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Identifier

000442931

Title

Σύνθεση ενός τροποποιημένου υποκαταστάτη πυραζολίου με φωσφονικές ομάδες και διερεύνηση της χημείας συναρμογής του με εφαρμογές στην κατιονανταλαγή και κατάλυση

Alternative Title

Synthesis of a modified pyrazole ligand with phosphonate groups and study of its coordination chemistry, with applications in cation exchange and catalysis

Author

Γιακουμάκης, Νικόλαος Σ.

Thesis advisor

Δημάδης, Κωνσταντίνος

Reviewer

Μήλιος, Κωνσταντίνος
Στούμπος, Κωνσταντίνος

Abstract

Phosphonic acids constitute a class of organic phosphorus compounds that have been widely studied in the last decades, presenting several unique properties. The functional group of phosphonic acids consists of a phosphorus atom bonded to three oxygen atoms (two hydroxy groups–P-OH and a double P=O bond) and a carbon atom. Depending on the number of phosphonate groups present in the organic molecule, the phosphonic compound can be monophosphonate, diphosphonate, triphosphonate, etc. Under specific chemical conditions, this functional group can act as a ligand and coordinate with various metal ions. This coordination leads to inorganic-organic hybrid polymeric materials, which belong to the general class of metal-phosphonate compounds. These materials possess remarkable chemical and thermal stability and are considered as ideal candidates for use in applications such as proton conductivity, ion exchange, gas absorption-desorption, gas separation, drug delivery, heterogeneous catalysis, etc. In the context of the need to synthesize novel rigid organic phosphonate linkers and consequently to synthesize novel metal-phosphonate compounds of high stability, the current dissertation presents the preparation of a new phosphonate linker, named 3,5-bis(4-phosphonophenyl)-1H-pyrazole, or PZDP (pyrazole diphosphonate). After its successful synthesis, its coordination chemistry with alkaline earth and transition metals was explored. The synthesis of novel metal-phosphonate compoundswas achieved via solvothermal methods and after a series of experiments, the materials Ca, Sr, Ba-PZDP, Zn-PZDP, and CoPZDP were isolated. In each case, the 2D inorganic layers are connected through the organic linker that acts as a pillar (2D-pillared or layer-pillared materials). Complete characterization of these compounds was achieved, and applications of the materials Zn-PZDP and Co-PZDP were sought. Specifically, the material Zn-PZDP is an anionic coordination polymer, and therefore its use for alkali metal cation exchange was evaluated, while the material Co-PZDP proved to be an effective heterogeneous catalyst for the oxidation of olefins to epoxides.

Language

Greek

Subject

Cation exchange

Coordination polymers

Heterogeneous catalysis

Metal-phosphonates

Olefin epoxidation

Synthesis of a novel linker (PZDP)

Synthesis of novel materials

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