Boosting the Reactivity of Bis-Lactones to Enable Step-Growth Polymerization at Room Temperature.

The development of new sustainable polymeric materials endowed with improved performances but minimal environmental impact is a major concern, with polyesters as primary targets. Lactones are key monomers thanks to ring-opening polymerization, but their use in step-growth polymerization has remained scarce and challenging. Herein, we report a powerful bis(γ-lactone) () that was efficiently prepared on a gram scale from malonic acid by Pd-catalyzed cycloisomerization.

Development of an Efficient Thionolactone for Radical Ring-Opening Polymerization by a Combined Theoretical/Experimental Approach.

The environmental impact of plastic waste has been a real problem for the past decades. The incorporation of cleavable bonds in the polymer backbone is a solution to making a commodity polymer degradable. When radical polymerization is used, this approach is made possible by radical ring-opening polymerization (rROP) of a cyclic monomer that allows for the introduction of a weak bond into the polymer backbone.

(P,C)-cyclometalated complexes derived from naphthyl phosphines: versatile and powerful tools in organometallic chemistry.

The chemistry of (P,C)-cyclometalated complexes derived from naphthyl phosphines [(P,C)M] is presented and analysed in this review. The three main synthetic approaches, namely P-chelation assisted C-H activation, oxidative addition and transmetalation, are described and compared. If a naphthyl framework inherently predisposes a phosphorus atom and transition metal to interact, a rigid metallacycle may induce some strain and distortion, as apparent from the survey of the single-crystal X-ray diffraction structures deposited in the Cambridge Structural Database (77 entries with metals from groups 7 to 11).

Base-Triggered Oxidative Addition to Gold.

The coordination of secondary phosphine oxides (SPO) was shown to efficiently promote the activation of C(sp )-I bonds by gold, as long as a base is added (NEt , K CO ). These transformations stand as a new type of chelation-assisted oxidative addition to gold. The role of the base and the influence of the electronic properties of the P-ligand were analyzed computationally.

pH Effect on Particle Aggregation of Vanillin End-Capped Polylactides Bearing a Hydrophilic Group Connected by a Cyclic Acetal Moiety.

To enhance the pH-responsiveness of poly(lactic acid) (PLA) particles, desired vanillin acetal-based initiators were synthesized and functional PLA was initiated at the chain end. PLLA-V6-OEG particles were prepared using polymers with various values of 2400-4800 g/mol. PLLA-V6-OEG was appropriated to achieve a pH-responsive behavior under physiological conditions within 3 min via the six-membered ring diol-ketone acetal.