TY  - JOUR
A1  - Merz, Julia
A1  - Dietz, Maximilian
A1  - Vonhausen, Yvonne
A1  - Wöber, Frederik
A1  - Friedrich, Alexandra
A1  - Sieh, Daniel
A1  - Krummenacher, Ivo
A1  - Braunschweig, Holger
A1  - Moos, Michael
A1  - Holzapfel, Marco
A1  - Lambert, Christoph
A1  - Marder, Todd  B.
T1  - Synthesis, Photophysical and Electronic Properties of New Red-to-NIR Emitting Donor-Acceptor Pyrene Derivatives
JF  - Chemistry - A European Journal
N2  - We synthesized new pyrene derivatives with strong bis(para ‐methoxyphenyl)amine donors at the 2,7‐positions and n ‐azaacene acceptors at the K‐region of pyrene. The compounds possess a strong intramolecular charge transfer, leading to unusual properties such as emission in the red to NIR region (700 nm), which has not been reported before for monomeric pyrenes. Detailed photophysical studies reveal very long intrinsic lifetimes of >100 ns for the new compounds, which is typical for 2,7‐substituted pyrenes but not for K‐region substituted pyrenes. The incorporation of strong donors and acceptors leads to very low reduction and oxidation potentials, and spectroelectrochemical studies show that the compounds are on the borderline between localized Robin‐Day class‐II and delocalized Robin‐Day class‐III species.
KW  - orylation
KW  - K-region
KW  - luminescence
KW  - polycyclic aromatic hydrocarbons
KW  - redox
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-207486
VL  - 26
IS  - 2
ER  - 
TY  - JOUR
A1  - Ji, Lei
A1  - Griesbeck, Stefanie
A1  - Marder, Todd B.
T1  - Recent developments in and perspectives on three-coordinate boron materials: a bright future
JF  - Chemical Science
N2  - The empty p\(_z\)-orbital of a three-coordinate organoboron compound leads to its electron-deficient properties, which make it an excellent π-acceptor in conjugated organic chromophores. The empty p-orbital in such Lewis acids can be attacked by nucleophiles, so bulky groups are often employed to provide air-stable materials. However, many of these can still bind fluoride and cyanide anions leading to applications as anion-selective sensors. One electron reduction generates radical anions. The π-acceptor strength can be easily tuned by varying the organic substituents. Many of these compounds show strong two-photon absorption (TPA) and two-photon excited fluorescence (TPEF) behaviour, which can be applied for e.g. biological imaging. Furthermore, these chromophores can be used as emitters and electron transporters in OLEDs, and examples have recently been found to exhibit efficient thermally activated delayed fluorescence (TADF). The three-coordinate organoboron unit can also be incorporated into polycyclic aromatic hydrocarbons. Such boron-doped compounds exhibit very interesting properties, distinct from their all-carbon analogues. Significant developments have been made in all of these areas in recent years and new applications are rapidly emerging for this class of boron compounds.
KW  - anorganic chemistry
KW  - boron
KW  - 3-coordinate boron
KW  - Lewis acids
KW  - OLED
KW  - polycyclic aromatic hydrocarbons
KW  - chromophore
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171912
VL  - 8
IS  - 2
ER  -