Enantiomeric Self-Recognition in Homo- and Heterodinuclear Macrocyclic Lanthanide(III) Complexes
Enantiomeric Self-Recognition in Homo- and Heterodinuclear Macrocyclic Lanthanide(III) Complexes
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DOI：
10.1021/ic2001909
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发表时间：
2011-06-20
影响因子：
4.6
通讯作者：
Lisowski, Jerzy
中科院分区：
文献类型：
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作者：
Lisowski, Jerzy
报道了对映纯手性大环L的镧系（III）双核mu-羟基桥接[Ln(2)L(2)(mu-OH)(2)X-2]（n+）配合物（其中X = H2O， NO3-或Cl-）的可控形成。根据COSY、NOESY、TOCSY和HMQC光谱，确定了这些配合物的H-1和C-13核磁共振。观察到的NOE连通性证实了溶液中二聚体固态结构的保留。得到的手性配合物的对映体性质和氢氧阴离子的结合反映在它们的CD光谱中。二聚体配合物的形成伴随着手性大环单元的完全对映体自我识别。NaOH与两种不同的单核镧系（III）配合物[Ln(1)L]（3+）和[Ln(2)L]（3+）的混合物反应，形成异双核[Ln(1)Ln(2)L(2)(mu-OH)(2)X-2]（n+）配合物以及相应的同双核配合物。[EuLuL2(mu-OH)(2)(H2O)(2)]（4+）的NOESY光谱直接证实了异双核配合物的形成，揭示了含Eu（III）离子的大环单元与含Lu （III）离子的大环单元之间的密切接触。虽然对于半径相似的两种镧系（III）离子，同源和异双核配合物的相对数量具有统计学意义，但当两种单核配合物含有明显不同大小的镧系（III）离子时，观察到明显倾向于形成异双核物种，例如La（III）和Yb（III）。杂双核配合物的形成伴随着基于手性的手性大环单元的自分选。NaOH与一对同手性或外消旋的单核配合物[Ln(1)L(RRRR)](3+)/[Ln(2)L(RRRR)](3+), [Ln(1)L(SSSS)](3+)/[Ln(2)L(SSSS)](3+)，或[Ln(1)L(rac)](3+)/[Ln(2)L(rac)]（3+）反应，得到同手性、同双核和同手性、异双核配合物的混合物。相反，在手性相反的两种不同的单核配合物的反应中，不会形成异手性、异双核配合物[Ln(1)L(RRRR)Ln(2)L(SSSS)(mu-OH)(2)X-2]（n+）。
The controlled formation of lanthanide(III) dinuclear mu-hydroxo-bridged [Ln(2)L(2)(mu-OH)(2)X-2](n+) complexes (where X = H2O, NO3-, or Cl-) of the enantiopure chiral macrocycle L is reported. The H-1 and C-13 NMR resonances of these complexes have been assigned on the basis of COSY, NOESY, TOCSY, and HMQC spectra. The observed NOE connectivities confirm that the dimeric solid-state structure is retained in solution. The enantiomeric nature of the obtained chiral complexes and binding of hydroxide anions are reflected in their CD spectra. The formation of the dimeric complexes is accompanied by a complete enantiomeric self-recognition of the chiral macrocyclic units. The reaction of NaOH with a mixture of two different mononuclear lanthanide(III) complexes, [Ln(1)L](3+) and [Ln(2)L](3+), results in formation of the heterodinuclear [Ln(1)Ln(2)L(2)(mu-OH)(2)X-2](n+) complexes as well as the corresponding homodinuclear complexes. The formation of the heterodinuclear complex is directly confirmed by the NOESY spectra of [EuLuL2(mu-OH)(2)(H2O)(2)](4+), which reveal close contacts between the macrocyclic unit containing the Eu(III) ion and the macrocyclic unit containing the Lu (III) ion. While the relative:amounts of homo- and heterodinuclear complexes are statistical for the two lanthanide (III) ions of similar radii, a clear preference for the formation of heterodinuclear species is observed when the two mononuclear complexes contain lanthanide(III) ions of markedly different sizes, e.g., La(III) and Yb(III). The formation of heterodinuclear complexes is accompanied by the self-sorting of the chiral macrocyclic units based on their chirality. The reactions of NaOH with a pair of homochiral or racemic mononuclear complexes, [Ln(1)L(RRRR)](3+)/[Ln(2)L(RRRR)](3+), [Ln(1)L(SSSS)](3+)/[Ln(2)L(SSSS)](3+), or [Ln(1)L(rac)](3+)/[Ln(2)L(rac)](3+), results in mixtures of homochiral, homodinuclear and homochiral, heterodinuclear complexes. On the contrary, no heterochiral, heterodinuclear complexes [Ln(1)L(RRRR)Ln(2)L(SSSS)(mu-OH)(2)X-2](n+) are formed in the reactions of two different mononuclear complexes of opposite chirality.