Molecular shuttles based on tetrathiafulvalene units and 1,5-dioxynaphthalene ring systems
Molecular shuttles based on tetrathiafulvalene units and 1,5-dioxynaphthalene ring systems
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DOI：
10.1002/chem.200305725
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发表时间：
2004-05-17
影响因子：
4.3
通讯作者：
Stoddart, JF
中科院分区：
文献类型：
--
作者：
Kang, SS;Vignon, SA;Stoddart, JF
合成并表征了六种不同的简并[2]轮烷。Ne轮烷含有两个四硫富瓦烯(TTF)单元或两个1，5-二氧基萘(DNP)环系，它们都是环双(百草枯对苯基)(CBPQT(4+))环的识别中心。三个不同的间隔基单元被结合到识别位点之间的[2]轮烷的哑铃成分中。它们包括聚醚链、三苯基和二苯醚连接物，所有这些都被研究过，以探索间隔物对穿梭过程速度的影响。动态H-1核磁共振谱数据表明，在含有三个不同间隔基的[2]轮烷中，穿梭过程的DeltaG(双匕首)值差异相对较小，而含TTF的轮烷(18kcal mol(-1))和含DNP的轮烷(15kcal mol(-1))之间的差异很大。这种3kcal摩尔(-1)的差异主要是基态效应的结果，反映了与DNP环系相比，TTF单元与CBPQT(4+)环的结合要强得多。对含有DNP的轮烷中穿梭过程的焓(DeltaH(双匕首))和熵(Deltaas(双匕首))分量的检查表明，三个间隔体之间存在显著差异，这一性质可能对设计新分子以并入分子电子和纳米机电(NEMS)设备很重要。
Six different degenerate [2]rotaxanes were synthesized and characterized. ne rotaxanes contained either two tetrathiafulvalene (TTF) units or two 1,5-dioxynaphthalene (DNP) ring systems, both of which serve as recognition sites for a cyclobis(paraquat-p-phenylene) (CBPQT(4+)) ring. Three different spacer units were incorporated into the dumbbell components of the [2]rotaxanes between the recognition sites. They include a polyether chain, a terphenyl unit, and a diphenyl ether linker, all of which were investigated in order to probe the effect of the spacers on the rate of the shuttling process. Data from dynamic H-1 NMR spectroscopy revealed a relatively small difference in the DeltaG(double dagger) values for the shuttling process in the [2]rotaxanes containing the three different spacers, in contrast to a large difference between the TTF-containing rotaxanes (18 kcal mol(-1)) and the DNP-containing rotaxanes (15 kcal mol(-1)). This 3 kcal mol(-1) difference is predominantly a result of a ground-state effect, reflecting the much stronger binding of TTF units to the CBPQT(4+) ring in comparison with DNP ring systems. An examination of the enthalpic (DeltaH(double dagger)) and entropic (DeltaS(double dagger)) components for the shuttling process in the DNP-containing rotaxanes revealed significant differences between the three spacers, a property which could be important in designing new molecules for incorporation into molecular electronic and nanoelectromechanical (NEMs) devices.