. Spojevi su karakterizirani IR (FTIR) i 1H NMR spektroskopijom. Iz izvedenih sinteza, uspjebno su dobivena i identificirana dva nova pendantna makrocikli ka spoja.The aim of this thesis was the synthesis of pendant macrocyclic compounds via Nalkylation reactions of macrocyclic amines. The macrocyclic Schiff base, prepared from a dialdehyde and diamine, was reduced using sodium borohydride. The reduced form was methylated using methyl-4-(bromomethyl) benzoate and methyl bromoacetate. The progress of each methylation reaction was monitored by thin-layer chromatography. Two novel pendant macrocycles were successfully obtained and characterized using IR (FT-IR) and ¹H NMR spectroscopy
Sodium ion batteries: principle of operation, battery structure, degradation of electrode materials and battery properties
No full textGlobalne promjene uzrokovane ljudskom djelatnošću pridonose hitnosti istraživanja novih oblika pohrane energije. Prvi korak je bio izum litij-ionske baterije no zbog nedostupnosti resursa i složenog procesa proizvodnje započeto je istraživanje natrij-ionskih baterija. Natrij-ionske baterije se mogu podijeliti na polućelijske i ćelijske sustave te je glavna razlika između tih sustava donor Na+ iona. Vrste natrij-ionskih baterija koje se istražuju su baterije na bazi oksida prijelaznih metala, polianiona, analoga prusko plave te natrij-sumporna baterija. Glavni problem natrij-ionskih baterija jest nedostatna količina Na+ iona što uzrokuje lošu elektrokemijsku učinkovitost i taloženje natrijevih iona na anodi što smanjuje ciklički vijek. Neke od strategija poboljšanja su modifikacija elektrodnih materijala, optimizacija elektrolita, nadopuna natrija i još neke metode poput upotrebe veziva. Važno je istaknuti i komercijalnu ulogu natrijevih baterija, koja bi u budućnosti mogla zasjeniti litij-ionske baterije po svim karakteristikama uz manje cijene i jednostavniji proces proizvodnje.Global changes caused by human activity contribute to the urgency of researching new forms of energy storage. The first step was the invention of the lithium-ion battery but due to resource unavailability and the complex manufacturing process, research into sodium-ion batteries has begun. Sodium-ion batteries can be divided into half-cell and full-cell systems, with the main difference between these systems being the donor of Na+ ions. Types of sodium-ion batteries being researched include transition metal oxide-based batteries, polyanion-based batteries, prussian blue analogs, and sodium-sulfur batteries. The main problem with sodium-ion batteries is the insufficient amount of Na+ ions which causes poor electrochemical efficiency and the deposition of sodium ions on the anode, reducing the cycle life. Some improvement strategies include electrode material modification, electrolyte optimization, sodium supplementation and other methods such as the use of binders. It is also important to highlight the commercial role of sodium-ion batteries which could potentially outshine lithium-ion batteries in all characteristics in the future at lower costs and with a simpler manufacturing process
Preparation of 4-brom-1,8-naphthalicanhydride derivatives
No full textU ovome završnom radu opisana je priprava derivata 4-brom-1,8-naftalanhdrida koja je uključivala reakcije nukleofilne aromatske supstitucije te adicijsko-eliminacijske reakcije naftalanhidridnog derivata s odgovarajućim anilinskim derivatima. Reakcija nukleofilne aromatske supstitucije na polaznom, 4-brom-1,8-naftalanhidridu rezultirala je pripravom azidnog derivata spoja 1 koji je korišten kao polazni spoj u drugom reakcijskom koraku za adicijsko-eliminacijsku reakciju s odabranim anilinskim derivatima. S ciljem ispitivanja utjecaja elektron-donorskih, odnosno elektronakceptorskih skupina, na prinos reakcije kao polazni anilinski derivati odabrani su para-nitroanilin te para-fenilendiamin. Predloženim sintetskim putem uspješno je pripravljen amino derivat, spoj 2, dok se spoj A pokušalo pripraviti, korištenjem dvije metode: i) koja je identična metodi priprave spoja 2 i ii) koja podrazumijeva drugi sintetski put. U svrhu ispitivanja upotrebe spoja 2 kao indikatora za određivanje koncentracije unutarstaničnog H2S, spoj 2 pokušalo se reducirati uvođenjem H2S u suvišku u otopinu spoja 2. Reakcija redukcije uspješno je provedena što je pretpostavljeno usporedbom otopine nereduciranog i reduciranog oblika spoja 2 pod UV lampom (365 nm). Strukture spojeva 1 i 2 pretpostavljene su 1H i 13C NMR spektroskopijom.In this thesis the preparation of 4-Bromo-1,8-Naphthalic anhydride derivatives was described which included nucleophilic aromatic substitution and addition-elimination reactions of naphthalic anhydride derivative with selected aniline derivatives. The reaction of nucleophilic aromatic substitution on the starting compound, 4-Bromo-1,8-Naphthalic anhydride resulted with the preparation of an azide derivative, compound 1 which