The synthesis of new phenazines as new electroluminescent materials (OLED) or suitable functionalized for their incorporation in Donor-Accepting polymers for photovoltaic applications. Regarding the first aspect of the PhD project: the strategy followed to synthesize phenazine and polyhalogenated phenazines is the acid-catalyzed electrocyclization of ortho anilated azobenzene derivatives. These intermediates can be prepared following two different strategies: by nucleophilic aromatic substitution carried out on ortho-fluoro-azobenzenes with anilines or by Pd-catalysed Buchwald-Hartwig ortho anilation of ortho-bromoazobenzene derivatives. The synthesis of starting ortho-bromo-azobenezenes has been realized by Pd catalyzed ortho-bromination of azobenzene and by diazo-copulation of diazonium salts of ortho-bromo anilines with electron-rich aromatic systems (N,N-dimethyl-aniline). The acid-catalyzed electrocyclization of ortho-anilated azo-derivatives yields phenazine derivatives bearing suitable functionalities (group R and Z) for their incorporation in polymeric backbones. Regarding the first aspect, in this second year, a series of thiophene-substituted anilines have been synthesized, under micellar condition, via Pd-catalysed Suzuki-Miyaura, starting from bromo substituted aniline (bromo in 2, 3, and 4 positions) and thiophene-boronic acid derivatives (B(OH)2 in 2 or 3 position).The corresponding phenazines using the other dithiophene-anilines have been prepared. The 1,4-thiophene-phenazine has been bromurated on the 5 free positions of the thiophene ring using N-Bromosuccinylimide (NBS) and the corresponding di-bromo derivative used in the preparation of the corresponding Donor-Acceptor polymer by reacting it with (9,9-dioctyl-9H-fluorene-2,7-diyl)diboronic acid and (((4-(hexyloxy)phenyl)azanediyl)bis(4,1- phenylene))diboronic acid. All the polymers were synthesized by SuzukiMiayura cross-coupling polycondensation in toluene under the catalysis of tetrakis(triphenylphosphine)palladium and then purified by Soxhlet extraction in methanol, acetone, hexane, and chloroform, respectively. Erasmus and Traineeship period at the University of Münster (WWU) - Germany Synthesis and characterization of new phenazine-based molecules as potential systems for thermally activated delayed fluorescence (TADF) devices. Recently fully organic thermally activated delayed fluorescence (TADF) systems are proposed as highly efficient emitters for organic light-emitting diodes (OLEDs) in alternative to costly noble-metal-based phosphorescent systems. Efficient TADF systems require a small energy difference between the singlet and triplet excited states to be overcome at a reasonably low temperature by promoting reverse triplet to singlet intersystem crossing (RISC). Within the systems taken into consideration, particular attention will also be addressed to the preparation of Fluorene systems containing phenazine moieties and to evaluate if this type of arrangement will be beneficial for emission efficiencies.

La sintesi di nuove fenazine come nuovi materiali elettroluminescenti (OLED) o opportunamente funzionalizzati per la loro incorporazione in polimeri Donor-Accepting per applicazioni fotovoltaiche. Per quanto riguarda il primo aspetto del progetto di dottorato: la strategia seguita per sintetizzare fenazina e fenazine polialogenate è l'elettrociclizzazione acido-catalizzata di derivati orto-anilati dell'azobenzene. Questi intermedi possono essere preparati seguendo due diverse strategie: per sostituzione nucleofila aromatica effettuata su orto-fluoro-azobenzeni con aniline o per orto-anilazione di Buchwald-Hartwig catalizzata da Pd di derivati dell'orto-bromoazobenzene. La sintesi di orto-bromo-azobenezeni di partenza è stata realizzata mediante orto-bromurazione di azobenzene catalizzata da Pd e mediante diazo-copulazione di sali di diazonio di orto-bromo aniline con sistemi aromatici ricchi di elettroni (N,N-dimetil-anilina). L'elettrociclizzazione acido-catalizzata di azo-derivati orto-anilati produce derivati della fenazina recanti funzionalità adatte (gruppo R e Z) per la loro incorporazione in catene polimeriche. Per quanto riguarda il primo aspetto, in questo secondo anno sono state sintetizzate una serie di aniline tiofene-sostituite, in condizione micellare, via Suzuki-Miyaura catalizzata da Pd, a partire da aniline bromo-sostituite (bromo in 2, 3 e 4 posizioni) e derivati dell'acido tiofene-boronico (B(OH)2 in posizione 2 o 3). Sono state preparate le corrispondenti fenazine utilizzando le altre ditiofene-aniline. La 1,4-tiofene-fenazina è stata bromurata sulle 5 posizioni libere dell'anello tiofenico utilizzando N-Bromosuccinylimide (NBS) e il corrispondente di-bromoderivato utilizzato nella preparazione del corrispondente polimero Donor-Acceptor facendolo reagire con ( acido 9,9-diottil-9H-fluoren-2,7-diil)diboronico e acido (((4-(esilossi)fenil)azanediil)bis(4,1-fenilene))diboronico. Tutti i polimeri sono stati sintetizzati mediante policondensazione ad accoppiamento incrociato SuzukiMiayura in toluene sotto la catalisi di tetrakis (trifenilfosfina) palladio e quindi purificati mediante estrazione Soxhlet in metanolo, acetone, esano e cloroformio, rispettivamente. Periodo Erasmus e Traineeship presso l'Università di Münster (WWU) - Germania Sintesi e caratterizzazione di nuove molecole a base di fenazina come potenziali sistemi per dispositivi a fluorescenza ritardata attivata termicamente (TADF). Recentemente, i sistemi TADF (fluorescenza ritardata attivata termicamente) completamente organici sono proposti come emettitori altamente efficienti per diodi organici a emissione di luce (OLED) in alternativa ai costosi sistemi fosforescenti a base di metalli nobili. I sistemi TADF efficienti richiedono che una piccola differenza di energia tra gli stati eccitati di singoletto e tripletto venga superata a una temperatura ragionevolmente bassa promuovendo l'incrocio tra tripletta inversa e intersistema di singoletto (RISC). Nell'ambito dei sistemi presi in considerazione, particolare attenzione sarà rivolta anche alla preparazione di sistemi fluorurati contenenti frazioni di fenazina e valutare se questo tipo di disposizione sarà vantaggiosa per le efficienze di emissione.

