sp Carbon chains surrounded by sp~3 carbon double helices:wire-like Pt(C ≡ C)_nPt moieties that are spanned by two alpha,omega-diphosphines that bear heteroatoms or alkyl substituents

摘要

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 )-(Ph2P(CH2)40(CH2)6O(CH2)4PPh2)Pt(C≡C)4Pt(Ph2P(CH2)4O(CH2)6O(CH2)4PPh2)(C6F5)(5),with termini-spanning diphosphines,and trans,trans-(C6F5)-(Ph2P(CH2)2C(CH3)2(CH2)8C(CH3)2(CH2)2PPh2)Pt(C ≡ C)_4-Pt(Ph2P(CH2)2C(CH3)2(CH2)8C(CH3)2(CH2)2PPh2)(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)3P p-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 sp~3 chains adopt a chiral double-helical conformation about the sp chain,with the endgroups denning 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.