was used as a starting compound in the second reaction step that involved addition-elimination reaction with the selected aniline derivatives. With the aim of investigation of influence electron-acceptor and electron-donor groups on the reaction yield, as starting aniline derivatives para-phenylenediamine and para-nitroaniline were chosen. Only the amino derivative, compound 2 was prepared using the proposed synthetic route, while for the synthesis of compound A two synthetic pathways were proposed. Method i) which is identical to methode used to prepare compound 2 and method ii) which implies another synthetic route. To investigate the use of compound 2 as an indicator for intracellular H2S, compound 2 was tried to be reduced with an excess H2S. The reduction was carried out successfully which was assumed by comparing the solutions of reduced and non-reduced forms of compound 2 under UV lamp (365 nm). Structures of compounds 1 and 2 were assumed by 1H and 13C NMR spectroscopy
Medicinal plants and polycystic ovary syndrome
No full textU ovom zavrbnom radu istra~uje se u inak pojedinih biljaka na simptome sindroma policisti nih jajnika, PCOS-a (engl. Polycystic ovary sindrom), te na samu prevenciju i lije enje sindroma. U tu svrhu, napravljen je pregled dugogodibnjih istra~ivanja ljekovitog bilja (Aloe vera (L.) Burm. f., Curcuma longa L., Cinnamomum Schaeff., Camellia sinensis (L.) Kuntze, Oenothera biennis L.) na utjecaj simptoma sindroma policisti nih jajnika. Sindrom policisti nih jajnika danas je sve u estaliji te predstavlja sve ve i problem u ~ivotu ~ena uzrokuju i, između ostalog, neplodnost. Prvi izbor lije enja su razni sinteti ki lijekovi, no s obzirom na nuspojave postoje ih lijekova potrebno je istra~iti druge metode. Pregledom literature utvrđeno je da Aloe vera i cimet vra aju cikli nost estrusa, normaliziraju spolne hormone i smanjuju inzulinsku rezistenciju. Kurkumin ima antioksidacijski i glikemijski u inak, smanjuje rezistenciju na inzulin te poboljbava metabolizam lipida. Ulje no urka pozitivno djeluje na morfologiju jajnika i spolne hormone, dok zeleni aj pozitivno djeluje na gubitak tjelesne mase kod ~ena s PCOS-om. Zaklju no tome, upotreba ljekovitog bilja nudi mogu nost smanjenja potrebe za sinteti kim lijekovima te doprinosi poboljbanju kvalitete ~ivota oboljelih ~ena.This thesis investigates the effects of various plants on the symptoms of polycystic ovary syndrome, PCOS, and on the prevention and treatment of the syndrome. To this end, a review of longterm studies on medicinal herbs (Aloe vera (L.) Burm. f., Curcuma longa L., Cinnamomum Schaeff., Camellia sinensis (L.) Kuntze, Oenothera biennis L.) and their impact on symptoms was conducted. Polycystic ovary syndrome is becoming increasingly common and represents a growing problem in women's lives, causing, among other issues, infertility. The first choice of treatment consists of various synthetic drugs, however, due to the side effects of existing medications, it is necessary to explore alternative methods. The literature review has found that Aloe vera and cinnamon restore estrous cyclicity, normalize sex hormones, and reduce insulin resistance. Curcumin has antioxidant and glycemic effects, reduces insulin resistance, and improves lipid metabolism. Evening primrose oil positively affects ovarian morphology and sex hormones, while green tea positively influences weight loss in PCOS women. In conclusion, implementation of medicinal herbs offers the potential to lower the need for medication and contributes to improving the quality of life for affected women
Theoretical determination of lattice energy in n -alkylen aromatic dialdehydes
No full textČvrste tvari koje se sastoje od atoma, iona ili molekula koje su posložene u visoko uređenu mikroskopsku strukturu prilikom čega tvore kristalnu rešetku koja se periodično prostire u svim smjerovima u prostoru, nazivaju se kristalne krutine ili kristali. Rendgenska difrakcija je analitička tehnika koja nam daje informacije o kristalnoj strukturi, njezinom kemijskom sastavu i fizičkim karakteristikama kristala. Za izračun energije kristalne rešetke primjenjuje se Born-Haberov kružni proces. Ova metoda temelji se Hessovom zakonu koji govori da prilikom prijelaza nekog kemijskog sustava iz jednog stanja u drugo ukupna oslobođena energija ne ovisi o putu reakcije. Ukupna energija kristalne rešetke uključuje entalpije svih procesa koji se odvijaju prilikom formiranja kristala iz elemenata, a to su: energija ionizacije, elektronski afinitet, energija disocijacije i energija sublimacije. U prvom dijelu ovog rada opisani su kristalni sustavi te njihova raspodjela prema Bravisu te kako se kristalnom difrakcijom određuje struktura kristala. Objašnjeno je i kako teorijski odrediti energiju kristalne rešetke te kako je ona povezana sa Born- Landeovom jednadžbom, jednadžbom Kapustinskog, Madelungovom konstanom i Born Haberovim ciklusom. U drugom dijelu