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34 35
Figure 6. Crystal structures of the ethyl-bridged palladium(II) complexes 34 [I] and 35 [II]
The Pd-Cl1 and Pd-C12 bonds are shorter in the complexes 34 and 35 than in the
corresponding symmetrical bisphosphine complexes [Pd- (P-P)C1 2 ]. [ 94]
Furthermore, the
metal–halide bond trans to the S atom is shorter than that trans to the P or As atom. This could
be due to the stronger trans influence [ 95]
of the P and As donor atoms than the S atom. The
longer Pd-Cl bond when P is the trans group is in agreement with previous NMR
investigations carried out on the corresponding mono- and dialkyl complexes. [ 96]
2.2.2. Pyridinylimine palladium(II) complexes and solid state-structures [III]
The pyridinylimine palladium(II) complexes (42, 43, and 44) were prepared in good yields
(55–77%) by stirring the ligands 39, 40, and 41, respectively, with [(COD)PdCl 2 ] in
dichloromethane. Chloride abstraction from compounds 42 and 43 with AgBF 4 afforded the
solvated diacetonitrile complexes 45 and 46 (Figure 7) although the reaction to the cationic
species proved to be somewhat complicated. In the case of the dimethylphenylamine complex
44, chloride abstraction led to decomposition, and the corresponding ion-pair compound was
not obtained. The complexes 42, 43, and 44 were characterized by elemental analysis and 1 H
NMR spectroscopy.
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