| Abstract: | The room‐temperature reaction of Cp*TaCl4] with LiBH4?THF followed by addition of S2CPPh3 results in pentahydridodiborate species (Cp*Ta)2(μ,η2:η2‐B2H5)(μ‐H)(κ2,μ‐S2CH2)2] ( 1 ), a classical B2H5]? ion stabilized by the binuclear tantalum template. Theoretical studies and bonding analysis established that the unusual stability of B2H5]? in 1 is mainly due to the stabilization of sp2‐B center by electron donation from tantalum. Reactions to replace the hydrogens attached to the diborane moiety in 1 with a 2 e {M(CO)4} fragment (M=Mo or W) resulted in simple adducts, {(Cp*Ta)(CH2S2)}2(B2H5)(H){M(CO)3}] ( 6 : M=Mo and 7 : M=W), that retained the diborane(5) unit. |
