Tuning the Coordination Properties of Pyrazoles towards Specific Applications via Judicial Choice of Peripheral Substitution

Authors

Shambhu KandelFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Chemistry

First Advisor's Name

Raphael G. Raptis

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Konstantinos Kavallieratos

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Prem P. Chapagain

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Yi Xiao

Fourth Advisor's Committee Title

committee member

Fifth Advisor's Name

Yukching Tse Dinh

Fifth Advisor's Committee Title

committee member

Keywords

Silver antibacterial, Palladium catalysts, Sensor, Pyrazole, Tunability, Mercury waste

Date of Defense

3-26-2019

Abstract

The tunability of pyrazoles make them probably the most versatile ligands, and this is one of the right reasons to its use. Pyrazolyl ligands have intrinsic antibacterial property. Synthesis of pyrazolyl complexes with silver can be of great interest in biological applications. The urgent need to find alternative of currently used antibiotics has been recognized as a major challenge of the 21^st century. Many ideas have been proposed, but re-emergence silver could be the most promising alternative to overcome the limitations of these antibiotics. In spite of the popularity of Sonogashira coupling reactions, there is still a room to improve the catalytic system to overcome the existing limitations. N-N donor ligands with palladium metal have shown better catalysis over the conventional ones. This work presents the synthesis of pyrazolyl ligands and their complexes with silver, palladium and mercury and exploring their applications accordingly. The work has been divided into four distinct regions of applications as follows.

Eight new silver pyrazolyl complexes with triphenyl phosphine or 1,3,5-triaza-7-phosphaadamantane as a co-ligand have been synthesized, characterized with single crystal X-ray, spectroscopic techniques and elemental analyses and their antibacterial property against Pseudomonas aeruginosa was investigated with a soft tissue and skin infection model. Water soluble complex was found to be more efficient than silver nitrate. This compound releases Ag⁺ slower than AgNO₃ and inhibits the physiological problems associated with the rapid release of Ag⁺. Five new tripodal (1R) pyrazolyl ligands were synthesized and their application in selective sensing of picric acid (PA) was successfully investigated. They are promising in sensing the picric acid in all physical states. Seven new mercury pyrazolyl complexes with broad versatility in geometry and nuclearity were synthesized. Two of them were used to extract mercury (Hg²⁺) from the mixture of Ln³⁺ in aqueous solution using chloroform as extractant and found promising. Nine palladium pyrazolyl complexes including three water soluble ones were synthesized. Two of them were used to catalyze the Sonogashira cross coupling reactions. The catalysts worked well in copper free, open air and mild reaction conditions. Reactivity of Pd-hexamer was also studied.

Identifier

FIDC007649

ORCID

https://orcid.org/0000-0003-4187-3230

Recommended Citation

Kandel, Shambhu, "Tuning the Coordination Properties of Pyrazoles towards Specific Applications via Judicial Choice of Peripheral Substitution" (2019). FIU Electronic Theses and Dissertations. 4034.
https://digitalcommons.fiu.edu/etd/4034