Construction of a monoanionic S,N,S-pincer ligand with a pyrrole core by sequential [1,2] phospho-Fries rearrangement. Characterization of palladium and silver coordination complexes
作者:Aurore Fraix、Martin Lutz、Anthony L. Spek、Robertus J. M. Klein Gebbink、Gerard van Koten、Jean-Yves Salaün、Paul-Alain Jaffrès
DOI:10.1039/b923351b
日期:——
The synthesis of an S,NH,S-pincer ligand possessing a pyrrole core and two O,O-diethylthiophosphonyl groups to design PS lateral coordination sites is reported. The synthetic procedure to produce this ligand makes use of the nitrogen atom of the pyrrole heterocycle to successively functionalize the ortho-positions with the two O,O-diethylthiophosphonyl moieties. The ortho-functionalization arises from a repetition of a [1,2] base-induced rearrangement allowing the transformation of O,O-diethyl-N-pyrollylthiophosphoramidate to ortho-thiophosphonate. The coordination properties of this tridentate S,NH,S-ligand have been investigated with silver and palladium metals. Reaction of the monoanionic S,N,S-pincer ligand 4 (O,O,O,O-tetraethylpyrrol-2,5-yl-dithiophosphonate) with PdCl2(MeCN)2 at room temperature in the presence of triethylamine gives rise to the formation of the η3-complex [Pd(η3-4′)Cl] 5. Ligand 4 also reacts with silver oxide in dichloromethane to produce complex 6 which, in the solid state, exists as a tetramer involving an almost linear arrangement of four silver atoms.
本文报道了具有吡咯核和两个O,O-二乙基硫代膦酰基的S,NH,S-钳形配体的合成,以设计PS侧向配位点。该配体的合成过程利用吡咯杂环的氮原子,依次将两个O,O-二乙基硫代膦酰基官能团与邻位相连。邻位官能化的过程是重复进行[1,2]碱诱导的重排,使O,O-二乙基-N-吡咯基硫代膦酰胺转化为邻位硫代膦酸盐。本文研究了这种三齿S,NH,S-配体与银和钯金属的配位性质。在室温下,在存在三乙胺的情况下,单阴离子S,N,S-钳形配体4(O,O,O,O-四乙基吡咯-2,5-基二硫代膦酸)与PdCl2(MeCN)2反应,生成η3-络合物[Pd(η3-4′)Cl] 5。配体4还在二氯甲烷中与氧化银反应,生成络合物6,在固态下,络合物6以四聚体的形式存在,其中四个银原子几乎呈线性排列。