d-NMR-Untersuchungen der behinderten Rotation am NC(X)-Bindungsfragment. XV. Beeinflussung der Rotationsbarriere im NR2C(X)R1-Bindungsfragment durch elektronische und sterische Substituenteneffekte

✍ Scribed by Dr. E. Kleinpeter; Dr. S. Behrendt; Dr. L. Beyer; Dr. W. Dietzsch; Prof. Dr. R. Borsdorf

• Book ID: 105352402
• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 869 KB
• Volume: 324
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/prac.19823240106

✦ Synopsis

d‐N.M.R. Investigations of the Restricted Rotation at the NC(X)‐Bonding Fragment. XV. Influence of the Rotational Barrier in the NR~2~C(X)–R^1^‐Bonding Fragment by Electronic and Steric Substituent Effects.

The rotational barriers ΔG^≠^ of the restricted rotation about partial C,N‐double bonds are determined for 4 series of urea‐derivatives, and analogous compounds by complete lineshape analysis and approximation equations. Some general conclusions are drawn about the validity range of the approximations independence on the low temperature splitting Δν, the possible corrections within the margin of error and the internal temperature measurement. The dependence of the determined free enthalpies of activation about the effect of heteroatoms X, the NR~2~‐substituents and the electronic and steric influence of the substituents R^1^ are discussed.