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We report a series of seven cationic heteroleptic copper(I) complexes of the form [Cu(P^P)(dmphen)]BF4, where dmphen is 2,9-dimethyl-1,10-phenanthroline and P^P is a diphosphine chelate, in which the effect of the bite angle of the diphosphine ligand on the photophysical properties of the complexes was studied. Several of the complexes exhibit moderately high photoluminescence quantum yields in the solid state, with ΦPL of up to 35%, and in solution, with ΦPL of up to 98%. We were able to correlate the powder photoluminescence quantum yields with the % Vbur of the P^P ligand. The most emissive complexes were used to fabricate both organic light-emitting diodes and light-emitting electrochemical cells (LECs), both of which showed moderate performance. Compared to the benchmark copper(I)-based LECs, [Cu(dnbp)(DPEPhos)]+ (maximum external quantum efficiency, EQEmax = 16%), complex 3 (EQEmax = 1.85%) showed a much longer device lifetime (t1/2 = 1.25 h and >16.5 h for [Cu(dnbp)(DPEPhos)]+ and complex 3, respectively). The electrochemiluminescence (ECL) properties of several complexes were also studied, which, to the best of our knowledge, constitutes the first ECL study for heteroleptic copper(I) complexes. Notably, complexes exhibiting more reversible electrochemistry were associated with higher annihilation ECL as well as better performance in a LEC.

Funding: C.L. thanks the Prof. & Mrs Purdie Bequests Scholarship and AstraZeneca for a PhD Studentship. The St Andrews researchers thank the Engineering and Physical Sciences Research Council (EP/M02105X/1 and EP/R035164/1) for financial support. A.K.P. acknowledges the Leverhulme Trust and the University of St Andrews for an Early Career Fellowship (ECF-2017-326). H.J.B. and M.S. acknowledge funding from the Spanish Ministry of Science, Innovation and Universities (MAT2017‐88821‐R and RYC-2016-21316, respectively). C.F.H. acknowledges the support of the Australian Research Council (ARC) Discovery grant scheme (DP200102947). We report a series of seven cationic heteroleptic copper(I) complexes of the form [Cu(P^P)(dmphen)]BF4, where dmphen is 2,9-dimethyl-1,10-phenanthroline and P^P is a diphosphine chelate, in which the effect of the bite angle of the diphosphine ligand on the photophysical properties of the complexes was studied. Several of the complexes exhibit moderately high photoluminescence quantum yields in the solid state, with ΦPL of up to 35%, and in solution, with ΦPL of up to 98%. We were able to correlate the powder photoluminescence quantum yields with the % Vbur of the P^P ligand. The most emissive complexes were used to fabricate both organic light-emitting diodes and light-emitting electrochemical cells (LECs), both of which showed moderate performance. Compared to the benchmark copper(I)-based LECs, [Cu(dnbp)(DPEPhos)]+ (maximum external quantum efficiency, EQEmax = 16%), complex 3 (EQEmax = 1.85%) showed a much longer device lifetime (t1/2 = 1.25 h and >16.5 h for [Cu(dnbp)(DPEPhos)]+ and complex 3 , respectively). The electrochemiluminescence (ECL) properties of several complexes were also studied, which, to the best of our knowledge, constitutes the first ECL study for heteroleptic copper(I) complexes. Notably, complexes exhibiting more reversible electrochemistry were associated with higher annihilation ECL as well as better performance in a LEC. Postprint

CFRM and EZ-C wish to thank the Engineering and Physical Sciences Research Council (EP/M02105X/1 and EP/R035164/1) for financial support. We would like to thank the Engineering and Physical Sciences Research Council and CRITICAT Centre for Doctoral Training for financial support (Ph.D. studentship to B. H.; EP/L016419/1). We report the first example of a charge-neutral linear 2-coordinate copper(I) complex bearing a sterically demanding acenaphthoimidazolylidene-based N-heterocyclic carbene ligand. The identity and geometry of the complex was confirmed by single-crystal XRD (X-Ray Diffraction) analysis. The complex is poorly emissive at room temperature, showing either ligand-centered (LC) emission at around 340 nm when excited at 300 nm or ligand-to-ligand charge-transfer (LLCT) emission at around 540 nm when excited at 420 nm; in chloroform, dual emission is observed upon photoexcitation at 300 nm. Nanosecond emission lifetimes were recorded for these processes. This is the first example of emissive linear copper(I) complexes containing this bulky NHC ligand. Postprint

