Structures and redox reactivities of copper complexes of (2-pyridyl)alkylamine ligands. Effects of the alkyl linker chain length.
Structures and redox reactivities of copper complexes of (2-pyridyl)alkylamine ligands. Effects of the alkyl linker chain length.
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DOI：
10.1021/ic034958h
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发表时间：
2003-10
影响因子：
4.6
通讯作者：
T. Osako;Y. Ueno;Y. Tachi;S. Itoh
中科院分区：
文献类型：
--
作者：
T. Osako;Y. Ueno;Y. Tachi;S. Itoh
以2-吡啶基烷基胺衍生物为支撑配体，研究了配体对铜配合物结构和氧化还原反应性的影响，特别关注了连接叔胺氮原子和吡啶核的烷基链长的影响：N[bond]CH（2）[bond]Py（Pym）vs N[bond]CH（2）CH（2）[bond]Py（Pye）.三齿配体（Phe）L（Pym 2）[N，N-二（2-吡啶甲基）-2-苯乙胺]（配合物1）的X-射线晶体学分析表明，它具有三角锥几何构型，其中金属离子与配体侧臂苯环上的一个邻位碳（苯乙基）之间存在具有η（1）-结合模式的d[键]pi相互作用。这与（Phe）L（Pye 2）[N，N-二[2-（2-吡啶基）乙基]-2-苯乙胺]（配合物2）中的d[键]pi相互作用和eta（2）-结合模式形成鲜明对比。这种d-pi相互作用已被证明会影响铜（I）络合物在CH（2）Cl（2）中的稳定性。由（Phe）L（Pym 2）负载的铜（I）络合物1的氧化产生双（μ-氧代）二铜（III）络合物，这也与具有配体（Phe）L（Pye 2）的铜（I）络合物2的情况形成鲜明对比，其在与O（2）的反应中优先提供（微-η（2）：η（2）-过氧）二铜（II）络合物。还发现金属结合位点的烷基连接基链长度的这种效应在RSSR（二硫化物）/2 RS（-）（硫醇盐）氧化还原体系中起作用。即，配体（S2，R）L（Pym 1）（二[2-[（烷基）（2-吡啶基甲基）氨基]乙基]二硫化物）与亚甲基连接基团（Pym）在与铜（I）离子的反应中诱导还原性二硫键断裂，得到双（微硫醇合）二铜（II）络合物，而具有乙烯连接基团（Pye）的配体，（S2，Bn）L（Pye 1）（二[2-[（苄基）（2-（2-吡啶基）乙基）氨基]乙基]二硫化物），得到二硫化物-二铜（I）配合物。通过考虑Pym和Pye配体体系中吡啶核给电子能力的差异，讨论了Cu（2）[bond]O（2）和Cu（2）[bond]S（2）体系中的配体效应.
Ligand effects on the structures and redox reactivities of copper complexes have been examined using (2-pyridyl)alkylamine derivatives as the supporting ligands, where particular attention has been focused on the effects of the alkyl linker chain length connecting the tertiary amine nitrogen atom and the pyridine nucleus: N[bond]CH(2)[bond]Py (Pym) vs N[bond]CH(2)CH(2)[bond]Py (Pye). X-ray crystallographic analysis of the copper(I) complex of tridentate ligand (Phe)L(Pym2) [N,N-di(2-pyridylmethyl)-2-phenylethylamine] (complex 1) has demonstrated that it possesses a trigonal pyramidal geometry in which a d[bond]pi interaction with an eta(1)-binding mode exists between the metal ion and one of the ortho carbons of the phenyl ring of the ligand side arm (phenethyl). The result shows sharp contrast to the d[bond]pi interaction with an eta(2)-binding mode existing in the copper(I) complex of (Phe)L(Pye2) [N,N-di[2-(2-pyridyl)ethyl]-2-phenethylamine] (complex 2). Such a d-pi interaction has been shown to affect the stability of the copper(I) complex in CH(2)Cl(2). Oxygenation of copper(I) complex 1 supported by (Phe)L(Pym2) produces a bis(mu-oxo)dicopper(III) complex, also being in sharp contrast to the case of the copper(I) complex 2 with ligand (Phe)L(Pye2), which preferentially affords a (micro-eta(2):eta(2)-peroxo)dicopper(II) complex in the reaction with O(2). Such an effect of the alkyl linker chain length of the metal binding site has also been found to operate in the RSSR (disulfide)/2RS(-) (thiolate) redox system. Namely, ligand (S2,R)L(Pym1) (di[2-[(alkyl)(2-pyridinylmethyl)amino]ethyl] disulfide) with the methylene linker group (Pym) induced the reductive disulfide bond cleavage in the reaction with copper(I) ion to give a bis(micro-thiolato)dicopper(II) complex, while the ligand with the ethylene linker group (Pye), (S2,Bn)L(Pye1) (di[2-[(benzyl)(2-(2-pyridinyl)ethyl)amino]ethyl] disulfide), gave a disulfide-dicopper(I) complex. These ligand effects in the Cu(2)[bond]O(2) and Cu(2)[bond]S(2) systems have been discussed by taking into account the difference in electron-donor ability of the pyridine nucleus between the Pym and Pye ligand systems.