کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1309702 | 975218 | 2009 | 7 صفحه PDF | دانلود رایگان |
The rigid, π-conjugated dicarboxylic acid 1,4-bis-[2-(4-carboxyphenyl)ethynyl]-2,5-dihexylbenzene {HO2C[PEP(hexyl)2EP]CO2H} has been used to synthesise the new crystalline coordination polymers {Zn(O2C[PEP(hexyl)2EP]CO2)(DMF)2} (1) and {Zn(O2C[PEP(hexyl)2EP]CO2)(DEF)2} (2) in N,N-dimethylformamide (DMF) and N,N-diethylformamide (DEF), respectively, under mild conditions. Single-crystal X-ray crystallography revealed that 1 and 2 are isostructural and consist of uncharged zigzag coordination chains in which [Zn(formamide)2]2+ fragments are bridged by (O2C[PEP(hexyl)2EP]CO2)2− ligands. The zigzag chains possess different intra-chain Zn⋯Zn⋯Zn angles due to the different volumes of the coordinating formamide molecules and subtle differences in the hydrophobic inter-chain interactions. Upon heating 1 and 2 to 200 °C, removal of the coordinating formamide molecules occurs, yielding the formamide-free compounds 1-DMF and 2-DEF of composition {Zn(O2C[PEP(hexyl)2EP]CO2)}. According to powder X-ray diffraction and FT-IR spectroscopy studies, these materials are not crystalline but still possess partial ordering of intact, yet modified coordination chains in a structural arrangement which appears to be related to the respective parent compounds. Compounds 1, 2, 1-DMF and 2-DEF exhibit blue photoluminescence. The emission maxima of 1-DMF and 2-DEF are red-shifted by ca. 25 nm with respect to λmax of 1 and 2, respectively.
The application of oligo(phenyleneethynylene) dicarboxylic acid molecules of nanometer length as linkers gave rise to two novel isostructural crystalline coordination polymers, {Zn(O2C[PEP(hexyl)2EP]CO2)(DMF)2} and {Zn(O2C[PEP(hexyl)2EP]CO2)(DMF)2}. The coordinating amide molecules can be removed from these compounds to yield the respective, partially ordered formamide-free compounds.Figure optionsDownload as PowerPoint slide
Journal: Inorganica Chimica Acta - Volume 362, Issue 10, 1 August 2009, Pages 3600–3606