Elektrilise kaksikkihi struktuur ja energia salvestamise karakteristikud ioonsetel vedelikel põhinevates kondensaatorites

Väitekirja elektrooniline versioon ei sisalda publikatsiooneElektrokeemilised energia salvestamise ja muundamise seadmed on aluseks tuleviku jätkusuutlikule energiamajandusele. Olgu selleks siis elektromagnet kiirgust elektrienergiaks muundavad päikesepatareid, autotranspordis kasutatavad kütuseelemendid, veest kütust tootvad elektrolüüserid, sekundaar-akumulaatorid iga-päeva elektroonikaseadmetes, superkondensaatorid, mis säästavad energiat kõrge võimsusega rakendustes või dielektrilised kondensaatorid elektroonilistes muundurites, kõrgtehnoloogilised elektrokeemilised seadmed on kõikjal meie ümber. Kõikide eelpool nimetatud seadmete puhul on aktiivseks osaks kahe erineva materjali vaheline piirpind, kus toimuvad elektrokeemilised reaktsioonid ja salvestub elektrienergia. Uute, kõrge effektiivusega elektrokeemiliste seadmete loomiseks on aga ülimalt oluline arusaam vastavat piirpinda mõjutavatest teguritest. Antud doktoritöö keskendub just mahtuvuslikele energia salvestamise seadmetele ja erinevustele elektrostaatiliste, dielektriliste ja pseudomahtuvuslike kondensaatorite vahel ioonse vedeliku ja elektroodi piirpinna vaheliste mõjude karakteriseerimise toel. Selle saavutamiseks rakendati ülitundlikke elektrokeemilisi, füüsikalisi ja spektroskoopilisi piirpinna analüüsi meetodeid, et reaalajas vaadelda muutuseid, mis leiavad aset elektrokeemilisel piirpinnal. Teadmised vastavatest fundametaaluuringutest on aidanud luua kõrgema spetsiifilise energiaga superkondensaatoreid ning viinud uudse dielektrilise kondensaatori tehnoloogia arendamiseni.Electrochemical energy storage and conversion devices are the basis of a sustainable energy economy of the future. Whether it is solar cells that convert electromagnetic radiation into electrical energy, fuel cells that consume chemical energy to power transportation, electrolysis cells that convert water into fuel, secondary batteries powering consumer electronics, supercapacitors that deliver considerable energy savings for high-power applications or dielectric capacitors that allow for efficient conversion between AC and DC signals, we are surrounded by advanced electrochemical devices. The active part of all of these devices is the interface between two dissimilar phases, where all the electrochemical reactions take place and energy is stored. In order to design more efficient electrochemical devices, however, detailed knowledge of this interface is of vital importance. This thesis focuses specifically on capacitive energy storage devices and the difference between purely electrostatic-, dielectric- and pseudo-capacitors from the perspective of their interfacial behaviour in ionic liquid electrolytes. This is achieved via advanced electrochemical, physical and spectroscopic analysis techniques that permit one to probe the properties of an electrochemical interface in real time. The knowledge from the fundamental studies has been applied to produce supercapacitors with higher specific energy and has led to the development of a new dielectric capacitor technology

Aktiveeritud süsinike mikrostruktuuri ja poorsuse mõju elektrilise kaksikkihi kondensaatorite omadustele

