om980587e_si_001.pdf (567.85 kB)
Alkylation-Induced O-Atom Rearrangement in Nickel S-Oxygenates
journal contribution
posted on 1998-10-03, 00:00 authored by John A. Bellefeuille, Craig A. Grapperhaus, Rizalia M. Buonomo, Joseph H. Reibenspies, Marcetta Y. DarensbourgReactions of organic halides MeI and Br(CH2)3Br with square planar nickel complexes of
tetradentate N2SS‘ or N2S‘2 ligands (S‘ = RS(O)) have been explored for their potential to
direct alkylation of metallosulfoxide sulfur and yield metal-bound organic sulfoxides. In
fact, as established by spectroscopic and electrochemical signatures, isolated products were
characterized as the result of O-atom rearrangements or transfers leading primarily to
metallosulfones (Ni−SO2R) and metallothiolates (Ni−SR) (which were subsequently alkylated
to nickel-bound thioethers). Proposed intermediates in the reactions of the monosulfoxide,
Ni-4*, N-(2-mercapto-2-(methylpropyl))-N‘-(2-sulfenato-2-(methylpropyl))-1,5-diazacyclooctanenickel(II) and the bis-sulfoxide, Ni-5*, N,N‘-bis(2-sulfenato-2-(methylpropyl))-1,5-diazacyclooctanenickel(II), with 1,3-dibromopropane include S-bound R‘S−OR moieties resulting
from ring closure of the pendant alkyl bromide on the nucleophilic sulfoxide oxygen. X-ray
crystal structures of N-(sulfinato-2-(methylpropyl))-N‘-(2-thia-2-(methylpropyl))-1,5-diazacyclooctanenickel(II) iodide and a bimetallic composed of two units of N-(2-mercapto-2-(methylpropyl))-N‘-(2-sulfinato-2-(methylpropyl))-1,5-diazacyclooctanenickel(II) linked by
(CH2CH2CH2) are reported.