Nickel−Manganese Sulfido Carbonyl Cluster Complexes. Synthesis, Structure, and Properties of the Unusual Paramagnetic Complexes Cp<sub>2</sub>Ni<sub>2</sub>Mn(CO)<sub>3</sub>(μ<sub>3</sub>-E)<sub>2</sub>, E = S, Se

The reaction of Mn<sub>2</sub>(CO)<sub>7</sub>(μ-S<sub>2</sub>) with [CpNi(CO)]<sub>2</sub> yielded the paramagnetic new compound Cp<sub>2</sub>Ni<sub>2</sub>Mn(CO)<sub>3</sub>(μ<sub>3</sub>-S)<sub>2</sub> (<b>1</b>) and a new hexanuclear metal product Cp<sub>2</sub>Ni<sub>2</sub>Mn<sub>4</sub>(CO)<sub>14</sub>(μ<sub>6</sub>-S<sub>2</sub>)(μ<sub>3</sub>-S)<sub>2</sub> (<b>2</b>). Structurally, compound <b>1 </b>contains two triply bridging sulfido ligands on opposite sides of an open Ni<sub>2</sub>Mn triangular cluster. EPR and temperature-dependent magnetic susceptibility measurements of <b>1</b> show that it contains one unpaired electron. The electronic structure of <b>1</b> 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 Cp<sub>2</sub>Ni<sub>2</sub>Mn(CO)<sub>3</sub>(μ<sub>3</sub>-Se)<sub>2</sub> (<b>3</b>) was obtained from the reaction of a mixture of Mn<sub>2</sub>(CO)<sub>10</sub> and [CpNi(CO)]<sub>2</sub> with elemental selenium and Me<sub>3</sub>NO·2H<sub>2</sub>O. It also has one unpaired electron. Compound <b>1</b> reacted with elemental sulfur to yield the dinickeldimanganese compound, Cp<sub>2</sub>Ni<sub>2</sub>Mn<sub>2</sub>(CO)<sub>6</sub>(μ<sub>4</sub>-S<sub>2</sub>)(μ<sub>4</sub>-S<sub>5</sub>), <b>4</b>, which can also be made from the reaction of Mn<sub>2</sub>(CO)<sub>7</sub>(μ-S<sub>2</sub>) with [CpNi(CO)]<sub>2</sub> and sulfur. Compound <b>4</b> was converted back to <b>1</b> by sulfur abstraction using PPh<sub>3</sub>. The reaction of Mn<sub>2</sub>(CO)<sub>10</sub> with [CpNi(CO)]<sub>2</sub> in the presence of thiirane yielded the ethanedithiolato compound CpNiMn(CO)<sub>3</sub>(μ-SCH<sub>2</sub>CH<sub>2</sub>S) (<b>5</b>), which was also obtained from the reaction of Mn<sub>4</sub>(CO)<sub>15</sub>(μ<sub>3</sub>-S<sub>2</sub>)(μ<sub>4</sub>-S<sub>2</sub>) with [CpNi(CO)]<sub>2</sub> in the presence of thiirane. Compound <b>5</b> reacted with additional quantities of thiirane to yield the new compound CpNiMn(CO)<sub>3</sub>[μ-S(CH<sub>2</sub>CH<sub>2</sub>S)<sub>2</sub>], <b>6</b>, which contains a 3-thiapentanedithiolato ligand that bridges the two metal atoms. Compound <b>6</b> was also obtained from the reaction of Mn<sub>2</sub>(CO)<sub>10</sub> with [CpNi(CO)]<sub>2</sub> and thiirane. The molecular structures of the new compounds <b>1</b>−<b>6</b> were established by single-crystal X-ray diffraction analyses.