Palladium(0) NHC complexes: a new avenue to highly efficient phosphorescence

Abstract

We report the first examples of highly luminescent di-coordinated Pd(0) complexes.

Hydrazine‐Free Facile Synthesis of Palladium‐Tetrakis(Triphenylphosphine)

“…The molar absorptivities (ε) were determined according to the Beer–Lambert law (Table ). The values of ε corresponded well with those previously reported for other Pd(0) complexes . Interestingly, as the energy of the band increases, it becomes significantly more absorptive, which is consistent with a more extended π‐network.…”

“…The complex thus prepared was analyzed by UV/Vis spectroscopy, and the molar extinction coefficients were determined in MeOH, DMSO, and CHCl 3 . In general, d 10 complexes have complicated electronic structures, and it is difficult to assign the UV/Vis bands.…”

Properties and prospects for rhenium(i) tricarbonyl N-heterocyclic carbene complexes

“…Amongst the various transition metal cations, typical luminescent complexes include those of Cu(I), 4 Ru(II), 2 Re(I), 5 Ir(III), 6 Au(I), 7 and Pt(II). 8 However, advances in this rapidly expanding field also include very recent examples of luminescent metal complexes of Ni(0) 9 , Pd(0), 10 and Rh(III). 11 The luminescent species including the above mentioned transition metal elements are not limited to mononuclear complexes, but include aggregated architectures with dominating metal-metal interactions as well as coordination polymers and clusters.…”

N-Heterocyclic Carbene-Based Tetradentate Pd(II) Complexes for Deep-Blue Phosphorescent Materials

“…63 NHC is a strong σ-donor and a relatively weak π-acceptor, which can shorten the metal−carbene bond length, shallow the LUMO energy level, and raise the d-d level of the excited state in the metal complexes; 22 these will be beneficial for the suppression of the thermally activated nonradiative decay and the enhancement of PLQY and radiative decay. In fact, NHCbased ligands have been adopted for the Pd(0) complexes by Zysman-Colman and co-workers in 2015, and a PLQY of 70.1% was achieved in toluene solution with a very short τ of 2.93 μs, 64 although these Pd(0) complexes were sensitive to molecular oxygen in air to afford Pd(II) peroxo adducts 64 to the full filled d 10 electronic structures of the Pd(0). However, the NHC-based tetradentate Pd(II) complexes have not been reported, and their stabilities and photophysical properties are still unknown.…”