Phenylalanine – a biogenic ligand with flexible η6- and η6:κ1-coordination at ruthenium(ii) centres
作者:Thomas Reiner、Dominik Jantke、Xiao-He Miao、Alexander N. Marziale、Florian J. Kiefer、Jörg Eppinger
DOI:10.1039/c3dt50589h
日期:——
The reaction of (S)-2,5-dihydrophenylalanine 1 with ruthenium(III) chloride yields the μ-chloro-bridged dimeric η6-phenylalanine ethyl ester complex 3, which can be converted into the monomeric analogue, η6:κ1-phenylalanine ethyl ester complex 12, under basic conditions. Studies were carried out to determine the stability and reactivity of complexes bearing η6- and η6:κ1-chelating phenylalanine ligands under various conditions. Reaction of 3 with ethylenediamine derivatives N-p-tosylethylenediamine or 1,4-di-N-p-tosylethylenediamine results in the formation of monomeric η6:κ1-phenylalanine ethyl ester complexes 14 and 15, which could be saponified yielding complexes 16 and 17 without changing the inner coordination sphere of the metal centre. The structure of η6:κ1-phenylalanine complex 17 and an N-κ1-phenylalanine complex 13 resulting from the reaction of 3 with an excess of pyridine were confirmed by X-ray crystallography.
(S)-2,5-二氢苯丙氨酸1与氯化钌(III)的反应生成γ-氯桥联二聚体Γ6-苯丙氨酸乙酯络合物3,后者在碱性条件下可转化为单体类似物Γ6:Γ1-苯丙氨酸乙酯络合物12。研究人员对Γ6-和Γ6:Γ1-螯合苯丙氨酸配体在各种条件下的稳定性和反应性进行了研究。3与乙二胺衍生物N-对甲苯磺酰乙二胺或1,4-二-N-对甲苯磺酰乙二胺的反应生成单体Γ6:Γ1-苯丙氨酸乙酯络合物14和15,后者可皂化生成络合物16和17,而不会改变金属中心的内配位层。Γ6:Γ1-苯丙氨酸络合物17和N-Γ1-苯丙氨酸络合物13的结构通过X射线晶体学得到了证实,它们是由3与过量吡啶反应生成的。