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Michael S. Inkpen

Assistant Professor of Chemistry
Inorganic Chemistry

M.Chem. 2008, Durham University, UK
Ph.D. 2013, Imperial College London, UK
Office: LJS 250
Phone: 213-821-1910
Fax: TBA
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Research Focus


We utilize well-defined molecular materials to investigate charge transport and self-assembly processes across nano- and mesoscopic length scales. We have a special interest in developing the chemistry of modular, redox-active, building blocks – to explore how their properties change as they are combined to construct extended structures in 1D, 2D and 3D (see below), and how these may ultimately be exploited for applications in areas such as molecular-scale electronics or energy storage.

Research in the group involves the design and synthesis of organic, organometallic and coordination compounds, as well as the application of electrochemical and scanning probe microscope (SPM)-based methods to study these in solution, on surfaces and in the solid state.

1D. Charge-transport through redox-active single-molecules

The use of molecules to build electronic circuits was historically motivated by the rapid size reductions of conventional electronic components in line with Moore’s Law. Single-molecule devices represent the limit in device miniaturization, with work over the past two decades demonstrating that molecules can indeed function as nanoscale wires, switches and diodes. However, photolithographic technologies have since advanced to a point where they can produce circuits with feature sizes approaching molecular dimensions. Rather than working towards immediate technological applications, present-day efforts in molecular-scale electronics focus on the increased functionality of these materials over their solid-state counterparts as well as on fundamental structure-property relationships. Routine, reproducible studies at the single-molecule level are now possible using SPM-based methods, where ‘molecular junctions’ form via the self-assembly of components between nanogap separated electrodes. Where previous studies have primarily used redox-inactive compounds which typically limit the mode of transport to single-step tunneling, we are working to systematically investigate multi-site redox-active species in which sequential tunneling processes are thought to dominate.

2D. Complex, functional self-assembled monolayers (SAMs)

By functionalizing surfaces with a single, often highly ordered, layer of chemisorbed molecules, it becomes possible to modify their properties at the nanoscale using organic chemistry. Such SAMs have been widely applied over the past 40 years: to protect reactive metal surfaces; probe fundamental electrochemical, charge transport and thermodynamic questions; alter metal work functions; or anchor proteins or catalysts. However, conventional approaches produce SAMs that exhibit severe limitations in terms of stability and/or function. Different strategies are being explored to address these issues, including the introduction of new surface-linker groups or the development of patterning techniques based on supramolecular interactions. We are particularly interested in how the structure and dimensionality of individual, electrochemically addressable, SAM components can be exploited to direct self-assembly. Post-assembly, we are developing in situ reaction chemistries that can impart additional function(s) and facilitate the construction of complex surface-based molecular architectures.

3D. ‘Covalent organometallic frameworks’ (COMFs) for energy storage

Metal- and covalent organic frameworks (MOFs and COFs) are emergent classes of crystalline, highly porous 2D and 3D materials. Whereas MOFs comprise metal centers or clusters bridged by coordinating organic ligands, COFs are built from purely organic materials linked by strong covalent bonds. These can be prepared in different topologies, readily modified post-assembly, and have been exploited for numerous applications ranging from gas storage to catalysis. Redox-active variants of such materials have recently emerged as promising candidates for electrochemical energy storage, though their use has been restricted by the poor stability and low electrical conductivity of the intrinsic framework structure. We are developing strategies to construct and characterize novel families of redox-active COMFs, where organometallic complexes are used directly as ‘struts’ and ‘nodes’. This approach takes advantage of the coordinative stability of these metal centers in different oxidation states

Selected publications


10) M. S. Inkpen*, Z.-F. Liu, H. Li, L. M. Campos, J. B. Neaton and L. Venkataraman*, “Non-chemisorbed gold-sulfur binding prevails in self-assembled monolayers”, Nature Chem., 2019, DOI: 10.1038/s41557-019-0216-y [link]

9)   E. A. DoudM. S. Inkpen, G. Lovat, E. Montes, D. W. Paley, M. L. Steigerwald, H. Vázquez*, L. Venkataraman* and X. Roy*, “In Situ Formation of N-Heterocyclic Carbene-Bound Single-Molecule Junctions”, J. Am. Chem. Soc., 2018, 140, 8944 [link]

8)   M. S. Inkpen*, Y. R. Leroux, P. Hapiot, L. M. Campos and L. Venkataraman*, “Reversible on-surface wiring of resistive circuits”, Chem. Sci., 2017, 8, 4340 [link]

7)   M. S. Inkpen, S. Scheerer, M. Linseis, A. J. P. White, R. F. Winter, T. Albrecht* and N. J. Long*, “Oligomeric ferrocene rings”, Nature Chem., 2016, 8, 825 [link]

6)   M. S. Inkpen, S. Du, M. Hildebrand, A. J. P. White, N. M. Harrison, T. Albrecht* and N. J. Long*, “The unusual redox properties of fluoroferrocenes revealed through a comprehensive study of the haloferrocenes”, Organometallics, 2015, 34, 5461 [link]

5)   M. S. Inkpen*, M. Lemmer, N. Fitzpatrick, D. Costa-Milan, R. J. Nichols, N. J. Long* and T. Albrecht*, “New insights into single-molecule junctions using a robust, unsupervised approach to data collection and analysis”, J. Am. Chem. Soc., 2015, 137, 9971 [link]

4)   M. S. Inkpen, A. J. P. White, T. Albrecht* and N. J. Long*, “Avoiding problem reactions at the ferrocenyl-alkyne motif: a convenient synthesis of model, redox-active complexes for molecular electronics”, Dalton Trans., 2014, 43, 15287 [link]

3)   M. S. Inkpen, T. Albrecht* and N. J. Long*, “Branched redox-active complexes for the study of novel charge transport processes”, Organometallics, 2013, 32, 6053 [link]

2)   M. S. Inkpen, A. J. P. White, T. Albrecht* and N. J. Long*, “Rapid Sonogashira cross-coupling of iodoferrocenes and the unexpected cyclo-oligomerization of 4-ethynylphenylthioacetate”, Chem. Commun., 2013, 49, 5663 [link]

1)   M. S. Inkpen, S. Du, M. Driver, T. Albrecht* and N. J. Long*, “Oxidative purification of halogenated ferrocenes”, Dalton Trans., 2013, 42, 2813 [link]

* indicates corresponding author(s)

† indicates co-first authors (equal contribution)


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