作者:Christian Meermann、Peter Sirsch、Karl W. Törnroos、Reiner Anwander
DOI:10.1039/b513370j
日期:——
A series of heteroleptic scandium SALEN complexes, [(SALEN)Sc(µ-Cl)]2 and (SALEN)Sc[N(SiHMe2)2] is obtained via amine elimination reactions using [Sc(NiPr2)2(µ-Cl)(THF)]2 and Sc[N(SiHMe2)2]3(THF) as metal precursors, respectively. H2SALEN ligand precursors comprising H2Salen [(1,2-ethandiyl)bis(nitrilomethylidyne)bis(2,4-di-tert-butyl)phenol], H2Salpren [(2,2-dimethylpropanediyl)bis(nitrilomethylidyne)bis(2,4-di-tert-butyl)phenol], H2Salcyc [(1R,2R)-(−)-1,2-cyclohexanediyl)bis(nitrilomethylidyne)bis(2,4-di-tert-butyl)phenol] and H2Salphen [((1S,2S)-(−)-1,2-diphenylethandiyl)bis(nitrilomethylidyne)bis(2,4-di-tert-butyl)phenol] are selected according to solubility and ligand backbone variation (“N–(R)–N” bite angle) criteria. Consideration is given to the feasibility of [Cl → NR2] and [N(SiHMe2)2
→ OSiR3] secondary ligand exchange reactions. X-ray crystal structure analyses of donor-free (Salpren)Sc(NiPr2), (R,R)-(Salcyc)Sc[N(SiHMe2)2], (Salen)Sc(OSitBuPh2) and (Salphen)Sc(OSiHtBu2) reveal (i) a very short Sc–N bond distance of 2.000(3) Å, (ii) weak β(Si–H)amido–Sc agostic interactions and (iii) an exclusive intramolecularly tetradentate and intrinsically bent coordination mode of the SALEN ligands with ∠(Ph,Ph) dihedral angles and Sc–[N2O2] distances in the 124.27(9)–127.7(3)° and 0.638(1)–0.688(1) Å range, respectively.
一系列异配体铝钪SALEN络合物[(SALEN)Sc(µ-Cl)]₂和(SALEN)Sc[N(SiHMe₂)₂]是通过利用[Sc(NiPr₂)₂(µ-Cl)]₂和Sc[N(SiHMe₂)₂]₃(THF)作为金属前驱体,经过胺消除反应获得的。H₂SALEN配体前驱体包括H₂Salen [(1,2-乙烷二基)双(氰基甲烯)双(2,4-二叔丁基)酚]、H₂Salpren [(2,2-二甲基丙烷二基)双(氰基甲烯)双(2,4-二叔丁基)酚]、H₂Salcyc [(1R,2R)-(−)-1,2-环己烷二基)双(氰基甲烯)双(2,4-二叔丁基)酚]和H₂Salphen [((1S,2S)-(−)-1,2-双苯乙烯二基)双(氰基甲烯)双(2,4-二叔丁基)酚]是根据溶解度和配体骨架变化(“N–(R)–N”咬合角)标准选择的。考虑了[Cl → NR₂]和[N(SiHMe₂)₂ → OSiR₃]的二级配体交换反应的可行性。对无供体(Salpren)Sc(NiPr₂)、(R,R)-(Salcyc)Sc[N(SiHMe₂)₂]、(Salen)Sc(OSitBuPh₂)和(Salphen)Sc(OSiHtBu₂)的X射线晶体结构分析揭示了(i) Sc–N键距离非常短,为2.000(3) Å,(ii) 弱的β(Si–H)氨基–Sc相互作用,以及(iii) SALEN配体具有独特的分子内四齿和内在弯曲的配位模式,其(Ph, Ph)二面角及Sc–[N₂O₂]距离分别在124.27(9)°至127.7(3)°和0.638(1) Å至0.688(1) Å范围内。