A series of chiral dizinc complexes of the type [(2,6-ArNC(Me)C5H3N}2C6H3O)Zn2(µ-Cl)Cl2] [Ar = 2,6-i-Pr2C6H3 (1a), 2,6-Me2C6H3 (1b), 2,4,6-Me3-C6H2 (1c), 2,4-Me2C6H3 (1d)] can be conveniently prepared in good yield by the template reaction of 2,6-OC(Me)C5H3N}2C6H3OH with an excess of the corresponding aniline and two equivalents of zinc dichloride in n-BuOH at elevated temperature. Alternatively, the pro-ligands, 2,6-(ArNC(Me)C5H3N}2C6H3OH [Ar = 2,6-i-Pr2C6H3 (L1-H), 2,6-Me2C6H3 (L2-H), 2,4,6-Me3C6H2 (L3-H), 2,4-Me2C6H3 (L4-H)], can be isolated and then treated with two equivalents of zinc dichloride to afford 1a–1d. Interaction of 1a with two equivalents of NaOAc in the presence of TlBF4 gives the diacetate-bridged salt [(L1)Zn2(µ-OAc)2](BF4) (2) while with Nadbm (dbm = dibenzoylmethanato) the bis(dbm)-chelated salt [(L1)Zn2(dbm)2](BF4) (3) is obtained. Hydrolysis occurs on reaction of 1a with TlOEt to furnish [(L1)Zn2(µ-OH)Cl2] (4) as the only isolable product. Conversely, reaction of 1a with Tlhp (hp = 2-pyridonate) affords the neutral bis(pyridonate)-bridged trimetallic complex [(L1)Zn3(µ-hp)2Cl3] (5) as the major product along with 4 as the minor one. Complex 4 and mixtures of 4/5 act as modest activators for the ring-opening polymerisation of ε-caprolactone. Single crystal X-ray diffraction studies have been performed on 1b, 1c, 2, 3, 4 and 5 reveal Zn⋯Zn separations in the range: 3.069(4)–4.649(6) Å.
一系列手性双
锌配合物[(2,6-ArNC(Me)
C5H3N}2C6H3O)Zn2(µ-Cl)C
L2] [Ar = 2,6-i-Pr2C6H3 (1a), 2,6-Me2C6H3 (1b), 2,4,6-Me3-
C6H2 (1c), 2,4-Me2C6H3 (1d)]可以通过模板反应在高温下用
正丁醇中的过量的相应
苯胺和两当量的二
氯化锌与2,6-OC(Me) }2C6H3OH反应制备,产率良好。或者,前
配体2,6-(ArNC(Me) }2C6H3OH [Ar = 2,6-i-Pr2C6H3 (L1-H), 2,6-Me2C6H3 (
L2-H), 2,4,6-Me3 (L3-H), 2,4-Me2C6H3 (L4-H)]可以分离出来,然后与两当量的二
氯化锌反应得到1a–1d。1a与两当量的NaOAc在Tl 存在下反应得到
双乙酸酯桥联盐[(L1)Zn2(µ-OAc)2](
BF4) (2),而与Nadbm (dbm = dibenzoylmethanato)反应得到双(二苯甲酰
甲烷)配位盐[(L1)Zn2(dbm)2]( ) (3)。1a与TlOEt反应发生
水解,得到唯一可分离的产品[(L1)Zn2(µ-OH)C
L2] (4)。相反,1a与Tlhp (hp = 2-
吡啶酮)反应得到中性双(
吡啶酮)桥联三
金属配合物[(L1)Zn3(µ-hp)2Cl3] (5)为主要产物,而4为次要产物。配合物4和4/5混合物是
ε-己内酯开环聚合的适度活化剂。对1b, 1c, 2, 3, 4和5进行了单晶X射线衍射研究,揭示了Zn⋯Zn分离范围为3.069(4)–4.649(6) Å。