ovog rada prikazan je način određivanja kristalne rešetke pomoću programa Crystal Explorer. U navedenom programu računata je energija kristalne rešetke za nekoliko spojeva iz skupine aromatskih dialdehida.Solid substances consisting of atoms, ions, or molecules that are arranged in a highly ordered microscopic structure, forming a crystal lattice that periodically extends in all directions in space, are called crystalline solids or crystals. X-ray diffraction is an analytical technique that gives information about the crystal structure, it is chemical composition, and physical characteristics of the crystal. Born- Haber circular process is used to calculate the crystal lattice energy. This method is based on Hess's law, which states that during the transition of a chemical system from one state to another, the total released energy does not depend on the reaction path. The total energy of the crystal lattice includes the enthalpies of all processes that take place during the formation of crystals from elements, namely: ionization energy, electron affinity, dissociation energy, and sublimation energy. In the first part of this work, crystal systems and their distribution according to Bravis are described, and how crystal structure is determined by diffraction. It also explains how to theoretically determine the energy of the crystal lattice and how it is related to the Born- Lande equation, the Kapustinski equation, the Madelung constant, and the Born- Haber cycle. In the second part of this work, determination of the crystal lattice energy using Crystal Explorer program is presented. In the aforementioned program, the energy of the crystal lattice was calculated for several dialdehyde compounds
Verification of the method for the determination of chlorite and chlorate
No full textKloriti i klorati su anorganski ioni koji se pojavljuju u uzorcima vode. Ove ionske vrste nastaju kao nusprodukti dezinfekcije pri koribtenju klorova dioksida. Budu i da imaju toksi an u inak potrebno ih je na vrijeme identificirati. Ionska kromatografija pogodna je za analizu klorita i klorata zbog svoje specifi nosti, automatizacije, visoke osjetljivosti, preciznosti te ponovljivosti. Također, priprema uzoraka za ionsku kromatografiju je jednostavna i brza, a za analizu je potrebno osigurati male koli ine uzorka. Job jedna prednost ionske kromatografije je ta bto ona omogu uje istovremenu detekciju razli itih aniona i kationa u uzorcima. Ovim diplomskim radom provedena je verifikacija ve postoje e metode za određivanje klorita i klorata u uzorcima vode ionskom kromatografijom. Kao parametri validacije ispitali su se: linearnost, ponovljivost, to nost, granica detekcije, granica kvantifikacije te koncentracijski raspon. Svi dobiveni rezultati zadovoljili su propisane kriterije prihvatljivosti (koeficijent korelacije r g 0,995, granica kvantifikacije 0,05 mg/L, ponovljivost RSD f 10 % te iskoribtenje od 100 ± 10%). Odabrano je osam izvora mjerne nesigurnosti koje su se analizirale: isto a standarda, mikropipeta 10-100 μL, mikropipeta 100-1000 μL, odmjerna tikvica 10 mL, kalibracijski pravac, ponovljivost mjerenja, iskoribtenje te ponovljivost pripreme uzorka. Od svih ispitanih izvora mjerne nesigurnosti, kod oba analita, najve i je utjecaj imao kalibracijski pravac. Izra unate su i sastavljena te probirena mjerna nesigurnost.Chlorites and chlorates are inorganic ions that appear in water samples. These ionic species are byproducts of disinfection when chlorine dioxide is used. Since they have toxic effects, it is necessary to identify them in a timely manner. Ion chromatography is suitable for the analysis of chlorites and chlorates due to its specificity, automation, high sensitivity, precision, and repeatability. Additionally, sample preparation for ion chromatography is simple and fast, and only small quantities of the sample are required for analysis. Another advantage of ion chromatography is that it enables the simultaneous detection of different anions and cations in samples. This thesis conducted a verification of an existing method for the determination of chlorites and chlorates in water samples by ion chromatography. The validation parameters examined were: linearity, repeatability, accuracy, detection limit, quantification limit, and concentration range. All obtained results met the prescribed acceptance criteria (correlation coefficient r g 0.995, quantification limit 0.05 mg/L, repeatability RSD f 10 %, and recovery of 100 ±10 %). Eight sources of measurement uncertainty were selected for analysis: standard purity, micropipette 10-100 μL, micropipette 100-1000 μL, 10 mL volumetric flask, calibration curve, measurement repeatability, recovery and reproducibility of sample preparation. Among all the examined sources of measurement uncertainty, for both analytes, calibration curve had the greatest impact. Combined and expanded measurement uncertainties were also calculated.