Väitekirja elektrooniline versioon ei sisalda publikatsiooneKuna elektrijaamu (tuule-, päikese-, hüdro-, tuumaenergia jne) mugavalt kaasas kanda ei saa, on ikka vaja uuemaid ja paremaid energiasalvestusseadmeid, mida saab tasku panna. Energiat saab salvestada näiteks superkondensaatorisse. Energiasalvestusseadmeid iseloomustab nende energia ja võimsus. Mida rohkem energiat saab seadmesse, näiteks elektriauto akusse, salvestada, seda kaugemale saab see auto sõita enne, kui aku tühjaks saab. Kui sama aku on ka suure võimsusega, siis suudab see aku energiat kiiremini välja anda ehk auto kiirendus on suurem. Superkondensaatorid on väga hea võimsusega energiasalvestusseadmed (hind võimuse ühiku kohta 4500 EUR (kWh)−1). Seega kasutatakse superkondensaatoreid põhiliselt rakendustes, kus on oluline energiat salvestada/kätte saada väga kiiresti. Näiteks nutitelefoni kaamera välk saab oma energia superkondensaatorilt. Üks tähtsamaid superkondensaatori koostisosi on elektroodid. Tavaliselt tehakse elektroodid poorsest süsinikust, mis on olemuselt sarnane aktiivsöega, mida kasutatakse näiteks söetablettides. Poorseid süsinikke iseloomustab eripind ehk suur pindala väikese massi kohta. Selles töös sünteesiti mitmeid huvitava ehitusega suure eripinnaga süsinikmaterjale, kasutades lähteainetena glükoosi, sahharoosi ja turvast. Sünteesitud süsinikmaterjalidest tehti edasi superkondensaatori elektroodid ja neid kasutati superkondensaatori katserakus. Nähti, et mõned sünteesitud materjalid koosnesid 1 μm (umbes 100 korda väiksem kui juuksekarva läbimõõt) kerakujulistest osakestest. Nende väikeste sfääride sees on keeruline poorne võrgustik, mille eripind oli suurusjärgus 2000 m2 g−1 ja kuhu pääsevad ligi ioonid ja molekulid. Uurimuse käigus selgus, et igasuguse suurusega poorid pole võrdselt head selleks, et saada suure võimsusega superkondensaatorit. Selgus, et suure võimsusega superkondensaatorite valmistamiseks on äärmiselt vajalikud poorid, mille läbimõõt on ligi 1 nm või laiem (läbimõõt, mis on sarnane DNA molekuli läbimõõdule).Since the conventional power plants (wind, solar, hydro, nuclear, etc) currently do not fit in the pocket there is still an ever-increasing problem of needing newer and better energy storage devices. A part of the solution seems to come in the form of a device called supercapacitor. At first approximation, any energy storage system can be described by two main key parameters: energy and power. An electric car with a high energy battery system means it can drive further without needing to refill. If the same system had high power, then the car's acceleration from would be fast. That said, at equal basis, supercapacitors are considered to be cheap for obtaining high power values (4500 EUR (kWh)−1). Thus supercapacitors are used in applications that require high power intakes and outputs. For example, a smartphone camera uses supercapacitors for the flash. One of the most influential supercapacitor components is electrodes. Most commonly the electrodes are made of carbon materials that are in nature similar to the carbon materials used in charcoal tablet and carbon materials in water filters. They all function because of a high active surface area. In the current study, several promising high surface area carbon materials were synthesised using glucose, saccharose and peat as precursors. Resulting materials were meticulously evaluated in a supercapacitor test cell and interpreted using modern structural analysis methods. Obtained results revealed that some synthesised materials consisted of 1 m (about 100 times smaller than the diameter of a human hair) spherical particles. Inside of these extremely small particles lays a complex porous network where a lot of additional surfaces is located (>2000 m2 g−1). These pores are accessible to small particles like ions and molecules that can find a home at pores. However, not all pores are equally good. Data indicated that the best pores for making high power supercapacitors were approximately 1 nm in diameter or wider (close to the diameter of a DNA molecule).https://www.ester.ee/record=b536185

The prediction of chemosensory effects of volatile organic compounds in humans

An introduction to indoor air pollution is given, and the chemosensory effects in humans of volatile organic compounds (VOCs), singly and in binary mixtures, are described, together with the bioassays already developed to quantify the effects of VOCs. The need for predictive models that can take over the bioassays is emphasised. Attention is drawn to the establishment of mathematical models to predict the chemosensory effects of VOCs in humans. Nasal pungency threshold (NPT), eye irritation threshold (EIT) and odour detection threshold (ODT) values are available for a series of VOCs that cover a large range of solute properties. Each of these sets of biological data are regressed against the corresponding solute descriptors, E, S, A, B and L to obtain quantitative structure activity relationships (QSARs) for log(l/NPT), log(l/ODT) and log(l/EIT) taking on the form: LogSP = c + e.E + s.S + a.A + b.B + l.L The availability of solute descriptors is investigated. It is shown that solute descriptors, E an excess molar refraction, S the solute dipolarity/polarizability, A the solute overall hydrogen-bond acidity, B the solute overall hydrogen-bond basicity and L the logarithmic value of the solute Ostwald solubility coefficient in hexadecane at 298K, can be obtained through the use of various thermodynamic measurements. In this way descriptors for some 300 solutes have been obtained. A headspace gas chromatographic method is also devised to determine the 1:1 complexation constant, K, between hydrogen bond donors and hydrogen bond acceptors in octan-1-ol. The 30 complexation constants measured are then correlated with α2H*, β2H, a combination of the solute 1:1 hydrogen bond acidity and basicity, respectively, to give: Log K1:1 = 2.950. α2H*β2H - 0.74