The reaction of [Ru3(CO)10(μ-dppm)] (1) with 4-ethynyl-2,2′-bipyridine (2) or 5-ethynyl-2,2′-bipyridine (3) affords the Ru3C2 clusters [Ru3(μ-H)(μ3-C2bpy)(CO)7(dppm)] (bpy = 4-bpy, 4 (22%); bpy = 5-bpy, 5 (55%)). Complexes 4 and 5 have been fully characterised by NMR spectroscopy, with 2D-COSY methods being used to aid 1H NMR assignments, and single crystal X-ray diffraction. The pendant bipyridyl moiety presents as a site for further reaction using the ‘Tinkertoy’ approach, and subsequent reactions of 4 and 5 with PdCl2(NCPh)2 affords the bimetallic complexes [Ru3(μ-H){μ3-C2bpy(κ2-N′,N–PdCl2)}(CO)7(dppm)] bpy = 4-bpy, 6 (55%); bpy = 5-bpy, 7 (35%)).

The authors are grateful to the University of St Andrews and EPSRC financial support (grants EP/P010482/1 and EP/M02105X/1). A.K.P thanks the Leverhulme Trust Early Career Fellowship (ECF-2017-326). I.D.W.S. acknowledges a Royal Society Wolfson Research Merit award. High‐efficiency pure blue phosphorescent organic light‐emitting diodes (OLEDs) remain one of the grand challenges, principally because the emissive complexes employed either do not possess sufficiently high photoluminescence quantum yields or exhibit unsatisfactory Commission International de l'Éclairage (CIE) coordinates. Here two deep‐blue‐emitting homoleptic iridium(III) complexes are reported and OLEDs are demonstrated with CIE coordinates of (0.15, 0.05) and maximum external quantum efficiency of 13.4%, which decreases slightly to 12.5% at 100 cd m−2. They represent examples of the most efficient OLEDs surpassing the CIEy requirement of the National Television System Committee (NTSC) and the European Broadcasting Union (EBU). Emitter orientation contributes to the excellent device performance. Postprint

Bipyridyl appended ruthenium alkynyl complexes have been used to prepare a range of binuclear homometallic ruthenium and heterometallic ruthenium–rhenium complexes. The two metal centers are only weakly coupled, as evinced by IR and UV–vis–near NIR spectroelectrochemical experiments and supported by quantum chemical calculations. The alkynyl complexes of the type [Ru(C≡Cbpy){Ln}] ({Ln} = {(PPh3)2Cp}, {(dppe)Cp*}, {Cl(dppm)2}) undergo reversible one-electron oxidations centered largely on the alkynyl ligands, as has been observed previously for closely related complexes. The homometallic binuclear complexes, exemplified by [Ru(C2bpy-κ2-N′N-RuClCp)(PPh3)2Cp] undergo two essentially reversible oxidations, the first centered on the (C2bpy-κ2-N′N-RuClCp) moiety and the second on the Ru(C≡Cbpy)(PPh3)2Cp fragment, leading to radical cations that can be described as Class II mixed-valence complexes. The heterometallic binuclear complexes [Ru(C2bpy-κ2-N′N-ReCl(CO)3){Ln}] display similar behavior, with initial oxid...

4-Ethynyl-2,2′-bipyridyl-substituted ruthenium alkynyl complexes have been prepared and used to access a range of binuclear homometallic ruthenium and heterometallic ruthenium–rhenium complexes. These have been characterized by a variety of spectroscopic and single-crystal X-ray diffraction experiments. The IR spectra of a number of these ruthenium alkynyls display multiple ν(C≡C) bands in the IR spectra, which are rationalized in terms of putative conformational isomers, whose calculated infrared stretching frequencies are comparable to those obtained experimentally. The mononuclear alkynyl ruthenium complexes undergo reversible one-electron oxidations centered largely on the alkynyl ligands, as inferred from the significant shift in ν(C≡C) frequency on oxidation, while the binuclear complex [Ru{C≡C-4-bpy-κ2-N,N′-RuClCp}(dppe)Cp*]+ undergoes initial oxidation at the very electron rich {RuCl(bpy)Cp} fragment, causing only a small change in ν(C≡C). A combination of IR and UV–vis spectroelectrochemical expe...