Ring-opening polymerisation of l- and rac-lactide using group 4 permethylpentalene aryloxides and alkoxides. Issue 14 (19th March 2021)

• Record Type: Journal Article
• Authors: Turner, Zoë R.; Lamb, Jessica V.; Robinson, Thomas P.; Mandal, Dipa; Buffet, Jean-Charles; O′Hare, Dermot
• Is Part Of: Dalton transactions. Volume 50:Issue 14(2021)
• Page Start: 4805
• Page End: 4818
• Publication Date: 2021-03-19
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d1dt00252j
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Group 4 permethylpentalene (C8 Me6 2− ; Pn*) aryloxide and alkoxide complexes have been synthesised, fully characterised and used for the polymerisation of lactide monomers. Abstract : A new family of group 4 permethylpentalene (C8 Me6 2− ; Pn*) aryloxide and alkoxide complexes have been synthesised and fully characterised by multinuclear NMR spectroscopy and single-crystal X-ray diffraction; (η 8 -C8 Me6 )Zr(OR)2 (R = t Bu (1 ), 2, 6-Me-C6 H3 (2 ), 2, 6- i Pr-C6 H3 (3 ) and 4-OMe-C6 H4 (4 )), (η 8 -C8 Me6 )Zr (OR) (R = 2, 6- t Bu-C6 H3 (5 ) and 2, 6- t Bu-4-Me-C6 H2 (6 )), (η 8 -C8 Me6 )ZrCp(OR) (R = t Bu (7 ), 2, 6-Me-C6 H3 (8 ) and 2, 6- i Pr-C6 H3 (9 )), (η 8 -C8 Me6 )TiCp(O-2, 6-Me-C6 H3 ) (10 ) and (η 8 -C8 Me6 )ZrCp Me (OR) (R = 2, 6-Me-C6 H3 (11 ), 2, 6- i Pr-C6 H3 (12 ) and 2, 4- t Bu-C6 H3 (13 )). 2, 3, 6, 7, 9, 10 and 12 were studied as initiators for the ring-opening polymerisation (ROP) of l -lactide, and 2, 3, 6, 7 and 10 were studied as initiators for the ROP of rac -lactide. 3 was found to be the most active initiator for the ROP of l -lactide ( k obs = 0.35 h −1 ) and 2 for the ROP of rac -lactide ( k obs = 0.21 h −1 ). These initiators produced isotactic PLA for the ROP of l -lactide and moderately heterotactic enriched (maximum P r of 0.69) or atactic PLA for the ROP of rac -lactide with polymer chains consisting of polylactic acid repeat units with –OR and –OH end groups.