title: Characterisation, degradation and regeneration of luminescent Ag29clusters in solution.
abstract: Luminescent Ag clusters are prepared with lipoic acid (LA) as the ligand. Using a combination of mass spectrometry, optical spectroscopy and analytical ultracentrifugation, the clusters are found to be highly monodisperse with mass 5.6 kDa. We assign the chemical composition [Ag29(LA)12]3-to the clusters, where LA likely binds in a bidentate fashion. The Ag29clusters show slow degradation, retaining their deep red emission for at least 18 months if stored in the dark. Purification or exposure to light results in faster degradation. No other cluster species are observed during the degradation process. Once degraded, the clusters could easily be regenerated using NaBH4, which is not usually observed for thiolate-capped Ag clusters.
authors.affiliation: Inorganic Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Universiteit Utrecht, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands. M.vanderLinden1@uu.nl and ID26, European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, 38000 Grenoble, France.
authors.forename: Marte
authors.identifier: http://orcid.org/0000-0002-4085-0320
authors.initials: M
authors.lastname: van der Linden
authors.affiliation: Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Centre for Biomolecular Research, Universiteit Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands and Netherlands Proteomics Center, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors.forename: Arjan
authors.initials: A
authors.lastname: Barendregt
authors.affiliation: Condensed Matter & Interfaces, Debye Institute for Nanomaterials Science, Universiteit Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
authors.forename: Arnoldus J
authors.identifier: http://orcid.org/0000-0001-5162-7258
authors.initials: AJ
authors.lastname: van Bunningen
authors.affiliation: Condensed Matter & Interfaces, Debye Institute for Nanomaterials Science, Universiteit Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
authors.forename: Patrick T K
authors.initials: PT
authors.lastname: Chin
authors.affiliation: Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Universiteit Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors.forename: Dominique
authors.initials: D
authors.lastname: Thies-Weesie
authors.affiliation: Inorganic Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Universiteit Utrecht, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands. M.vanderLinden1@uu.nl.
authors.forename: Frank M F
authors.initials: FM
authors.lastname: de Groot
authors.affiliation: Condensed Matter & Interfaces, Debye Institute for Nanomaterials Science, Universiteit Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
authors.forename: Andries
authors.initials: A
authors.lastname: Meijerink