bimolecular rate-determining step. Controlled methanolysis of both 3a and 3′a release the metal-free dimeric bases, (4-Bn-iPrHBIPH)2 and (4-allyl-iPrHBIPH)2, providing a convenient route to these potentially useful ditopic ligands. When the R′ groups are bulkier than Me (2b, 2′b and 2′c), the dimerization is hindered or fully disabled, favoring the formation of paramagnetic NMR-silent species, which have been
稳定的和以其他方式选择性地不能实现2,6- bisimino -4-甲家族ř -1,4- dihydropyridinate铝(III)二烷基配合物[为AlR” 2(4-R-我PrBIPH)](R = BN,烯丙基; R ′= Me,Et,i Bu)已被合成,利用了在我们小组中开发的相应的4- R -1,4-
二氢吡啶吡啶前体的制备方法。所有的
二氢吡啶鎓(-1)二烷基铝配合物已经通过1 H - 13 C-NMR,元素分析和在2'a的情况下,也通过X射线衍射研究得到了充分表征。在110°C的
甲苯溶液中加热后,二甲基衍
生物2a和2'a通过双环加成选择性地二聚。该反应导致形成两个新的CC键,涉及两个4 - R -1,4-
二氢吡啶酸片段的两个间位,从而形成双核铝物种[Me 2 Al(4-R- i PrHBIP) ] 2(R = Bn(3a);烯丙基(3′a))。实验动力学表明,2'a的二聚化遵循第二