Ruthenium Complexes Bearing Axially Chiral Bipyridyls: The Mismatched Diastereomer Showed Red Circularly Polarized Phosphorescence

Abstract

RutheniumII complexes bearing three axially chiral bipyridyl ligands were synthesized as a new family of chiral complex dyes, and Δ‐(S)‐ and Λ‐(S)‐diastereomers were obtained. The X‐ray crystal structure analyses, spectroscopy, and DFT calculations suggested that all the bipyridyls maintained chirality in both the ground and excited states, and the Δ‐(S)‐ and Λ‐(S)‐isomers are the matched (more relaxed) and mismatched (more constrained) pairs, respectively. The mismatched Λ‐(S)‐isomer exhibited red circularly polarized phosphorescence (CPP) both in solution and in the solid state. The solution state CPP is the most intense of ruthenium complexes, while the solid state CPP is the first example of them. It is supposed that, for the Λ‐(S)‐isomer, the six cumulative CH/π interactions suppress further distortion in the T1 state.

Luminescent Iridium Complexes with a Sulfurated Bipyridine Ligand: PCET Thermochemistry of the Disulfide Unit and Photophysical Properties

“…In principle, different stereoisomers of a given complex can result in different emission properties, and since [1] + may exist as different stereoisomers, this possibility cannot be ruled out completely. 51 However, measurements with different excitation laser powers revealed that the long-lived luminescence decay component becomes increasingly pronounced at high ex- + indeed peaks at an emission wavelength (618 nm, Figure S13) similar to the emission of [1] + , see Table 3. Furthermore, the luminescence lifetime of [2] + (416 ns, Figure S14) is similar to the value of the long-lived component obtained from fitting of the luminescence decay of [1] + in MeCN (404 ns, Figure S11), thereby supporting the hypothesis that [1] + is not photo-stable and undergoes lightinduced decomposition to [2] + .…”

“…The steady-state emission spectra of [1] PF 6 recorded at 77 K (Figure S15) show only a single emission band and do not provide further evidence for true dual emission. In principle, different stereoisomers of a given complex can result in different emission properties, and since [1] + may exist as different stereoisomers, this possibility cannot be ruled out completely . However, measurements with different excitation laser powers revealed that the long-lived luminescence decay component becomes increasingly pronounced at high excitation powers, indicating the formation of a photo-decomposition product.…”

Mechano-Stimulus and Environment Dependent Circularly Polar-ized TADF in Chiral Copper(I) Complexes and their Application in OLEDs

“…However, the dihedral angle between the Cbz ligand and the plane defined by the metal center and the P atoms is only 26 This work glum = 2.3•10 -2 kr = 3•10 5 s -1 the BINAP and the Cbz ligands of the surrounding complex molecules occur in the single crystalline solid state, which stabilizes the ground state, but would destabilize CT states that experience a different electron density distribution (vide infra). 2)) 26.34 (18).…”

“…[17] Some chiral aggregates and Cu I clusters have been found to reach relatively high dissymmetry values of up to ±2•10 -2 , but such compounds are difficult to process for applications. [18]…”

Helical Induction, Chiroptical Properties, and Quantitative Prediction of the Dissymmetry Factor on the Circularly Polarized Phosphorescence of Iminopyrrolyl Platinum(II) Complexes

“…In recent years, chiral platinum, − iridium, − ruthenium, rhenium, and chromium , complexes bearing chiral and achiral ligands have been reported as circularly polarized phosphorescence (CPP) emitters. In contrast to the octahedral complexes, the reported chiral Pt­(II) complexes possess unique helicene, − , binaphthyl, , cyclophane, , cylinder-like, and other second-order , chiral structures owing to the square planar coordination, leading to diverse and rich photophysical properties (Figure S1).…”