Facile and Highly Efficient Strategy for Synthesis of Functional Polyesters via Tetramethyl Guanidine Promoted Polyesterification at Room Temperature

A facile and highly efficient strategy for the synthesis of functional polyesters from 10-undecenoic acid, which is abundantly available and derived from ricin oil, has been successfully achieved using 1,1,3,3-tetramethyl guanidine (TMG) as a promoter at room temperature. The experimental results indicate that high molecular weight polyesters have been obtained and a variety of functional groups, such as alkenyl, alkynyl, nitro, epoxy, hydroxyl, and bromoisobutyrate, can be incorporated as pendant groups. The structures of the obtained polymers were demonstrated by ¹H and ¹³C NMR spectroscopy and their thermal properties were studied by DSC and TGA

Real-Time and in Situ Investigation of “Living”/Controlled Photopolymerization in the Presence of a Trithiocarbonate

Polymerization of methyl acrylate under ultraviolet (UV) irradiation in the presence of <i>S</i>-1-dodecyl-<i>S</i>′-(α,α′-dimethyl-α″-acetic acid) trithiocarbonate (DDMAT) was investigated by in situ ¹H nuclear magnetic resonance spectroscopy. Effects of light intensity, wavelength, and concentration of DDMAT on the polymerization behaviors were studied in detail. The experimental results demonstrate that the “living” features of the photopolymerization are related to the concentration of DDMAT. “Living”/controlled radical polymerization was successfully achieved with a high concentration of DDMAT. However, with a low concentration of DDMAT, the polymerization proceeded in an uncontrolled manner and produced polymers with high molecular weights and broad polydispersities. Photochemical behavior of DDMAT was studied in detail, and the results showed that the photolysis of DDMAT was reversible at high concentration, whereas contrarily, DDMAT decomposed irreversibly at low concentration. A possible mechanism was proposed for the reversible photolysis of DDMAT at high concentration, which may involve both reversible termination and reversible addition–fragmentation chain transfer approaches

2,2′-Biimidazole-Based Conjugated Polymers as a Novel Fluorescent Sensing Platform for Pyrophosphate Anion

Three novel conjugated polymers based on 2,2′-biimidazole have been successfully designed and synthesized through the Suzuki coupling reactions, and their fluorescence sensing ability to metal ions and anions was investigated. The emission of the two polymers with hydrophilic side chains can be efficiently quenched by Cu²⁺ through a photoinduced electron transfer process. Moreover, the polymer–Cu²⁺ complexes exhibit excellent “turn on” sensing properties for detection of pyrophosphate (PPi) anion. These complex sensors possess high selectivity avoiding the interference from other anions, very fast response (less than 3 min) to PPi, and the detection limit of about 0.17 ppm. In addition, the linear detection range of PPi can be tuned conveniently by changing the amount of Cu²⁺ ions. Thus, the conjugated polymers can be used as a novel fluorescent sensing platform, and this work provides a new strategy for the development of PPi sensors