Professor Nick Norman
 |
|
Our research interests are in the general area of main group element chemistry and focus primarily on the synthesis and characterisation of novel molecular species as well as applications to new solid state materials. A project in this group would result in a broad range of synthetic skills as well as exposure to an extensive range of analytical methods applicable to the characterisation of molecules and materials.
Low Oxidation State Boron Chemistry
The primary area in which we are currently active is the field of low-oxidation state boron chemistry with a particular emphasis on diborane(4) compounds, B2R4, where R is typically an amido, alkoxy or thiolate group but also including subhalides such as B2F4. Specific research projects which are the focus of current work include:
B-B Bond Oxidative Addition to Transition Metal Centres and Metal Catalysed Diboration Reactions
Currently we are studying the synthesis and reactivity of paramagnetic cobalt boryl species such as [Co(PMe3)3{B(cat)}2] (cat = catecholate). These compounds are the only well characterised paramagnetic metal boryl complexes and exhibit some unusual structural features including short B-B interactions. Preliminary reactivity studies have shown that paramagnetic cobalt boryls (one of which is shown below) will catalyse certain organic diboration reactions to afford products not encountered in other systems and that they can act as boryl transfer reagents.
More recent work has shown that cobalt(I) boryls can also be isolated an example of which is illustrated below.
We are also looking at platinum catalysed asymmetric diboration reactions in collaboration with Professor Paul Pringle using chiral monodentate phosphine ligands. An example of a recently characterised catalyst precursor is shown.
KC Lam, WH Lam, Z Lin, TB Marder and NC Norman, Inorg Chem, 2004, 43, 2541.
The Preparation of Electron-Rich Thiolate-Based Systems as Constituents of Molecular Electronic Materials
In recent work we have shown that electron-rich thiocatecholate diborane(4) compounds, analogous to electron rich alkenes, form co-crystalline materials with electron acceptors including TCNE and TCNQ. Future work will focus on more electron-rich alkane dithiolato species with a view to preparing novel electronic materials.
TB Marder, NC Norman, AG Orpen, MJ Quayle and CR Rice, J Chem Soc, Dalton Trans, 1999, 2127.
Diboronic Acid and associated Borates, Thioborates and Imido Borates
We have recently prepared, and structurally characterised for the first time, diboronic acid, B2(OH)4. Further studies have shown that the condensed species B4O2(OH)4 can be isolated and also that controlled thermolysis provides a route to boron(II) oxide for which we have obtained the first spectroscopic data. Future studies are aimed at preparing new classes of B-B bonded borates, thioborates (derived from B2(SH)4) and imido borates (derived from B2(NH2)4). This work is in collaboration with Dr Chris Russell.
With regard to the amido diborane(4) compounds, we have recently characterised examples of primary amido species B2(NHR)4 and as well as novel imido-borate anions [B2(NR)4]4- derived from deprotonation reactions. Examples are illustrated below.
RA Baber, NC Norman, AG Orpen and J Rossi, New J Chem, 2003, 27, 773.
New Low-Oxidation State Boron Fluorides
Recent work as part of a collaborative project with Dr Peter Timms and Professor David Rankin's group in Edinburgh has resulted in the structural characterisation, by X-ray and electron diffraction, of the highly novel species B8F12, B10F12, (F2B)3BCO and (Cl2B)3BCO. Current work is aimed at preparing new higher molecular weight fluorides and exploring their chemistry.
JC Jeffery, NC Norman, JAJ Pardoe and PL Timms, Chem Commun, 2000, 2367.
JAJ Pardoe, NC Norman and PL Timms, Polyhedron, 2002, 21, 543.
JAJ Pardoe, NC Norman, PL Timms, S Parsons, I Mackie, CR Pulham and DWH Rankin, Angew Chem Int Ed, 2003, 42, 571.
PL Timms, NC Norman, JAJ Pardoe, ID Mackie, SL Hinchley, S Parsons and DWH Rankin, Dalton Trans, 2005, 607.
More Speculative Projects
Two projects are planned to start soon. The first involves the inorganic functionalisation of diamond surfaces in collaboration with Drs Chris Russell and Paul May and the second involves the preparation of exotic gas phase species as a route to the chemical vapour deposition of novel inorganic phases. The initial focus of the latter project is to prepare HCP as a precursor to carbon phosphide and is in collaboration with Chris Russell, Paul May and Neil Allan.