126 research outputs found
Synthesis of Nitrogen Doped Carbon Nanodots and their Applications as Functional Materials
No full textI carbon dots (CDs) sono i nanomateriali a base di carbonio di piú recente scoperta e rappresentano l'argomento centrale di questa tesi. Questo nanomateriale è costituito da nanoparticelle 0D quasi sferiche con interessanti proprietà redox, ampio spettro di assorbimento ed emissione, e elevata stabilità chimica e fotochimica. Queste attraenti proprietà hanno fatto crescere l'interesse della comunità scientifica verso la preparazione e l’uso di queste nanoparticelle in molte aree applicative, dalle bio-applicazioni a utilizzi in campo energetico.
Il capitolo 1 offre una panoramica generale dello stato dell'arte dei CDs. Sono discusse le strutture e proprietà delle quattro tipologie esistenti: graphene quantum dots (GQD),
carbon quantum dots (CQD), carbon nanodots (CND) e carbon polymer dots (CPD).
Il Capitolo 2 dimostra che CNDs chirali (sCND) possono essere prontamente preparati usando una sintesi multicomponente assistita da microonde. Queste nanoparticelle, con una dimensione di circa 3 nm, sono altamente solubili in acqua e mostrano dicroismo circolare speculare sia nella regione dell’ultravioletto-visibile che in quella infrarossa dello spettro elettromagnetico. La strategia sintesica proposta offre interessanti opportunità per lo sviluppo di diverse nanoparticelle di carbonio chirali. Come esempi rappresentativi, abbiamo riportato la preparazione di CNDs con diverse proprietà di assorbimento e fluorescenza attraverso l’impiego di diversi precursori responsabili della formazione del core o di molecole dopanti. Questa semplice (ed efficace) metodologia ci ha ispirato nell’esplorare nuove opportunità applicative, ad esempio l’impiego di queste nanoparticelle come templati per la formazione di aggregati cromoforici (porfirinici) chirali in acqua. Infine, vengono discussi gli effetti della superficie chirale dei CDs su proteine e cellule.
Il capitolo 3 riporta la progettazione, la sintesi e la caratterizzazione dei CNDs dopati con fluorofori BODIPY (BCNDs). L’approccio sintetico riportato consiste in una sintesi idrotermica multicomponente che è risultata versatile per la preparazione di materiali con proprietà ottiche specifiche. Le evidenze sperimentali, emerse dallo studio, hanno suggerito che le molecole di fluoroforo sono state incorporate con successo nella struttura delle nanoparticelle attraverso la possibile reazione del gruppo carbossilico del BODIPY con le ammine di arginina ed etilen diammina. I BCNDs ottenuti sono risultati altamente solubili in acqua, possiedono gruppi amminici superficiali che possono essere ulteriormente funzionalizzati, e presentano la tipica emissione di fluorescenza verde del BODIPY. Studi fotofisici hanno rivelato che la resa quantica di fotoluminescenza (PLQY) del BODIPY influenza la PLQY delle nanoparticelle risultanti. Questo dato ha dimostrato che la modifica strutturale del BODIPY risulta nella produzione di nanoparticelle con una migliore emissione di fluorescenza. Inoltre, considerato il crescente interesse verso la produzione di nuovi emettitori per elettrochemiluminescenza (ECL), aventi emissioni variabili dello spettro del visibile e in grado di essere facilmente modificabili, abbiamo studiato anche le proprietà ECL di queste nanoparticelle.
Il capitolo 4 si concentra sull'uso di CNDs dopati con azoto (NCNDs) come elementi costitutivi per la preparazione di ibridi covalenti donatore-accettore di con zinco ftalocianine (ZnPc). I gruppi amminici degli NCNDs sono stati fatti reagire con gli acidi carbossilici di un derivato di ZnPc tramite un protocollo di accoppiamento con carbodiimide. Lo studio dimostra la presenza di due (o più) unità di ZnPc per nanoparticella e le indagini fotofisico hanno dimostrato le proprietà donatoreaccettore del materiale ibrido.Carbon dots (CDs) are the latest member to join the large family of carbon-based nanomaterials and represent the central topic of this dissertation. This nanomaterial consists on quasi-spherical 0D nanoparticles with rich redox chemistry, wide light absorption and emission and high chemical and photo-stability. These favorable properties have increased the interest of the scientific community toward preparation and application of these nanoparticles in many applicative areas, ranging from biological to energy related applications.
