Wöhler Jannika, Meyer Marco, Prescimone Alessandro, Housecroft Catherine E, Constable Edwin C
Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland.
Dalton Trans. 2022 Aug 30;51(34):13094-13105. doi: 10.1039/d2dt01799g.
The N^N chelating ligands 6,6'-bis(but-3-en-1-yl)-2,2'-bipyridine (1), 6-(but-3-en-1-yl)-6'-methyl-2,2'-bipyridine (2), 6,6'-bis(pent-4-en-1-yl)-2,2'-bipyridine (3) and 6-(pent-4-en-1-yl)-6'-methyl-2,2'-bipyridine (4) have been prepared, characterized, and incorporated into the heteroleptic [Cu(N^N)(P^P)][PF] complexes in which P^P is either POP (bis(2-(diphenylphosphanyl)phenyl)ether) or xantphos (9,9-dimethyl-9-xanthene-4,5-diyl)bis(diphenylphosphane). The eight coordination compounds have been fully characterized, including the single crystal structures of [Cu(1)(xantphos)][PF], [Cu(1)(POP)][PF]·CHCl, [Cu(2)(xantphos)][PF], [Cu(2)(POP)][PF] and [Cu(3)(POP)][PF]·0.5EtO. The [Cu(N^N)(P^P)] cations exhibit a partially reversible or irreversible Cu/Cu oxidation at more positive potentials than the benchmark [Cu(bpy)(P^P)] and [Cu(Mebpy)(P^P)] complexes consistent with the increase in steric hindrance of the terminal alkenyl substituents. When excited in the region of the metal-to-ligand charge transfer (MLCT) absorption, solutions of the [Cu(N^N)(P^P)][PF] complexes are weak emitters with maxem in the range 565-578 nm. However, powdered samples achieve photoluminescence quantum yields in the range of 28.5 to 62.3%, with the highest PLQY found for [Cu(3)(POP)][PF] with an excited-state lifetime, , of 16.1 μs. For [Cu(3)(POP)][PF], the excited state lifetime was measured in MeTHF at 293 and 77 K, and the increase in from 1.77 to 59.4 μs upon cooling supports thermally activated delayed fluorescence (TADF) at ambient temperatures.
已制备、表征了N^N螯合配体6,6'-双(丁-3-烯-1-基)-2,2'-联吡啶(1)、6-(丁-3-烯-1-基)-6'-甲基-2,2'-联吡啶(2)、6,6'-双(戊-4-烯-1-基)-2,2'-联吡啶(3)和6-(戊-4-烯-1-基)-6'-甲基-2,2'-联吡啶(4)，并将它们引入到杂配体[Cu(N^N)(P^P)][PF]配合物中，其中P^P为POP(双(2-(二苯基膦基)phenyl)醚)或xantphos(9,9-二甲基-9-呫吨-4,5-二基)双(二苯基膦)。已对这八种配位化合物进行了全面表征，包括[Cu(1)(xantphos)][PF]、[Cu(1)(POP)][PF]·CHCl、[Cu(2)(xantphos)][PF]、[Cu(2)(POP)][PF]和[Cu(3)(POP)][PF]·0.5EtO的单晶结构。[Cu(N^N)(P^P)]阳离子在比基准[Cu(bpy)(P^P)]和[Cu(Mebpy)(P^P)]配合物更正的电位下表现出部分可逆或不可逆的Cu/Cu氧化，这与末端烯基取代基空间位阻的增加一致。当在金属到配体电荷转移(MLCT)吸收区域激发时，[Cu(N^N)(P^P)][PF]配合物的溶液是弱发射体，最大发射波长在565-578nm范围内。然而，粉末样品的光致发光量子产率在28.5%至62.3%之间，[Cu(3)(POP)][PF]的光致发光量子产率最高，激发态寿命为16.１μs。对于[Cu(3)(POP)][PF]，在293K和77K下于甲基四氢呋喃中测量了激发态寿命，冷却后激发态寿命从1.77μs增加到59.4μs，这支持了室温下的热激活延迟荧光(TADF)。
