The application domain of accurate and efficient CE-B3LYP and CE-HF model energies for intermolecular interactions in molecular crystals is extended by calibration against density functional results for 1794 molecule/ion pairs extracted from 171 crystal structures. The mean absolute deviation of CE-B3LYP model energies from DFT values is a modest 2.4 kJ mol À1 for pairwise energies that span a range of 3.75 MJ mol À1. The new sets of scale factors determined by fitting to counterpoise-corrected DFT calculations result in minimal changes from previous energy values. Coupled with the use of separate polarizabilities for interactions involving monatomic ions, these model energies can now be applied with confidence to a vast number of molecular crystals. Energy frameworks have been enhanced to represent the destabilizing interactions that are important for molecules with large dipole moments and organic salts. Applications to a variety of molecular crystals are presented in detail to highlight the utility and promise of these tools.

chromaticity standards defined by the National Television System Committee (NTSC) and European Broadcasting Union (EBU) with Commission Internationale de l'Éclairage (CIE) coordinates of (0.14, 0.08) and (0.15, 0.06), respectively; 2) possess high photoluminescence quantum yields (Φ PL ) that translate into high external quantum efficiencies in the OLED, particularly at useful brightnesses (at least 100 cd m −2 for displays and 1000 cd m −2 for lighting); and 3) exhibit competitive device stabilities to fluorescent complexes. [1] Of the phosphorescent complexes studied, iridium(III) compounds have attracted the widest interest as emitters in electroluminescent devices due to their high Φ PL , short phosphorescence lifetimes (τ PL ) and facile color tunability based on the choice of ligands around the metal center. [2] Despite these properties, the design of highly efficient pure blue phosphorescent iridium complexes remains a challenging target to achieve. [3] In order to tune the emission to the blue, electronwithdrawing substituents are typically incorporated on the cyclometalating ligands of the iridium complexes. Three issues arise when employing this strategy. The first is that the electrochemical stability of fluoro substituents, the most popular electron-withdrawing substituent, such as in the widely studied FIrpic [iridium(III)bis(4,6-difluopyridinato-N,C 2′ )picolinate] sky blue emitter, [4] is poor, translating to greatly reduced device stability; [5] while the use of other more strongly electron-withdrawing substituents do not necessarily translate into blueremitting complexes, despite deepening the highest occupied molecular orbital (HOMO) of the compound. [6] The second is that as the energy of the emissive triplet state increases, nonradiative recombination via thermally accessible metal-centered excited states becomes increasingly problematic, leading to emitter degradation. [7] Finally, most iridium(III) complexes do not meet the deep blue chromaticity requirements, and instead possess CIE y ordinates greater than 0.1 as their triplet energies are not sufficiently high (at least 2.8 eV); [3b,8] those that do possess maximal external quantum efficiency (EQE max ) values < 10%. [9] Another strategy to tune the emission of charge-neutral iridium(III) complexes to the blue is to replace the coordinating pyridine rings that are typically employed with more sigma-donating heterocycles that serve to destabilize the lowest unoccupied molecular orbital (LUMO) of the complexes, such as imidazoles [10] and N-heterocyclic carbene (NHC) ligands. [9b,10b,11] 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 ...

Structure-property relationships are the key to modern crystal engineering, and for molecular crystals this requires both a thorough understanding of intermolecular interactions, and the subsequent use of this to create solids with desired properties. There has been a rapid increase in publications aimed at furthering this understanding, especially the importance of non-canonical interactions such as halogen, chalcogen, pnicogen, and tetrel bonds. Here we show how all of these interactions - and hydrogen bonds - can be readily understood through their common origin in the redistribution of electron density that results from chemical bonding. This redistribution is directly linked to the molecular electrostatic potential, to qualitative concepts such as electrostatic complementarity, and to the calculation of quantitative intermolecular interaction energies. Visualization of these energies, along with their electrostatic and dispersion components, sheds light on the architecture of molecular crystals, in turn providing a link to actual crystal properties.

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){L n }] ({L n } = {(PPh 3 ) 2 Cp}, {(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(C 2 bpy-κ 2 -N′N-RuClCp)(PPh 3 ) 2 Cp] undergo two essentially reversible oxidations, the first centered on the (C 2 bpy-κ 2 -N′N-RuClCp) moiety and the second on the Ru(CCbpy)(PPh 3 ) 2 Cp fragment, leading to radical cations that can be described as Class II mixed-valence complexes. The heterometallic binuclear complexes [Ru(C 2 bpy-κ 2 -N′N-ReCl(CO) 3 ){L n }] display similar behavior, with initial oxidation on the ruthenium fragment giving rise to a new optical absorption band with Re → Ru(CCbpy) charge transfer character. The heterometallic complexes also exhibit irreversible reductions associated with the Re hetereocycle moiety. ■ EXPERIMENTAL SECTIONGeneral Considerations. All reactions were performed under an atmosphere of high purity argon or nitrogen using standard Schlenk techniques. Reaction solvents either were purified and dried using an Special Issue: Organometallic Electrochemistry

We report a series of seven cationic heteroleptic copper(I) complexes of the form [Cu(P^P)(dmphen)]BF 4 , 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 Φ PL of up to 35%, and in solution, with Φ PL of up to 98%. We were able to correlate the powder photoluminescence quantum yields with the % V bur of the P^P ligand. The most emissive complexes were used to fabricate both organic lightemitting 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, EQE max = 16%), complex 3 (EQE max = 1.85%) showed a much longer device lifetime (t 1/2 = 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.