【作者】 陈敏；

【导师】 徐信；

【作者基本信息】 苏州大学 ， 化学， 2019， 硕士

【摘要】 本论文主要研究了基于含膦三齿β-二亚胺配体锌末端氢化物的合成及其反应性能。主要包括以下几个方面:1.基于含膦三齿β-二亚胺配体锌末端氢化物的合成。我们课题组开发了两种含膦三齿β-二亚胺配体前体HL(L=CH3C(2,6-Pr2C6H3N)CHC(CH3)(NCH2(CH2)nPPh2;n=1 或 2)。利用此配体前体与二乙基锌反应得到锌的乙基配合物,乙基配合物与2,6-二异丙基苯酚反应得到锌的芳氧基配合物,该配合物与苯基硅烷反应最终得到锌末端氢化物。2.锌末端氢化物反应性能研究。(1)锌氢化物可以与含羰基类不饱和底物发生插入反应。例如与查尔酮反应时,得到1,4-加成产物;而CO2能够插入到锌氢键之间,得到锌的甲酸盐配合物。(2)首次实现过渡金属诱导锌的氢化物发生脱氢偶联反应得到含低价Zn-Zn键的三金属配合物。两当量的锌末端氢化物与零价过渡金属配合物Pd(PPh3)4或Pt(PPh3)4反应,还原消除氢气,得到[Zn2TM](TM=Pd或Pt)三金属配合物。而锌末端氢化物与Ni(COD)2在相同条件下反应,得到σ-Zn-H型配合物,并没有发生氢气消除反应。DFT计算表明,钯金属中心的氧化加成和还原消除是形成Zn-Zn键的重要原因,而镍金属中心则不易发生还原消除,因此无法生成Zn-Zn键。但当α-Zn-H型配合物与一氧化碳或异腈反应后则可以消除氢气,从而得到新型低价Zn-Zn键配合物。(3)锌的氢化物与铬、钴和锰等3d金属配合物等当量反应,可以得到一系列杂双金属配合物。与[η5-C5H4Me)Mn(CO)3]和Cr(CO)6反应时,得到氢桥联的锌过渡金属配合物,而与Co2(CO)8反应时锌氢发生还原消除,得到含锌钴键配合物。更多还原

【Abstract】 The dissertation focuses on studying the synthesis and reactivity of a new type of phosphine-containing β-diketiminato ligand zinc hydrides.1.Synthesis of zinc hydrides.We designed a new type of β-diketiminato ligand precursor bearing a pendant phosphine group.Metalation of ligand precursors with ZnEt2 gave zinc monoalkyl complexes,which reacted with an equimolar amount of 2,6-diisopropylphenol to give zinc aryloxide complexes with the liberation of ethane.Finally,the target zinc hydrides were obtained through the metathesis reactions of with PhSiH3 under mild conditions.2.Reactivity of zinc hydrides.(1)Addition reaction occurs between unsaturated small molecules and zinc hydrides.Zinc hydrides reacted with chalcone to afford 1,4-addition products.However,they were readily converted into zinc formats upon the addition of CO2(1.0 atm)at room temperature.(2)Transition metal-induced dehydrogenative homocoupling of zinc(Ⅱ)hydrides to Zn(Ⅰ)-Zn(Ⅰ)bonded complexes were developed.When zinc hydrides with the widely used zero-valent Pd(PPh3)4 or Pt(PPh3)4 in a 2:1 reductive elimination of H2 occurred and gave zinc-zinc bonded complexes.The reactions between zinc hydrides with zero-valent nickel reagent Ni(COD)2(COD:1,5-cyclooctadiene)were also performed in a 2:1 molar ratio.The reactions gave heterotrimetallic hydride-bridged[Zn-Ni-Zn]complexes.DFT computation study indicated that an oxidative addition/reductive elimination process at the palladium center might be responsible for the formation of a covalent Zn-Zn bond.Further reactions of hydride-bridged complexes[Zn-Ni-Zn]with CO or isonitrile resulted in the reductive elimination of H2 and the formation of low-valent unsupported Zn(Ⅰ)-Zn(Ⅰ)bonded complexes.(3)The reactions between zinc hydrides and transition metals in a 1:1 ratio gave bimetallic complexes.When zinc hydrides were mixed with[(r)5-C5H4Me)Mn(CO)3]or Cr(CO)6,hetetotrimetallic hydride-bridged complexes were produced.However,the addition of Co2(CO)8 reagent on zinc hydrides resulted in the release of H2 and the formation of complexes by the reductive elimination.更多还原