Exploring synthetic pathways to cationic heteroleptic cyclometalated iridium complexes derived from dipyridylketone
作者:Giorgio Volpi、Claudio Garino、Carlo Nervi
DOI:10.1039/c2dt30399j
日期:——
Reactions between 2,2′-dipyridylketone (L1) and different amines gave a series of iminic ligands, and their chemical reductions produced the related amines. The organic ligands were employed in the syntheses of the corresponding new phosphorescent six-member ring bis-cyclometalated heteroleptic iridium(III) complexes of general formula [Ir(ppy)2(L)]+ (ppy = 2-phenylpyridine), namely IrLn. The metal complexes containing N-(dipyridin-2-ylmethylene)butan-1-amine (IrL2), N-(dipyridin-2-ylmethyl)butan-1-amine (IrL5), N-(dipyridin-2-ylmethyl)butane-1,4-diamine with amino groups protected by Boc (IrL6-Boc) and TFA (IrL6-TFA), and N-(dipyridin-2-ylmethyl)-N-methylbutan-1-amine (IrL8) were characterized and their electronic and spectroscopic properties interpreted by DFT calculations. Organoiridium complexes containing amines and imines were found to have high and low photoemission quantum yields, respectively, and their features rationalized by quantum mechanic calculations. Some of these complexes show reasonable quantum yields (up to 13%), long lifetime (up to 2.3 μs) and high stability. Complementary and alternative synthetic pathways to get cationic heteroleptic cyclometalated Ir complexes bearing a tethered primary amino group have been explored with the aim to obtain organometallic phosphorescent derivatives suitable for surface functionalization.
2,2′-dipyridylketone (L1) 与不同胺的反应产生了一系列亚氨基配体,它们的化学还原产生了相关的胺。利用这些有机配体合成了通式为 [Ir(ppy)2(L)]+ (ppy = 2-苯基吡啶)的相应的新磷光六元环双环甲基化杂环铱(III)配合物,即 IrLn。含有 N-(二吡啶-2-基亚甲基)丁烷-1-胺(IrL2)、N-(二吡啶-2-基亚甲基)丁烷-1-胺(IrL5)、N-(二吡啶-2-基亚甲基)丁烷-1,4-二胺且氨基受 Boc(IrL6-Boc)和 TFA(IrL6-TFA)保护的金属配合物、和 N-(二吡啶-2-基甲基)-N-甲基丁-1-胺(IrL8)进行了表征,并通过 DFT 计算解释了它们的电子和光谱特性。研究发现,含有胺和亚胺的有机铱配合物分别具有较高和较低的光辐射量子产率,并通过量子力学计算合理地解释了它们的特征。其中一些配合物显示出合理的量子产率(高达 13%)、长寿命(高达 2.3 μs)和高稳定性。为了获得适合表面功能化的有机金属磷光衍生物,我们探索了获得带有系链伯氨基的阳离子异极环化铱配合物的互补和替代合成途径。