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Abstract The reactivity of phosphaalkynes, the isolobal and isoelectronic congeners to alkynes, with metal alkylidyne complexes is explored in this work. Treating the tungsten alkylidyne [tBuOCO]W≡CtBu(THF)2(1) with phosphaalkyne (10) results in the formation of [O2C(tBuC=)W{η2‐(P,C)−P≡C−Ad}(THF)] (13‐tBuTHF) and [O2C(AdC=)W{η2‐(P,C)−P≡C−tBu}(THF)] (13‐AdTHF); derived from the formal reductive migratory insertion of the alkylidyne moiety into a W−Carenebond. Analogous to alkyne metathesis, a stable phosphametallacyclobutadiene complex [tBuOCO]W[κ2‐C(tBu)PC(Ad)] (14) forms upon loss of THF from the coordination sphere of either13‐tBuTHFor13‐AdTHF. Remarkably, the C−C bonds reversibly form/cleave with the addition or removal of THF from the coordination sphere of the formal tungsten(VI) metal center, permitting unprecedented control over the transformation of a tetraanionic pincer to a trianionic pincer and back. Computational analysis offers thermodynamic and electronic reasoning for the reversible equilibrium between13‐tBu/AdTHFand14.
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Living Coordination Polymerization of a Six‐Five Bicyclic Lactone to Produce Completely Recyclable Polyester
Abstract The development of chemically recyclable polymers promises a closed‐loop approach towards a circular plastic economy but still faces challenges in structure/property diversity and depolymerization selectivity. Here we report the first successful coordination ring‐opening polymerization of 4,5‐trans‐cyclohexyl‐fused γ‐butyrolactone (M1) with lanthanide catalysts at room temperature, producing P(M1) withMnup to 89 kg mol−1, high thermal stability, and a linear or cyclic topology. The same catalyst also catalyses selective depolymerization of P(M1) back toM1exclusively at 120 °C. This coordination polymerization is also living, enabling the synthesis of well‐defined block copolymer.
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- Award ID(s):
- 1664915
- PAR ID:
- 10072976
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 57
- Issue:
- 38
- ISSN:
- 1433-7851
- Page Range / eLocation ID:
- p. 12558-12562
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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