New cyclopentadienyl molybdenum polynuclear clusters from ring opening of Woollins' reagent via phosphorus-selenium bond scission, phosphorus-phosphorus coupling and deselenation pathways

Cothermolysis of [(Ph)P(Se)(μ-Se)]2 or Woollins' reagent (WR) with Cp2Mo2(CO)4 (2) in toluene at 110 °C gave three metal cluster products as [Cp2Mo2{(μ-Se)2(PPh(Se))}{(μ-Se)(PPh)3] (3), Cp4Mo4(CO)3(μ-Se)4 (4) and a pair of polymorphic complexes of Cp3Mo3(CO)4[Se3(PPh)2] (5a and 5b) in moderate yields. However, a similar reaction at 70 °C gave only polymorphs 5a and 5b.91