Mono{hydrotris(mercaptoimidazolyl)borato} Complexes of Manganese(II), Iron(II), Cobalt(II), and Nickel(II) Halides

A series of [TmMeM(μ-Cl)]2 and TmRMCl (TmR = tris(mercaptoimidazolyl)borate; R = Me, tBu, Ph, 2,6-iPr2C6H3
(Ar); M = Mn, Fe, Co, Ni) complexes have been prepared by treatment of NaTmMe or LiTmR with an excess
amount of metal(II) chlorides, MCl2. Treatment of TmRMCl (R = tBu, Ph, Ar) with NaI led to a halide exchange to
afford TmRMI. The molecular structures of [TmMeM(μ-Cl)]2 (M = Mn, Ni), [TmMeNi(μ-Br)]2, TmtBuMCl (M = Fe, Co),
TmPhMCl (M = Mn, Fe, Co, Ni), TmArMCl (M = Mn, Fe, Co, Ni), TmPhMI (M = Mn, Co), and TmArMI (M = Fe,
Co, Ni) have been determined by X-ray crystallography. The TmR ligands occupy the tripodal coordination site of
the metal ions, giving a square pyramidal or trigonal bipyramidal coordination geometry for [TmMeM(μ-Cl)]2 and a
tetrahedral geometry for the TmRMCl complexes, where the S−M−S bite angles are larger than the reported N−M−N
angles of the corresponding hydrotris(pyrazolyl)borate (TpR) complexes. Treatment of TmPh2Fe with excess FeCl2
affords TmPhFeCl, indicating that TmR2M as well as TmRMCl is formed at the initial stage of the reaction between
MCl2 and the TmR anion.