Reactions of PNCNP and POCOP Pincer Platinum Hydride Complexes with Phenylacetylene and Carbon Disulfide: The Influence of the Pincer Backbone on the Structures of Unsaturated Auxiliary Ligands

Abstract

In order to get information about the influence of the pincer backbone on the structure and reactivity of a pincer complex, bisphosphiamine PNCNP and bisphosphinite POCOP pincer platinum hydride complexes, [2,6-(tBu2PY)2C6H3]PtH (Y = NH, 1a; O, 2a), were reacted with phenylacetylene and carbon disulfide. The reactions with phenylacetylene in the presence of CuI/Et2NH produced the corresponding σ-alkynyl complexes [2,6-(tBu2PY)2C6H3]PtC≡CPh (Y = NH, 1b; O, 2b). The reactions with carbon disulfide produced the corresponding dithioformato complexes [2,6-(tBu2PY)2C6H3]PtSC(S)H (Y = NH, 1c; O, 2c). The PNCNP complex 1a is easier to react with carbon disulfide than the POCOP complex 2a. X-ray crystal structure analysis indicated that the PNCNP pincer backbone influences the phenylacetylido and dithioformato auxiliary ligands in the resulting complexes more significantly than the POCOP pincer backbone. The dithioformato auxiliary ligand adopts different coordination modes in complexes 1c and 2c. The results provide useful information about how PNCNP and POCOP pincer backbones influence the reactivity of the metal center and the coordination of unsaturated auxiliary ligands.