四價錳錯合物之逐步還原與反應性之探討

Abstract

本研究延續先前本實驗室任少緯學長之論文，以兩分子含磷硫 之三牙配位基H2PS2與製備出錳錯合物MnIV(PS2)2，於室溫及空氣下穩定之四價錳錯合物，以CV電化學確定其可能存三價、二價之氧化態，並藉由還原劑CoCp2、KC8等，分別獲得二價三價之錳錯合物[MnIII(PS2)2]─ 、[MnII(PS2)2]2─ 晶體，以X-ray單晶繞射獲得其結構，並針對其不同的電子組態進行EPR、SQUID、NMR-Evans Methods鑑定。並且發現了錳三價錯合物中之硫醇基(Thiolate)配位基具有顯著的親核性質，因此以親電試劑(CH3)3OBF4作為甲基提供試劑，實現了硫醇基烷化的反應並獲得其結構[MnIII(PS2)(PSS-CH3)]，此反應於前週期過渡金屬是並不常見的，此結構也證實了[MnIII(PS2)2]錯合物所具有的反應潛力，未來希望能透過不同的烷基加成修飾，來達到活化此系列錯合物的效果。This study was continued from the previous works in our groups. The manganese (IV) complex MnIV(PS2)2 which is stable under air and room temperature was synthesized by the dithiolate-phousphine tridentate ligands H2PS2. Cyclic voltammetry revealed the probability oxidation state of Mn(III) / Mn(II) are existing. The [MnIII(PS2)2] / [MnII(PS2)2] complex was reduced by CoCp2 / KC8. The molecular structure CoCp2[MnIII(PS2)2] and Na2[MnII(PS2)2] was acquired from the X-ray diffraction. The EPR, SQUID, NMR-Evans methods were used for the identification of their electron configuration. Furthermore, The significant nucleophilicity was found with the thiolate ligand of the [MnIII(PS2)2]. Therefore the electrophilic reagent (CH3)3OBF4 was used as a reagent for providing the methyl cation (Me+). The thiolate-alkylation was successful and the single crystal [MnIII(PS2)(PSS-CH3)] was obtained and the thiolate-alkylation with complex is not common early-transition metals. The result shows the potential for activating these series of complex through different alkyl addition.