13c-nmr based evaluation of the electronic and steric interactions in aromatic amines色谱仪建立评价芳香胺的电子和立体交互.pdfVIP

Int. J. Mol. Sci. 2005, 6, 52-62 International Journal of Molecular Sciences ISSN 1422-0067 © 2005 by MDPI /ijms/ 13C-NMR Based Evaluation of the Electronic and Steric Interactions in Aromatic Amines Anna Zakrzewska 1, Ryszard Gawinecki 1,*, Erkki Kolehmainen 2 and Borys Ośmiałowski 1 1 Department of Chemistry, Technical Agricultural University, Seminaryjna 3, PL-85-326 Bydgoszcz, Poland 2 Department of Chemistry, P.O. Box 35, FIN-40014, University of Jyväskylä, Finland * Author to whom correspondence should be addressed: Phone: (+48) 052 3749070; Fax: (+48) 052 3731160. E-mail: gawiner@mail.atr.bydgoszcz.pl Received: 16 April 2004; in revised form: 24 January 2005 / Accepted: 25 January 2005 / Published: 31 January 2005 Abstract: Chemical shifts of the para carbon atoms, δ(13C-4), in a series of aromatic O amines were used to calculate the σ , σ and σ substituent constants for different amino p R R groups. 1-Pyrrolidino, N,N-di-n-butylamino and N,N-diethylamino groups were found to be the most strong electron-donors. ortho-Substitution decreases the donor properties of the amino group. The amino groups in 2,6-di-i-propylaniline and N,N-2,6- tetramethylaniline have very weak electron-donor properties. The nitrogen atom in benzoquinuclidine