Synthesis of the sensor material cetylpyridinium tetraphenyl borate
No full textAnionski tenzidi su površinski aktivne tvari koje smanjuju površinsku napetost, a strukturno su sastavljeni od hidrofobne i hidrofilne skupine. Disocijacijom u vodenim otopinama nastaju negativno nabijeni organski anioni. Ova vrsta tenzida je prisutna u komercijalnim sredstvima za čišćenje i u proizvodima za osobnu higijenu. Jedna od mogućnosti određivanja anionskih tenzida jest putem potenciometrijskih senzora. Najvažnija komponenta potenciometrijskih senzora je membrana, koja je sastavljena od ionofora, plastifikatora i PVC-a, a ionofori su ključan dio jer omogućuju selektivno i reverzibilno vezanje iona analita, što omogućuje njihovo određivanje. Sintezom ionskog para cetilpiridinijevog tetrafenil borata (CP-TPB) omogućava se njegova ugradnja u polimernu membranu potenciometrijskih senzora, koji služe za određivanje anionskih tenzida.Anionic surfactants are surface-active compounds that reduce surface tension and are composed of hydrophylic and hydrophobic group. Dissociation in aqueous solutions produces negatively charged organic anions. This type of surfactant is present in commercial cleaning products and hygiene products. One of the possibilities of detecting anionic surfactants is through potentiometric sensors. The most important component of the potentiometric sensors is the membrane, which is composed of ionophores, plasticizers and PVC, and ionophores are a key part of membranes because they enable selective and reversible binding of analyte ions, which enables their detection. The synthesis of ion pair cetylpyridinium tetraphenyl borate (CP-TPB) enables its incorporation in the polymer membrane of potentiometric sensors, which are used to detection of the anionic surfactants
Green synthesis of silver nanoparticles using fungus Ophiostoma novo-ulmi
No full textZelena sinteza je metoda koja za sintezu nano estica koristi netoksi ne i biorazgradive kemikalije. U ovome istraživanju prvi put je prikazana sinteza nano estica srebra upotrebom vodenog ekstrakta gljive Ophiostoma novo-ulmi i vodene otopine AgNO3. Ophiostoma novoulmi je fitopatogena gljiva mjebinarka koji uzrokuje holandsku bolest brijesta (DED). Biosintetizirane nano estice srebra karakterizirane su UV-Vis, FT-IR i PXRD tehnikama. Rezultati karakterizacije sintetiziranih nano estica ukazuju na uspjebnu sintezu koribtenjem ekstrakta O. novo-ulmi kao reduciraju eg i stabiliziraju eg sredstva, s UV-Vis maksimumom na ≈ 413 nm. FT-IR analizom su identificirani glavni fitokemijski spojevi koji bi mogli biti odgovorni za bio-redukcijski potencijal. Prema rezultatima PXRD, promjer kristalita AgNP-a izra unat pomo u Scherrer-ove jednadžbe iznosi 30 nm, sa plobno centriranom kubi nom (fcc) strukturom.Green synthesis is a method that uses non-toxic, biodegradable chemicals for the synthesis of nanoparticles. In the present study, we report for the first time a green approach to the synthesis of silver nanoparticles (AgNPs) using an aqueous extract of the fungus Ophiostoma novo-ulmi and an aqueous solution of AgNO3. Ophiostoma novo-ulmi is a phytopathogenic ascomycete that causes Dutch elm disease (DED), a devastating vascular wilt disease of elms. The biosynthesised nanoparticles were characterised by UV-Vis, FTIR and PXRD. The results of the characterisation of the synthesised nanoparticles indicate the successful synthesis using O. novo-ulmi extract as a reducing and capping agent, with a UV-Vis absorption peak at≈ 413 nm. FTIR identified major phytochemical compounds that could be responsible for the bio-reducing potential. According to the PXRD results, the AgNP crystallite diameter calculated using the Scherrer equation is 30 nm, with a face centred cubic (fcc) structure
Chemistry of the thermosphere
