摘要
The host-guest relationship between cucurbit[8]uril,phenanthrolines and some methyl substituted 1,10-phenanthrolines has been investigated by using 1H NMR spectroscopy and fluorescence spectroscopy.The results showed that phenanthrolines as molecular guests bind in the cavity and portal of cucurbit[8]uril in a ratio of 2:1 (guest to host).The phenanthroline isomers 1,10-,1,7-and 4,7-showed red shifts between 47 and 108 nm and pronounced in-creases in fluorescent intensity.These same isomers produced inclusion complexes with cucur-bit[8]uril which had moderate to fast exchange rates on the 1H NMR time scale.The methyl substituted 1,10-phenanthrolines studied gave stable inclusion complexes in a ratio of 2:1 which showed slow exchange rates.These guests formed p-p stacked pairs which were cavity bound but also partly protruded from only one portal forming unsymmetrical host-guest complexes.In addition,these p-p stacked pairs formed orientation isomers within the confines of the cucur-bit[8]uril cavity.
The host-guest relationship between cucurbit[8]uril,phenanthrolines and some methyl substituted 1,10-phenanthrolines has been investigated by using 1H NMR spectroscopy and fluorescence spectroscopy.The results showed that phenanthrolines as molecular guests bind in the cavity and portal of cucurbit[8]uril in a ratio of 2:1 (guest to host).The phenanthroline isomers 1,10-,1,7-and 4,7-showed red shifts between 47 and 108 nm and pronounced in-creases in fluorescent intensity.These same isomers produced inclusion complexes with cucur-bit[8]uril which had moderate to fast exchange rates on the 1H NMR time scale.The methyl substituted 1,10-phenanthrolines studied gave stable inclusion complexes in a ratio of 2:1 which showed slow exchange rates.These guests formed p-p stacked pairs which were cavity bound but also partly protruded from only one portal forming unsymmetrical host-guest complexes.In addition,these p-p stacked pairs formed orientation isomers within the confines of the cucur-bit[8]uril cavity.
基金
the National Natural Science Foundation of China(Grant Nos.20261002&20362003)
the International Collaborative Project of the Minist ry of Science and Technology(Grant No.2003DF000030)
the Foundation of the Governor of Guizhou Province
the Key Project of Natural Science Foundat ion of Guizhou Province(Grant No.20023004)
the Foundation for the Qualified Scient ist Program of Guizhou Province(Grant No.20020204).
