Ternäre Komplexe in Lösung IV. Einfluss von 2,2′‐Bipyridyl auf Stabilität und Acidität des Cu 2+ ‐Adenosin‐5′‐monophosphat‐N(1)‐oxid‐1:1‐Komplexes

The ternary Cu 2+ −2,2′‐bipyridyl‐adenosine‐5′‐monophosphate‐N(1)‐oxide complex was investigated and compared with the binary Cu 2+ ‐adenosine‐5′‐monophosphate‐N(1)‐oxide complex (I) (cf. [2]). In both complexes Cu 2+ is bound to the o ‐amino‐N‐oxide group of adenosine‐5′‐monophosphate‐N(1)‐oxide (HL). The stabilities of the complexes monoprotonated at the phosphate group are of the same order: log K   Cu CuHL= 11,20, and log K   CuBipy CuBipyHL= 11,19. The acidity constants for the deprolonation of the phosphate group in these complexes are slightly different (pK   H CuHL= 5,55, and p K   H CuBipyHL= 5,88), but as expected both values are lower than the corresponding value p K   H H   2 L= 6,12 of the ligand.