70 



r 



two O's. The arrow in Fig. 17b indicates that the metal attracts an 

 electron from the quinolinol (Leverenz). The same can be ex- 

 pected to happen also in the complex of inosine, and if the metal 



I 



/ 



N 



Mg 

 N 



I. 



Mg 

 0^ I 



N 



\ 



N 



w 



a b 



Fig. 17. a: Mg complex of oxypurine. b: Mg complex of oxyquinolinol. 



H 

 HN 



V 



N= 



OH 

 P-0 



\ \ 



\_j:i.::s^o\p=o 



\ 







K. H H H H -r-. ^ 



^ I I I I /f^=o 

 CH-C— C — C— C— OH 



I I 



OH OH 

 — — 



I 



H 



Fig, 18. Possible structure of Mg complex of ATP (interatomic dis- 

 tances are arbitrary). 



forms a quadridentate chelate linking up also with the phosphates, 

 it may attract electrons also from the latter. The metal may thus 

 serve as a bridge, across which electrons can pass from phosphate 

 to purine. So the Mg actually not only may connect the two ends 

 of a molecule; it may make one single, unique electronic system 

 of the phosphate chain and the purine with common nonlocalized 