Polü(3,4-etüleendioksütiofeeni) õhukeste kilede valmistamine ja stabiilsus rakendusteks läbipaistva elektroodina

Väitekirja elektrooniline versioon ei sisalda publikatsiooneJuhtivad polümeerid on sellised orgaanilised polümeerid, mis juhivad elektrit. See põnev materjalide klass on juba 20. sajandi lõpust pälvinud teadusmaailma suurt tähelepanu, sest võib osutuda kasulikuks paljudes erinevates rakendustes, alates sensoritest ja lõpetades päikesepatareidega. Näiteks on paljudes seadmetes vaja kasutada läbipaistvaid elektroode, mille materjaliks on tänapäeval harilikult indiumtinaoksiidi (ITO) kiled. Aga ITO kiled on kallid ja nendele oleks hea odavam asendus leida. Just siin võib juhtiv polümeer kasuks tulla. Erinevalt ITOst on juhtivad polümeerid ka hea painduvusega, mis võimaldaks valmistada painduvaid elektroonikaseadmeid. Polü(3,4-etüleendioksütiofeen) (PEDOT) on üks juhtiv polümeer, mis võiks läbipaistvaks elektroodimaterjaliks sobida. PEDOT on üsna kõrge juhtivuse, hea läbipaistvuse ning juhtivate omaduste küllaltki suure stabiilsusega. Paraku ei ole ükski neist omadustest siiski veel päris ideaalne, mistõttu tuleb otsida lahendusi nende omaduste parandamiseks. Antud doktoritöös uuriti kahte erinevat PEDOTi õhukeste kilede valmistamise meetodit. Ühe meetodi puhul pärineb polümeeri moodustav monomeer gaasifaasist ja teisel juhul lahusest. Määrati, millistes etappides kile kasv toimub ja kuidas saada paremate omadustega kilet. Uuriti ka PEDOTi kilede vananemist ja nende juhtivuse vastupidavust erinevates keskkondades. Selgus, et uuritud PEDOTi kiled ei juhi elektrit nii hästi kui ITO ja nende juhtivus ei ole ka nii stabiilne. Ent avastati siiski üks rakendus, milles PEDOT on ITOst parem. Triboelektriline nanogeneraator on energiatootmisseade, mis suudab toota elektrit ka väikeste igapäevaelu liikumiste mehaanilisest energiast, mis muidu raisku läheb. PEDOTi kile kasutamine sellise seadme elektroodimaterjalina võimaldab kolm korda suuremat võimsustihedust kui ITO ja PEDOTi kile on selleks ka piisavalt stabiilne.Conductive polymers are organic polymers, which conduct electricity. This fascinating class of materials has gained a lot of scientific attention starting already from the end of the 20th century, because it may become useful in numerous applications, from sensors to solar panels. For example, transparent electrodes consisting of indium tin oxide (ITO) films are used in a large number of devices. But ITO films are expensive and a cheaper solution would be greatly appreciated. For this purpose, a conductive polymer may be a better solution. Conductive polymers are also flexible while ITO is brittle, enabling preparation of flexible electronic devices. Poly(3,4-ethylenedioxythiphene) (PEDOT) is a conductive polymer, which could be used as a transparent electrode material. PEDOT has a relatively high conductivity, good transparency and quite stable conductive properties. However, none of these properties is perfect at the current level of development. Therefore, it is still necessary to find ways for improving these properties. Two different preparation methods for PEDOT thin films were studied in this thesis. For one method the source of polymerizing monomer is a gas phase, for another method a solution. During this work the stages of film growth were investigated and better film formation conditions were determined. Aging of PEDOT and stability of conductance were investigated in different conditions. It was found out that investigated PEDOT films are not so highly conductive and stable conductors as ITO. However, in one application PEDOT was better than ITO. A triboelectric nanogenerator is a device, which could produce electricity from the mechanical energy of small movements, which would be otherwise wasted. As an electrode material for this device, PEDOT film enables to have three times higher power densities than ITO film and it is sufficiently stable

Instrumental and chemometric methodologies to assess sensory quality of Mediterranean food

