Spectroelectrochemical (IR,UV/VIS) Determination of the Reduction Pathways for a Series of [Re(CO)C3(alpha-diimine)LE']E0E/E+ (LE'=Halide, Otf, THF, MeCN, n-PrCN, PPhC3C' P(OMe)C3) Complexes Stor, G.J.; Hartl, F.; van Outersterp, J.W.M.; Stufkens, D.J.

The remarkable photochemistry of fac-XMn(CO)sub3(alpha-diimine) (X=halide). Formation of Mnsub2(CO)sub6(alpha-diimine)sub2 via the mer-isomer and photocatalytic disproportionation in the presence of PRsub3 Stor, G.J.; Morrison, S.L.; Stufkens, D.J.; Oskam, A. Published in: Organometallics DOI:10.1021/om00019a021Link to publication Citation for published version (APA):Stor, G. J., Morrison, S. L., Stufkens, D. J., & Oskam, A. (1994). The remarkable photochemistry of facXMn(CO)sub3(alpha-diimine) (X=halide). Formation of Mnsub2(CO)sub6(alpha-diimine)sub2 via the mer-isomer and photocatalytic disproportionation in the presence of PRsub3. Organometallics, 13, 2641-2650. DOI: 10.1021/om00019a021 General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. This article describes the remarkable photochemistry of complexes fac-XMn(CO)&~-diimine) (X = C1, Br, I) upon irradiation into their lowest-energy CT band. The primary photoprocess is loss of CO, as was established by flash photolysis and low-temperature IR spectroscopy. The CO-loss product reacted thermally and photochemically to give mer-XMn(CO)s(a-diimine), which in turn transformed thermally into thefac isomer at temperatures above 213 K. Irradiation of mer-XMn(CO)&~-diimine) resulted in the formation of the 16-electron radical complexes Mn+(CO)s(a-diimine*-), which were identified at room temperature by ESR spectroscopy and which dimerized to give Mn&O)&-diimine)2 for a-diimine = bpy. At low temperatures these radical complexes formed rather stable adducts Mn+(C0)3(a-diimine0-)(PR3) with PRs (R = nBu, OMe). At room temperature these adducts initiated the catalytic substitution of X-by PR3 in the starting complex fac-XMn(CO)s(a-diimine). The primary photoprocess of facXMn(CO)s(a-diimine) (loss of CO) most likely occurs from the lowest LF state. Contrary to this, irradiation of mer-XMn(CO)s(a-diimine) gives rise to homolysis of the Mn-X bond. This remarkable difference in photochemical behavior of the fuc and mer isomers is discussed.

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UvA-DARE is a service provided by the library of the University of Amsterdam (http://dare.uva.nl) UvA-DARE (Digital Academic Repository)X-ray structure of fac-IMn(CO)3(bpy) and electronic structures and transitions of the compexes fac-XMn(CO)3(bpy)(X= Cl, I) and mer-ClMn(CO)3(bpy) Stor, G.J.; Stufkens, D.J.; Vernooijs, P.; Baerends, E.J.; Fraanje, J.; Goubitz, K. Published in: Inorganic Chemistry DOI:10.1021/ic00110a042Link to publication Citation for published version (APA):Stor, G. J., Stufkens, D. J., Vernooijs, P., Baerends, E. J., Fraanje, J., & Goubitz, K. (1995). X-ray structure of fac-IMn(CO)3(bpy) and electronic structures and transitions of the compexes fac-XMn(CO)3(bpy)(X= Cl, I) and mer-ClMn(CO)3(bpy). Inorganic Chemistry, 34, 1588-1594. DOI: 10.1021/ic00110a042 General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. MO calculations have been performed on the complexesfuc-XMn(CO)3(bpy) (X = C1, I) and mer-ClMn(CO)s-(bpy) in order to establish the influence of X on the electronic transitions of the fuc and mer isomers and to interpret the differences in photochemical behavior of thefuc and mer complexes. SCF calculations were performed with the Amsterdam density-functional program package ADF. The structural data used for the calculations were partly derived from the X-ray structure offuc-IMn(C0)3(bpy) presented in the article. The theoretical data for thefuc isomers show that the two highest occupied orbitals have metal-halide antibonding character and that the LUMO is a n* (bpy) orbital. The first absorption band is therefore assigned to electronic transitions having mixed metal-halide to bpy CT character. The second absorption band is assigned to CT transitions from the corresponding metal-halide bonding orbitals to bpy. From a comparison of the theoretical and spectroscopic data, the intensities of these two absorption bands appear to depend on the metal character of the orbitals from which the electronic transitions originate. The main difference between the theoretical data of the fuc-and merClMn(C0)3(bpy) complexes is the higher energy of the highest filled orbitals in the case of the mer isomer. This difference is in accordance with the spectroscopic data and may also explain the differences in photochemistry between the two isomers.

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