Lisowski Jerzy, Ripoli Silvia, Di Bari Lorenzo
Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via Risorgimento 35, 56126 Pisa, Italy.
Inorg Chem. 2004 Feb 23;43(4):1388-94. doi: 10.1021/ic0353918.
We investigate the role of axial ligands on the near-IR-optical and paramagnetic NMR spectra of the complex YbL where L is the stereodefined enantiopure chiral macrocycle (L = hexaazapentacyclo[25.3.1.1(12,24).0(4,9).0(19,24)]dotriaconta-1(31),2,10,12,14,16(32),17,25,27,29-decaene). The conformation in solution of the lanthanide complex is characterized by analyzing the pseudocontact 1H NMR shifts and is consistent with X-ray data of single crystal of analogue systems. The macrocycle is confined within a thin equatorial disk, leaving the cation open to at least two axial sites, on the opposite hemispheres. We recorded, assigned, and analyzed the 1H NMR spectra of several species upon changing the anion in solution, calculating the magnetic susceptibility anisotropy tensor for each. Near-IR circular dichroism is used to investigate the solution equilibria involving the competing ligands and to derive a spectroscopic series for Yb.
我们研究了轴向配体对配合物YbL近红外光学光谱和顺磁核磁共振光谱的作用，其中L是立体定义的对映体纯手性大环（L = 六氮杂五环[25.3.1.1(12,24).0(4,9).0(19,24)]三十六-1(31),2,10,12,14,16(32),17,25,27,29-癸烯）。通过分析赝接触1H NMR位移对镧系配合物在溶液中的构象进行了表征，且与类似体系单晶的X射线数据一致。大环被限制在一个薄的赤道盘内，使得阳离子在相对的半球上至少有两个轴向位点开放。我们记录、归属并分析了在溶液中改变阴离子时几种物种的1H NMR光谱，计算了每种物种的磁化率各向异性张量。利用近红外圆二色性研究了涉及竞争配体的溶液平衡，并推导了Yb的光谱序列。
