Zusammenfassung
The reactivity of the tetrahedral dipnictogen complexes [{CpMo(CO)(2)}(2)(mu,eta(2):eta(2)-EE ')] (E, E ' = P, As, Sb, Bi; "Mo2EE '") towards different one-electron oxidation agents is reported. Oxidation with [Thia][TEF] (Thia(+) = C12H8S2+; TEF- = Al{OC(CF3)(3)}(4)(-)) leads to the selective formation of the radical monocations [Mo2EE '](+), which immediately dimerize to the unprecedented ...
Zusammenfassung
The reactivity of the tetrahedral dipnictogen complexes [{CpMo(CO)(2)}(2)(mu,eta(2):eta(2)-EE ')] (E, E ' = P, As, Sb, Bi; "Mo2EE '") towards different one-electron oxidation agents is reported. Oxidation with [Thia][TEF] (Thia(+) = C12H8S2+; TEF- = Al{OC(CF3)(3)}(4)(-)) leads to the selective formation of the radical monocations [Mo2EE '](+), which immediately dimerize to the unprecedented dicationic E2E '(2) ligand complexes [{CpMo(CO)(2)}(4)(mu(4),eta(2):eta(2):eta(2):eta(2)-E ' EEE ')](2+)via E-E bond formation. Single crystal X-ray diffraction revealed that, in the case of Mo2PAs and Mo2PSb, P-P bond formation occurs yielding zigzag E2P2 (E = As (1), Sb (2)) chains, whereas Mo2SbBi forms a Sb2Bi2 (5) cage, Mo2AsSb an unprecedented As2Sb2 unit representing an intermediate stage between a chain- and a cage-type structure, and Mo2AsBi a novel planar As2Bi2 (4a) cycle. Therefore, 1-5 bear the first substituent-free, dicationic hetero-E-4 ligands, stabilized by transition metal fragments. Furthermore, in the case of Mo2AsSb, the exchange of the counterion causes changes in the molecular structure yielding an unusual, cyclic As2Sb2 ligand. The experimental results are corroborated by DFT calculations.
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