Reaction of dirhodium(II) tetraacetate with S-methyl-L-cysteine
Date
2019-08-12
Journal Title
Journal ISSN
Volume Title
Publisher
Taylor & Francis
Abstract
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.
Description
This 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.
Keywords
Dirhodium(II) tetraacetate, S-methyl-L-cysteine, ESI–MS, UV–vis spectroscopy, crystal structure
Citation
Brunskill, 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:10.1080/00958972.2019.1651845