L'oli d'oliva, el vi o els fruits secs són productes típics de la regió Mediterrània que ofereixen un valor afegit gràcies als seus beneficis per a la salut i excel·lents característiques sensorials. Per aquest motiu és necessari un control de la qualitat i autenticitat d'aquests productes, que són altament susceptibles a fraus i adulteracions. Un aspecte important és l'avaluació de la qualitat sensorial, que descriu paràmetres percebuts pels sentits (gust, visió, olor i tacte) mitjançant panells validats i entrenats d'experts. Aquests panells tendeixen a ser subjectius i requereixen llargs temps d'anàlisi i alts costos. Com a conseqüència hi ha hagut un increment en el desenvolupament de tècniques d'anàlisi capaces de simular les respostes obtingudes amb el panell de tast humà. L'anomenat 'panell electrònic' ofereix respostes objectives mitjançant l'ús de tècniques multivariants que permeten establir correlacions entre els descriptors definits pels humans i els senyals obtingudes instrumentalment. Aquesta tesi pretén oferir tècniques instrumentals alternatives, ràpides i senzilles per determinar la qualitat sensorial d'aliments com l'oli d'oliva, el vi o les ametlles. Els estudis duts a terme inclouen el tractament de les respostes sensorials obtingudes mitjançant metodologies de referència (principalment panells de tast humans), l'optimització dels procediments analítics per treballar amb tècniques instrumentals i el desenvolupament d'eines quimiomètriques adequades per construir els models multivariants. També s'han desenvolupat estratègies de fusió de dades per combinar les diferents dades instrumentals que simulen els sentits humans (olor, gust i visió).El aceite de oliva, el vino o los frutos secos son productos típicos de la región Mediterránea que ofrecen un valor añadido gracias a sus beneficios para la salud y excelentes características sensoriales. Por este motivo es necesario un control de la calidad y autenticidad de estos productos, que son altamente susceptibles a fraudes y adulteraciones. Un aspecto importante es la evaluación de la calidad sensorial, que describe parámetros percibidos por los sentidos (gusto, visión, olor y tacto) mediante paneles validados y entrenados de expertos. Estos paneles tienden a ser subjetivos, requieren largos tiempos de análisis y altos costes. Como consecuencia ha habido un incremento en el desarrollo de técnicas de análisis capaces de simular las respuestas obtenidas con el panel de cata humano. El llamado 'panel electrónico' ofrece respuestas objetivas mediante el uso de técnicas multivariantes que permiten establecer correlaciones entre los descriptores definidos por los humanos y las señales obtenidas instrumentalmente. Esta tesis pretende ofrecer técnicas instrumentales alternativas, rápidas y sencillas para determinar la calidad sensorial de alimentos como el aceite de oliva, el vino o las almendras. Los estudios llevados a cabo incluyen el tratamiento de las respuestas sensoriales obtenidas mediante metodologías de referencia (principalmente paneles de cata humanos), la optimización de los procedimientos analíticos para trabajar con técnicas instrumentales y el desarrollo de herramientas quimiométricas adecuadas para construir los modelos multivariantes. También se han desarrollado estrategias de fusión de datos para combinar los diferentes datos instrumentales que simulan los sentidos humanos (olor, gusto y visión).Olive oil, wine or nuts are typical products of the Mediterranean region that offer added value thanks to its health benefits and excellent sensory characteristics. Therefore, the control the quality and authenticity of these products is necessary, mainly because they are highly susceptible to fraud and adulterations. An important aspect is the evaluation of sensory quality that describe parameters perceived by the senses (taste, sight, smell and touch) using validated and trained panels of experts. These panels tend to be subjective, requiring long-time analysis and high costs. As a result there has been an increase in the development of analytical techniques capable to simulate the responses obtained with the human taste panel. The so-called 'electronic panel' provides objective responses using multivariate techniques, which establish correlations between descriptors defined by humans and signals obtained instrumentally. This thesis aims to offer fast and simple alternative instrumental techniques to determine the sensory quality of foods such as olive oil, wine and almonds. Studies carried out include the treatment of sensory responses obtained by reference methodologies (mainly human taste panels), optimization of analytical procedures to work with instrumental techniques and the development of appropriate chemometric tools to build multivariate models. Data fusion strategies have also been studied by combining different instrumental data that simulate the human senses (smell, taste and sight)

Orgaaniliste ühendite adsorptsiooni uurimine monokristalsetel elektroodidel in situ STM meetodiga

