TY  - JOUR
A1  - Schwarze, Thomas
A1  - Sperlich, Eric
A1  - Müller, Thomas
A1  - Kelling, Alexandra
A1  - Holdt, Hans-Jürgen
T1  - Synthesis efforts of acyclic bis(monoalkylamino)maleonitriles and macrocyclic bis(dialkylamino)maleonitriles as fluorescent probes for cations and a new colorimetric copper(II) chemodosimeter
JF  - Helvetica chimica acta
N2  - In this article, we report on the synthesis of acyclic bis(monoalkylamino)maleonitriles and on the intended synthesis of macrocyclic bis(dialkylamino)maleonitriles to get fluorescent probes for cations. During our efforts to synthesize macrocyclic bis(dialkylamino)maleonitriles, we were only able to isolate macrocyclic bis(dialkylamino)-fumaronitriles. The synthesis of macrocyclic bis(dialkylamino)maleonitriles is challenging, due to the fact that bis-(dialkylamino)fumaronitriles are thermodynamically more stable than the corresponding bis(dialkylamino)-maleonitriles. Further, it turned out that the acyclic bis(monoalkylamino)maleonitriles and macrocyclic bis-(dialkylamino)fumaronitriles are no suitable tools to detect cations by a strong fluorescence enhancement. Further, only the bis(monoalkylamino)maleonitriles, which are bearing a 2-pyridyl unit as an additional complexing unit, are able to selectively recognize copper(II) by a color change from yellow to red.
KW  - copper
KW  - fumaronitrile
KW  - ligands
KW  - macrocycles
KW  - maleonitrile
Y1  - 2021
U6  - https://doi.org/10.1002/hlca.202100028
SN  - 1522-2675
VL  - 104
IS  - 6
SP  - e2100028
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Behrendt, Felix Nicolas
A1  - Schlaad, Helmut
T1  - Entropy-Driven Ring-Opening Disulfide Metathesis Polymerization for the Synthesis of Functional Poly(disulfide)s
JF  - Macromolecular rapid communications
N2  - Metal-free entropy-driven disulfide metathesis polymerization of unsaturated L-cystine based macrocycles produces high-molar-mass heterofunctional poly(disulfide)s, i.e., poly(ester-disulfide-alkene) and poly(amide-disulfide-alkene); M-w(app) = 44-60 kDa, (sic) > 1.7. The polymerization is fast and reaches equilibrium within 1-5 minutes (monomer conversion 70-90%) in polar aprotic solvents such as N,N-dimethylacetamide, dimethylsulfoxide, or y-valerolactone. Thiol-terminated polymers are stable in bulk or when dissolved in weakly polar solvents, but rapidly depolymerize in dilute polar solution.
KW  - disulfide
KW  - macrocycles
KW  - metathesis
KW  - ring-opening polymerization
Y1  - 2018
U6  - https://doi.org/10.1002/marc.201700735
SN  - 1022-1336
SN  - 1521-3927
VL  - 39
IS  - 6
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Senge, Mathias O.
A1  - Ryppa, Claudia
A1  - Fazekas, Marijana
A1  - Zawadzka, Monika
A1  - Dahms, Katja
T1  - 5,10-A2B2-Type meso-Substituted PorphyrinsuA Unique Class of Porphyrins with a Realigned Dipole Moment
JF  - Chemistry - a European journal
N2  - Current applications in porphyrin chemistry require the use of unsymmetrically substituted porphyrins. Many current industrial interests in optics and biomedicine require systems with either pushpull (electron-donating and -withdrawing groups) or amphiphilic systems (hydrophobic and hydrophilic groups). In this context we present the class of 5,10-A2B2-type porphyrins for which two different substituents are positioned in diagonally opposite meso positions. Thus, the intramolecular dipole moment in these tetrapyrroles is positioned along a beta-beta vector passing through two pyrrole rings. This is opposite to the situation of the frequently used 5,15-A2BC porphyrins for which the dipole moment is oriented along a mesomeso axis. We have elaborated syntheses of the 5,10-A2B2 porphyrins by using transition-metal-catalyzed transformations of 5,10-A2 porphyrins or direct substitutions reactions thereof; this gives the target molecules in 2277% overall yields. The compounds exhibit interesting structural, spectroscopic, and optical features and can serve as building blocks for new porphyrin arrays and applications.
KW  - macrocycles
KW  - nitrogen heterocycles
KW  - nonlinear optics
KW  - porphyrinoids
KW  - tetrapyrroles
Y1  - 2011
U6  - https://doi.org/10.1002/chem.201101934
SN  - 0947-6539
VL  - 17
IS  - 48
SP  - 13562
EP  - 13573
PB  - Wiley-VCH
CY  - Weinheim
ER  -