Structure of a monolayer of Pd-diethynylbiphenyl deposited on chromium studied by total reflection EXAFS

Poly-yne polymers containing transition metals are an interesting class of materials for their chemical and physical properties. In order to better understand the properties of such materials, a good knowledge of their structure is necessary. In this study we have determined the local structure around Pd in Pd-diethynylbiphenyl (Pd-DEBP, [Pd(PBu3)2C16H4]n) polymer containing a diethynylbiphenyl unit as the organic spacer. Thin films of the material were deposited onto a Cr substrate and were studied by means of extended X-ray absorption structure spectroscopy (EXAFS) in total reflection mode. The bond lengths between Pd and its neighbors as well as the C–C distances in the linear chain are determined and compared with literature data reported for model complexes.