Synthesis of two covalently linked bis(2,2′:6′,2″-terpyridine) (terpy) chelating ligands with different length spacers, comparison of the crystal structures of their mononuclear nickel(II) complexes, and kinetic and mechanistic studies of the reaction of one ligand with [Fe(terpy)2]2+
作者:Gleb U. Priimov、Peter Moore、Philip K. Maritim、Pamela K. Butalanyi、Nathaniel W. Alcock
DOI:10.1039/a907543g
日期:——
Two new covalently linked bis(2,2â²â¶6â²,2â²â²-terpyridine)-chelating hexadentate ligands, 1,3-bis(2,2â²â¶6â²,2â²â²-terpyridyl-5-ylmethylsulfanyl)propane (L1), and 1,4-bis(2,2â²â¶6â²,2â²â²-terpyridyl-5-ylmethylsulfanyl)butane (L2), and their six-coordinate mononuclear metal complexes [ML][PF6]2 (M = Fe and Ni; L = L1 and L2) have been prepared and characterised. The X-ray structures of [NiL](PF6)2 (L = L1 and L2) have been compared to establish that L2 has the optimum length of linker to give the least strained mononuclear complex. The marked stability of [ML]2+ is demonstrated by kinetic studies that show that one equivalent of L1 is capable of substituting both 2,2â²â¶6â²,2â²â²-terpyridine (terpy) ligands of [Fe(terpy)2]2+ to give [FeL1]2+ in a two stage kinetic process.
两种新型共价连接的双(2,2′-¶6′,2′′-吡啶)-螯合六齿配体,1,3-二(2,2′-¶6′,2′′-吡啶-5-基甲基硫醇)丙烷(L1)和1,4-二(2,2′-¶6′,2′′-吡啶-5-基甲基硫醇)丁烷(L2),以及它们的六配位单核金属复合物[ML][PF6]2(M = Fe 和 Ni; L = L1 和 L2)已被合成和表征。通过比较[NiL](PF6)2(L = L1 和 L2)的X射线结构,确认L2具有最佳的连接长度,从而形成应变最小的单核复合物。通过动力学研究证明了[ML]2+的显著稳定性,结果显示一当量的L1能够在一个两阶段的动力学过程中替代[Fe(terpy)2]2+中的两个2,2′-¶6′,2′′-吡啶(terpy)配体,生成[FeL1]2+。