Spontaneous helical folding of bis(Ni-salphen) complexes in solution and in the solid state: spectroscopic tracking of the unfolding process induced by Na+ ions
Spontaneous helical folding of bis(Ni-salphen) complexes in solution and in the solid state: spectroscopic tracking of the unfolding process induced by Na+ ions
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双（Ni-salphen）配合物在溶液和固态中的自发螺旋折叠：Na离子诱导的展开过程的光谱跟踪
DOI：
10.1039/c3dt53397b
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Hirohiko Houjou
中科院分区：
文献类型：
--
作者：
Hiroto Achira;Muneyuki Ito;Toshiki Mutai;Isao Yoshikawa;Koji Araki;Hirohiko Houjou
合成了4种含2-亚甲基丙烷-1，3-二基的双水杨酸镍配合物，并对其结构进行了表征。晶体结构分析表明，其中一个配合物折叠成螺旋结构，其中两个Ni原子相互之间的距离为3.2 π。NMR测量表明，在溶液中保持类似的折叠状态，通过未折叠状态再折叠的能垒为47 kJ mol−1。折叠后的配合物的紫外-可见吸收结构也发生了明显的红移。此外，钠离子引起的配合物的展开，和相应的光谱归因于一个几乎孤立的状态。DFT计算很好地再现了能垒和折叠引起的红移。
Four kinds of bis(Ni-salphen) complexes containing a 2-methylenepropane-1,3-diyl linker were synthesised and characterised. Crystal structural analysis revealed that one of the complexes folded into a helical structure, in which two Ni atoms were at a distance of 3.2 Å from each other. NMR measurements suggested that a similar folded state was maintained in solution, and the energy barrier for refolding through an unfolded state was 47 kJ mol−1. The folded complex also exhibited a significant bathochromic shift in its UV-Vis absorption structure. Addition of sodium ions caused unfolding of the complexes, and the corresponding spectra were attributed to a virtually isolated state. DFT calculations reproduced well the energy barrier and folding-induced bathochromic shift.