Väitekirja elektrooniline versioon ei sisalda publikatsioone.Kaasaegsete elektrooniliste seadmete tootjate eesmärgiks on valmistada väiksemaid mobiiltelefone ja arvuteid, kuid samal ajal pakkudes kõrgemaid tehnilisi näitajaid. Vältimatult toob see kaasa vajaduse väiksemate elektrooniliste komponentide ja suurema võimsusega mälu moodulite jaoks. Juhul, kui ühe transistori suurus oleks nagu üksik molekul, võiks mälumaht oluliselt kasvada, ning samas elektrooniliste komponentide suurus vähendada. Selline ongi elektroonika võimalik helge tulevik, mis pakub rohkem arvutuskiirust väiksema suuruse puhul. Selleks, et mõista, kuidas see asi toimib, tuleb vaadelda ideaalselt siledat metallpinda, millele adsorbeerunud orgaanilised molekulid saavad olla kompaktses monokihis. Moodustunud kahedimensionaalses kihis võib iga molekuli käsitleda, kui ühte transistorina. Sellistest transistoritest moodustanud vooluringis on ruutsentimeetri kohta suhteline mälu maht miljon korda suurem, kui praegustel kiipidel. See on hea näide, miks adsorptsiooniuuringud on oluline teema tänapäeva teaduses ja tehnoloogias. Pinnauuringud annavad hea ülevaate adsorptsioonprotsessidest faasidevahelisel piirpinnal. Käesolevas töös rakendati nüüdisaegset pinnauuringu meetodit nagu in situ skaneeriv tunnelmikroskoopiat (STM). STM meetodiga on võimalik visualiseerida pinnastruktuuri atomaarne struktuur ning samuti on näha iga adsorbeerunud molekul. Seega STM meetod annab olulist infot pinna struktuurist ja kvaliteedist, ning võimaldab visualiseerida reaalajas elektroodi pinnal muutusi, nagu orgaaniliste molekulide adsorptsioon potentsiaali all. Antud doktoritöö raames käsitleti mitmeid erinevaid alateemasid. Tehti kindlaks antimooni monokristalli pinna struktuur in situ STM meetodiga, mille tulemusena näidati, et antimonil ja vismutil on väga sarnane pinna struktuur, ning mõlemad metallid sobivad orgaaniliste ühendite adsorptsiooni uurimiseks. Samuti võivad antimon ja vismut asendada elavhõbedat elektroanalüütilistes ja katalüütilistes rakendustes ja uuringutes, kuna on vähem mürgised, ning sama heade katalüütiliste omadustega. Teisena uuriti tiokarbamiidi adsorptsiooni vismutil in situ STM ja impedantsspektroskoopia meetodiga vismuti monokristallil. Tiokarbamiid on oluline ühend, mis leiab laia rakendust kaasaegses tehnoloogias, ning teda kasutatakse pindaktiivse läikemoodustajana elektrosadestamise puhul, kuna tiokarbamiidi lisand annab väga sileda elektrosadestatud pinna. Samuti on ta kasutusel korrosioonihibiitorina kuna elektrokeemilise eritöötluse tulemusena tekitatakse metallpindadele kaitsev polümerkiht. Käesolevas töös määrati tiokarbamiidi adsorptsiooni parameetreid ning tehti kindlaks adsorptsiooni limiteerivad staadiumid. In situ STM meetodiga leiti, et tiokarbamiid ei moodusta sarnaselt 4,4’-bipüridiiniga kompaktselt kahedimensionaalset kihti vaid adsorbeerub tugevasti Bi monokristalli defektsetel kohtadel. Antud töös 4,4’-bipüridiini molekulide adsorptsiooni seaduspärasust vismuti monokristallil. 4,4’-bipüridiini uuringud on olulised molekuli elektrooniliste omaduste tõttu, mida saab rakendada nanoelektroonikas ning kõrge tihedusega mälumoodulite valmistamisel. Töös tehti kindlaks 4,4 '-bipüridiini adsorptsioonkihistruktuuri vismuti pinnal in situ STM meetodi abil. Lisaks, modelleeriti adsorbeerunud kihti kasutades selleks kaasaegseid arvutuskeemia meetodeid - tiheduse funktsionaali teooriat. Arvutuste tulemusena saadi olulist informatsiooni 4,4’-bipüridiini monokihi moodustumise kohta vismuti monokristallil. Leiti, et eksperimentaalsed in situ STM andmed ja teoreetilised arvutused on heas kooskõlas.Nowadays all modern electronic devices like cellphones and computers have trend to be miniaturized, but at the same time offering a higher level of performance. This inevitably leads towards the need for smaller electronic components and memory modules, providing at the same time better performance and higher memory capacity. Bringing a single transistor to the size of one molecule can drastically increase a memory module capacity and decrease the size of single electronic components. This idea has a bright future offering more performance in a smaller package. To understand how it works, one has to consider an ideally flat metal surface, where organic molecules can form a compact single layer, as a result of the adsorption phenomena. Every single molecule in such configuration can be considered as a single transistor and a square centimeter of such memory chip will outperform any present one by a million times in terms of capacity. This is a good example why adsorption studies are important topic in modern science and technology. Modern surface analysis methods can provide a deep insight over adsorption processes. Therefore, in the present work the state of the art of atomic level surface studies applying the in situ scanning tunneling microscopy (STM) have been implemented. It is capable of visualizing surface structure under atomic resolution and every single molecule adsorbed is visible. This technique provides important information about the state of the surface structure, for example, is it a rough or atomically flat. The great benefit of in situ STM method is that one can observe the changes at the surface in real time, like the visualization of the adsorption of organic molecules under potential control experiment. During this PhD work several subtopics were considered. The first one was to characterize the surface structure of the antimony (111) single crystal electrode by in situ STM. It was proven, that antimony has a very similar structure to the bismuth (111) single crystal, and both of them are very well suitable objects for adsorption studies of the organic molecules. Bismuth and antimony are also a good substitution as catalytically active materials for replacement of more poisonous and dangerous mercury. The second topic studied was the adsorption visualization of thiourea at bismuth (111) single crystal electrode. Thiourea is an important compound having wide application in the modern technology. Thiourea is used as a brightening agent in electroplating – giving a very smooth electrodeposited surfaces, and as a corrosion inhibitor – forming adsorbed polymer layers at the metal surfaces. In this work electrochemical in situ STM and impedance spectroscopy was used to study the adsorption kinetics of thiourea at bismuth surface. The thermodynamic adsorption parameters were analyzed and the adsorption limiting stages were defined. In situ STM data revealed that, differently from 4,4’-bipyridine, thiourea does not adsorb in a compact two dimensional layer, but thiourea adsorbs only at the surface defects of bismuth surface. The third topic studied was 4,4’-bipyridine molecule adsorption at well-defined single crystal bismuth (111) electrode. 4,4’-bipyridine related studies are important due to interesting electronic properties of 4,4-bipyridine molecule, which can be implemented in fabricating as nanoelectronic circuits and high density memory modules. Therefore, in present work the adsorption of 4,4’-bipyridine at bismuth surface was determined by the electrochemical in situ STM method and additionally modeled with the modern computation chemistry approximation – density functional theory. It was found, that experimental data are in good agreement with theoretical calculations and provide an essential information about the 4,4’-bipyridine single layer formation at bismuth (111) single crystal electrode

