Synthetic Control of Heteroatonvcontaining Dynamic Complexes by Taking Advantage of Kinetic Stabilization

本课题的主要目的是开发具有空间保护基团的新型配体，并将其应用于杂原子间具有独特化学键的新型动态配合物的合成和分离。我们成功地合成了体积极大的双齿配体{Bbt(Me)PCH_2}_2(1)及其铂配合物[PtCl_2(1)](2)。今年，我们尝试合成了相应的零价铂配合物[Pt(1)](3)，这应该是一个很好的前体，为前所未有的铂配合物携带一个Pt=S双键[PtS(1)]。虽然尝试用钠或萘化锂还原2，但没有观察到生成3的证据。另一方面，我们成功合成了含有Tbt和mesityl （Mes）基团的新型β-二氯基亚酸锂[Li{TbtNC(Me)CHC(Me)NMes}](4)，这是第一个不含杂原子供体的单体β-二氯基亚酸锂。β-二亚胺酸锂4与MCl_4(thf)_2 （M = Ti, Zr, Hf）反应生成相应的4族金属配合物[M{TbtNC(Me)CHC(Me)NMes}(thf)n] （5a: M = Ti, n = 0,5b: M = Zr, n = 1,5c: M = Hf, n = 1）。在tmeda和LiCl存在下，用KC_8还原5a-c得到意想不到的亚胺配合物[M(NTbt)-{MesNC(Me)CHC(Me)}(μ-Cl)_2Li(tmeda)] (6a: M = Ti, 6b: M = Zr, 6c: M = Hf)，产率高。用KC_8处理苯中的铪络合物6c，在无添加剂的情况下，得到了产率82%的亚胺络合物[HfCl(NTbt)- {MesNC(Me)CHC(Me)}(thf] （7c）。这些亚胺配合物6a-c和7c很可能是通过相应的二价4族金属配合物形成的。

The main purposes of this project are the development of novel ligands bearing steric protection group and their application toward the synthesis and isolation of novel dynamic complexes bearing unique chemical bonds between heteroatoms. We have succeeded in the synthesis of the extremely bulky bidentate ligand, {Bbt(Me)PCH_2}_2 (1), and its platinum complex, [PtCl_2(1)](2). In this year, we attempted to synthesize the corresponding zero valent platinum complex, [Pt(1)](3), which should be a good precursor for the unprecedented platinum complex bearing a Pt=S double bond, [PtS(1)]. Although reduction of 2 using sodium shot or lithium naphthalenide was attempted, no evidence for the generation of 3 was observed. On the other hand, we succeeded in the synthesis of a new lithium β-diketiminate bearing Tbt and mesityl (Mes) groups, [Li{TbtNC(Me)CHC(Me)NMes}] (4), which is the first heteroatomrdonor-free monomeric lithium β-diketiminate. Lithium β-diket-iminate 4 reacted with MCl_4(thf)_2 (M = Ti, Zr, Hf) to give the corresponding group 4 metal complexes [M{TbtNC(Me)CHC(Me)NMes}(thf)n] (5a : M = Ti, n = 0, 5b : M = Zr, n = 1, 5c : M = Hf, n = 1), respectively. The reduction of 5a-c with KC_8 in the presence of tmeda and LiCl was found to afford unexpected imido complexes [M(NTbt)-{MesNC(Me)CHC(Me)}(μ-Cl)_2Li(tmeda)] (6a : M = Ti, 6b : M = Zr, 6c : M = Hf) in good yields. The treatment of hafnium complex 6c in benzene with KC_8 gave imido complex [HfCl(NTbt)- {MesNC(Me)CHC(Me)}(thf] (7c) in 82% yield in the absence of additives. These imido complexes 6a-c and 7c are most likely formed via the corresponding divalent group 4 metal complexes.