Synthesis of Planar Chiral N‐Heterocyclic‐Substituted Pyridinophanes

Kramer, Joshua; Nieger, Martin; Bräse, Stefan

doi:10.1002/ejoc.201201286

Cited by 12 publications

(16 citation statements)

References 50 publications

(38 reference statements)

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“…Finally, the cyclophane formation with a dithiol and a photolytic dethionation resulted in pyridinophane 1 . In our hands, the five‐step synthesis resulted in improved yields of 37 % as compared to the literature‐reported yield of 19 % . To date, the only known functionalization method of the heterophane scaffold is the introduction of a nitrile group in ortho ‐position to the nitrogen through a cyanation reaction of the pyridinophane N ‐oxide with trimethylsilyl cyanide .…”

Section: Resultsmentioning

confidence: 71%

“…In our hands, the five‐step synthesis resulted in improved yields of 37 % as compared to the literature‐reported yield of 19 % . To date, the only known functionalization method of the heterophane scaffold is the introduction of a nitrile group in ortho ‐position to the nitrogen through a cyanation reaction of the pyridinophane N ‐oxide with trimethylsilyl cyanide . Thus, for the synthesis of pyridinophanes with substituents other than nitrile, such as the alkyne‐substituted pyridinophane 4 , a new synthesis route had to be developed.…”

Section: Resultsmentioning

confidence: 85%

“…The synthesis of pyridinophane 1 was carried out according to a recently reported synthesis starting from commercially available 2,5‐pyridinedicarboxylic acid . In brief, after a esterification of the dicarboxylic acid, subsequent treatment with NaBH 4 , and bromination afforded one building block for the pyridinophane scaffold.…”

Section: Resultsmentioning

confidence: 99%

“…In particular, electron‐withdrawing heteroatoms, such as nitrogen, can introduce additional polarity into the polymer backbone, while still being able to conserve the chemical flexibility of the poly‐ p ‐xylylene platform. Compared to the extensive literature related to functional [2.2]paracyclophane precursors for CVD polymerization, very little is known about synthetic pathways to functional heterophane precursors . An example of a dimeric heterophane that features a nitrogen heterocycle instead of benzene is [2](1,4)benzeno[2](2,5)pyridinophane (pyridinophane 1 ), which was first mentioned in literature in 1972, although the compound was obtained only in poor yields of 1 % .…”

Section: Introductionmentioning

confidence: 99%

“…In 1973, an improved synthesis with better yields (60 %) was reported . An alternative synthesis from commercially available precursors was reported by Vögtle et al., but it was only recently, that a simplification of this synthetic route with multigram yields was published . In 1995, Itoh and co‐workers carried out the first CVD polymerization of unfunctionalized heterophanes; this process yielded tough polymer films, probably due to considerable crosslinking .…”

Section: Introductionmentioning

confidence: 99%

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Polylutidines: Multifunctional Surfaces through Vapor‐Based Polymerization of Substituted Pyridinophanes

Gall

Hussal

Kramer

et al. 2017

Chemistry A European J

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We report a new class of functionalized polylutidine polymers that are prepared by chemical vapor deposition polymerization of substituted [2](1,4)benzeno[2](2,5)pyridinophanes. To prepare sufficient amounts of monomer for CVD polymerization, a new synthesis route for ethynylpyridinophane has been developed in three steps with an overall yield of 59 %. Subsequent CVD polymerization yielded well-defined films of poly(2,5-lutidinylene-co-p-xylylene) and poly(4-ethynyl-2,5-lutidinylene-co-p-xylylene). All polymers were characterized by infrared reflection-absorption spectroscopy, ellipsometry, contact angle studies, and X-ray photoelectron spectroscopy. Moreover, ζ-potential measurements revealed that polylutidine films have higher isoelectric points than the corresponding poly-xylylene surfaces owing to the nitrogen atoms in the polymer backbone. The availability of reactive alkyne groups on the surface of poly(4-ethynyl-2,5-lutidinylene-co-p-xylylene) coatings was confirmed by spatially controlled surface modification by means of Huisgen 1,3-dipolar cycloaddition. Compared to the more hydrophobic poly-p-xylylyenes, the presence of the heteroatom in the polymer backbone of polylutidine polymers resulted in surfaces that supported an increased adhesion of primary human umbilical vein endothelial cells (HUVECs). Vapor-based polylutidine coatings are a new class of polymers that feature increased hydrophilicity and increased cell adhesion without limiting the flexibility in selecting appropriate functional side groups.

