Jan Freudenberg
YOU?
Author Swipe
FRET‐Enhanced Singlet Fission in Pentacene Derivatives Open
Conversion of solar energy with high quantum efficiencies is a key challenge in energy technologies. Excitation energy transfer (EET) mechanisms, such as Förster resonance energy transfer (FRET), play a crucial role in facilitating minimal…
View article: Ring Contraction of Cyclooctatetraenes toward Non‐Benzenoid Polycyclic Aromatic Hydrocarbons by Au(111)‐Catalysis and Bulk Pyrolysis
Ring Contraction of Cyclooctatetraenes toward Non‐Benzenoid Polycyclic Aromatic Hydrocarbons by Au(111)‐Catalysis and Bulk Pyrolysis Open
The Au(111)‐catalyzed cyclodehydrogenation of tetraphenylated diacenaphtho‐cyclooctatetraene ( DA‐COT ) and tetraacenaphtho‐cyclooctatetraene ( TA‐COT ) was investigated and compared with their uncatalyzed bulk pyrolysis. On Au(111), a str…
View article: Exceptionally High Two‐Photon Absorption Cross Sections in Quinoidal Diazaacene‐Bithiophene Derivatives
Exceptionally High Two‐Photon Absorption Cross Sections in Quinoidal Diazaacene‐Bithiophene Derivatives Open
This study addresses the two‐photon absorption (2PA) properties of (azaacene‐annulated) heterophenoquinones through a synergistic approach combining detailed experimental and theoretical analyses. Exceptionally large 2PA cross sections are…
View article: Exceptionally High Two‐Photon Absorption Cross Sections in Quinoidal Diazaacene‐Bithiophene Derivatives
Exceptionally High Two‐Photon Absorption Cross Sections in Quinoidal Diazaacene‐Bithiophene Derivatives Open
This study addresses the two‐photon absorption (2PA) properties of (azaacene‐annulated) heterophenoquinones through a synergistic approach combining detailed experimental and theoretical analyses. Exceptionally large 2PA cross sections are…
View article: Self‐Assembly of Amphiphilic Polyphenylene Dendrimers with Different Surface Functionalization in Solvent/Non‐Solvent Mixtures
Self‐Assembly of Amphiphilic Polyphenylene Dendrimers with Different Surface Functionalization in Solvent/Non‐Solvent Mixtures Open
This work compares the self‐assembly of nanometer‐sized amphiphilic Janus‐type and patched polyphenylene dendrimers (PPDs) in solvent/non‐solvent mixtures utilizing static and dynamic light‐scattering measurements. First‐ and second‐genera…
Stability of Shielded Pentacenes under Ambient Conditions Open
The stabilization of pentacene through variation of substituents serves as a test bed to access stable organic semiconductors, transferable to the larger soluble acenes and azaacenes. Pentacene is stable enough for derivatization via wet‐c…
CCDC 2353082: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
View article: Electrochemical Exfoliation of Graphene and Formation of its Copolyamide 6/66 Nanocomposites by Wet Phase Inversion and Injection Molding
Electrochemical Exfoliation of Graphene and Formation of its Copolyamide 6/66 Nanocomposites by Wet Phase Inversion and Injection Molding Open
Electrochemically exfoliated graphene (EEG) is compounded with copolyamide 6/66 (PA6/66) to investigate the influence of the carbonaceous filler material on the thermal, rheological, and mechanical properties of the composite. Toward that …
View article: Diels‐Alder Reactivity of Triisopropylsilyl Ethynyl Substituted Acenes
Diels‐Alder Reactivity of Triisopropylsilyl Ethynyl Substituted Acenes Open
We investigated the Diels‐Alder reaction of 6,13‐bis(triisopropylsilylethynyl)pentacene ( 1 ) with small dienophiles such as (bridged) dihydronaphthalenes/cyclohexenes that yielded adducts at the central ring, the other dienophiles predomi…
View article: Impact of Calcium and Phosphorus Levels on Optical Deterioration in Primary and Secondary Intraocular Lens Calcification
Impact of Calcium and Phosphorus Levels on Optical Deterioration in Primary and Secondary Intraocular Lens Calcification Open
This study is the first to quantify calcification and demonstrate the relationship to optical deterioration in IOLs, substantially contributing to understand how visual impairment arises in patients with calcified IOLs.
