含胺取代之聯吡啶釕錯化合物在光誘導電子轉移反應中的影響

Abstract

本論文研究 [Ru(bpy)2(4,4’-dabpy)]2+ 和[Ru(bpy)2(5,5’-dabpy)]2+ 兩種位向配位基的釕金屬錯合物作為電子提供者的同異。合成出六種以不同胺基酸為橋基的衍生物，分別是[Ru(bpy)2(4,4’-dabpy-(gly- A)2)]2+、[Ru(bpy)2(4,4’-dabpy-(phe-A)2)]2+、[Ru(bpy)2(4,4’-dabpy-(ile-A)2 )]2+、[Ru(bpy)2(4,4’-dabpy-(ile-A))]2+、[Ru(bpy)2(5,5’-dabpy-(phe-A)2 )]2+、[Ru(bpy)2(5,5’-dabpy-(ile-A)2)]2+。

利用冷光光譜的Quantum Yield及Time –Resulted luminescence decay的方式可測得電子轉移速率常數。[Ru(bpy)2(4,4’-dabpy-(gly- A)2)]2+、[Ru(bpy)2(4,4’-dabpy-(phe-A)2)]2+、[Ru(bpy)2(4,4’-dabpy-(ile-A)2 )]2+ 的電子轉移速率常數分別是 3.2 x 106 、 1.1 x 107 、 1.5 x 107 s-1，[Ru(bpy)2(5,5’-dabpy-(phe-A)2)]2+、[Ru(bpy)2(5,5’-dabpy-(ile-A)2)]2+則是2.1 x 107 、 2.4 x107 s-1；我們發現，兩種電子提供者會因為取代基位向不同而有不同程度的電子提供能力，進而影響電子傳遞的效果。其中，[Ru(bpy)2(5,5’-dabpy)]2+ 的電子提供能力較好，其胺基酸衍生物的電子傳遞速率亦較快。

在生命系統的電子轉移效應中，除了胺基酸的種類是ㄧ大關鍵外，取代基的位向亦扮演了重大的角色。

A donor-bridge-acceptor system was designed to investing the electron transfer efficienty, where donors were Ru(bpy)2(4,4’-dabpy), and Ru(bpy)2(5,5’-dabpy), acceptor is 2,4-dinitrobezene, and the amino acids (glycine, phenylalanine, isoleuecine) were bridging molecules . Six complexes [Ru(bpy)2(4,4’-dabpy-(gly-A)2)]2+, [Ru(bpy)2(4,4’-dabpy- (phe-A)2)]2+, [Ru(bpy)2(4,4’-dabpy-(ile-A)2)]2+, [Ru(bpy)2(4,4’-dabpy- (ile-A))]2+,[Ru(bpy)2-(5,5’-dabpy-(phe-A)2)]2+, and [Ru(bpy)2(5,5’-dabpy-(ile-A)2)]2+ have been prepared.

The electron transfer rate constants of [Ru(bpy)2(4,4’-dabpy- (gly-A)2)]2+, [Ru(bpy)2(4,4’-dabpy-(phe-A)2)]2+, and [Ru(bpy)2- (4,4’-dabpy-(ile-A)2)]2+ are 3.2 x 106, 1.1 x 107, and 1.5 x 107 s-1, respectively, and the electron transfer rate constants of [Ru(bpy)2- (5,5’-dabpy-(phe-A)2)]2+, [Ru(bpy)2(5,5’-dabpy-(ile-A)2)]2+ are 2.1 x 107 and 2.5 x 107 s-1, respectively. In the amino-acid series, isoluecine bridge gives the fastest electron transfer rate, followed by phenylalanine and glycine which is consist with the -donating abilities of the bridge molecules.

The trend in the donor side showed the 5,5’-substituted amine bipyridine gives faster electron transfer rate, again, is consist with the electron donating ability of the donor. These results indicate the substitution position of ligand plays an important role for electron transfer in complexes.