Theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond

The copper-sulphur bond which binds cysteinate to the metal centre is a key factor in the spectroscopy of blue copper proteins. We present theoretical calculations describing the electronically excited states of small molecules, including CuSH, CuSCH_3, (CH_3)_2SCuSH, (imidazole)-CuSH and (imidazole...

Full description

Bibliographic Details
Main Authors:	Do, Hainam, Besley, Nicholas A.
Format:	Article
Language:	English
Published:	American Chemical Society 2012
Online Access:	http://eprints.nottingham.ac.uk/29975/ http://eprints.nottingham.ac.uk/29975/ http://eprints.nottingham.ac.uk/29975/ http://eprints.nottingham.ac.uk/29975/1/cush.pdf

id	nottingham-29975
recordtype	eprints
spelling	nottingham-299752017-10-13T19:52:18Z http://eprints.nottingham.ac.uk/29975/ Theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond Do, Hainam Besley, Nicholas A. The copper-sulphur bond which binds cysteinate to the metal centre is a key factor in the spectroscopy of blue copper proteins. We present theoretical calculations describing the electronically excited states of small molecules, including CuSH, CuSCH_3, (CH_3)_2SCuSH, (imidazole)-CuSH and (imidazole)_2-CuSH, derived from the active site of blue copper proteins that contain the copper-sulphur bond in order to identify small molecular systems that have electronic structure that is analogous to the active site of the proteins. Both neutral and cationic forms are studied, since these represent the reduced and oxidised forms of the protein, respectively. For CuSH and CuSH^+, excitation energies from time-dependent density functional theory with the B97-1 exchange-correlation functional agree well with the available experimental data and multireference configuration interaction calculations. For the positive ions, the singly occupied molecular orbital is formed from an antibonding combination of a 3d orbital on copper and a 3pπ orbital on sulphur, which is analogous to the protein. This leads several of the molecules to have qualitatively similar electronic spectra to the proteins. For the neutral molecules, changes in the nature of the low lying virtual orbitals leads the predicted electronic spectra to vary substantially between the different molecules. In particular, addition of a ligand bonded directly to copper results in the low-lying excited states observed in CuSH and CuSCH_33 to be absent or shifted to higher energies. American Chemical Society 2012-08-09 Article PeerReviewed application/pdf en http://eprints.nottingham.ac.uk/29975/1/cush.pdf Do, Hainam and Besley, Nicholas A. (2012) Theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond. Journal of Physical Chemistry A, 116 (33). pp. 8507-8514. ISSN 1089-5639 http://pubs.acs.org/doi/abs/10.1021/jp305807z doi:10.1021/jp305807z doi:10.1021/jp305807z
repository_type	Digital Repository
institution_category	Local University
institution	University of Nottingham Malaysia Campus
building	Nottingham Research Data Repository
collection	Online Access
language	English
description	The copper-sulphur bond which binds cysteinate to the metal centre is a key factor in the spectroscopy of blue copper proteins. We present theoretical calculations describing the electronically excited states of small molecules, including CuSH, CuSCH_3, (CH_3)_2SCuSH, (imidazole)-CuSH and (imidazole)_2-CuSH, derived from the active site of blue copper proteins that contain the copper-sulphur bond in order to identify small molecular systems that have electronic structure that is analogous to the active site of the proteins. Both neutral and cationic forms are studied, since these represent the reduced and oxidised forms of the protein, respectively. For CuSH and CuSH^+, excitation energies from time-dependent density functional theory with the B97-1 exchange-correlation functional agree well with the available experimental data and multireference configuration interaction calculations. For the positive ions, the singly occupied molecular orbital is formed from an antibonding combination of a 3d orbital on copper and a 3pπ orbital on sulphur, which is analogous to the protein. This leads several of the molecules to have qualitatively similar electronic spectra to the proteins. For the neutral molecules, changes in the nature of the low lying virtual orbitals leads the predicted electronic spectra to vary substantially between the different molecules. In particular, addition of a ligand bonded directly to copper results in the low-lying excited states observed in CuSH and CuSCH_33 to be absent or shifted to higher energies.
format	Article
author	Do, Hainam Besley, Nicholas A.
spellingShingle	Do, Hainam Besley, Nicholas A. Theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond
author_facet	Do, Hainam Besley, Nicholas A.
author_sort	Do, Hainam
title	Theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond
title_short	Theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond
title_full	Theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond
title_fullStr	Theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond
title_full_unstemmed	Theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond
title_sort	theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond
publisher	American Chemical Society
publishDate	2012
url	http://eprints.nottingham.ac.uk/29975/ http://eprints.nottingham.ac.uk/29975/ http://eprints.nottingham.ac.uk/29975/ http://eprints.nottingham.ac.uk/29975/1/cush.pdf
first_indexed	2018-09-06T11:59:14Z
last_indexed	2018-09-06T11:59:14Z
_version_	1610859313305223168

Theoretical study of the electronic spectra of small molecules that incorporate analogues of the copper-cysteine bond

Similar Items