The dehydrogenation of primary and secondary amineâboranes (RNH2·BH3 and R2NH·BH3; R = alkyl groups) was studied using the bulky N-heterocyclic carbene IPr (IPr = [(HCNDipp)C:]; Dipp = 2,6-iPr2C6H3) as a stoichiometric dehydrogenation agent. In the case of primary amineâboranes, carbene-bound adducts IPr·BH2âNH(R)âBH3 were obtained in place of the desired polymers [RNHâBH2]n. The secondary amineâborane iPr2NH·BH3 participated in dehydrogenation chemistry with IPr to afford the aminoborane [iPr2NBH2] and the dihydroaminal IPrH2 as products. Attempts to induce H2 elimination from the arylamineâborane DippNH2·BH3 yielded a reaction mixture containing the known species IPr·BH2NHDipp, IPr·BH2NH(Dipp)âBH3, free DippNH2 and IPrH2. The new hindered aryl-amine borane adduct Ar*NH2·BH3 [Ar* = 2,6-(Ph2CH)2-4-MeC6H2] underwent a reaction with IPr to give IPr·BH3 and free Ar*NH2, consistent with the presence of a weaker NâB dative bond in Ar*NH2·BH3 relative to its less hindered amineâborane analogues.
使用大体积 N-杂环卡宾 IPr (IPr = [(HCNDipp)C:]; Dipp = 2,6 研究了
伯胺和仲胺
硼烷(RNH2·
BH3 和 R2NH· ;R = 烷基)的脱氢-iPr2C6H3) 作为
化学计量脱氢剂。在
伯胺-
硼烷的情况下,得到卡宾结合的加合物IPr·
BH2-NH(R)- 来代替所需的聚合物[RNH- ]n。仲胺
硼烷 iPr2NH· 参与与 IPr 的脱氢
化学反应,得到
氨基
硼烷 [iPr2N ] 和二
氢胺醛 IPrH2 作为产物。尝试诱导从芳基胺
硼烷 DippNH2· 中消除 H2,得到了含有已知物质 IPr· NHDipp、IPr· NH(Dipp)· 、游离 DippNH2 和 IPrH2 的反应混合物。新的受阻芳基胺
硼烷加合物 Ar*NH2· [Ar* = 2,6-(Ph2CH)2-4-MeC6H2] 与 IPr 发生反应,得到 IPr· 和游离 Ar*NH2,这与存在一致相对于其受阻较少的胺
硼烷类似物,Ar*NH2· 中的 N–B 配位键较弱。