Goswami Bhupendra, Feuerstein Thomas J, Yadav Ravi, Köppe Ralf, Lebedkin Sergei, Kappes Manfred M, Roesky Peter W
Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstrasse 15, 76131, Karlsruhe, Germany.
Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
Chemistry. 2021 Mar 1;27(13):4401-4411. doi: 10.1002/chem.202004833. Epub 2021 Feb 2.
The synthesis of calcium complexes ligated by three different chiral iminophosphonamide ligands, L-H (L=[Ph P{N(R)CH(CH )Ph} ]), L'-H (L'=[Ph P{NDipp}{N(R)CH(CH )Ph}]), (Dipp=2,6- Pr C H ), and L''-H (L''=[Ph P{N(R)CH(CH )naph} ]), (naph=naphthyl) is presented. The resulting structures [L Ca], [L' Ca], and [L'' Ca] represent the first examples of enantiopure homoleptic calcium complexes based on this type of ligands. The calcium complexes show blue-green photoluminescence (PL) in the solid state, which is especially bright at low temperatures. Whereas the emission of [L'' Ca] is assigned to the fluorescence of naphthyl groups, the PL of [L Ca] and [L' Ca] is contributed by long-lived phosphorescence and thermally activated delayed fluorescence (TADF), with a strong variation of the PL lifetimes over the temperature range of 5-295 K. Furthermore, an excellent catalytic activity was found for these complexes in hydroboration of ketones at room temperature, although no enantioselectivity was achieved.
本文介绍了由三种不同的手性亚氨基膦酰胺配体L-H（L = [Ph₂P{N(R)CH(CH₃)Ph}]）、L'-H（L' = [Ph₂P{NDipp}{N(R)CH(CH₃)Ph}]，Dipp = 2,6 - Pr₂C₆H₃）和L''-H（L'' = [Ph₂P{N(R)CH(CH₃)naph}]，naph = 萘基）连接的钙配合物的合成。所得结构[L₂Ca]、[L'₂Ca]和[L''₂Ca]代表了基于此类配体的对映纯均配钙配合物的首个实例。这些钙配合物在固态下呈现蓝绿色光致发光（PL），在低温下尤为明亮。虽然[L''₂Ca]的发射归因于萘基的荧光，但[L₂Ca]和[L'₂Ca]的PL由长寿命磷光和热激活延迟荧光（TADF）贡献，在5 - 295 K的温度范围内PL寿命有很大变化。此外，尽管未实现对映选择性，但发现这些配合物在室温下对酮的硼氢化反应中具有出色的催化活性。