(2023). DEVELOPING OF NEW FLUOROPHENAZINE AND FLUOROACRIDINE BASED MOLECULAR ACCEPTORS FOR TANDEM ORGANIC PHOTOVOLTAIC CELLS. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2023).

DEVELOPING OF NEW FLUOROPHENAZINE AND FLUOROACRIDINE BASED MOLECULAR ACCEPTORS FOR TANDEM ORGANIC PHOTOVOLTAIC CELLS

YOUSIF, DAWOD SALIM
2023

Abstract

The synthesis of new phenazines as new electroluminescent materials (OLED) or suitable functionalized for their incorporation in Donor-Accepting polymers for photovoltaic applications. Regarding the first aspect of the PhD project: the strategy followed to synthesize phenazine and polyhalogenated phenazines is the acid-catalyzed electrocyclization of ortho anilated azobenzene derivatives. These intermediates can be prepared following two different strategies: by nucleophilic aromatic substitution carried out on ortho-fluoro-azobenzenes with anilines or by Pd-catalysed Buchwald-Hartwig ortho anilation of ortho-bromoazobenzene derivatives. The synthesis of starting ortho-bromo-azobenezenes has been realized by Pd catalyzed ortho-bromination of azobenzene and by diazo-copulation of diazonium salts of ortho-bromo anilines with electron-rich aromatic systems (N,N-dimethyl-aniline). The acid-catalyzed electrocyclization of ortho-anilated azo-derivatives yields phenazine derivatives bearing suitable functionalities (group R and Z) for their incorporation in polymeric backbones. Regarding the first aspect, in this second year, a series of thiophene-substituted anilines have been synthesized, under micellar condition, via Pd-catalysed Suzuki-Miyaura, starting from bromo substituted aniline (bromo in 2, 3, and 4 positions) and thiophene-boronic acid derivatives (B(OH)2 in 2 or 3 position).The corresponding phenazines using the other dithiophene-anilines have been prepared. The 1,4-thiophene-phenazine has been bromurated on the 5 free positions of the thiophene ring using N-Bromosuccinylimide (NBS) and the corresponding di-bromo derivative used in the preparation of the corresponding Donor-Acceptor polymer by reacting it with (9,9-dioctyl-9H-fluorene-2,7-diyl)diboronic acid and (((4-(hexyloxy)phenyl)azanediyl)bis(4,1- phenylene))diboronic acid. All the polymers were synthesized by SuzukiMiayura cross-coupling polycondensation in toluene under the catalysis of tetrakis(triphenylphosphine)palladium and then purified by Soxhlet extraction in methanol, acetone, hexane, and chloroform, respectively. Erasmus and Traineeship period at the University of Münster (WWU) - Germany Synthesis and characterization of new phenazine-based molecules as potential systems for thermally activated delayed fluorescence (TADF) devices. Recently fully organic thermally activated delayed fluorescence (TADF) systems are proposed as highly efficient emitters for organic light-emitting diodes (OLEDs) in alternative to costly noble-metal-based phosphorescent systems. Efficient TADF systems require a small energy difference between the singlet and triplet excited states to be overcome at a reasonably low temperature by promoting reverse triplet to singlet intersystem crossing (RISC). Within the systems taken into consideration, particular attention will also be addressed to the preparation of Fluorene systems containing phenazine moieties and to evaluate if this type of arrangement will be beneficial for emission efficiencies.
PAPAGNI, ANTONIO
Fenazine; Buchwald; Suzuki; Catalisi micellare; Polimeri Fotovoltaic
Phenazines; Buchwald Hartwig; Suzuki Coupling; Micellar Catalysis; Photovoltaic Polymer
CHIM/06 - CHIMICA ORGANICA
English
19-apr-2023
35
2021/2022
embargoed_20260419
(2023). DEVELOPING OF NEW FLUOROPHENAZINE AND FLUOROACRIDINE BASED MOLECULAR ACCEPTORS FOR TANDEM ORGANIC PHOTOVOLTAIC CELLS. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2023).
File in questo prodotto:
File Dimensione Formato  
phd_unimib_821574.pdf

embargo fino al 19/04/2026

Descrizione: PhD Dawod Salim Yousif [Tesi Definitivo]
Tipologia di allegato: Doctoral thesis
Dimensione 11.06 MB
Formato Adobe PDF
11.06 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/414324
Citazioni
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
Social impact