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 K1(CuA2). 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+)(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.
Tanaka
Motoharu
M
Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan. motanaka@yo.rim.or.jp
Tabata
Masaaki
M
D010618:Phenanthrolines / Q000737:chemistry*; D010649:Phenylalanine / Q000737:chemistry*
D010618:Phenanthrolines; C038556:bis(1,10-phenanthroline)copper(1+) ion; D010649:Phenylalanine