전위차법을 이용한 페놀성 두 팔을 가진 크라운계 화합물과 전이금속과의 착물에 관한 연구

Abstract

페놀성 양팔을 가진 4,13 디아자-18-크라운-6-에테르계 리간드 2-6을 Mannich 반응을 통해 합성하였으며, 리간드와 금속 이온간의 착물 형성에 있어서 리간드에 양팔로 존재하는 페놀기의 영향과 디아자 크라운고리의 효과를 비교하기 위해서 모델화합물 7과 8을 합성하였다. 리간드의 양성자 첨가 평형상수와 금속 착물의 안정수 상수를 95% 메탄올 용액에서 전위차 적정법으로 측정한 결과, 염기성 조건에서 리간드 2-6과 전이금속 이온간의 안정도 상수의 크기는 Co^2-

The aminomethylation of phenols with para-substituents by the Mannich reaction has successfully been accomplished to produce tin1 Mannich bases 2-6. The compounds 7-8 have been also synthesized in order to identify the effect of side arms and the macrocycle in the complex formation. The protonation constants of ligands and stability constants of the double armed 4,13-diaza-18-crown-6-ethers containing nitrogen and oxygen donors with metal ions have been determined by potentiometric method at 25℃ in 95% methanol solution. Under the basic condition, the double-armed crown ethers 2-6 revealed stronger interaction with divalent metal ions than the simple monocyclic crown ether 1. The stability constants for these metal ions were Co^2-Zn^2- in increasing order, which were in accordance with Williams-Irving series. It is noteworthy that the ligands 2-6, which have phenolic side arms and a macrocycle, bound strongly with metal ions than the ligand 1 and 7. On the other hand, the ligand 8, which has phenolic side arms with a pyperazine ring provided comparable stability constants to those with the ligands 2-6. This fact demonstrates that phenolic side arms play more important role than the aza-crown ether ring in the process of making a complex with metal ions especially in the basic condition. In particular, the log K_ML values for complexation of divalent metal ions with the ligands 2-6 had the sequence, ie., 2(R=OCH_3) <3(R=CH_3) <4(R=H) <5(R=Cl) <6(R=CF_3). The stability currants of ligands containing electron-withdrawing group showed larger stability constants than ligands containing of electron donating group. This substituent effect is attributed to the solvent effect in that the aryl oxide with an electron donating group has a tendency to be tied strongly with protic solvents.

The aminomethylation of phenols with para-substituents by the Mannich reaction has successfully been accomplished to produce tin1 Mannich bases 2-6. The compounds 7-8 have been also synthesized in order to identify the effect of side arms and the macrocycle in the complex formation. The protonation constants of ligands and stability constants of the double armed 4,13-diaza-18-crown-6-ethers containing nitrogen and oxygen donors with metal ions have been determined by potentiometric method at 25℃ in 95% methanol solution. Under the basic condition, the double-armed crown ethers 2-6 revealed stronger interaction with divalent metal ions than the simple monocyclic crown ether 1. The stability constants for these metal ions were Co^2-Zn^2- in increasing order, which were in accordance with Williams-Irving series. It is noteworthy that the ligands 2-6, which have phenolic side arms and a macrocycle, bound strongly with metal ions than the ligand 1 and 7. On the other hand, the ligand 8, which has phenolic side arms with a pyperazine ring provided comparable stability constants to those with the ligands 2-6. This fact demonstrates that phenolic side arms play more important role than the aza-crown ether ring in the process of making a complex with metal ions especially in the basic condition. In particular, the log K_ML values for complexation of divalent metal ions with the ligands 2-6 had the sequence, ie., 2(R=OCH_3) <3(R=CH_3) <4(R=H) <5(R=Cl) <6(R=CF_3). The stability currants of ligands containing electron-withdrawing group showed larger stability constants than ligands containing of electron donating group. This substituent effect is attributed to the solvent effect in that the aryl oxide with an electron donating group has a tendency to be tied strongly with protic solvents.