The 2-Indenylidene Chloropalladate {PdCl[Ind(Ph2PS)2]}(nBu4N): A Versatile Pincer Complex with “Innocent” and “Noninnocent” Behavior

The chloropalladate pincer complex {PdCl­[Ind­(Ph2PS)2]}­(nBu4N) (2) has been prepared, and its reactivity has been thoroughly investigated. Alkyl halides such as iodomethane and benzyl chloride react at the electron-rich 2-indenylidene moiety, leading to the 2-indenyl pincer complexes {PdI­[Ind­(Me)­(Ph2PS)2]} (3) and {PdCl­[Ind­(Bn)­(Ph2PS)2]} (4), respectively. The ligand backbone is also involved in the reaction of 2 with the electron-deficient alkyne MeCO2CCCO2Me. Formally, one of the pincer ligand side arms is elongated and the original complex 5, featuring three fused metallacycles, is obtained. Nucleophiles such as PPh3 and NHCy2 also react readily with 2, to give the corresponding 2-indenylidene complexes by displacement of the chloride at Pd. In addition, treatment of 2 with PhCCLi affords {Pd­(CCPh)­[Ind­(Ph2PS)2]}­(nBu4N) (8), the first alkynylpalladate to be isolated. All the new compounds have been characterized by multinuclear NMR spectroscopy and mass spectrometry. The structures of complexes 3, 5, and 8 have been further analyzed by means of X-ray diffraction studies.