Coinage Metal Complexes of Bis(quinoline-2-ylmethyl)phenylphosphine-Simple Reactions Can Lead to Unprecedented Results

The different coordination behavior of the flexible yet sterically demanding, hemilabile P,N ligand bis(quinoline‐2‐ylmethyl)phenylphosphine (bqmpp) towards selected Cu^I, Ag^I and Au^I species is described. The resulting X‐ray crystal structures reveal interesting coordination geometries. With [Cu(MeCN)₄]BF₄, compound 1 [Cu₂(bqmpp)₂](BF₄)₂ is obtained, wherein the copper(I) atoms display a distorted square planar and square pyramidal geometry. The steric demand and π‐stacking of the ligand allow for a short Cu⋅⋅⋅Cu distance (2.588(9) Å). Cu^I complex 2 [Cu₄Cl₃(bqmpp)₂]BF₄ contains a rarely observed Cu₄Cl₃ cluster, probably enabled by dichloromethane as the chloride source. In the cluster, even shorter Cu⋅⋅⋅Cu distances (2.447(1) Å) are present. The reaction of Ag[SbF₆] with the ligand leads to a dinuclear compound (3) in solution as confirmed by ³¹P{¹H} NMR spectroscopy. During crystallization, instead of the expected phosphine complex 3, a tris(quinoline‐2‐ylmethyl)bisphenyl‐phosphine (tqmbp) compound [Ag₂(tqmbp)₂](SbF₆)₂4 is formed by elimination of quinaldine. The Au(I) compound [Au₂(bqmpp)₂]PF₆ (5) is prepared as expected and shows a linear arrangement of two phosphine ligands around Au^I.

Recent Progress in Luminescent Cu(I) Halide Complexes: A Mini-Review

Copper(I) halide complexes are well sought-after materials due to their rich structural diversities and photophysical properties. Profoundly, there is a direct relationship between each structural variation and luminescence of these complexes, for a purported use. In this review, recent publications within the last 2 years about copper(I) halide complexes, centering on their structural dimensionalities with derivatives of nitrogen, phosphorus, and sulfur ligands, have been considered alongside their effects on luminescence.

Near-infrared emitting copper(I) complexes with a pyrazolylpyrimidine ligand: exploring relaxation pathways

Mononuclear copper(I) complexes [CuL2]I (1), [CuL2]2[Cu2I4]·2MeCN (2) and [CuL2]PF6 (3) with a new chelating pyrazolylpyrimidine ligand, 2-(3,5-dimethyl-1H-pyrazol-1-yl)-4,6-diphenylpyrimidine (L), were synthesized. In the structures of complex cations [CuL2]+, Cu+ ions coordinate...

Fabrication of a Solution-Processed White Light Emitting Diode Containing a Single Dimeric Copper(I) Emitter Featuring Combined TADF and Phosphorescence

Luminescent copper(I) complexes showing thermally activated delayed fluorescence (TADF) have developed to attractive emitter materials for organic light emitting diodes (OLEDs). Here, we study the brightly luminescent dimer Cu2Cl2(P∩N)2 (P∩N = diphenylphosphanyl-6-methyl-pyridine), which shows both TADF and phosphorescence at ambient temperature. A solution-processed OLED with a device structure ITO/PEDOT:PSS/PYD2: Cu2Cl2(P∩N)2/DPEPO (10 nm)/TPBi (40 nm)/LiF (1.2 nm)/Al (100 nm) shows warm white emission with moderate external quantum efficiency (EQE). Methods for EQE increase strategies are discussed.

P∩N Bridged Cu(I) Dimers Featuring Both TADF and Phosphorescence. From Overview towards Detailed Case Study of the Excited Singlet and Triplet States

We present an overview over eight brightly luminescent Cu(I) dimers of the type Cu₂X₂(P∩N)₃ with X = Cl, Br, I and P∩N = 2-diphenylphosphino-pyridine (Ph₂Ppy), 2-diphenylphosphino-pyrimidine (Ph₂Ppym), 1-diphenylphosphino-isoquinoline (Ph₂Piqn) including three new crystal structures (Cu₂Br₂(Ph₂Ppy)₃ 1-Br, Cu₂I₂(Ph₂Ppym)₃ 2-I and Cu₂I₂(Ph₂Piqn)₃ 3-I). However, we mainly focus on their photo-luminescence properties. All compounds exhibit combined thermally activated delayed fluorescence (TADF) and phosphorescence at ambient temperature. Emission color, decay time and quantum yield vary over large ranges. For deeper characterization, we select Cu₂I₂(Ph₂Ppy)₃, 1-I, showing a quantum yield of 81%. DFT and SOC-TDDFT calculations provide insight into the electronic structures of the singlet S₁ and triplet T₁ states. Both stem from metal+iodide-to-ligand charge transfer transitions. Evaluation of the emission decay dynamics, measured from 1.2 ≤ T ≤ 300 K, gives ∆E(S₁-T₁) = 380 cm⁻¹ (47 meV), a transition rate of k(S₁→S₀) = 2.25 × 10⁶ s⁻¹ (445 ns), T₁ zero-field splittings, transition rates from the triplet substates and spin-lattice relaxation times. We also discuss the interplay of S₁-TADF and T₁-phosphorescence. The combined emission paths shorten the overall decay time. For OLED applications, utilization of both singlet and triplet harvesting can be highly favorable for improvement of the device performance.