Host–Guest Driven Self‐Assembly of Linear and Star Supramolecular Polymers

Abstract

Supramolekulare Plastizität: Die bemerkenswerte Wirt‐Gast‐Chemie von Phosphonatcavitanden wurde zum Aufbau selbstorganisierter supramolekularer Polymere genutzt (siehe Bild), die reversibel auf die Bindung von Gastspezies hin entstehen und je nach Templat von der linearen in eine sternförmig verzweigte Form wechseln. Ein Thiophosphonatcavitand mit ähnlicher Struktur, aber ohne Komplexierungsvermögen wirkt als Kettenende und bestimmt den Polymerisationsgrad.

Host–Guest‐Driven Copolymerization of Tetraphosphonate Cavitands

“…However, the conformational mobility of the spacer allows for the formation of cyclic species, absent in the parent homopolymer. [9] Viscosity measurements demonstrated the strong influence that both monomer concentration and temperature exert on the conversion of cyclic oligomeric species to linear polymeric chains. [24] The crystal structure of the copolymer between methyl viologen and 1 a/1 c validates the proposed interaction mode among the monomeric units and shows the preference of the system for linear polymerization in the solid state.…”

“…www.chemeurj.org the corresponding resorcinarenes III a-c, ready to be functionalized with dichlorophenylphosphine. This reaction gave rise to a tetraphosphonite intermediate, which was oxidized in situ by addition of H 2 O 2 [9] to give tetraphosphonate cavitands 1 a-c. On account of the stereospecificity of this reaction, only the isomers having four inward-facing phosphonate bridges were formed in all cases. The target guests 2 a, 2 b and 2 c were prepared in two steps (Scheme 3) by treatment of isonicotinoyl chloride hydrochloride with ethylene glycol, 1,6-hexanediol and polyethylene glycol, respectively.…”

“…Target hosts 1 a, 1 b and 1 c were synthesized in three steps, starting from the already reported monohydroxy-footed silylcavitand I [9] (Scheme 2). Different dimerization protocols were followed to bind together two units of I. Esterification reactions with adipic acid and 3,5-pyridinedicarboxylic acid in the presence of 1,3-dichlorohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP), were employed for II b and II c, respectively.…”

“…[7] The incorporation of multiple switchable functionalities into a single monomer leads to topological control of the realized supramolecular systems, [8] which allows for interconversion between different polymeric architectures. [9] The vast majority of supramolecular polymers reported so far are assembled through hydrogen bonding or metalligand coordination. [10] A less travelled route employs hostguest interactions as the driving force for polymerization.…”

Surface Nanomechanics of Biomolecules and Supramolecular Systems

“…Phosphonate cavitands are synthetic abiotic receptors (hosts) [39,40,43] with molecular recognition properties that have been exploited in gas sensing [44], supramolecular polymers [45,46], surface self-assembly [47], and product protection [48]. They are specifically designed to target small molecules bearing amino-functionalities via a synergistic combination of weak interactions such as H-bonding, dipole−dipole, and CH−π interactions.…”