Syntheses, Structures, and Dynamic Properties of Dicobalt π Complexes of Diplatinum Polyynediyl Complexes Academic Article uri icon

abstract

  • Reactions of Co2(CO)6(μ-Ph2PCH 2PPh2) and polyynediyl complexes trans, trans-(C 6F5)(p-tol3P)2Pt(C≡C) mPt)(Pp-tol3)2(C6F 5) (PtC2mPt) are conducted in refluxing toluene. With PtC8Pt, a 1:1 adduct, trans, trans-(C6F 5)(p-tol3P)2PtC=CC2[Co 2(CO)4(μ-PPh2CH2PPh 2)](C=C)2Pt(Pptol3) 2(C6F5) (1), is isolated in 53% yield after silica gel chromatography and crystallographically characterized. The dicobalt moiety binds to a PtC=C C=C linkage remote from the bulky platinum endgroups, with the P-Pt-P axis of the (p-tol3P)2PtC=CC(Co) 2 moiety nearly parallel to the cobalt-cobalt bond and that of the (p-tol3P)2PPtC=CC=CC(Co)2 moiety roughly perpendicular. The 31P and 1HNMR spectra of 1 evidence dynamic behavior. At the low-temperature limit, three 31P signals are observed (2:1:1), corresponding to the p-tol3P ligands on one endgroup and those that have cis/trans relationships to the cobalt-cobalt bond on the other. Low-temperature 31P and 1H NMR spectra show multiple Ph2PCrZ2PPh2 signals, which are analyzed. In the case Of PtC12Pt, a 2:1 adduct is the major isolable product (12%). NMR data show that the dicobalt moieties bind to the central C=C linkages furthest from the endgroups. In the case Of PtC16Pt, mass spectra show that 2:1 adducts can form, but 31P NMR spectra are not homogeneous, suggesting mixtures of isomers differing in the dicobalt positions. © 2009 American Chemical Society.

author list (cited authors)

  • Kuhn, H., Hampel, F., & Gladysz, J. A.

citation count

  • 5

publication date

  • August 2009