Photolytic Homolysis of the Metal-Carbon (sp3 or sp2) Bond of Alkyl or Acyl Transition-metal Complexes: an Electron Spin Resonance Study using Spin Trapping; and a Note on Aminyl Oxides

DOI: 10.1039/DT9810002159

Source and publish data:

Journal of the Chemical Society, Dalton Transactions p. 2159 - 2163 (1981)

Update date:2022-08-03

Topics:

Authors:

Hudson, Andrew

Lappert, Michael F.

Lednor, Peter W.

MacQuitty, Jonathan J.

Nicholson, Brian K.

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Article abstract of DOI:10.1039/DT9810002159

Irradiation of the following metal alkyls has been carried out in CH2Cl2 (or PhMe) in the presence of nitrosodurene, RNO (R = C6HMe4-2,3,5,6), in the cavity of an e.s.r. spectrometer: (R' = CH2Ph or CH2SiMe3), , (R' = Me, Et, or CH2Ph), cis- (R' = CH2SiMe3 or CH2CMe3), (R' = Me or CH2SiMe3), and (H2oep = 2,3,7,8,12,13,17,18-octaethylporphyrin and R' = Me, L = NC5H5; or R' = Et, L = OH2).Similar experiments have been performed on (i) the acylmetal complexes (R'' = CH2Cl, Me, Et, CH2Ph, or CHPh2) or (R'' = Me or CH2Ph), and (ii) the metal-metal bonded (M = Ru or Os).Finally, the dark reaction between the stable iron(I) complex and RNO in CH2Cl2 has been investigated.As a consequence, from the alkyls, metallo-aminyl oxides were observed, except for ML(n) = a platinum(I), gold(0), or cobalt(II) moiety, but the alkylaminyl oxides RN(O)R' were found in every case ; two of these (R' = CH2SiMe3 or CH2CMe3) are new and show remarkably different β-proton hyperfine couplings, attributed in part to a conformational difference allowing for close Si***O proximity for R' = CH2SiMe3, and also to the greater steric requirements of the neopentyl group.From the acyls, the corresponding metallo-aminyl oxide was invariably detected, but never the spin-trapped acyl radical RN(O)COR''; however, the corresponding spin-trapped alkyl radical RN(O)R'' was observed but only for the case of R'' = CH2Ph or CHPh2.The remaining experiments led to the e.s.r. characterisation of , ML(n) = Ru(CO)4(SiMe3), Os(CO)4(SiMe3), or Fe(μ-C3H5)(CO)3.