Inorganic Chemistry, Vol.46, No.23, 9975-9978, 2007
An attempt to discriminate between the hydrophobic and aromatic pi-pi interactions in the Copper(II) ternary complexes CuLA with L=1,10-phenanthroline or 2,2'-bipyridyl and A = para-X-substituted phenylalaninates
For the title complexes, the value of formation constant K(CuL + A) is higher than that of K-1(CuA(2)). According to the mechanistic consideration, log K(CuL + A) is calculated for regular Cu(II) complexes with neither special enhancement nor diminution of the stability constant. Then, the difference of log K(CuL + A)(obs)-log K(CuL +A)(calc) represents extrastabilization due to the hydrophobic interactions and the aromatic pi-pi interactions. The former has been found to be proportional to the free energy of the transfer of side chains of aminocarboxylates A. The discrimination between the hydrophobic and the aromatic pi-pi interactions has been attempted.