Chapter 1 provides a general overview of the state of the art of CDs. The structures and the relative properties of the four CDs typologies are discussed: graphene quantum dots (GQDs), carbon quantum dots (CQDs), carbon nanodots (CNDs) and carbon polymer dots (CPDs).
Chapter 2 shows that chiral carbon carbon nanodots (sCNDs) can be readily prepared using hydrothermal microwave-assisted synthesis. These nanoparticles, with size around 3 nm, are highly soluble in water and display mirror-image profile both in the UV– Vis and in the infrared regions, as detected by electronic and vibrational circular dichroism, respectively. We proposed the presence of a chiral shell that is originated by cyclohexanediamine moieties incorporated on the dots. The proposed synthetic strategy opens up exciting opportunities for developing a variety of chiral nanodots. As representative examples, we report the preparation of CNDs with different absorption and emission properties by using different core precursor or doping molecules. This simple (and effective) synthetic methodology inspires us towards exciting opportunities, such as the use of these nanoparticles as templates for the formation of chiral chromophoric (porphyrin) assemblies in water. Finally, the effects that the chiral surface of CDs has on protein and cells is discussed.
Chapter 3 reports the design, synthesis and characterization of CNDs doped with BODIPY dyes (BCNDs) showing the versatility of a multicomponent hydrothermal synthesis for preparing materials with predictable optical properties. Experimental evidences suggest that the BODIPY has been successfully incorporated in the nanodots through a carboxylic moiety on the meso-phenyl ring that likely reacts with the amines of Arg and EDA. The BCNDs are highly water soluble, possess amino groups on the surface that are amenable for further functionalization and present the typical green fluorescence emission of the BODIPY. The photoluminescence quantum yield (PLQY) of the dye affects the PLQY of the resulting nanoparticles demonstrating that structural modifications of the BODIPY precursor lead to nanodots with enhanced fluorescence emission. In addition, in the quest for novel ECL emitters, able to emit across a palette of colors and to be easily modified for bioconjugation reaction, we studied the ECL properties of these nanoparticles. Our findings show that BCNDs are good ECL emission that can be mainly modulated through post-synthetic surface modification, and the dye is likely incorporated in the core of the nanodots. The rational brought forward in this work could be extended for preparing multicolored CNDs by using different BODIPY precursors.
Chapter 4 focuses on the use of nitrogen doped CNDs (NCNDs) as building blocks for the preparation of donor-acceptor covalent hybrids with zinc phthalocyanines (ZnPc). The amino groups from the NCNDs and the carboxylic acid from a ZnPc are combined through a carbodiimide coupling protocol. The study show the presence of two (or more) units of ZnPcs per nanoparticle and an in-depth photophysical investigation reveals the donor-acceptor properties of the hybrid materials
Symmetry‐Breaking Charge‐Transfer Chromophore Interactions Supported by Carbon Nanodots
No full textCarbon dots (CDs) and their derivatives are useful platforms for studying electron-donor/acceptor interactions and dynamics therein. Herein, we couple amorphous CDs with phthalocyanines (Pcs) that act as electron donors with a large extended p-surface and intense absorption across the visible range of the solar spectrum. Investigations of the intercomponent interactions by means of steady-state and pump-probe transient absorption spectroscopy reveal symmetry-breaking charge transfer/separation and recombination dynamics within pairs of phthalocyanines. The CDs facilitate the electronic interactions between the phthalocyanines. Thus, our findings suggest that CDs could be used to support electronic couplings in multichromophoric systems and further increase their applicability in organic electronics, photonics, and artificial photosynthesisFil: Cacioppo, Michele. Università degli Studi di Trieste; ItaliaFil: Scharl, Tobias. Universitat Erlangen-Nuremberg; AlemaniaFil: Dordevic, Luka. Università degli Studi di Trieste; ItaliaFil: Cadranel, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Arcudi, Francesca. Università degli Studi di Trieste; ItaliaFil: Guldi, Dirk. Universitat Erlangen-Nuremberg; AlemaniaFil: Prato, Maurizio. Università degli Studi di Trieste; Itali
Synthesis and excited state processes of arrays containing amine-rich carbon dots and unsymmetrical rylene diimides
