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Nickel−Manganese Sulfido Carbonyl Cluster Complexes. Synthesis, Structure, and Properties of the Unusual Paramagnetic Complexes Cp2Ni2Mn(CO)3(μ3-E)2, E = S, Se
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posted on 2004-04-19, 00:00 authored by Richard D. Adams, Shaobin Miao, Mark D. Smith, Horatio Farach, Charles Edwin Webster, Josiah Manson, Michael B. HallThe reaction of Mn2(CO)7(μ-S2) with [CpNi(CO)]2 yielded the paramagnetic new compound Cp2Ni2Mn(CO)3(μ3-S)2
(1) and a new hexanuclear metal product Cp2Ni2Mn4(CO)14(μ6-S2)(μ3-S)2 (2). Structurally, compound 1 contains
two triply bridging sulfido ligands on opposite sides of an open Ni2Mn triangular cluster. EPR and temperature-dependent magnetic susceptibility measurements of 1 show that it contains one unpaired electron. The electronic
structure of 1 was determined by Fenske−Hall molecular orbital calculations which show that the unpaired electron
occupies a low lying antibonding orbital delocalized unequally across the three metal atoms. The selenium homologue
Cp2Ni2Mn(CO)3(μ3-Se)2 (3) was obtained from the reaction of a mixture of Mn2(CO)10 and [CpNi(CO)]2 with elemental
selenium and Me3NO·2H2O. It also has one unpaired electron. Compound 1 reacted with elemental sulfur to yield
the dinickeldimanganese compound, Cp2Ni2Mn2(CO)6(μ4-S2)(μ4-S5), 4, which can also be made from the reaction
of Mn2(CO)7(μ-S2) with [CpNi(CO)]2 and sulfur. Compound 4 was converted back to 1 by sulfur abstraction using
PPh3. The reaction of Mn2(CO)10 with [CpNi(CO)]2 in the presence of thiirane yielded the ethanedithiolato compound
CpNiMn(CO)3(μ-SCH2CH2S) (5), which was also obtained from the reaction of Mn4(CO)15(μ3-S2)(μ4-S2) with [CpNi(CO)]2 in the presence of thiirane. Compound 5 reacted with additional quantities of thiirane to yield the new
compound CpNiMn(CO)3[μ-S(CH2CH2S)2], 6, which contains a 3-thiapentanedithiolato ligand that bridges the two
metal atoms. Compound 6 was also obtained from the reaction of Mn2(CO)10 with [CpNi(CO)]2 and thiirane. The
molecular structures of the new compounds 1−6 were established by single-crystal X-ray diffraction analyses.