No full textTermosfera je gornji dio atmosfere koji karakteriziraju iznimno visoke temperature. Proteže se od 80-90 km nadmorske visine do između 500 i 1000 km iznad površine Zemlje, ine i ju najširim dijelom atmosfere. Osim niskog tlaka, u termosferi su uo ene nagle varijacije vrijednosti temperature, koje rastu s nadmorskom visinom. Glavne komponente termosfere su atomski kisik, atomski dušik, helij i vodik. Kemijske reakcije u termosferi, esto potaknute sun evim zra enjem, te proces molekularne difuzije, koji razdvaja plinove prema masi, igraju važnu ulogu u ovom atmosferskom sloju. Cirkulacija u termosferi je uzrokovana atmosferskim plimama i valovima, dok se na visini od 100 do 1000 km iznad Zemljine površine pojavljuje polarna svjetlost. Ovaj fenomen nastaje zbog interakcije Sun evog vjetra s atmosferom, a boja polarnih svjetlosti ovisi o sudarima kisikovih i dušikovih atoma s elektronima.The thermosphere is the upper part of the atmosphere characterized by extremely high temperatures. It extends from 80-90 km above sea level to between 500 and 1000 km above the Earth's surface, making it the widest part of the atmosphere. Besides the low pressure, the thermosphere experiences rapid temperature variations, which increase with altitude. Its main components are atomic oxygen, atomic nitrogen, helium and hydrogen. Chemical reactions in the thermosphere, often triggered by solar radiation, and the process of molecular diffusion, which separates gases by mass, play a significant role in this atmospheric layer. Circulation in the thermosphere is caused by atmospheric tides and waves, while polar lights appear at altitudes ranging from 100 to 1000 km above the Earth's surface. This phenomenon arises from the interaction of the solar wind with the atmosphere, and the color of the polar lights depends on collisions between oxygen and nitrogen atoms with electrons
Bioactivity, pharmacology and toxicology of selected compounds in coffee
No full textKava je jedno od najpopularnijih pi a u svijetu. Sastoji se od oko 700 spojeva koji joj daju karakteristi an okus i miris. Biljka kava lan je obitelji Rubiaceae. Najva~nije vrste kave su Coffea arabica L. i C. canephora Pierre ex Froehner, koje ine 40 - 60 % svjetske proizvodnje. Sastojci kave, uklju uju i kofein, klorogenu kiselinu, trigonelin, diterpene (kafestol i kahweol), melanoidine i druge spojeve doprinose njenom jedinstvenom okusu i mirisu. Brojna istra~ivanja utvrdila su da kava sadr~i bioaktivne spojeve s potencijalnim zdravstvenim koristima. U ovom zavrbnom radu detaljno su istra~eni bioaktivnost, farmakologija i toksikologija odabranih spojeva u kavi, s posebnim naglaskom na kofein, klorogenu kiselinu, trigonelin, melanoidine i diterpene. Kofein je poznat po svojim stimulativnim u incima na sredibnji ~iv ani sustav, dok klorogena kiselina posjeduje antioksidacijska svojstva koja mogu pomo i u prevenciji kroni nih bolesti poput kardiovaskularnih bolesti i dijabetesa. Melanoidini, nastali tijekom pr~enja, također pokazuju antioksidacijske i antiglikacijske aktivnosti. Međutim, istra~ivanja također ukazuju na potencijalne toksi ne u inke, osobito u visokim dozama, uklju uju i rizik od razvoja gastrointestinalnih smetnji i poreme aja spavanja.Coffee is one of the most popular beverages in the world. It consists of about 700 compounds that give it its characteristic flavor and aroma. The coffee plant belongs to the Rubiaceae family. The most important coffee species are Coffea arabica L. and C. canephora Pierre ex Froehner, which make up 40 - 60 % of global production. The components of coffee, including caffeine, chlorogenic acid, trigonelline, diterpenes (cafestol and kahweol), melanoidins, and other compounds, contribute to its unique flavor and aroma. Numerous studies have found that coffee contains bioactive compounds with potential health benefits. This final thesis thoroughly investigates the bioactivity, pharmacology, and toxicology of selected compounds in coffee, with special emphasis on caffeine, chlorogenic acid, trigonelline, melanoidins, and diterpenes. Caffeine is known for its stimulating effects on the central nervous system, while chlorogenic acid possesses antioxidant properties that may help prevent chronic diseases such as cardiovascular disease and diabetes. Melanoidins, formed during roasting, also exhibit antioxidant and anti-glycation activities. However, research also points to potential toxic effects, especially in high doses, including the risk of developing gastrointestinal issues and sleep disorders