An Extremely Bright Heteroleptic Bis(dipyrrinato)zinc(II) Complex

Abstract

Let your light shine: The first example of a heteroleptic bis(dipyrrinato)zinc(II) complex, 7a, was synthesized from two types of dipyrrins prepared by a new deboration protocol for BODIPYs. Complex 7a showed a higher fluorescence quantum yield (0.76 in toluene) than the corresponding homoleptic complexes 5a and 6. The superiority of 7a as a luminophore was more prominent in more polar CH2Cl2 (see picture).

Symmetry-Breaking Charge Transfer of Visible Light Absorbing Systems: Zinc Dipyrrins

“…47 Interestingly, a recent study on related mesityl-substituted zinc dipyrrins (zDIP2 and zDIP4) has reported that the quantum yields of the homoleptic complexes are strongly dependent on solvent polarity, decreasing from 20–30% in toluene to ≤5% in dichloromethane. 44 The authors proposed that this decrease in polar solvents is due to thermal promotion from a locally excited state on a single dipyrrin ligand to a nonemissive, charge-separated state (i.e., D + –Zn–D – ); 44 however, no additional photophysical data was provided to support this hypothesis. Strong excitonic coupling between nonorthogonal ligands has also been suggested as another nonradiative deactivation pathway of zinc π-extended dipyrrin complexes.…”

Bis(dipyrrinato)zinc(II) Complexes: Emission in the Solid State

“…Hereafter, the structures and luminescent properties of the five complexes were disclosed and discussed, together with those of 1a 2 Zn and 1c 2 Zn synthesized previously. 8 The complexes' spectroscopic properties in solution are summarized in Table 1, and their absorption spectra are shown in Figure 1a. The regions of absorption maxima (488−511 nm), molar extinction coefficients (1.2 × 10 5 −1.6 × 10 5 M −1 cm −1 ), and emission wavelengths (510−558 nm) are typical of bis(dipyrrinato)zinc(II) complexes and are attributable to the 1 π−π* transition of the dipyrrin core.…”

“…The regions of absorption maxima (488−511 nm), molar extinction coefficients (1.2 × 10 5 −1.6 × 10 5 M −1 cm −1 ), and emission wavelengths (510−558 nm) are typical of bis(dipyrrinato)zinc(II) complexes and are attributable to the 1 π−π* transition of the dipyrrin core. 8 For complexes 2a 2 Zn− 2c 2 Zn, there is an additional absorption band around 370 nm, attributable to the 1 π−π* transition of the anthracene subunit. The constant absorption and emission wavelengths suggest that the meso-aryl groups of the complexes have little effect on the ground and photoexcited electronic states of the dipyrrin subunit.…”

Triarylamine-Conjugated Bis(dipyrrinato)zinc(II) Complexes: Impact of Triarylamine on Photochemical Property and Multi-Redox Reaction

“…The structural feature implies that interaction in the ground state between the two moieties is not outstanding. Other structural features were almost the same as those of other bis(dipyrrinato)zinc(II) complexes: 8 The zinc centers adopted tetrahedral coordination spheres (dihedral angles: 87.45 and 82.90°for 1 and 2), and the zincnitrogen bond lengths spanned from 1.9681.976 ¡ (average: 1.973 ¡) for 1, and 1.9651.968 ¡ (average: 1.967 ¡) for 2. Figure 3 shows normalized UV-vis spectra of triarylamineconjugated bis(dipyrrinato)zinc(II) complexes 1 and 2 in toluene.…”