Four complexes were prepared by the reaction of Ni(II) with three pyrrolidine based diamideâdiamine ligands. The two amine groups in the ligand N,Nâ²-bis(S-prolyl)-1,2-ethanediamine (S,S-bprolenH2) were oxidatively dehydrogenated during the preparation of the Ni(II) complex in air. The reaction involved O2 to yield a complex of a tetradentate ligand with 1-pyrroline terminal groups. The Ni(II) complex with S,S-bprolenH2 was synthesised under oxygen-free conditions, and the Ni(II) complexes with the analogous ligands N,Nâ²-bis(S-prolyl)-R,R-1,2-cyclohexanediamine (R,R-(S,S)-bprolchxnH2) and N,Nâ²-bis(S-prolyl)-1,2-benzenediamine (S,S-bprolbenH2) were prepared in air. The complexes
were characterised by X-ray crystallography, 1H and 13C NMR spectroscopy and IR spectroscopy. The Ni(III/II) reduction potentials of complexes with pyridyl and pyrrolidine based tetradentate diamide ligands were measured by cyclic voltammetry to assess the stability of the Ni(III) oxidation state, but did not show any correlation with the ease of ligand oxidation.
通过Ni(II)与三种以
吡咯烷为
基础的二胺–二
酰胺配体的反应,制备了四个配合物。在
配体N,N'-双(S-丙
氨基)-1,2-
乙二胺(S,S-bprolenH2)的制备过程中,两个胺基在空气中被
氧化
脱氢。该反应涉及O2,生成一种具有1-
吡咯啉末端基团的四齿
配体的配合物。在无
氧条件下合成了与S,S-bprolenH2的Ni(II)配合物,而与类似
配体N,N'-双(S-丙
氨基)-R,R-1,2-
环己烷二胺(R,R-(S,S)-bprolchxnH2)及N,N'-双(S-丙
氨基)-1,2-
苯二胺(S,S-bprolbenH2)的Ni(II)配合物则是在空气中制备的。这些配合物通过X射线晶体学、1H和13C NMR光谱以及红外光谱进行表征。采用循环伏安法测定了与以
吡啶和
吡咯烷为
基础的四齿二
酰胺配体的配合物的Ni(III/II)还原电位,以评估Ni(III)
氧化态的稳定性,但未表现出与
配体氧化难易程度的相关性。