Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou Industrial Park, Jiangsu, P R China.
Dalton Trans. 2012 Mar 7;41(9):2582-91. doi: 10.1039/c1dt11716e. Epub 2011 Dec 14.
In order to enhance the photoluminescence of cyclometalated iridium(III) complexes, which are potentially useful for biolabeling and bioimaging, a series of benzyl ether branched dendritic moieties with carbazolyl termini were introduced to the cyclometalating C^N ligands of the heteroleptic Ir(III) complexes. The complexes also contain a bidentate bipyridine ligand with a carboxyl group for further bioconjugation or functionalization. The dendritic benzyl ether moieties with carbazolyl peripheral groups have demonstrated a dual function as both a Förster resonance energy transfer (FRET) donor and an oxygen shield to the Ir(III) complex core. The peripheral carbazolyl groups absorb UV light more intensively and transfer energy efficiently to the Ir(III) complex core via the FRET effect, and thus the photoluminescence of the Ir(III) complex at around 560 nm is significantly enhanced. Furthermore, the benzyl ether dendrimers containing carbazolyl termini can shield the Ir(III) complex core to weaken the oxygen quenching effect, which leads to a further enhancement of the PL of the Ir(III) complex.
为了增强具有潜在生物标记和生物成像应用价值的金属铱配合物的光致发光性能，在杂化铱（III）配合物的金属化 C^N 配体中引入了一系列带有咔唑末端的苄基醚支化树枝状部分。这些配合物还含有一个带有羧基的双吡啶配体，可用于进一步的生物偶联或功能化。带有咔唑外围基团的树枝状苄基醚部分具有作为Förster 共振能量转移（FRET）供体和铱（III）配合物核心的氧屏蔽的双重功能。外围咔唑基团更强烈地吸收紫外光，并通过 FRET 效应有效地将能量转移到 Ir(III) 配合物的核心，从而显著增强了 Ir(III) 配合物在 560nm 左右的光致发光。此外，含有咔唑末端的苄基醚树枝状聚合物可以屏蔽 Ir(III) 配合物的核心，减弱氧猝灭效应，从而进一步增强 Ir(III) 配合物的 PL。
