02/10/2026
By Kwok Fan Chow

The Kennedy College of Science, Department of Chemistry, invites you to attend a Ph.D. Research Proposal defense by Harshit Kumar entitled “Perfluorophenyl Azides for Covalent Functionalization of Glassy Carbon and Synthesis of Clickable Gold Nanoclusters.”

Date: Monday, Feb. 23, 2026
Time: 2 p.m.
Location: Olney Hall, Room 518

Committee:

  • Advisor: Mingdi Yan, Department of Chemistry, University of Massachusetts Lowell
  • Olof Ramstrom, Department of Chemistry, University of Massachusetts Lowell
  • Pengyuan Liu, Department of Chemistry, University of Massachusetts Lowell
  • Lawrence Wolf, Department of Chemistry, University of Massachusetts Lowell

Abstract:
Efficient coupling chemistries provide powerful routes to create robust, covalently bound interfaces under mild conditions with spatial and temporal control. Perfluoroaryl azides (PFPAs) are particularly attractive in this context because activation by irradiation or heat generates reactive nitrenes that can rapidly form covalent bonds with nearby molecules and surfaces. Our long-term goal is to use PFPAs as a general platform for material synthesis and interface engineering for a wide range of applications from catalysis, energy to biomedical fields.

In the first part of the proposal, the fundamental chemistry of PFPA is established, with emphasis on practical synthetic strategies to access PFPA derivatives suitable for materials applications. The evolution and mechanistic aspects of PFPA chemistry are discussed. The aim is to tune the chemical and physical properties of molecules, such as hydrophilicity, solubility, aromaticity, etc., that are required for surface application. In this direction, diverse linkers are being explored and proposed. Different PFPA-based heterobifunctional molecules were synthesized containing different functionalities such as amine, carboxylic acid etc. These studies provide a toolkit of PFPA-based reagents that support controlled covalent attachment.
The second part aims to apply PFPA chemistry to glassy carbon (GC), a widely used electrode material that is chemically robust yet challenging to functionalize in a controlled manner. PFPA-mediated modification was used to covalently functionalize GC electrodes. PFPA-modified surfaces were characterized and quantified through cyclic voltammetry studies using electrochemically responsive ferrocene molecules. Following modification, cobalt tetraphenylporphyrin (Co-TPP) or gold nanocluster was immobilized on PFPA-modified GC. Preliminary results showed that the modified GC exhibits catalytic activity toward the oxygen reduction reaction (ORR). The future aims to build and optimize an efficient PFPA-based catalytic GC system through incorporating different functionalities on GC surfaces.

In the final part, the proposal extends PFPA chemistry to nanomaterials by synthesizing PFPA-capped gold nanoclusters. Different synthetic routes were explored to introduce PFPA as the ligands on gold nanoclusters. Indirect nanocluster synthesis methods, such as surface reaction or ligand exchange, remain a challenge in introducing PFPA on gold nanoclusters. However, direct synthesis methods using thiol-conjugated pentafluoro derivatives yielded gold nanoclusters. Future aims to substitute the para-positioned fluorenes with azides to achieve a clickable gold nanocluster.

Together, this proposal positions PFPA as a unified chemical handle for covalent assembly, aiming to enable the transformation of inert substrates into functional interfaces and providing handles for advanced materials design.

All interested students and faculty members are invited to attend.