@misc{BehrendtSchlaad2016,
  author    = {Behrendt, Felix Nicolas and Schlaad, Helmut},
  title     = {Metathesis polymerization of cystine-based macrocycles},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-395080},
  pages     = {4},
  year      = {2016},
  abstract  = {Macrocycles based on L-cystine were synthesized by ring-closing metathesis (RCM) and subsequently polymerized by entropy-driven ring-opening metathesis polymerization (ED-ROMP). Monomer conversion reached ∼80\% in equilibrium and the produced poly(ester-amine-disulfide-alkene)s exhibited apparent molar masses (Mappw) of up to 80 kDa and dispersities (Đ) of ∼2. The polymers can be further functionalized with acid anhydrides and degraded by reductive cleavage of the main-chain disulfide.},
  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{BehrendtHessLehmannetal.2019,
  author    = {Behrendt, Felix Nicolas and Hess, Andreas and Lehmann, Max and Schmidt, Bernd and Schlaad, Helmut},
  title     = {Polymerization of cystine-derived monomers},
  series = {Polymer Chemistry},
  volume    = {10},
  journal   = {Polymer Chemistry},
  number    = {13},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1759-9954},
  doi       = {10.1039/c9py00118b},
  pages     = {1636 -- 1641},
  year      = {2019},
  abstract  = {Cystine was used as a platform chemical to prepare cyclic and acyclic monomers for entropy-driven ringopening polymerization (ED-ROMP) via olefin or disulfide metathesis and for step-growth polymerization. The olefin ED-ROMP of an olefin/disulfide containing 16-atom macrocycle using the 3rd generation Grubbs catalyst was examined in greater detail. Kinetic studies revealed that the catalyst turned inactive during the polymerization, which limited the achievable (apparent) polymer molar mass to similar to 70 kg mol(-1). Such limitation could be overcome with the disulfide ED-ROMP of the same macrocycle to yield polymers with molar masses of up to 180 kg mol(-1). The step-growth polymerizations of acyclic diene and dithiol monomers via olefin metathesis or oxidation were far less effective and yielded just low molar mass polymers or oligomers; photopolymerization of a thiol-ene monomer produced a polyester with a molar mass of 35 kg mol(-1).},
  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}
}
@article{BehrendtSchlaad2017,
  author    = {Behrendt, Felix Nicolas and Schlaad, Helmut},
  title     = {Metathesis polymerization of cystine-based macrocycles},
  series = {Polymer Chemistry},
  volume    = {8},
  journal   = {Polymer Chemistry},
  number    = {2},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1759-9954},
  doi       = {10.1039/c6py01864e},
  pages     = {366 -- 369},
  year      = {2017},
  abstract  = {Macrocycles based on L-cystine were synthesized by ring-closing metathesis (RCM) and subsequently polymerized by entropy-driven ring-opening metathesis polymerization (ED-ROMP). Monomer conversion reached similar to 80\% in equilibrium and the produced poly (ester-amine-disulfide-alkene)s exhibited apparent molar masses (M-w(app)) of up to 80 kDa and dispersities (D) of similar to 2. The polymers can be further functionalized with acid anhydrides and degraded by reductive cleavage of the main-chain disulfide.},
  language  = {en}
}
@article{DebsharmaBehrendtLaschewskyetal.2019,
  author    = {Debsharma, Tapas and Behrendt, Felix Nicolas and Laschewsky, Andre and Schlaad, Helmut},
  title     = {Ring-opening metathesis polymerization of biomass-derived levoglucosenol},
  series = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker},
  volume    = {58},
  journal   = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker},
  number    = {20},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1433-7851},
  doi       = {10.1002/anie.201814501},
  pages     = {6718 -- 6721},
  year      = {2019},
  abstract  = {The readily available cellulose-derived bicyclic compound levoglucosenol was polymerized through ring-opening metathesis polymerization (ROMP) to yield polylevoglucosenol as a novel type of biomass-derived thermoplastic polyacetal, which, unlike polysaccharides, contains cyclic as well as linear segments in its main chain. High-molar-mass polyacetals with apparent weight-average molar masses of up to 100kgmol(-1) and dispersities of approximately 2 were produced despite the non-living/controlled character of the polymerization due to irreversible deactivation or termination of the catalyst/active chain ends. The resulting highly functionalized polyacetals are glassy in bulk with a glass transition temperature of around 100 degrees C. In analogy to polysaccharides, polylevoglucosenol degrades slowly in an acidic environment.},
  language  = {en}
}