Control of Excited‐State Conformations in B,N‐Acenes

Lu, Zhenpin; Quanz, Henrik; Ruhl, Julia; Albrecht, G.; Logemann, Christian; Schlettwein, Derck; Schreiner, Peter R.; Wegner, Hermann A.

doi:10.1002/ange.201814104

“…This is in agreement with the studies of Lu et al. in 2019, [16] who showed that, the large Stokes shift is due to the twisting of the C 2 B 2 N 2 core in the diazadiboranapthalenes 6 in the excited state, which can be prevented in different matrices. Interestingly, our phosphorescence measurements showed a short‐lived phosphorescence of all diazadiboratriphenyles 7 a – h between 12.5 and 15.0 msec (see Supporting Information for details).…”

Section: Figuresupporting

confidence: 93%

“…Recently, our group reported a synthetic route to diazadiboranaphthalenes 6 and investigated their photophysical properties [16] . In these studies, we were able to show that the diazadiboranaphthalenes 6 exhibits two solvent‐dependent emissions, and the one at longer wavelength was attributed to a twisted intramolecular charge transfer (TICT).…”

Section: Figurementioning

confidence: 99%

Diazadiboraacenes: Synthesis, Spectroscopy and Computations

Ruhl

¹

,

Oberhof

²

,

Dreuw

³

et al. 2023

Angewandte Chemie

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The incorporation of heteroatoms into hydrocarbon compounds greatly expands the chemical space of molecular materials. In this context, B−N doping takes a center stage due to its isosterism with a C=C‐bond. Herein, we present a new and modular synthetic concept to access novel diazadiborabenzo[b]triphenylenes 7 a–h using the B−N doped biradical 16 as intermediate. Characterization of the photophysical properties revealed the emission spectra of the diazadibora benzo[b]triphenylenes 7 a–h can conveniently be tuned by small changes of the substitution on the boron‐atom. All of the diazadibora compounds show a short life‐time phosphorescence. Additionally, we were able to rationalize the excited‐state relaxation of the diazadiboraacene 7 a via intersystem crossing by quantum chemical calculations. The new synthetic strategy provides an elegant route to various novel B−N doped acenes with great potential for applications in molecular materials.

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A Bidentate Ligand Featuring Ditopic Lewis Acids in the Second Sphere for Selective Substrate Capture and Activation

Beagan

¹

,

Kiernicki

²

,

Zeller

³

et al. 2023

Angewandte Chemie

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We present a ligand platform featuring appended ditopic Lewis acids to facilitate capture/ activation of diatomic substrates. We show that incorporation of two 9-borabicyclo[3.3.1]nonane (9-BBN) units on a single carbon tethered to a pyridine pyrazole scaffold maintains a set of unquenched nitrogen donors available to coordinate Fe II , Zn II , and Ni II . Using hydride ion affinity and competition experiments, we establish an additive effect for ditopic secondary sphere boranes, compared to the monotopic analogue. These effects are exploited to achieve high selectivity for binding NO 2 À in the presence of competitive anions such as F À and NO 3 À . Finally, we demonstrate hydrazine capture within the second-sphere of metal complexes, followed by unique activation pathways to generate hydrazido and diazene ligands on Zn and Fe, respectively.

show abstract

A Bidentate Ligand Featuring Ditopic Lewis Acids in the Second Sphere for Selective Substrate Capture and Activation

Beagan

¹

,

Kiernicki

²

,

Zeller

³

et al. 2023

View full text Add to dashboard Cite

We present a ligand platform featuring appended ditopic Lewis acids to facilitate capture/ activation of diatomic substrates. We show that incorporation of two 9-borabicyclo[3.3.1]nonane (9-BBN) units on a single carbon tethered to a pyridine pyrazole scaffold maintains a set of unquenched nitrogen donors available to coordinate Fe II , Zn II , and Ni II . Using hydride ion affinity and competition experiments, we establish an additive effect for ditopic secondary sphere boranes, compared to the monotopic analogue. These effects are exploited to achieve high selectivity for binding NO 2 À in the presence of competitive anions such as F À and NO 3 À . Finally, we demonstrate hydrazine capture within the second-sphere of metal complexes, followed by unique activation pathways to generate hydrazido and diazene ligands on Zn and Fe, respectively.

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Control of Excited‐State Conformations in B,N‐Acenes

Abstract: Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Cited by 5 publications

References 44 publications

Diazadiboraacenes: Synthesis, Spectroscopy and Computations

Diazadiboraacenes: Synthesis, Spectroscopy and Computations

A Bidentate Ligand Featuring Ditopic Lewis Acids in the Second Sphere for Selective Substrate Capture and Activation

A Bidentate Ligand Featuring Ditopic Lewis Acids in the Second Sphere for Selective Substrate Capture and Activation

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