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摘要
The reaction of one equiv of 1-alkynylphosphines, R(2)PC CR' (R = E(t) (i)Pr, or Ph and R' = Ph or Mes), with Cp(2)Zr(pyr)(eta(2)-Me(3)SiC CSiMe(3)) resulted in formation of monoalkyne complexes. In the case where R = Et, (i)Pr, or Ph and R' = Ph, a "ligand free" zirconacyclopropene complex is produced. These complexes are stabilized by intermolecular donation of the phosphorus lone-pair in the dimeric complexes [Cp(2)Zr(eta(2)-R(2)PC CPh)](2) (R = Et, (i)Pr, or Ph). However, with R = Ph and R' = Mes, the zirconocyclopropene-pyridine comples Cp(2)Zr(pyr)(eta(2)-Ph(2)PC CMeS) is formed. Homocoupling of the 1-alkynylphosphines was demonstrated by reaction of a second equiv of Ph(2)PC CPh with [Cp(2)Zr(eta(2)-PhPC CPh)](2) to give the diphosphinozirconacyclopentadiene Cp(2)Zr[2,5-(Ph(2)P)(2)-3,4-Ph(2)C(4)] with high regioselectivity (77%). The zirconacyclopropene complexes also react with one equiv of PhC CPh or EtC CEt to give zirconacyclopentadienes in which the phosphino substituent preferentially adopts the 2-position (alpha) of the zirconacyclopentadiene ring. These unsymmetrical zirconacyclopentadienes undergo substitution of the R(2)PCCR' moiety with the less bulky alkynes PhC CPh or EtC CEt. The substituents on the 1-alkynylphosphines significantly influence the rates of alkyne substitution such that sterically more demanding substituents in either the alpha- (-P(i)Pr(2)) or beta- (-Mes) position of the zirconacycle lead to faster exchange. The alpha-phosphinozirconacyclopentadienes were readily converted to 1-phosphinobutadienes via reaction with benzoic acid. The zirconacyclopentadiene Cp(2)Zr[2-Ph(2)P-3,4,5-Ph(3)C(4)] was converted to the corresponding thiophene oxide by the oxo-transfer reaction with sulfur dioxide. In the case of ((1Z,3E)-3-ethyl-2-phenylhexa-1,3-dienyl)diphenylphosphine and (3,4,5-triphenylthiophen-2-yl oxide)diphenylphosphine, the molecules were isolated as their phosphine oxides. Reactions of the zirconacyclopropene complexes [Cp(2)Zr(eta(2)-Ph(2)PC CPh)](2) and Cp(2)Zr(pyr)(eta(2)-Ph(2)PC CMes) with the diyne (F(5)C(6))C C-1,4-(C(6)H(4)-C C(C(6)F(5)) gave bis(zirconacycle)s terminated with phosphino groups. These bis(zirconacycle)s were converted to the corresponding phosphino-terminated oligomers by protonolysis with hydrochloric acid. In addition, the Ph,PCCMes moiety Of [Cp(2)Zr(2-Ph(2)P-3-Mes-4-(C(6)F(5))C(4)]-1,4-C(6)H(4)-Cp(2)Zr[2-Ph(2)P-3-Mes-4-(C(6)F(5))C(4)] was exchanged with PhC=CPh to give the phenylene(zirconacyclopentadiene) Cp(2)Zr[2,3-Ph(2)-4-(C(6)F(5))C(4)]-1,4-C(6)H(4)-Cp(2)Zr[2,3-Ph(2)-4-(C(6)F(5))C(4)].
- 出版日期2009-2-23
