C-H Bond Activation Reactions in π-Allene-Osmium-Triisopropylphosphine Complexes with Cyclopentadienyl or Hydridotris(pyrazolyl)borate Ligands: Formation of Isopropenyldiisopropylphosphine versus Hydride-Alkenylcarbyne Derivatives
C-H Bond Activation Reactions in π-Allene-Osmium-Triisopropylphosphine Complexes with Cyclopentadienyl or Hydridotris(pyrazolyl)borate Ligands: Formation of Isopropenyldiisopropylphosphine versus Hydride-Alkenylcarbyne Derivatives
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DOI：
10.1021/om100568r
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发表时间：
2010-09-27
期刊：
影响因子：
2.8
通讯作者：
Onate, Enrique
中科院分区：
文献类型：
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作者：
Castro-Rodrigo, Ruth;Esteruelas, Miguel A.;Onate, Enrique
研究了双溶剂型配合物[OsCp（MeCN）（2）（（PPr 3）-Pr-i）] PF_6（1; Cp = α）和[OsTp（kappa（1）-OCMe_2）（2）（（PPr 3）-Pr-i）] BF_4（1a; Tp = β-三（吡唑基）硼酸酯）与联二烯的反应。配合物1与1-甲基-1-（三甲基硅基）丙二烯和1，1-二甲基丙二烯反应，得到π-丙二烯衍生物[OsCp（eta（2）-CH 2 =C=CRMe）（MeCN）（（PPr 3）-Pr 1）] PF 6（R = SiMe 3（2），Me（3））。在80 ° C的氟苯中，配合物2和3是中等稳定的，并且通过从膦的异丙基取代基到丙二烯的配位双键的氢转移而演变成异丙烯基二异丙基膦衍生物[OsCp{kappa P-3，C，C-（PPr 2）-Pr-i[C（Me）= CH 2]}（MeCN）] PF 6（4）。在乙烯气氛下，乙腈配体。4被烯烃取代。所得的π-亚乙基衍生物[OsCp（eta（2）-CH 2 = CH 2）{κ P-3，C，C-（PPr 2）-Pr-1 [C（Me）= CH 2]}] PF 6（5）通过在80 ℃下在2atm乙烯下搅拌3在氟苯中的一锅合成程序获得。用乙炔二羧酸二甲酯处理2和3得到[OsCp{eta（2）-CH（CO2 Me）=CH（CO2 Me）}{（KP）-P-3，C，C-（PPr 2）-Pr-1 [C（Me）= CH 2] PF 6（6）。Ia与1，1-二甲基丙二烯反应产生[OsTp（eta（2）-CH 2 =C= CMe 2）（kappa（1）-OCMe 2）（（PPr 3）-Pr 1）] BF 4（7）。与Cp对应物相比，配合物7通过丙二烯末端CH 1基团的氢原子的双迁移而演变为双烯基碳炔衍生物[OsHTp（等价于CCH= CMe 2）（（PPr 3）-Pr 1）BF 4（8）。其中一个迁移到丙二烯的中心碳原子，另一个迁移到金属中心。8的烯基碳炔基团在氢化物配体的存在下选择性地去质子化，以提供去质子化-烯基亚乙烯基OsHTp{=C=CHC（Me）= CH 2}（（PPr 3）-Pr 1）（9）。还报道了2，5，8和9的X射线结构。
The reactions of the bis(solvento) complexes [OsCp(MeCN)(2)((PPr3)-Pr-i)]PF6 (1; Cp = cyclopentadienyl) and [OsTp(kappa(1)-OCMe2)(2)((PPr3)-Pr-i)]BF4 (1a; Tp = hydridotris(pyrazolyl)borate) with allenes have been investigated. Complex 1 reacts with 1-methyl-1-(trimethylsilyl)allene and 1,1-dimethylallene to give the pi-allene derivatives [OsCp(eta(2)-CH2=C=CRMe)(MeCN)((PPr3)-Pr-i)]PF6 (R = SiMe3 (2), Me (3)). In fluorobenzene at 80 degrees C, complexes 2 and 3 are moderately stable and evolve into the isopropenyldiisopropylphosphine derivative[OsCp{kappa P-3,C,C-(PPr2)-Pr-i[C(Me)=CH2]}(MeCN)]PF6(4)by hydrogen transfer from an isopropyl substituent of the phosphine to the coordinated double bond of the allene. Under an ethylene atmosphere the acetonitrile ligand. of 4 is displaced by the olefin. The resulting pi-ethylene derivative [OsCp(eta(2)-CH2=CH2){kappa P-3,C,C-(PPr2)-Pr-i[C(Me)=CH2]}]PF6 (5) is obtained through a one-pot synthesis procedure by the stirring of 3 in fluorobenzene at 80 degrees C under 2 atm of ethylene. Treatment of 2 and 3 with dimethyl acetylenedicarboxylate gives [OsCp{eta(2)-CH(CO2Me)=CH(CO2Me)}{(KP)-P-3,C,C-(PPr2)-Pr-i[C(Me)=CH2]PF6 (6). The reaction of la with 1,1-dimethylallene leads to [OsTp(eta(2)-CH2=C=CMe2)(kappa(1)-OCMe2)((PPr3)-Pr-i)]BF4 (7). In contrast to its Cp counterpart, complex 7 evolves into the hydride-alkenylcarbyne derivative [OsHTp(equivalent to CCH=CMe2)((PPr3)-Pr-i)BF4 (8), by means of a double migration of the hydrogen atoms of the terminal CH, group of the allene. One of them migrates to the central carbon atom of the allene, and the other one goes to the metal center. The alkenylcarbyne group of 8 is selectively deprotonated in the presence of the hydride ligand to afford the hydride-alkenylvinylidene OsHTp{=C=CHC(Me)=CH2}((PPr3)-Pr-i) (9). The X-ray structures of 2, 5, 8, and 9 are also reported.