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Section: Resultsmentioning

confidence: 71%

Section: Resultsmentioning

confidence: 85%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Polylutidines: Multifunctional Surfaces through Vapor‐Based Polymerization of Substituted Pyridinophanes

Gall

Hussal

Kramer

et al. 2017

Chemistry A European J

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Molecular Insights into [2.2]Paracyclophane‐Based Functional Materials: Chemical Aspects Behind Functions

Hassan

2024

Adv Funct Materials

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Many of the functions and features of practically useful materials are the province of molecular‐level chemistry and their modulation at different length‐scale. This report illustrates the molecular‐level chemistry behind functions and features of the [2.2]paracyclophane‐based materials with a particular focus on the most recent explorations on through‐space conjugated small‐molecule organic emitters, π‐stacked macrocyclic molecules and polymers, poly(p‐phenylenevinylene)s featuring well‐defined donor‐acceptors sequence control, and surface engineering of technologically‐relevant parylenes that finds broad applications across the field of chemical science and technology. This report largely deals with the potential and opportunities associated with molecular features and functions of planar chirality, conformational behaviors, strain‐induced non‐planarity of the aromatics, the profound impacts of through‐space conjugation and π‐electron interactions/delocalization on optoelectronic properties of the π‐conjugated organic emitters, polymers and extended structures consisting of cyclophanes. A special focus is put on the concept of supramolecular polymers using chemically‐programmed chiral cyclophanes via non‐covalent stacking and controlled conformational arrangements. Illustrating cyclophane as precursors/monomers and fabrication strategies for their incorporation in structurally‐controlled (poly(p‐xylylene)s formed via chemical vapor deposition polymerization and post‐deposition fabrication for interface engineering is described. Demonstrating a rather different approach of electronically‐dictated ring‐opening metathesis polymerization employing strained cyclophane‐diene precursors that generate conjugated poly(p‐phenylenevinylene)s with well‐defined (i.e., low dispersity) and donor‐acceptor sequence control is also discussed. This report will serve as an indispensable one‐stop reference for organic, and polymer chemists, as well as material scientists working with cyclophanes for research innovations.

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From Molecules to Materials: Collaborative Research at the Chemistry—Materials Science Interface and Lessons Learned in Cyclophane Chemistry

Hassan,

Zysman‐Colman,

Lahann

et al. 2024

Adv Funct Materials

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In the spirit of pursuing collaborative research at the interface of chemistry and materials science for engineering cyclophane‐based functional systems, the journey from molecules to materials and a portion of the accomplishments exploring technologically‐relevant small‐molecule organic emitters, polymer thin films, and supra‐sensing through supramolecular host‐guest interactions (molecular self‐assembly) is shared. This report highlights diverse research trajectories and the importance of active collaboration within the chemistry community. It is also intended to serves young scientists who are committed to research in interdisciplinary domains. This inspires fostering global research networks and promoting industrial−academic symbiosis that bring innovations to the education environment and curriculum by sharing mutual experiences, knowledge, and specialized skills which may cut across several inter‐related disciplines.

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Synthesis of Planar Chiral N‐Heterocyclic‐Substituted Pyridinophanes

Cited by 12 publications

References 50 publications

Polylutidines: Multifunctional Surfaces through Vapor‐Based Polymerization of Substituted Pyridinophanes

Polylutidines: Multifunctional Surfaces through Vapor‐Based Polymerization of Substituted Pyridinophanes

Molecular Insights into [2.2]Paracyclophane‐Based Functional Materials: Chemical Aspects Behind Functions

From Molecules to Materials: Collaborative Research at the Chemistry—Materials Science Interface and Lessons Learned in Cyclophane Chemistry

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