No full textCombining carbon dots (CDs) with p-extended chromophores is an attractive way to study the electronic and energy processes of the former as a key step to many applications, including photosensing, photocatalysis, or photosensitization. CDs, in conjugation with chromophores, can have value in preparing donor–acceptor hybrids, and can also be used as scaffolds to support electronic communication between dyes. In this work, we conjugate two different rylene diimides, naphthalene and perylene diimides (NDI and PDI, respectively), with amorphous nitrogen-doped carbon dots. We take advantage of the imidization reaction between the amine-rich surface of the carbon dots and the monimide monoanhydride precursors of NDIs and PDIs, under microwave assisted conditions. The resulting (nano)hybrids were characterized also by spectroscopic methods. In particular, time-resolved spectroscopy for the multichromophoric array, consisting of CDs and both rylene diimides, allowed us to elucidate the complex inter-chromophoric interactions taking place in the excited state.Fil: Dordevic, Luka. Università degli Studi di Trieste; ItaliaFil: Haines, Philipp. Universitat Erlangen-Nuremberg; AlemaniaFil: Cacioppo, Michele. Università degli Studi di Trieste; ItaliaFil: Arcudi, Francesca. Università degli Studi di Trieste; ItaliaFil: Scharl, Tobias. Universitat Erlangen-Nuremberg; AlemaniaFil: Cadranel, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Guldi, Dirk. Universitat Erlangen-Nuremberg; AlemaniaFil: Prato, Maurizio. Università degli Studi di Trieste; Itali
Chiral-chiral interactions as determining factors in gelation processes
No full textThe design of chiral materials represents an interesting field in chemistry and nanotechnology due to the multiple applications that they could access. In this context, chiral gels represent a feasible material concept and could be obtained by proper chiral precursors, giving the advantage to obtain chiral scaffolds readily employable as chiral media, sensors, catalysts and chiro-optics tools. In the wide panorama of chiral gels, studies are generally focused on hydro- or organogels where organic chiral gelators activate the gelation process in aqueous or organic liquid media. Apart from the widely employed organic molecules as gelators, organic salts resulted in high valuable supramolecular building blocks in the field. Consequently, the use of chiral organic salts could represent an interesting alternative, and advantageous strategy, to access chiral gel materials. With respect to organic medium, we focused on the less investigated Deep Eutectic Solvents (DES) that represent a greener alternative with interesting physico-chemical properties. In the context of chiral gels, this contribution would give first insights into the study of chiral eutectogels through the employment of chiral organic salts, composed of diimidazolium based cations and L- or D-tartrate anions. Moreover, chiral small molecules have been employed during the gelation process to study the effect on the supramolecular gel structure formation, the related properties, and the feasibility of obtaining multicomponent gels. Our results demonstrate how chiral-chiral interaction could be a useful tool to tune gel properties
Screening for Early Signs of Paternal Perinatal Affective Disorder in Expectant Fathers: A Cluster Analysis Approach
No full textPrevious studies documented gender-related differences in the expression of Perinatal Affective Disorders. However, little attention has been paid to screening the male population during the perinatal period. This study was based on three aims: (1) to investigate the mental health of expectant fathers based on their levels of depression, anxiety, addiction, anger attacks/hostility, and somatization, identifying psychological profiles; (2) to analyze the association between these profiles and the individual variable of perceived stress; (3) and to examine the association between these profiles and the couple’s variable of marital adjustment. A total of 350 Italian expectant fathers in the last trimester of pregnancy were asked to fill in questionnaires concerning perceived stress, dyadic adjustment, psychiatric symptomatology, and depression. Three different clusters were found: “psychologically healthy men” (68%) with low levels of symptoms on all the scales; “men at risk of externalized behavioral problems” (17.1%), characterized by one or more addictive or risky behaviors and moderate levels of scales scores; and “men experiencing psychological distress” (14.9%), with the highest scores on all the scales. A significant association emerged among the perceived stress, marital adjustment, and cluster membership. These results highlight the importance of screening fathers in perinatal health services, which are still predominantly mother-centered, and underscore the necessity to create tailored and personalized interventions
Triptych for solo piano
No full textCurt Cacioppo, piano. Capstone CPS-8734. This recording, which also includes compositions by Curt Cacioppo, Marino Baratello, and Joseph Hudson, was funded in part by a generous grant from the Faculty Research Fund. --author-supplied description; Appears on recording #98
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