Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
Inorg Chem. 2010 Dec 20;49(24):11550-5. doi: 10.1021/ic101694z. Epub 2010 Nov 11.
The reaction of an α-free, β,β'-linked bis(dipyrromethene) ligand with Fe(3+) or Co(3+) led to noninterconvertible triple-stranded helicates and mesocates. In the present context, a stable α-free ligand 2 has been developed and complexation of ligands 1 and 2 with diamagnetic Co(3+), Ga(3+), and In(3+) has been studied. The triple-stranded M(2)1(3) (M = Ga, In) and M(2)2(3) (M = Co, Ga, In) complexes were characterized using matrix-assisted laser desorption ionization time-of-flight spectrometry, (1)H NMR and UV-vis spectroscopy, and X-ray crystallography. Again, the (1)H NMR analysis showed that both the triple-stranded helicates and mesocates were generated in this metal-directed assembly. Consistent with our previous finding on coordinatively inert Co(3+) complexes, variable-temperature NMR spectroscopy indicated that the triple-stranded helicate and mesocate of labile In(3+) did not interconvert in solution, either. However, the diastereoselectivity of the M(2)2(3) complexes was found to improve with an increase in the reaction temperature. Taken together, this study complements the coordination chemistry of poly(dipyrromethene) ligands and provides further insight into the formation of helicates versus mesocates.
无α位、β,β'-连接的双二吡咯甲烷配体与 Fe(3+)或 Co(3+)反应生成不可相互转化的三链螺旋和中笼。在本研究中，开发了一种稳定的无α位配体 2，并研究了配体 1 和 2 与顺磁性 Co(3+)、Ga(3+)和 In(3+)的络合作用。采用基质辅助激光解吸电离飞行时间质谱、(1)H NMR 和紫外-可见光谱以及 X 射线晶体学对三链 M(2)1(3)（M = Ga，In）和 M(2)2(3)（M = Co，Ga，In）配合物进行了表征。同样，(1)H NMR 分析表明，在这种金属导向的组装过程中，既生成了三链螺旋，也生成了中笼。与我们以前关于配位惰性 Co(3+)配合物的发现一致，变温 NMR 光谱表明，不稳定的 In(3+)的三链螺旋和中笼在溶液中也不能相互转化。然而，发现 M(2)2(3)配合物的非对映选择性随反应温度的升高而提高。总之，这项研究补充了多二吡咯甲烷配体的配位化学，并进一步深入了解了螺旋和中笼的形成。
