Room-temperature phosphorescence from 1:1:1 inclusion compounds of .beta.-cyclodextrin with brominated alcohols and acenaphthene
Room-temperature phosphorescence from 1:1:1 inclusion compounds of .beta.-cyclodextrin with brominated alcohols and acenaphthene
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DOI：
10.1021/ja00193a028
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发表时间：
1989-05
影响因子：
15
通讯作者：
S. Hamai
中科院分区：
文献类型：
--
作者：
S. Hamai
苊（AN）与0-环糊精（CDx）和乙醇的1：1包合物形成1：1：1包合物。在检查的伯醇中，1-丙醇最容易与CDx和AN的1：1包合物缔合。当溴代醇以1：1：1的比例存在时，硝酸铵的室温磷光是由重原子效应引起的。根据关于通过NaNO 2猝灭AN磷光的实验，我们已经估计AN与已经容纳2-溴乙醇（BE）分子的CDx缔合的速率常数（k3）为1 × 1010 mol-1dm-23 s-1，并且AN从1：1：1包合化合物，包括BE，为8 X 104 s-1。在CDx-BE-AN系统中，k3比与BE未掺入其中的游离CDx缔合的速率常数（k1）大2个数量级，而k4比从CDx与AN的1：1包合物解离的速率常数（k2）小1个数量级。这些发现表明，CDx腔内的客体分子（BE）加速了AN与CDx的缔合速率，并且相反地使AN的解离速率从1：1：1包结化合物。多核芳烃如苊（AN），萘，和芘不仅在含有Tl+作为重原子微扰剂的胶束溶液中观察到，而且在含有1，2-二溴乙烷的环糊精溶液中也观察到。[4· 5]作为环糊精溶液中的磷光诱导机制，Scypinsky和Cline Love提出了由发光体、环糊精和1，2-二溴乙烷形成的三分子复合物。5使用他们的环糊精技术，可以获得可重复的，高质量的室温磷光光谱。在先前的论文中，我们已经报道了在O-环糊精（CDx）与萘的两个1：1包合物之间发生自缔合。随后，已经发现，CDx与芘的1：1包合化合物进一步与伯醇或环状醇分子缔合以产生1：1：1包合化合物。7因为芘不会深入到
Acenaphthene (AN) has been found to form a 1: 1: 1 inclusion compound by complexing with a 1: 1 inclusion compound of 0-cyclodextrin (CDx) and alcohol. Of the primary alcohols examined, 1-propanol most easily associates with a 1: 1 inclusion compound of CDx and AN. When brominated alcohol is included in the 1: 1: 1 inclusion compound, a room-temperature phosphorescence of AN is induced by a heavy-atom effect. From experiments on the AN phosphorescence quenching by NaN02, we have estimated a rate constant (k3) for the association of AN with CDx, which already accommodates a 2-bromoethanol (BE) molecule, to be 1 X 1010 mol-1 dm1 23 s" 1 and a rate constant (k4) for the dissociation of AN from the 1: 1: 1 inclusion compound including BEto be 8 X 104 s" 1. In the CDx-BE-AN system, k3 is 2 orders of magnitude larger than the rate constant (k,) for the association with free CDx into which BE is not incorporated, whereas k4 is 1 order of magnitude smaller than the rate constant (k2) for the dissociation from the 1: 1 inclusion compound of CDx with AN. These findings indicate that a guest molecule (BE) inside the CDx cavity accelerates the association rate of AN with CDx and conversely decelerates the dissociation rate of AN from the 1: 1: 1 inclusion compound.Room temperature phosphorescences of polynuclear aromatic hydrocarbons such as acenaphthene (AN), naphthalene, and pyrene are observed not only in micellar solutions containing Tl+ as a heavy-atom perturbe/" 4 but also in cyclodextrin solutions containing 1, 2-dibromoethane. 4· 5 As a phosphorescence-inducing mechanism in cyclodextrin solutions, Scypinsky and Cline Love have proposed the formation of a trimolecular complexamong a luminophor, cyclodextrin, and 1, 2-dibromoethane. 5 Usingtheir technique with cyclodextrin, one can obtain reproducible, good-quality room-temperature phosphorescence spectra. In a previous paper, 6 we have reported that a self-association occurs between two 1: 1 inclusion compounds of 0-cyclodextrin (CDx) with naphthalene. Subsequently, it has been found that a 1: 1 inclusion compound of CDx with pyrene further associates with a primary or cyclic alcohol molecule to produce a 1: 1: 1 inclusion compound. 7 Because pyrene does notdeeply enter the