Nigel Clayden

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School Position: Senior Lecturer in Chemistry; Director of Teaching; Plagiarism and Collusion Officer; Chair, Chemistry Teaching Executive, member of the Wolfson Materials & Catalysis Centre.

Dr. Clayden studied for his B.A. in Chemistry at St Catherines College, Oxford University. Dr. Clayden's D. Phil., also from Oxford University, was concerned with shielding effects in NMR spectra and their use in conformational analysis. After a post-doctoral stint at MIT with Professor Waugh Dr. Clayden returned to Oxford University as a Shell Research Fellow. In 1986 Dr. Clayden joined ICI at the Wilton Research Centre where he managed a solid state NMR and materials NMR imaging. Dr. Clayden moved to UEA in 1994 where he is a member of the Molecular Structure Centre.

Nigel’s main interests lie in three areas. First, the characterisation of inorganic materials by solid state NMR methods. Thus, C-13 CPMAS demonstrates that halo alkyl phosphonates will react to incorporate imidazole and can be used in supported zirconium phosphonate catalysts. Second, the determination of protein dynamics through solution state NMR N-15 relaxation parameters. In the case of the in the E9 colicin system analysis of the relaxation data in the translocation domain has indicated local ordering around the TolB box. Third, the application of radio-frequency methods in µSR. In a recent experiment muon depolarisation of the FMuF state in SrF2 was studied using spin-locked muon polarisation and matched radiofrequency fields in the rotating frame.

Selected Publications

N. J. Clayden, S. Esposito and A. Aronne.
Chemical heterogeneity in phosphosilicate gels by NMR magnetisation exchange
Dalton Transactions, 2001, 2003 – 2008. 
DOI: 10.1039/b100474n

N. J. Clayden, S. Esposito, C. Ferone, M. Pansini.
Substitution clustering in a non-stoichiometric celsian synthesized by the thermal transformation of barium exchanged zeolite X
Journal of Solid State Chemistry, 2006, 179, 1957-1964. 
DOI:  10.1016/j.jssc.2006.03.021

C.J. Macdonald, K. Tozawa, E.S. Collins, C.N. Penfold, R. James, C. Kleanthous, N. J. Clayden, G.R. Moore.
Characterisation of a mobile protein-dependent epitope in the translocation domain of colicin E9
J. Biomol., 2004, 30, 81- 96

N. J. Clayden and S.P. Cottrell.
Muon spin relaxation study of Zr(H₂PO₄)(PO₄)•2H₂O
Phys. Chem. Chem. Phys., 2006, 8, 3094 - 3098. 
DOI: 10.1039/b603913h

Inorganic Materials

• Phosphosilcate gels, P2O5 – xSiO2, used as sensors
• Functionalised zirconium phosphonate supported catalysts
• Muon spin relaxation studies of proton conductors

Protein dynamics

Inorganic Materials

Multinuclear solid state NMR spectroscopy both static and MAS are being used to investigate the structure and dynamics in a range of inorganic materials.

1. Phosphosilcate gels, P₂O₅ – xSiO₂, used as sensors

Solid state ¹H, ²⁹Si and ³¹P MAS NMR have been used to investigate the microstructure of phosphosilicate gels prepared by a new procedure. Molar compositions of 5, 10, 20 and 30 mol% P₂O₅ in P₂O₅ -SiO₂ were studied. After drying to 400^oC the dried gels have very similar structures formed by a siloxane framework containing cross-linked phosphorus. Upon exposure to moisture, as in a functioning device, hydrolysis of the Si-O-P bonds takes place and and effectively trapped molecules of orthophosphoric acid are formed. Unlike earlier samples, the residual co-polymerisation of phosphate and silicate tetrahedral was much reduced and although it increased with phosphorus content, it still represented less than 70% of the phosphorus. Furthermore there was no evidence for six-coordinated silicon in the glassy matrix

2. Functionalised zirconium phosphonate supported catalysts

This project, in collaboration with Professor M Bochmann, involves the synthesis and evaluation of functionalised zirconium phosphonates (ZrPs) and their use as a new family of generic catalyst supports. ZrP materials are unique in possessing well-defined crystalline surfaces coated with organic substituents which allow the precise tailoring of the surface chemistry. Based on preliminary results with ZrP-supported olefin polymerisation catalysts, the method will be used to design a range of novel ZrP-supported lanthanide and transition metal catalysts for a range of applications, including polymerisations, Lewis-acid catalysed transformations and in particular esterification and polymerisation catalysts.

