Joachim Brunn
Technische Hochschule
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Monatshefte Fur Chemie | 1992
Dieter Ströhl; Steffen Thomas; Erich Kleinpeter; Reiner Radeglia; Joachim Brunn
SummaryThe aryl13C chemical shifts of Cl-substituted 4-amino-, 4-diazonium-N,N-dimethylanilines, N,N-dimethylanilines and differently substituted naphthalenes were assigned by means of different NMR methods. The assignments were compared with chemical shifts obtained by using empirical additivity relationship for mono substituted aromatic substances. As a means of substitutent interactions, the chemical shift difference between calculated and experimental values (Δδci) has been used. In the presence of remarkable steric and electronic substituent interactions, large deviations from additivity (Δδci values up to 15.4 ppm) were found. Which originate primarily from steric interactions between the substitutents. In order to account therefore, correction increments have been developed by employing the Δδci values obtained from 1,2-disubstituted benzenes or naphthalenes. The13C chemical shifts of more than seventy substituted benzenes and naphthalenes have been predicted. The results corroborate that reasonable calculation of chemical shifts in sterically hindered benzenes is possible by using the extended additivity rule. The Δδci values are much lower and allow reasonable structural assignments.For external users of this incremental system, a computer program for IBM compatible PC/AT was developed. By means of this program, the13C chemical shifts for different benzenes and naphthalenes with or without 1,2-disubstituted correction increments will be calculated and the corresponding spectrum displayed. The program can assist the successful assignment of experimental13C chemical shifts.
Journal Fur Praktische Chemie-chemiker-zeitung | 1985
Dieter Ströhl; Reiner Radeglia; Joachim Brunn; J. Kriwanek; E. Fanghänel
Zeitschrift für Chemie | 2010
Joachim Brunn; Margit Großmann
Zeitschrift für Chemie | 2010
Klaus Doerffel; Joachim Brunn; Wolfram Höbold; Reiner Radeglia
Zeitschrift für Chemie | 2010
Joachim Brunn; Christine Beck; Reiner Radeglia; Zlatko Šrank
Zeitschrift für Chemie | 2010
Joachim Brunn; Christine Beck
Journal Fur Praktische Chemie-chemiker-zeitung | 1989
Dieter Ströhl; Reiner Radeglia; Joachim Brunn; Egon Fanghänel
Journal Fur Praktische Chemie-chemiker-zeitung | 1970
Klaus Doerffel; Joachim Brunn
Journal Fur Praktische Chemie-chemiker-zeitung | 1970
R. Boltze; Joachim Brunn; Klaus Doerffel; W. Höbold; G. Opitz
Zeitschrift für Chemie | 2010
Joachim Brunn; Hans‐Dieter Bormann; Irene Wenderoth