Glöckler E, Kapp L, Wölper C, Schumacher M, Gröschel AH, Schulz S. Homoleptic and heteroleptic ketodiiminate zinc complexes for the ROP of cyclic l-lactide.
RSC Adv 2023;
13:29879-29885. [PMID:
37842672 PMCID:
PMC10568404 DOI:
10.1039/d3ra06529d]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 10/04/2023] [Indexed: 10/17/2023] Open
Abstract
Homo- and heteroleptic ketodiiminate zinc complexes L12Zn2 (1, L1 = [Me2NC2H4NC(Me)CH]2CO), L2(ZnCp)2 (2, L2 = [Me2NC3H6NC(Me)CH]2CO, Cp = C5H5) and L2HZnCp* (3, Cp* = C5Me5) were synthesized and characterized by 1H and 13C NMR and IR spectroscopy as well as by elemental analysis and single crystal X-ray diffraction (sc-XRD, 2, 3). The catalytical activity of heteroleptic complexes 2 and 3 were tested in the ring-opening polymerization (ROP) of l-lactide. Homobimetallic complex 2 showed the highest activity and selectivity for the synthesis of cyclic polylactide (cPLLA; TOF = 17 460 h-1) at 100 °C in toluene solution, while linear polymers are formed with mononuclear complex 3.
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