sp Carbon chains surrounded by sp 3 carbon double helices: wire-like Pt(C[triple bond, length as m-dash]C) n Pt moieties that are spanned by two α,ω-diphosphines that bear heteroatoms or alkyl substituents Academic Article uri icon

abstract

  • Reactions of trans-(C6F5)L2PtCl (2, L = Ph2P(CH2)4O(CH2)2CH=CH2; 6, L = Ph2P(CH2)2C(CH3)2(CH2)3CH=CH2) and H(C≡C)2H (HNEt2, cat. CuI) give trans-(C6F5)L2Pt(C≡C)2H (3, 7; 86-97%). Oxidative homocouplings (O2, cat. CuCl/TMEDA, acetone) yield trans, trans-(C6F5)L2Pt(C≡C)4PtL2(C6F5) (4, 8; 75-86%). Reactions with Grubbs’ catalyst, followed by hydrogenation, give mainly trans, trans-(C6F5)(Ph2γP(CH2)4O(CH2)6O(CH2)4PPh2)∟Pt(C≡C)4Pt┌(Ph2P(CH2)4O(CH2)6O(CH2)4P┘Ph2)(C6F5) (5), with termini-spanning diphosphines, and trans, trans-(C6F5)(Ph2γP(CH2)2C(CH3)2(CH2)8C(CH3)2(CH2)2PPh2)Pt┌(C≡C)4γPt(Ph2P(CH2)2C(CH3)2(CH2)8C(CH3)2(CH2)2P┌Ph2)(C6F5) (9), with trans-spanning diphosphines, respectively. Reactions of trans, trans-(C6F5)(p-tol3P)2Pt(C≡C)4Pt(Pp-tol3)2(C6F5) with Ph2P(CH2)2C(CH3)2(CH2)8C(CH3)2(CH2)2PPh2 and p-tol2P(CH2)3(CF2)8(CH2)3Pp-tol2 give 10 (70%), the isomer of 9 with termini-spanning diphosphines, and the analogous adduct of the fluorinated diphosphine. However, the latter oligomerizes upon attempted workup. The crystal structure of 5 shows that the sp3 chains adopt a chiral double-helical conformation about the sp chain, with the endgroups defining a 164.1° angle. Additional conformational properties of the preceding complexes are analyzed in detail, and dynamic properties are probed by low temperature NMR experiments. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

author list (cited authors)

  • de Quadras, L., Bauer, E. B., Stahl, J., Zhuravlev, F., Hampel, F., & Gladysz, J. A.

citation count

  • 36

publication date

  • January 2007