报告题目：N-heterocyclic carbenes on gold: forming an ultra-stable self-assembled monolayer for use in biotechnology applications

报告人：Queen’s University，Horto教授

时间：2015年3月30日下午3点30分

地点：化学馆241

Dr. Hugh Horton, is a Professor of Chemistry and Associate Dean (International) in the Faculty of Arts and Science at Queen’s University, Canada. He holds a BSc from York University, Toronto and a PhD from the University of Cambridge where he was a Commonwealth Scholar. He subsequently held a Natural Sciences and Engineering Research Council of Canada (NSERC) Postdoctoral Fellowship at the University of Western Ontario, and a Commonwealth Research Fellowship at the University of St Andrews, Scotland, in 2005. He has been a faculty member in the Department of Chemistry at Queen's since 1997, and Full Professor since 2012. He is an active member of the Canadian Society for Chemistry (CSC), having been Treasurer since 2013, and was previously the CSC’s Director of Accreditation for undergraduate chemistry programs.

Dr. Horton's research is in the field of surface chemistry, where his research group's main focus is an exploration of the forces controlling the interaction of small molecules with surfaces. He and his students have worked on developing new scanning probe microscope techniques for the measurement of nanoscale forces. More recently, he has been exploring the formation of a new class of materials based on N-heterocyclic carbenes – these unusual molecules, which are are usually highly unstable, can be used to form very strong carbon-metal bonds to metal surfaces, creating an extraordinary stable organic-metal junction with applications in nanoscale electronics and biosensing (see Nature Chemistry, 6, 409-414, 2014).

Title and Abstract for Talk

N-heterocyclic carbenes on gold: forming an ultra-stable self-assembled monolayer for use in biotechnology applications

In this talk, I will describe our recent breakthrough in forming self-assembled monolayers (SAMs) at surfaces using N-heterocyclic carbenes (NHCs). Functionalizing a surface by chemically attaching a single layer of molecules to that surface such as to change its physical and chemical properties is key to many technological applications, including drug delivery, the detection of biomolecules, and the design of nano-patterned materials for use in semiconductor or microfluidic systems, to name a few. N-heterocyclic carbenes are unique molecules in that they contain an sp2-conjugated C atom that contains a sigma lone pair yet are stable in air and can be treated as “off-the-shelf” reagents. While there is an extensive literature describing the use of NHCs as ligand in transition metal complexes, here we apply NHCs in a completely new way to materials chemistry: as a means of forming SAMs on gold and other transition metal surfaces. The NHC SAMs so formed are ultra-stable under strong oxidizing conditions, to strong acid and base, and to refluxing in both organic solvent and in aqueous systems in air. This is a key improvement over alkanethiol-based SAMs on Au, which for over 20 years have represented the state-of-the-art in terms of SAM formation in coupling organic monolayers to metals, yet have found limited applications due to the relatively poor stability of the SAM, particularly under oxidizing conditions. Following an introduction to the field, I will discuss some potential applications in electrochemical-based detection methods. I will then describe our work to apply NHCs as replacements for alkanethiols in surface plasmon resonance detection. We observe that NHC-based surface plasmon resonance detection chips are superior in performance and stability to those commercially available.