ALKYLATION-INDUCED O-ATOM REARRANGEMENT IN NICKEL S-OXYGENATES

Reactions of organic halides Mel and Br(CH2)(3)Br with square planar n ickel complexes of tetradentate N2SS' or N2S'(2) ligands (S' = RS(=O)) have been explored for their potential to direct alkylation of metall osulfoxide sulfur and yield metal-bound organic sulfoxides. In fact, a s established by spectroscopic and electrochemical signatures, isolate d products were characterized as the result of O-atom rearrangements o r transfers leading primarily to metallosulfones (Ni-SO2R) and metallo thiolates (Ni-SR) (which were subsequently alkylated to nickel-bound t hioethers). Proposed intermediates in the reactions of the monosulfoxi de, Ni-4, -2-(methylpropyl))-1,5-diazacyclooc-tanenickel(II) and the bis-sulfoxide, Ni-5, -2-(methylpropyl))-1,5-diazacyclooctanenickel(II ), with 1,3-dibromopropane include S-bound R'S-OR moieties resulting f rom ring closure of the pendant alkyl bromide on the nucleophilic sulf oxide oxygen. X-ray crystal structures of a-2-(methylpropyl))-1,5-diaz acyclooctanenickel(II) iodide and a bimetallic composed of two units o f o-2-(methylpropyl))-1,5-diazacyclooctanenickel(II) linked by (CH2CH2 CH2) are reported.