View article: Breaking Strong Alkynyl-Phenyl Bonds: Poly(<i>para</i>-phenylene ethynylene)s under Mechanical Stress
Breaking Strong Alkynyl-Phenyl Bonds: Poly(<i>para</i>-phenylene ethynylene)s under Mechanical Stress Open
Stronger chemical bonds withstand higher mechanical forces; thus, the rupture of single bonds is preferred over the rupture of double or triple bonds or aromatic rings. We investigated bond scission in poly(dialkyl-p-phenylene ethynylene)s…
Azaacene Diradicals Based on Non‐Kekulé Meta‐Quinodimethane with Large Two‐Photon Cross‐Sections in the Infrared Spectral Region Open
Non‐Kekulé quinoidal azaacences m‐A ( 1 a , b ) were synthesized and compared to their para ‐ and ortho ‐quinodimethane analogues. m‐A display high diradical characters ( 1 b : y 0 = 0.88) due to their meta ‐quinodimethane ( m ‐QDM) topolo…
Azaacene Diradicals Based on Non‐Kekulé Meta‐Quinodimethane with Large Two‐Photon Cross‐Sections in the Infrared Spectral Region Open
Non‐Kekulé quinoidal azaacences m‐A ( 1 a , b ) were synthesized and compared to their para ‐ and ortho ‐quinodimethane analogues. m‐A display high diradical characters ( 1 b : y 0 = 0.88) due to their meta ‐quinodimethane ( m ‐QDM) topolo…
Exceptionally High Two-Photon Absorption in Diazaacene-Bithiophene Derivatives: A Combined Experimental and Theoretical Approach Open
This study delves into the enhancement of two-photon absorption (2PA) properties in diazaacene-bithiophene derivatives through a synergistic approach combining theoretical analysis and experimental validation. By investigating the structur…
Azaacene Diradicals Based on Non-Kekulé Meta- Quinodimethane Open
Non-Kekulé quinoidal azaacences m-A (1a,b) were synthesized and compared to their para- and ortho-quinodimethane analogues. m-A display high diradical characters (1b: y0 = 0.88) due to their meta-quinodimethane (m-QDM) topology. Electron p…
Experimental Evidence of Direct Exchange Interaction Mediating Intramolecular Singlet Fission in Weakly-Coupled Dimers Open
The electronic interaction between an optically active singlet state ($S_1S_0$) and a dark state of singlet multiplicity, known as correlated triplet pair ($^1[TT]$), plays a crucial role in the effective transformation from $S_1S_0$ to $^…
Stabilizing Azaheptacenes Open
The symmetrical 7,16-diaza-6,8,15,17-tetrakis(triisopropylsilylethynyl)heptacene was obtained by a Pd-catalyzed reaction of a 2,3-diamino-1,4-diethynylanthracene with a 2,3-dibromo-1,4-diethynyl anthracene. Positioning the TIPS-ethynyl gro…
Pentacene to Octacene: The Limit of Fourfold TIPS-Ethynylation Open
Soluble acenes beyond hexacene are rare. Their sensitivity complicates isolation, purification and application in devices. To increase the stability of acenes, functionalization with trialkylsilylethynyl substituents prevents [4 + 4] dimer…
Stabilization of Acenes: “Geländer”‐Pentacenes Open
We report soluble tetrakis‐biphenylyl substituted pentacenes comprised of sp 2 carbons and synthesized from pentacene‐5,7,12,14‐tetraone. Intramolecular Yamamoto coupling of two tetrakis(chlorobiphenylyl)pentacenes yields helical, doubly w…
Thermolysis of Biphenylene toward Cyclo‐<i>ortho</i>‐phenylenes Open
The solvent and catalyst free thermolysis of biphenylenes at 350 °C furnishes [n]cyclo‐ ortho ‐phenylenes ([n]COPs, n =4–10) in one step and in high yields. At 400 °C biphenylene dimerizes into tetraphenylene, but lower reaction temperatur…
Thermolysis of Biphenylene toward Cyclo‐<i>ortho</i>‐phenylenes Open
The solvent and catalyst free thermolysis of biphenylenes at 350 °C furnishes [n]cyclo‐ ortho ‐phenylenes ([n]COPs, n =4–10) in one step and in high yields. At 400 °C biphenylene dimerizes into tetraphenylene, but lower reaction temperatur…
Halogenated Phenazinothiadiazoles: Electron‐Transporting Materials Open
Triisopropylsilyl‐(TIPS)‐alkynylated phenazinothiadiazoles were prepared by the condensation of halogenated ortho ‐quinones and TIPS‐alkynylated 5,6‐diamino‐2,1,3‐benzothiadiazole with different combinations of halogen substituents. The co…
Doubly Bridged Anthracenes: Blue Emitters for OLEDs Open
The photooxidative stability of a series of doubly bridged anthracenes was evaluated after their preparation via twofold macrocyclization of a bis(resorcinyl)anthracene. Lightfastness correlates with the energy levels of the highest occupi…
CCDC 2278704: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
CCDC 2278705: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
CCDC 2214002: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
CCDC 2214000: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
CCDC 2214003: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …