@article{SchwarzeSperlichMuelleretal.2021,
  author    = {Schwarze, Thomas and Sperlich, Eric and M{\"u}ller, Thomas and Kelling, Alexandra and Holdt, Hans-J{\"u}rgen},
  title     = {Synthesis efforts of acyclic bis(monoalkylamino)maleonitriles and macrocyclic bis(dialkylamino)maleonitriles as fluorescent probes for cations and a new colorimetric copper(II) chemodosimeter},
  series = {Helvetica chimica acta},
  volume    = {104},
  journal   = {Helvetica chimica acta},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1522-2675},
  doi       = {10.1002/hlca.202100028},
  pages     = {e2100028},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}
@article{BehrendtSchlaad2018,
  author    = {Behrendt, Felix Nicolas and Schlaad, Helmut},
  title     = {Entropy-Driven Ring-Opening Disulfide Metathesis Polymerization for the Synthesis of Functional Poly(disulfide)s},
  series = {Macromolecular rapid communications},
  volume    = {39},
  journal   = {Macromolecular rapid communications},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1022-1336},
  doi       = {10.1002/marc.201700735},
  pages     = {4},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@phdthesis{Behrendt2018,
  author    = {Behrendt, Felix Nicolas},
  title     = {New bio-based polymers},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-418316},
  school      = {Universit{\"a}t Potsdam},
  pages     = {vii, 153},
  year      = {2018},
  abstract  = {Redox-responsive polymers, such as poly(disulfide)s, are a versatile class of polymers with potential applications including gene- and drug-carrier systems. Their degradability under reductive conditions allows for a controlled response to the different redox states that are present throughout the body. Poly(disulfide)s are typically synthesized by step growth polymerizations. Step growth polymerizations, however, may suffer from low conversions and therefore low molar masses, limiting potential applications. The purpose of this thesis was therefore to find and investigate new synthetic routes towards the synthesis of amino acid-based poly(disulfide)s. The different routes in this thesis include entropy-driven ring opening polymerizations of novel macrocyclic monomers, derived from cystine derivatives. These monomers were obtained with overall yields of up to 77\% and were analyzed by mass spectrometry as well as by 1D and 2D NMR spectroscopy. The kinetics of the entropy-driven ring-opening metathesis polymerization (ED-ROMP) were thoroughly investigated in dependence of temperature, monomer concentration, and catalyst concentration. The polymerization was optimized to yield poly(disulfide)s with weight average molar masses of up to 80 kDa and conversions of ~80\%, at the thermodynamic equilibrium. Additionally, an alternative metal free polymerization, namely the entropy-driven ring-opening disulfide metathesis polymerization (ED-RODiMP) was established for the polymerization of the macrocyclic monomers. The effect of different solvents, concentrations and catalyst loadings on the polymerization process and its kinetics were studied. Polymers with very high weight average molar masses of up to 177 kDa were obtained. Moreover, various post-polymerization reactions were successfully performed. This work provides the first example of the homopolymerization of endo-cyclic disulfides by ED-ROMP and the first substantial study into the kinetics of the ED-RODiMP process.},
  language  = {en}
}
@article{SengeRyppaFazekasetal.2011,
  author    = {Senge, Mathias O. and Ryppa, Claudia and Fazekas, Marijana and Zawadzka, Monika and Dahms, Katja},
  title     = {5,10-A2B2-Type meso-Substituted PorphyrinsuA Unique Class of Porphyrins with a Realigned Dipole Moment},
  series = {Chemistry - a European journal},
  volume    = {17},
  journal   = {Chemistry - a European journal},
  number    = {48},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0947-6539},
  doi       = {10.1002/chem.201101934},
  pages     = {13562 -- 13573},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}