Electron Theory in Organic Chemistry. 



669 



Si 



In the case where there are several circuits (1, 2, ... /i) in 



a field it is easy to prove that Sj is given by 



Li, M12, Mi3....Mi„ 

 M12, L 2 , 0, 



Mis, 0, L 3 , 



Mi„, 0, 



0, 







S is therefore of the order 

 M is 



= - 



0, 2u n ( 



ftll„ 



8Mi2 



8Mi„ 







, Li, 



M l2 ... 



• • M ln 





8Mi2 



' Ml2 



L 2 ... 



... 



= 



8Mi» 



"^6 



, M,. 



... 



. . L„ 



ier | 



SMI 2 



ad" J * 









Now since 



m . 



very small and 



is 



still smaller; and since, if the 



always positive, if M is very small 

 f SM \ 2 

 80 ia ' olJ — - \"gg"J 

 coefficient of mutual induction between two vibration centres 

 in a molecule is very small, the bands of the molecule are 

 practically the bands of the two centres superimposed on one 

 another, with little or no change in position, we deduce that 

 "if two vibration centres or groups occur in a molecule in such 

 a way as not to influence one another's absorption bands they 

 will not stabilize one another." Hence their chemical pro- 

 perties will also be uninfluenced by one another. For 

 example, the absorption band of benzylamine is in the same 

 position as the a series of benzene, and quite different from 

 the two bands of aniline. It is not surprising, therefore, to 

 find that whereas aniline differs markedly from aliphatic 

 amines, benzylamine resembles them. This is most noticeable 

 in the well-known fact that the intermediate product in the 

 action of nitrous acid on aniline is stable enough to exist, but 

 not that in the action of the same reagent on benzylamine. 



Also, since the value of M between them has been found 

 to be small, we would not expect to find any stabilizing 

 effect between two unsaturated carbons separated by a 

 methylene group, and there is no reason to expect a sub- 

 stance -CH 2 — OH 2 — CH 2 — to exist. 



Further, since the effect on the absorption spectrum of 

 the introduction of a methyl group is usually slight, it is 

 not expected that the stability of the unsaturated group or 

 of the C — H linkages of the methyl group will be increased. 

 The latter is in fact diminished. This is due to another cause 

 which will be dealt with later. 



