Brunskill, ValerieEnriquez Garcia, AlejandraJalilehvand, FaridehGelfand, Benjamin S.Wu, Mengya2021-07-302019-08-12Brunskill, V., Enriquez Garcia, A., Jalilehvand, F., Gelfand, B. S., & Wu, M. (2019). Reaction of dirhodium(II) tetraacetate withS-methyl-L-cysteine. Journal of Coordination Chemistry, 72(13), 2177–2188. doi:10.1080/00958972.2019.16518451029-0389http://hdl.handle.net/1880/113676https://dx.doi.org/10.11575/PRISM/39047This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Coordination Chemistry on 2019-08-12, available online: http://www.tandfonline.com/10.1080/00958972.2019.1651845.The reaction of antitumor active dirhodium(II) tetraacetate, [Rh2(AcO)4], with S-methyl-L-cysteine (HSMC) was studied at the pH of mixing (=4.8) in aqueous media at various temperatures under aerobic conditions. The results from UV–vis spectroscopy and electrospray ionization mass spectrometry (ESI–MS) showed that HSMC initially coordinates via its sulfur atom to the axial positions of the paddlewheel framework of the dirhodium(II) complex, and was confirmed by the crystal structure of [Rh2(AcO)4(HSMC)2]. After some time (48?h at 25?°C), or at elevated temperature (40?°C), Rh-SMC chelate formation causes breakdown of the paddlewheel structure, generating the mononuclear Rh(III) complexes [Rh(SMC)2]+, [Rh(AcO)(SMC)2] and [Rh(SMC)3], as indicated by ESI–MS. These aerobic reaction products of [Rh2(AcO)4] with HSMC have been compared with those of the two proteinogenic sulfur-containing amino acids methionine and cysteine. Comparison shows that the (S,N)-chelate ring size influences the stability of the [Rh2(AcO)4] paddlewheel cage structure and its RhII–RhII bond, when an amino acid with a thioether group coordinates to dirhodium(II) tetraacetate.enUnless otherwise indicated, this material is protected by copyright and has been made available with authorization from the copyright owner. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Dirhodium(II) tetraacetateS-methyl-L-cysteineESI–MSUV–vis spectroscopycrystal structurejournal article10.1080/00958972.2019.1651845