摘要/Abstract

通过原位形成的胺基取代苯基锂与PhAsCl₂反应合成二胺基-胂配体，并进一步由二胺基-胂配体与[Fe（N（TMS）₂）₂]₂反应合成了（二胺基-胂）亚铁配合物[（κ-N，N，As-^dfpN₂As） Fe（THF）₂]（3）.通过配合物3与有机叠氮化物DippN₃反应实现了首例砷亚胺金属配合物[（κ-N，N，N-^dfpN₂AsN^Dipp） Fe（THF）]（4）的合成.配合物4可与2，6-二甲基苯基异腈以及三苯基膦发生乃春转移反应，生成配合物[（κ-N，N，As-^dfpN₂As） Fe（CNC₆H₃Me₂-2，6）₃]（5）和[（κ-N，N，As-^dfpN₂As） Fe（PPh₃）]（6）以及相应的有机物产物DippNCNC₆H₃Me₂-2，6和Ph₃PCNC₆H₃Me₂-2，6.这些配合物通过了各种谱学手段表征，其中配合物3～5的结构还通过单晶X射线衍射得到确认.
关键词: 胂, 砷亚胺, 铁, 乃春, 基团转移
Treatment of (2,6-F₂C₆H₃)(2-BrC₆H₄)NH with 2 equiv. of ⁿBuLi, followed by the interaction with 0.5 equiv. of PhAsCl₂ and quenching with aqueous solution, afforded the new bis(amido)-arsorane ligand ((o-(N-(2,6-₂C₆H₃)NH)C₆H₄)₂AsPh (denoted as H₂(^dfpN₂As)). The interaction of H₂(^dfpN₂As)) with 0.5 equiv. of[Fe(N(TMS)₂)₂]₂ resulted in amine elimination and gave the bis(amido)-arsorene-iron(Ⅱ) complex[(κ-N,N,P-dfpN₂As)Fe(THF)₂] (3). Further treatment of 3 with the organic azide DippN₃ rendered the formation of the first iminoarsorane-transition-metal complex[(κ-N,N,N-^dfpN₂AsN^Dipp)Fe(THF)] (4) as an air- and moisture-sensitive green solid. Reactivity study indicated that 4 can undergo nitrene-transfer reactions with excess amounts of 2,6-dimethylphenylisocyanide and PPh₃ to produce the nitrene-transfer products DippNCNC₆H₃Me₂-2,6 and Ph₃PCNC₆H₃Me₂-2,6, respectively and the corresponding bis(amido)-arsorane-iron(Ⅱ) complexes[(κ-N,N,As-^dfpN₂As)Fe(CNC₆H₃Me₂-2,6)₃] (5) and[(κ-N,N,As-^dfpN₂As)Fe(PPh₃)] (6). These complexes were fully characterized by various spectroscopic methods. Solution magnetic susceptibility measurements and ⁵⁷Fe Mössbauer spectroscopy (δ=0.88 mm/s,|ΔE_Q|=1.50 mm/s; δ=0.90 mm/s,|ΔE_Q|=2.53 mm/s; and δ=0.65 mm/s,|ΔE_Q|=2.23 mm/s for 3, 4, and 6, respectively) indicated that 3, 4 and 6 are high-spin iron(Ⅱ) complexes, whereas the well-resolved diamagnetic NMR spectra of 5 in combination with its ⁵⁷Fe Mössbauer spectrum data (δ=0.05 mm/s,|ΔE_Q|=0.40 mm/s) revealed its low-spin iron(Ⅱ) nature. The molecular structures of 3~5 have been characterized by single-crystal X-ray diffraction studies. The dianionic bis(amido)-arsorane ligands in 3 and 5 chelate to the metal centers in a fac-fashion with the Fe-As distances being 0.2562(3) and 0.2293(1) nm, respectively. The dianionic bis(amido)-iminoarsorane ligand in 4 binds to the iron(Ⅱ) center in a fac-fashion. The Fe-As distance (0.285 nm) observed in 4 is longer than the sum of the covalent radii of Fe and As, indicating the absence of strong Fe-As interaction in the iminoarsorane-iron(Ⅱ) complex. Its As-N distance of 0.1752(3) nm is found comparable to those of the As-N bonds in the reported iminoarsoranes and bis(arsoranylidene) ammonium compounds.




Key words: arsorane, iminoarsorane, iron, nitrene, group-transfer


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