3. Muon spin relaxation studies of proton conductors

Muons are being used as extrinsic probes of the proton/muonium dynamics in proton conductors to complement ¹H NMR. Zero field muon spin relaxation is dominated by the local nuclear dipolar field which is then averaged by dynamics processes with increasing temperature. In the case of HZr₂(PO₄)₃.xH₂O HMuO is formed which undergoes a fast local motion around 160 K, in contrast HMuO is static in Zr(H₂PO₄)(PO₄).2H₂O up to 320 K. One question arising from this work are the factors which determine whether addition or substitution occurs: that is addition to H₂MuO⁺ or substitution to HMuO. Radiofrequency methods in muon spin relaxation are also being developed. At its simplest cw irradiation of the nuclear spin will decouple the muon and nuclear spin dipolar fields leading to a marked reduction in the zero field relaxation rate. More sophisticated experiments involving polarisation transfer between the muon and a nuclear spin are being explored using the FMuF state found in CaF2.

Protein dynamics

N relaxation rates R₁, R₂ and the NH heteronuclear nOe are being used to study the backbone dynamics of proteins in the E9 colicin system, with the recent emphasis on the disordered translocation domain. Data analysis is carried out using in-house Windows based computer programs: R2R1Win, rotational diffusion anisotropy from the R₂/R₁ ratio, LSWin, Lipari-Szabo model free approach, LocalWin, for Lipari-Szabo analysis in which the global rotational diffusion is taken as a local variable and RSAWin for reduced spectral density analysis. Moment of inertia calculations are carried out using moment. Proteins studied include: Im9, DNase domain, apo and metal bound, R domain, intact colicin and a fusion protein of the terminal 61 residues of the translocation domain and the DNase domain.

Research Funding

EPSRC

Zirconium phosphates: A new class of generic catalyst supports with tailored surfaces
Bochmann, M, Clayden, NJ and Graham, M (Johnson Matthey)
01-Apr-05 - 31-Mar-09
£353,694

Development of Scientific Applications of Radio-Frequency Muon Spin Resonance - Commissioning the new RF Spectrometer
Cottrell, SP (CCLRC), Connor, JNL(Manchester), Davis, E(Leicester), Jayasooriya, UA, Cox, S (CCLRC), Clayden, NJ, Lord, J (CCLRC), and King, P(CCLRC)
04-Feb-02 – 03-Feb-05
£331,101

CCLRC

Muon-fluorine polarisation transfer: RB620018
Clayden, NJ, Cottrell SP (CCLRC)
11-Sep-2006 – 22-Sep-2006

Multinuclear decoupling of muons in Al(OH)xF3-x: RB620364
Clayden, NJ, Tressaud, A, Dambournet, D
07-Dec-2006 – 12-Dec-2006

Muon studies of proton conductors: RB15165
Clayden, NJ, Jayasooriya, UA
04-Jul-2005 – 07-Jul-2005

High temperature Li dynamics in the cathode material LiMn2O4:RB 14647
Indris, S, (Hanover) Clayden, NJ, Jayasooriya, UA
1-Dec-2003 - 4-Dec-2003

FZ Juelich
Beta-NMR Study of the Solid Electrolyte LiMn2O4
EU Access to Research Infrastructure programme
Heitjans, P, (Hanover) Indris, S, (Hanover) Clayden, NJ, Jayasooriya, UA
4-Apr-2003 - 14-Apr-2003
£100,000

CEC/INTAS

Grain-oriented crystallisation and new polar glass-ceramic textures
Clayden, NJ
01-Jan-00 - 31-Dec-02
£3,353