Click construction of spiro- and bridged-quatrefoil polymer topologies with kyklo-telechelics having an azide group.
Unprecedented tetracyclic polymer topologies with spiro- and a bridged-type quatrefoil forms are effectively constructed through an alkyne-azide, click-linking reaction by employing a kyklo-telechelic poly(tetrahydrofuran), poly(THF), precursor having an azide group, obtained through an electrostatic self-assembly and covalent fixation (ESA-CF) process, and complementary tetrafunctional alkyne reagents of either a pentaerythritol derivative or a four-armed star telechelic polymer precursor.
Synthesis of Organic/Inorganic Hybrid Quatrefoil-Shaped Star-Cyclic Polymer Containing a Polyhedral Oligomeric Silsesquioxane Core
We report the synthesis of quatrefoil-shaped star-cyclic polystyrene, star-cyclic PS, containing a polyhedral oligomeric silsesquioxane (POSS) core via the combination of atom transfer radical polymerization (ATRP) and click chemistry techniques. The obtained star-cyclic PS represents a new chain topology in the category of nonlinear-shaped polymers. Using octa(3-chloropropyl) polyhedral oligomeric silsesquioxane, POSS-(Cl)8, as the starting material, its azidation and subsequent click reaction with a slight excess of propargyl 2-bromobutyrate afforded octafunctional initiator, POSS-(Br)8. 8-arm star-linear PS-N3 was obtained by the azidation of star-linear PS-Br, which was synthesized by the ATRP of styrene using POSS-(Br)8 as the initiator. Model reaction between α,ω-diazido-terminated PS (N3-PS-N3) and difunctional propargyl ether confirmed that bimolecular click cyclization reaction can effectively occur under highly dilute conditions. Next, intramolecular click ring closure of star-linear PS-N3 was c...
Macrocycles. 17. The Role of Cyclization in Kinetically Controlled Polycondensations. 2.† Polyamides
Two series of kinetically controlled polycondensations were conducted yielding polyamides of aliphatic dicarboxylic acids. First, the bis(trimethylsilyl) derivatives of 1,3-diaminobenzene, 4,4‘-diaminodiphenylmethane, 1,12-diamino-4,9-dioxadodecane, and 1,12-diaminododecane were polycondensed with dicarboxylic acid dichlorides in N-methylpyrrodidone below 0 °C. After optimization of the reaction conditions mainly cyclic polyamides were detectable in the MALDI−TOF mass spectra (up to 13 000 Da) of the semiaromatic polyamides in contrast to the Carothers−Flory theory. In the case of silylated aliphatic diamines, side reactions of the acid chlorides prevented a complete conversion of the amino groups, so that the reaction products mainly consisted of cycles and linear chains having two amino end groups. Second, normal interfacial polycondensations were performed either with 1,6-diaminohexane and adipoyl chloride or with 1,12-diaminododecane and decane-1,10-dicarbonyl chloride. When the loss of acid chloride ...