Palladium(II) Complexes of N ‐(2‐Thienylmethylidene)aniline Derivatives

Coordination reactions of N ‐(2‐thienylmethylidene)aniline derivatives, L, with PdCl 2 or [PdCl 4 ] 2− in ethanol yield stable complexes of the type trans ‐(L) 2 PdCl 2 with the azomethine nitrogen atoms as σ donors. These are not readily convertible to othor ‐palladated complexes. An X‐ray crystallographic study of the complex (L 2 ) 2 PdCl 2 reveals a centrosymmetric geometry. The structure is in the triclinic space group \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\bar 1 $\end{document} with a = 8.633(2) Å, b = 12.759(3) Å, c = 8.398(2) Å, α = 96.65(5)°, β = 111.47(5)*, γ= 101.28(6)°, and Z = 1. The final R factor is 0.043 (Rw = 0.044) for 2396 observed reflections. There is no real bonding between a thiophene sulfur atom and a central palladium ion. However, a long distance interaction between S and Pd does exist.