Abstract
The reaction of the antimony(I) compound ArSb (1) (where Ar = C6H3-2,6-(CHNtBu)(2)) with various dimeric allyl palladium(II) complexes [Pd(η(3)-allyl)(μ-X)](2) (where allyl = C3H5 or C3H4Me; X = Cl or CF3CO2) in a 1 : 1 stoichiometric ratio gave unique complexes with the μ-ArSb moiety bridging two palladium fragments, i.e. [{Pd(η(3)-C3H5)Cl}(2)(μ-ArSb)] (2), [{Pd(η(3)-C3H4Me)Cl}(2)(μ-ArSb)] (3) and [{Pd(η(3)-C3H5)(CF3CO2)}(2)(μ-ArSb)] (4). Compound 1 serves formally as a 4e donor in 2-4.
The treatment of 2 with another equivalent of ArSb led to the formation of the [Pd(η(3)-C3H5)(Cl)(μ-ArSb)] complex (5), proving that 1 is able to function as a 2e donor in target complexes as well. The structures of 2-5 were described in detail both in solution (NMR and mass spectrometry) and in the solid state (single crystal X-ray diffraction analysis).
DFT methods were used to compare bonding in the 1 : 1 (5) and 1 : 2 (2) complexes. Furthermore, a comprehensive Sb-121 Mossbauer spectroscopic investigation of complexes 2 and 5 along with parent ArSbCl2 (6) and 1 was performed.
For comparison, complexes [Fe(CO)(4)(ArSb)] (7) and [Mo(CO)(5)(ArSb)] (8) were also included in this study.