Department of Chemsitry

Professor D.M. O'Hare

Inorganic Chemistry

dermot.ohare@chem.ox.ac.uk

Telephone: 44 (0) 1865 272 686

Research Group Website

Research

Introduction

We have a wide range of research interests. They all involve synthetic chemistry ranging from organometallic chemistry, CO2 reduction to the synthesis of new microporous solids. Some currently active projects are summarised below.

 CO2 Chemistry

The role of carbon dioxide as a greenhouse gas and its contribution to global warming is widely recognised by both scientists and governmental agencies. It is now imperative that new reactions and processes are discovered that can either efficiently store or utilise the abundant and renewable CO2 resource in an environmentally friendly manner. However, we face a fundamental challenge because carbon dioxide is so kinetically and thermodynamically stable We have recently reported the first example of the selective hydrogenation of CO2 to CH3OH, using an FLP-based non-metal protocol at low pressures (1-2 atm). Current investigations are focussed on increasing the stability of the system towards hydroxylic agents, and hopefully thereby rendering the system catalytic.

 

 

 

Key Novel Aspects

Chemistry operates at low temperature and pressure (100 °C, 1 bar).


It does not require expensive and toxic transition metal catalysts.

100% selective homogeneous conversion of CO2 to methanol; does not produce undesirable side-products such as carbon monoxide or methane.

Current technology is not selective for methanol and therefore is not carbon efficient. Side products such as carbon monoxide and methane are as undesirable as CO2.

In-Situ Diffraction Studies

The group is developing in-situ XRD methods for use on BeamlineI12 at the Diamond Light Source.

 

 

 

 

 

 

 

 

 

 

 

 


 

 

We are interested in studying the following reactions:

  1. Crystallisation from Solution
  2. Intercalation Reactions
  3. Hydrothermal Reactions
  4. Sol-Gel Syntheses
  5. Solid State Syntheses in Molten-Salt Fluxes
  6. Classical Solid Phase Reactions

 

 

 

Organometallic Compounds; synthesis, characterisation and electronic properties

The O’Hare group is interested in synthesising novel organometallic compounds. Our most recent work has concerned development of a synthesis of permethylpentalene (Pn*) ligand and its organometallic compounds.

 

 

 

 

 Applications of Layered Double Hydroxides 

The group has studied the synthesis and applications of Layered Double Hydroxides(LDHs). They are synthesized using standard hydrothermal routes, with different additives and temperature conditions being used to control structure. These have general formula [A(1-x)Mx(OH)2]x+.An.mH2O]
A2+ = Ca, Cd, Co, Cu, Li, Mg, Ni, Pd, Pt, Zn
M3+ = Al, Cr, Fe, V
X = anion (eg. CO32–, OH, Cl-, Br-, NO3-, SO42–)
The ability of these compounds to accommodate species between the layers means they have a wide variety of applications where it is advantageous to absorb/release molecules.

Hydrothermal and Organometallic Actinide Chemistry 

The O'Hare group has developed a number of new Uranyl fluorides and oxyfluorides. The aim of this is to exploit potential for co-operative effects of f-electrons and shape-selectivity derived from structural porosity. There is also interest in characterisation of the physicochemical properties of these novel materials. These properties include:

– thermal
– optical, magnetic and electronic
– ion-exchange
sorbents, porosity, surface area
– catalysis

 

 

 

Catalytic Dechlorination of PCBs

For the past few years the DOH group has been interested in a catalytic approach to dechlorinations of PCBs to yield biphenyl. The process being developed was discovered in the mid-nineties. Although there are other methods for destruction of PCBs in large quantities, there is currently no industrial method for destroying PCBs where they are a pollutant in low concentrations. The group is interested in understanding more about the mechanism of the process in question and developing the process to be able to work towards a possible industrial solution to this pollution problem.

Selected Publications

CO2 Chemistry

Non-metal Mediated Homogeneous Hydrogenation of CO2 to CH3OH , A. E. Ashley, A. L. Thompson and D. O'Hare, Angew Chemie, Int. Ed., (2009), 48, 9839.

Pentalene Chemistry

Permethylpentalene Chemistry, A.E. Ashley, A.R. Cowley, D. O'Hare, Eur. J. Org. Chem., (2007), 2239-2242.

The Hexamethylpentalene Dianion and other Novel Reagents for Organometallic Pentalene Chemistry, A.E. Ashley, A.R. Cowley, D. O'Hare, Chemical Communications, (2007), 1512-1514

Homoleptic Permethylpentalene Complexes: ‘Double Metallocenes’ of the First Row Transition Metals, A.E. Ashley, R.T. Cooper, G.G. Wildgoose, J.C. Green, D. O’Hare, J. Am. Chem. Soc., (2008), 130(46), 15662-15677.

BispermethylpentaleneUranium, Dalton Transactions, (2010), 39, 3384-3395.


Electronic Properties and Catalysis

Electronic Communication through Unsaturated Hydrocarbon Bridges in Bimetallic Organometallic Complexes, P. Aguirre-Etcheverry and D. O'Hare, Chem. Rev., (2010), 110, 4839-4864.

Layered Double  Hydroxide Chemistry

Staging during anion-exchange intercalation into [LiAl2(OH)6]Cl·yH2O: structural and mechanistic insights, G.R. Williams, A.M. Fogg, J. Sloan,C. Taviot-Guého, D. O'Hare, Dalton Transactions, (2007), 3499 - 3506

Recent developments in the use of layered double hydroxides as reservoirs and controlled release media, A.I. Khan, A. Ragavan, B.Fong, T.G. Dunbar, C. Markland, Mark O’Brien, G.R. Williams, and D. O’Hare, Ind. Eng. Chem. Res., 2009, 48, 10196-10205.

Synthesis of Porous Solids

TOF-2: A Large 1D Channel Thorium Organic Framework. K.M. Ok, J. Sung, G. Hu, R.M.J. Jacobs, D. O'Hare, J. Am. Chem. Soc.,  (2008), 130, 3762-3763.

Resin-assisted Solvothermal Synthesis Metal-Organic Frameworks, Y. Du, A.L.Thompson  and D. O’Hare, Chemical  Communications, (2008), 5987 - 5989.

Time-Resolved In Situ XRD Studies

Incorporation of phosphorus oxyacids into layered double hydroxides, G.R. Williams and D. O’Hare, Solid State Sciences, (2009), 11, 1229 -1238.

PCB Dechlorination

Catalytic dechlorination of polychlorinated biphenyls (PCBs) using amine functionalised titanocenes, A.E.D. Fletcher, J.D. Hyatt, K.M. Ok and D. O’Hare, Green Chem., (2009),  11, 1343 – 1348.

Novel catalysts for dechlorination of polychlorinated biphenyls (PCBs) and other chlorinated aromatics, A.E.D. Fletcher, J. Moss, A.R. Cowley, D. O'Hare, Chemical Communications, 2007, 2971-2973.

 

 


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