School of Chemistry and Materials Science & Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China.
Dalton Trans. 2019 Feb 12;48(7):2430-2441. doi: 10.1039/c8dt04538k.
Considerable attention has been focused on Cu(i)-diimine-phosphine complexes because of their good room-temperature phosphorescence since 1979, but no attention has been focused on the exploration and exploitation by using them as smart acid-base responsive switching luminescent materials. Herein, the reaction of [Cu(MeCN)4]PF6, 2-(2-naphthyl)-1H-imidazo[4,5-f][1,10]phenanthroline (nimpH) and chelating diphosphine ligands bis[(2-diphenylphosphino)phenyl] ether (POP) and 9,9-dimethyl-4,5-bis(diphenylphosphino)-9H-xanthene (xantphos) or (±)-2,2'-bis(diphenylphosphino)-1,1'-binaphthalene (BINAP) in a 1 : 1 : 1 ratio afforded three ionic [Cu(nimpH)(PP)]PF6 complexes (PP = POP, 1a; xantphos, 2a; BINAP, 3a) and three neutral [Cu(nimp)(PP)] complexes (PP = POP, 1b; xantphos, 2b; BINAP, 3b) in neutral and strong alkaline media, respectively. The non-emissive complexes 1a, 2a and 3a exhibit turn-on luminescence upon exposure to the strong base NaOH and tetrabutylammonium fluoride (TBAF), and the intensely emissive complexes 1b, 2b and 3b display turn-off luminescence upon exposure to trifluoroacetic acid (TFA) in CH2Cl2 solutions. Naked-eye repeatable off-on-off or on-off-on luminescence behaviors of these complexes are observed in CH2Cl2 with reversible base-acid or acid-base responses. On the other hand, the addition of TBAF to neutral complexes 1b, 2b and 3b results in obvious luminescence enhancement, especially for the diluted solutions and complexes with the flexible diphosphine ligand POP. The plausible mechanisms of the above results are discussed.
自 1979 年以来，由于其良好的室温磷光，人们对 Cu(i)-二亚胺-膦配合物给予了相当多的关注，但尚未关注将其作为智能酸碱响应开关发光材料进行探索和开发。在此，[Cu(MeCN)4]PF6、2-(2-萘基)-1H-咪唑并[4,5-f][1,10]菲咯啉(nimpH)与螯合双膦配体双[(2-二苯基膦基)苯基]醚(POP)和 9,9-二甲基-4,5-双(二苯基膦基)-9H-呫吨(xantphos)或(±)-2,2'-双(二苯基膦基)-1,1'-联萘(BINAP)以 1:1:1 的比例反应，在中性和强碱性介质中分别得到三个离子[Cu(nimpH)(PP)]PF6 配合物(PP=POP, 1a；xantphos, 2a；BINAP, 3a)和三个中性[Cu(nimp)(PP)]配合物(PP=POP, 1b；xantphos, 2b；BINAP, 3b)。非发光配合物 1a、2a 和 3a 在暴露于强碱 NaOH 和四丁基氟化铵(TBAF)时表现出开启发光，而强发光配合物 1b、2b 和 3b 在暴露于三氟乙酸(TFA)时在 CH2Cl2 溶液中显示关闭发光。这些配合物在 CH2Cl2 中具有可重复的肉眼可见的关-开-关或开-关-开发光行为，具有可逆的酸碱响应。另一方面，向中性配合物 1b、2b 和 3b 中加入 TBAF 会导致明显的发光增强，尤其是对于稀释溶液和具有柔性双膦配体 POP 的配合物。讨论了上述结果的可能机制。
