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Identifier

000425986

Title

Design and development of innovative nanoporous covalent organic frameworks

Alternative Title

Σχεδιασμός και ανάπτυξη καινοτόμων νανοπορωδών ομοιοπολικών οργανικών σκελετών

Author

Μποσβέλη, Άρτεμις Δ.

Thesis advisor

Τρικαλίτης, Παντελής

Reviewer

Βασιλικογιαννάκης, Γεώργιος
Στρατάκης, Μανώλης

Abstract

Covalent Organic Frameworks (COFs) are a novel class of crystalline porous materials that allows the atomically precise integration of organic units into extended structures with periodic skeletons and ordered nanopores. COF architectures offer confined molecular spaces for the interplay of photons, electrons, holes, ions and guest molecules, thereby exhibiting unique properties and functions, such as gas storage and separation. The objective of this work was the design, synthesis and characterization of novel organic linkers and their successful implementation for the development of new porous organic materials. The targeted ligands were symmetric aldehydes and one hexagonal amine which were used for the synthesis of new imine-based COFs. In total five (5) new COFs were synthesized, presenting various topologies. In addition to the typical solvothermal reaction used for the development of COFs and for comparison purposes, we explored the use of aniline as a modulator at ambient conditions, towards the synthesis of single crystalline COFs. All of the materials were structurally characterized using powder X-ray diffraction experiments, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Gas sorption studies were carried out for the new materials. The new COFs were obtained in polycrystalline form, however only some of them could be activated successfully. Their porosity along with gas sorption properties were studied in detail, providing important findings. In particular, COF 1a, COF 4 and COF 5 were found to present high CO₂ uptake with high selectivity at 1 bar and at 273, 283 298 K. The corresponding data place these solids among the best COF-type materials for CO₂ uptake, with high isosteric heat of adsorption at zero coverage (Q_st⁰ for COF 1a is 29.5 kJ mol^-1). The results of the present Thesis provide important information for the targeted synthesis of novel COFs based on imine bonds, using reticular chemistry rules. Our findings help to better understand how these system forms and the evaluation of their gas sorption properties provide important knowledge towards understanding the underlying structure-property relationship.

Language

English

Subject

COFs

Gas sorption

Porous materials

Πορώδη υλικά

Προσρόφηση αερίων

Issue date

2019-11-29

Collection

School/Department--School of Sciences and Engineering--Department of Chemistry--Post-graduate theses