雙核金屬大環錯合物之合成與其熱力學及水解磷酸酯鍵之動力學研究

Abstract

藉由設計及合成不同的錯合物，探討其熱力學性質及做為人工水解酶催化受質的效力是本實驗室感興趣的研究主題，對於鑭系金屬大環配位子的錯合物尤感興趣，由於鑭系金屬擁有高氧化態、路易士酸性強、高配位數及電子密度高等特性，且與大環配位子形成之錯合物穩定性高，使其非常適合應用在研究人工水解酶的領域上，並且希望能藉此研究更了解鑭系金屬在配位化學上的特性。 本實驗室先前已合成並研究一系列之錯合物，發現錯合物中金屬離子的配位水數目越多以及錯合物所帶之正電荷越高，其水解DNA的模型受質BNPP (bis(4-nitrophenyl)-phosphate)的效果越好。 在本論文中，我們合成了新的雙體大環錯合物，m-12N3O-dimer(1, 3-bis(1, 4, 10-triaza-7-oxacyclododec-1-ylmethyl)benzene)及m-ODO2A-dimer(1, 3-bis[4, 10-bis(carboxymethyl)- 1, 4, 10-triaza-7-oxacyclododec-1-ylmethyl]benzene)，分別與過渡金屬與鑭系金屬錯合後進行熱力學實驗決定穩定常數以及水解催化BNPP與RNA的模型受質HPNP(2-hydroxypropyl-4-nitrophenyl phosphate)的動力學實驗，並與前人已研究之錯合物及已發表之文獻比較其差異性。 由初步的水解實驗結果顯示雙核鑭系金屬大環錯合物水解BNPP及HPNP的速率都隨著環境中pH的上升而增加，直到pH10-10.5開始下降。另外其整體效率比單體錯合物LnODO2A+高上四至五個數量級；但是卻比EuDO2A+差了約一個數量級。

We have been interested in the design, synthesis and characterization of artificial nucleases and ribonucleases by employing macrocyclic lanthanide complexes. We use lanthanide ions to interact with ligands to form complexes. Because their high coordination number, Lewis acidity, charge density and oxidation states, they could be suitable for hydrolysis of the model compound of DNA / RNA, BNPP / HPNP. In our previous studies, we found that with more number of inner-sphere coordinated water molecules and a positive charge in the complexes, the more efficiency for hydrolysis. However, different ligands and lanthanide ions will influence the efficiency. In this research, we synthesize two new ligands, m-12N3O-dimer(1, 3-bis(1, 4, 10-triaza-7-oxacyclododec-1-ylmethyl)benzene) and m-ODO2A-dimer(1, 3-bis[4, 10-bis(carboxymethyl)- 1, 4, 10-triaza-7-oxacyclododec-1-ylmethyl]benzene) complex with transition and lanthanide ions, respectively. The result of hydrolysis studies shows that the complexes in dimer form are more effective than in monomer form with the same moiety. But the m-Eu2(ODO2A-dimer) has still lower efficiency compare to EuDO2A+. Besides hydrolysis studies, the thermodynamic characteristics are also important. These could help us to understand the whole mechanism of hydrolysis and the coordination features with lanthanide ions more accurately, and develop more efficient complexes in the future.