From a Molecule to a Drug: Chemical Features Enhancing Pharmacological Potential

This book collects contributions published in the Special Issue “From a Molecule to a Drug: Chemical Features Enhancing Pharmacological Potential” and dealing with successful stories of drug improvement or design using classic protocols, quantum mechanical mechanistic investigation, or hybrid approaches such as QM/MM or QM/ML (machine learning). In the last two decades, computer-aided modeling has strongly supported scientists’ intuition to design functional molecules. High-throughput screening protocols, mainly based on classical mechanics’ atomistic potentials, are largely employed in biology and medicinal chemistry studies with the aim of simulating drug-likeness and bioactivity in terms of efficient binding to the target receptors. The advantages of this approach are quick outcomes, the possibility of repurposing commercially available drugs, consolidated protocols, and the availability of large databases. On the other hand, these studies do not intrinsically provide reactivity information, which requires quantum mechanical methodologies that are only applicable to significantly smaller and simplified systems at present. These latter studies focus on the drug itself, considering the chemical properties related to its structural features and motifs. Overall, such simulations provide necessary insights for a better understanding of the chemistry principles that rule the diseases at the molecular level, as well as possible mechanisms for restoring the physiological equilibrium

Density Functional Theory

Density Functional Theory (DFT) is a powerful technique for calculating and comprehending the molecular and electrical structure of atoms, molecules, clusters, and solids. Its use is based not only on the capacity to calculate the molecular characteristics of the species of interest but also on the provision of interesting concepts that aid in a better understanding of the chemical reactivity of the systems under study. This book presents examples of recent advances, new perspectives, and applications of DFT for the understanding of chemical reactivity through descriptors forming the basis of Conceptual DFT as well as the application of the theory and its related computational procedures in the determination of the molecular properties of different systems of academic, social, and industrial interest