Newman tension

The Newman-voltage is a ring voltage that the 1.5 Repulsion of non- hydrogen referred -atoms. It is named after the American chemist Melvin Spencer Newman (1908–1993) at the suggestion of Albert Eschenmoser .

description

A high Newman stress occurs when the torsion angle between atoms 1 and 4 and atoms 2 and 5 in a chain of five atoms 1 to 5 is −60 ° and + 60 ° or + 60 ° and −60 °, respectively amounts. The sequence + synclinal / −synclinal (or gauche + / gauche−) for two consecutive dihedral angles leads to a Newman stress of around 15.5  kJ / mol (3.7  kcal / mol ) for two methyl groups , for example in the case of n -pentane .

See also

• Pitzer tension
• Prelog tension
• Baeyer tension

Individual proof

1. ^ Gerhard Quinkert , Ernst Egert , Christian Griesinger : Aspects of organic chemistry: Structure . Helvetica Chimica Acta ( Wiley-VCH Verlag ), 1996. P. 101 ( limited preview in the Google book search).