کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1312767 | 975497 | 2007 | 5 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Experimental and calculated circular dichroism spectra of monoaza[5]helicenes Experimental and calculated circular dichroism spectra of monoaza[5]helicenes](/preview/png/1312767.png)
Circular dichroism (CD) spectra have been measured in the range of 400–200 nm on CH3OH solutions of both enantiomers for the almost complete series of monoaza[5]helicenes, namely the molecules where the hetero N atom occupies positions 1, 3, 4, 5, 6, and 7, respectively (the 2 isomer is missing due to difficulties in the synthesis). CD spectra recorded at controlled room temperature allow one to define precise racemization rates, that are nicely interpreted on the basis of DFT molecular orbital calculations. Time-dependent DFT methods provide us with calculated CD and UV spectra, that are compared with the corresponding experimental data. We discuss the role of the N atom in determining the height of the racemization barrier and in shaping the appearance of the CD spectra.
The rates of racemization the mono aza[5]helicenes were measured with the use of circular dichroism spectra, and the data interpreted on the basis of DFT molecular orbital calculations.Figure optionsDownload as PowerPoint slide
Journal: Inorganica Chimica Acta - Volume 360, Issue 3, 15 February 2007, Pages 908–912