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首页> 外文期刊>Chemistry: A European journal >Synthesis and supramolecular properties of molecular clips with anthracene sidewalls
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Synthesis and supramolecular properties of molecular clips with anthracene sidewalls

机译：具有蒽侧壁的分子夹的合成及超分子性质

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Novel molecular clips with anthracene sidewalls (1a-c) were synthesized; they form stable host-guest complexes with a variety of electron-deficient aromatic and quinoid molecules. According to single-crystal structure analyses of clip 1c and 1,2,4,5-tetracyanobenzene (TCNB) complex 14@ 1b the clips' anthracene sidewalls have to be compressed substantially during the complex formation to provide attractive pi-pi interactions between the aromatic guest molecule and the two anthracene sidewalls in the complex. Re compression and expansion of aromatic sidewalls are calculated by molecular mechanics to be low-energy processes, so the energy required for compression of the anthracene sidewalls during complex formation is apparently overcompensated by the gain in energy resulting from the attractive pi-pi interactions. The finding that complexes of the clips 1a-c are more stable than those of the corresponding clips 2a-c can be explained in terms of the larger van der Waals contact surfaces of the anthracene sidewalls in la-c (relative to the naphthalene sidewalls in 2a-c). Color changes resulting from charge-transfer (CT) bands are observed in complex formation by 1a-c: from colorless to red or purple with TCNB (14), and from yellow to green with 2,4,7-trinitro-9-fluorenone TNF (17). Independently, the host 1b and guest 14 fluoresce from their respective excited singlet states, whilst in the complex 14@1b the charge-transfer state quenches the higher-energy singlet states of the two components, and as a result luminescence is only observed from this new CT state. To the best of our knowledge, complex 14@1b is the first example of CT luminescence from a host-guest complex. The binding constant determined for the formation of the TCNB complex 14@1b from a UV/Vis titration experiment (K-a = 12400m(-1)) agrees well with the value (K-a = 12800M(-1)) obtained by H-1 NMR titration.
机译：合成了具有蒽侧壁（1a-c）的新型分子夹。它们与各种缺电子的芳族和醌型分子形成稳定的主体-客体复合物。根据夹子1c和1,2,4,5-四氰基苯（TCNB）络合物14 @ 1b的单晶结构分析，在络合物形成过程中，夹子的蒽侧壁必须充分压缩，以提供两个键之间的有吸引力的pi-pi相互作用。芳族客体分子和两个蒽侧壁形成复合物。芳香族侧壁的再压缩和膨胀通过分子力学计算为低能量过程，因此，在复杂的形成过程中，蒽侧壁压缩所需的能量显然被有吸引力的pi-pi相互作用所获得的能量补偿过高。夹子1a-c的复合物比相应的夹子2a-c的复合物更稳定的发现可以用la-c中的蒽侧壁的较大范德华接触表面来解释（相对于萘中的萘侧壁）。 2a-c）。在1a-c的复合物形成中观察到了由电荷转移（CT）带引起的颜色变化：使用TCNB（14）从无色变为红色或紫色，使用2,4,7-三硝基-9-芴酮从黄色变为绿色。 TNF（17）。独立地，主体1b和客体14从它们各自的激发单线态发出荧光，而在复合物14 @ 1b中，电荷转移态淬灭了两个组分的高能单线态，因此仅从该状态观察到发光新的CT状态。据我们所知，复合物14 @ 1b是宿主-客体复合物CT发光的第一个例子。通过UV / Vis滴定实验确定的TCNB络合物14 @ 1b形成的结合常数（Ka = 12400m（-1））与通过H-1 NMR获得的值（Ka = 12800M（-1））非常吻合滴定。

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