Bridging between Boron & Nanoworld: Versatile Combinations & Emerging Applications

Abstract

The work presented in this thesis entails the research carried out in the Inorganic Materials and Catalysis Laboratory group (LMI) under the supervision of Prof. Francesc Teixidor over the course of the Doctoral program. The dissertation is presented as a compendium of articles published or to be published in the near future. The doctoral thesis delves into the multifaceted world of boron chemistry, particularly focusing on θ-metallacarboranes, and their integration with tailored nanoparticles, uncovering a realm of novel applications and opportunities. The characterizations and applications of θ-metallacarboranes and nanoparticles together present a dynamic frontier in modern materials chemistry with an expansive range of possibilities. The thesis begins with a brief Introduction on the diverse facets of metallacarboranes and nanoparticles serving as a foundation for comprehending the subsequent chapters. The comprehensive investigations commence with a detailed and thorough study on the electrochemical properties of metallacarboranes, particularly cobaltabis(dicarbollide) and ferrabis(dicarbollide), in both aqueous and non-aqueous systems with a comparative study of Metallacarboranes vs. Ferrocene. Ferrocene and its derivatives have long been the benchmark internal reference in electrochemistry for various processes. Yet, their applications are constrained by challenges related to solubility and chemical modifications. In this regard, the chapter deals with potential advent of metallacarboranes as 'universal' internal reference systems. The following chapter on Metallacarboranes & Proteins stems from the pre-requisite knowledge of the strong non-covalent interaction between [o-COSAN]- and amine groups through N-H···B-H dihydrogen bond formation. Visualization of proteins in their native form and environment without any interferences has always been a challenging task. Hence, in this study we have tackled the 'surface' of a protein with respect to their interaction with the 'small molecule' redox-active probe, [o-COSAN]-, employing facile and robust electrochemical measurements. These studies aid in gaining a deeper insight on protein surfaces which can be valuable for modifying proteins for drug designs and bio-technology. Tailoring metallacarboranes onto surface engineered magnetic nanoparticles opens a new avenue for exploring and exploiting the virtues of both these materials. Thus, the subsequent chapter explores the synthesis and characterization of magnetic nanoparticles and delves into the applications of the conjecture: Metallacarboranes & MNPs. Synthesis of size-controlled, colloidally stable magnetic nanoparticles with appreciable magnetic properties has always been a challenge. Hence, in the chapter we propose a novel method for the synthesis of colloidally stable magnetic nanoparticles without any surfactant or capping agents. The tailoring of the metallacarboranes onto the surface functionalized magnetic nanoparticles is achieved, yet again, by exploiting the strong non-covalent di-hydrogen bonds. The chapter explores the application of these hybrid materials in photocatalysis of alcohols as well as begets the question of modifying a system according to the needs. The lack of fluorescence as well as the capability of metallacarboranes as efficient and robust catalysts are further explored in the chapter on Metallacarboranes & Energy wherein the ability of [o-COSAN]- as a 'small molecule' electrode is investigated. The catalytic prowess of the metallacarboranes is studied in detail. Extending the study further into the lack of fluorescence in metallacarboranes, the ability of [o-COSAN]- as an efficient fluorescence quencher with regard to amine functionalized carbon quantum dots is studied. The fundamentals of the photophysical process underlying between Metallacarboranes & C-dots are investigated thoroughly and in-depth. These hybrid materials incorporating the virtue of an 'on/off' fluorescence switching mode opens new avenues to be ventured. The thesis navigates through various applications of metallacarboranes and nanoparticles aiming to address critical challenges and open new avenues for scientific advancement and technological progress.

Date of Award	2 Nov 2023
Original language	English
Supervisor	Francesc Teixidor Bombardó (Director)