π-back-bonding between the metal and the chelated olefin fragment. The metallacyclopropane ring in 1 will undergo ring expansion (coupling of the olefin) with a variety of unsaturated substrates. The addition of Ph2CO leads to a 2-oxaniobacyclopentane ring in 4 while PhC⋮CPh produces a niobacyclopent-3-ene derivative, [Nb(OC6H3Pri-CMeCH2CPhCPh)(OC6H3Pri2-2,6)2] (5), which was structurally characterized
二
氯化
铌[Nb(OC 6 H 3 Pr i 2 -2,6)3 Cl 2 ](OC 6 H 3 Pr i 2 -2,6 = 2,6-二异丙基苯氧化物)还原(每Nb 2 Na)在
四氢呋喃(THF)溶剂以产生暗绿色配合物[
铌(OC 6 H ^ 3
镨我-η 2 -CMe CH 2)(OC 6 H ^ 3
镨我2 -2,6)2(THF)](1) 。的固态结构1示出了α-甲基
乙烯基是强η 2结合的所述
铌金属中心。据称,通过在ad 2 -Nb(III)芳氧基中的CH键活化,然后通过β氢提取/消除H 2来进行芳氧基的邻异丙基的脱氢反应以生成1。在THF
配体1可以通过
吡啶(PY)和BU被取代吨NC,得到加合物[
铌(OC 6 H ^ 3
镨我-η 2 -CMe CH 2)(OC 6 H ^ 3
镨我2 -2,6 )2(L)2 ](L = PY,2 ; L =卜吨NC,3)。的固态结构3只示出了两个
配体异与与η没有相