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Complexes LZnR (L=C6F5NC(CF3)C(H)C(CF3)O; R=Me 1; Et 2) and L2Zn(thf)2 (3) were synthesized and analyzed by NMR (1H, 13C, 19F) and IR spectroscopy, elemental analysis, and single crystal X‐ray diffraction. Complexes 1 and 2 are dinuclear in the solid state but monomeric in toluene solution according to diffusion‐ordered spectroscopy (DOSY‐NMR). They showed poor activity in the ring opening polymerization (ROP) of lactide (LA) but moderate activity in the presence of benzyl alcohol (BnOH), yielding polymers with high number average molecular weight (Mn) and moderately controlled molecular weight distribution (PDI). Homonuclear‐decoupled 1H NMR analysis of polylactic acid (PLA) obtained from rac‐LA showed isotactic enrichment of the polymer microstructure, and kinetic studies of the ROP of L‐LA with complex 2 showed a first order dependence of the monomer concentration. Analyses of low molecular weight polymers by 1H NMR and MALDI‐ToF mass spectrometry demonstrated the coordination‐insertion mechanism (CIM). [ABSTRACT FROM AUTHOR]

Alkane elimination reactions of equimolar amounts of 17Fnac2H (17Fnac2H = FC[C(CF3)NC6F5]2H) with ZnEt2 and AlMe3 as well as 16Fnac2H (16Fnac2H = HC[C(CF3)NC6F5]2H) with GaMe3 yielded the corresponding heteroleptic complexes of 17Fnac2ZnEt (1), 17Fnac2AlMe2 (2), and 16Fnac2GaMe2 (3), whereas reactions of two equivalents of 16Fnac2H and 17Fnac2H with either ZnEt2 or Cp*2Zn gave homoleptic ZnII complexes (16Fnac2)2Zn (4) and (17Fnac2)2Zn (5), respectively. 1–5 were characterized by IR and NMR spectroscopy (1H, 13C, 19F), elemental analysis and single‐crystal X‐ray diffraction. [ABSTRACT FROM AUTHOR]

New polynuclear zinc complexes containing tridentate Schiff base ligands were successfully synthesized and fully characterized. The solid-state structure of the complexes was determined using single crystal X-ray diffraction. The complexes display a tetranuclear cubane-like core structure [Zn4O4] and sowed good catalytic activity towards the ring-opening polymerization ( ROP) of rac-lactide ( rac- LA) and ε-caprolactone ( ε- CL) under solvent-free conditions. The polylactic acid ( PLA) obtained from rac- LA showed isotactic enrichment, as proved by homonuclear decoupled 1H- NMR analysis. These complexes also showed good activity and superior control towards the ROP of rac- LA and ε- CL in the presence of benzyl alcohol as a co-initiator. Furthermore, kinetic studies demonstrated that the ROP of rac- LA and ε- CL has a first order dependence on both monomer ( rac- LA and ε- CL) and catalyst concentration. [ABSTRACT FROM AUTHOR]