Free radicals derived from 1,4-diaza-1,3-butadiene. II. Adducts with metal carbonyls and reactions with derivatives of group VB elements

The paramagnetic adducts formed when photochemically generated Mti(CO), or Rk(CO), radicals are trapped by N,N'-di-t-butyl-l,4-diaza-1,3-butadiene(t-Bu-DAB) have been characterized by ESR spectroscopy. Adducts containing phosphorus have also been observed but attempts to produce adducts containing As, Sb or Bi have been unsuccessful. In a number of systems an identical ESR spectrum was observed. This has been shown to arise from the N, N'-di-t-butylpyrazinium cation.