1H, 13C, 15N NMR and X-Ray Diffractometry in Structural Studies of Macrocyclic Lactams Containing Pyridine Moiety |
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| Authors: | Daniel T Gryko Agnieszka Pęcak Wiktor Koźmiński Piotr Piątek Janusz Jurczak |
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| Institution: | 1. Institute of Organic Chemistry, Polish Academy of Sciences , Kasprzaka, 44/52, 01-224, Warsaw;2. Department of Chemistry , University of Warsaw , Pasteura 1, 02-093, Warsaw, Poland;3. Department of Chemistry , University of Warsaw , Pasteura 1, 02-093, Warsaw, Poland |
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| Abstract: | Abstract We examined complexing sites of the Pb2+ complex of the macrocyclic lactam 1 using 15N NMR and other spectroscopies and we have found that the amide groups undergo conformational changes to allow the complexation process to proceed via the pyridine nitrogen atom and carbonyl and ethereal oxygen atoms. X-Ray analysis of compound 1 was carried out successfully. Space group I41/a, a=28.332(4)Å, b=28.332(4)Å, c=10.7379(4)Å, Z=16, V=8619.3(18)Å3, Dc=1.197gcm?3, R1=0.0479 (based on 2510 reflections I>2sgrave](I). It shows presence of intramolecular hydrogen bonds, which are broken during the complexation. Molecules form supramolecular tetragonal assemblies in the crystal, which form channels the walls of which are 7.42 Å apart. |
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| Keywords: | Macrocyclic lactam X-ray diffractometry 15N NMR complexation |
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