Halide impact on emission of mononuclear copper(<scp>i</scp>) complexes with pyrazolylpyrimidine and triphenylphosphine
作者:Katerina A. Vinogradova、Victor F. Plyusnin、Arkady S. Kupryakov、Marianna I. Rakhmanova、Natalia V. Pervukhina、Dmitrii Yu. Naumov、Lilia A. Sheludyakova、Elena B. Nikolaenkova、Viktor P. Krivopalov、Mark B. Bushuev
DOI:10.1039/c3dt53040j
日期:——
A series of mononuclear heteroleptic copper(I) halide complexes, [CuL(PPh3)X] (X = Cl, Br, I), based on 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)pyrimidine (L) and triphenylphosphine, have been synthesized by reaction between CuX (X = Cl, Br, I), L and PPh3 in a molar ratio of 1/1/1 in MeCN solutions. The copper atom, showing the distorted tetrahedral environment, is bound by the N,N-chelating ligand L, triphenylphosphine and a halide ion. The complexes [CuL(PPh3)Cl] and [CuL(PPh3)Br] are isostructural. In CH2Cl2 solutions, L and the complexes [CuL(PPh3)X] (X = Cl, Br, I) display a luminescence band with λmax = 377 nm and a lifetime of 1.9 ns (ligand-based luminescence (LL*)). However, the complex [CuL(PPh3)I] has an additional weak luminescence band with λmax = 681 nm and a lifetime of 96 ns of 3MLCT origin. In the solid state, L shows the splitting of the luminescence band to λmax = 365 and 384 nm and a slight increase of the lifetime to 2.66 ns. Solid samples of the complexes [CuL(PPh3)X] demonstrate 3MLCT luminescence bands at 620 nm (X = Cl), 605 nm (X = Br) and 559 nm (X = I) with lifetimes in the range 3.6–11.2 μs, whereas the LL* band (377 nm) is absent. Quantum yields and rate constants of radiative and nonradiative processes were determined in CH2Cl2 solutions and in the solid state for all complexes. The luminescence quantum yield and lifetimes for the solid samples increase in the order [CuL(PPh3)Cl] < [CuL(PPh3)Br] < [CuL(PPh3)I]. This is due to the increase of radiative decay and simultaneous suppression of nonradiative decay. The complex [CuL(PPh3)I] shows a high quantum yield of 29.4% and an excited state lifetime of 11.2 μs.
通过 CuX(X = Cl、Br、I)、L 和 PPh3 在 MeCN 溶液中以 1/1/1 的摩尔比发生反应,合成了一系列基于 4-(3,5-二苯基-1H-吡唑-1-基)-6-(哌啶-1-基)嘧啶(L)和三苯基膦的单核异极铜(I)卤化物配合物 [CuL(PPh3)X](X = Cl、Br、I)。铜原子显示出畸变的四面体环境,并与 N,N-螯合配体 L、三苯基膦和卤离子结合。[CuL(PPh3)Cl]和[CuL(PPh3)Br]复合物结构相同。在 CH2Cl2 溶液中,L 和配合物 [CuL(PPh3)X](X = Cl、Br、I)显示出一条发光带,λmax = 377 nm,寿命为 1.9 ns(配体发光(LL*))。然而,[CuL(PPh3)I] 复合物还有一个额外的弱发光带,λmax = 681 nm,寿命为 96 ns(3MLCT)。在固态下,L 显示发光带分裂为 λmax = 365 和 384 nm,寿命略微延长至 2.66 ns。复合物[CuL(PPh3)X]的固体样品在 620 nm(X = Cl)、605 nm(X = Br)和 559 nm(X = I)处显示出 3MLCT 发光带,寿命范围为 3.6-11.2 μs,而 LL* 发光带(377 nm)不存在。测定了所有复合物在 CH2Cl2 溶液和固态下辐射和非辐射过程的量子产率和速率常数。固体样品的发光量子产率和寿命按照 [CuL(PPh3)Cl] < [CuL(PPh3)Br] < [CuL(PPh3)I] 的顺序增加。这是由于辐射衰变的增加和非辐射衰变的同时抑制。复合物 [CuL(PPh3)I] 的量子产率高达 29.4%,激发态寿命为 11.2 μs。