Vanadium(v) phenolate complexes for ring opening homo- and co-polymerisation of ε-caprolactone, l-lactide and rac-lactide

Abstract

rac-lactide afforded co-polymers with low lactide content; the reverse addition was ineffective.

Use of Metal Catalysts Bearing Schiff Base Macrocycles for the Ring Opening Polymerization (ROP) of Cyclic Esters

“…As part of a programme aimed at exploring the use of earth abundant metal catalysts for ROP, [23][24][25] the manganese complexes 9 and 10 (Scheme 3) were screened for their ability to ROP ε-caprolactone in the presence of benzyl alcohol [14]. Results were compared against the acyclic salt compounds 11 and 12.…”

“…Furthermore, the systems 27 and 29 exhibit an induction period that, following a 15%-20% Scheme 6. Zinc complexes (25) and (26). Scheme 6.…”

Synthesis and molecular structural studies of racemic chiral-at-vanadium(v) complexes using an unsymmetric achiral phenolic bidentate ligand

“…The 51 V NMR spectrum of complex 1 showed a singlet at δ = −498.1 ppm ( w 1/2 ≈ 198 Hz), which is comparable to the reported chemical shift values of the tetrahedral complexes. 19,20 In addition, 2 showed a singlet at δ = −244.3 ppm ( w 1/2 ≈ 347 Hz), which was shifted further downfield than that of 1 . The different chemical shifts of the signals of 1 and 2 are due to the different electron-withdrawing or electron-donating strengths of the coordinating chlorine atom or alkoxide and phenoxide, respectively.…”

“…1.58 Å). 14,15,19,20,22 The V-O single bonds for 1 [V(1)-O(2) 1.7902 (10) and V(1)-O(3) 1.7892 (10)] are slightly longer than those of 2 [V(1)-O(2) 1.771 (10) and V(1)-O (3) 1.744 (9)]. This difference between structures of 1 and 2 can be attributed to the strong electron-withdrawing nature of the chlorine ligand of 2, which shortens the V-O bond lengths of the coordinated oxygen atoms due to the strong donating natures of the oxygen atoms attached to the vanadium(V) centre.…”

Molecular Catalysis for Precise Olefin Polymerization and ROP 2015

“…In the third paper, our laboratory continued our investigations into the coordination chemistry (and resultant catalytic properties) of bulky bi-phenols of the type 2,2 ' -RCH[4,6-(tBu) 2 C 6 H 4 OH] 2 (R = Me, Ph), tri-phenols 2,6-bis(3,5-di-tert-butyl-2-hydroxybenzyl)-4-methylphenol and tetra-phenols α,α,α/,α/-tetrakis(3,5-di-tert-butyl-2-hydroxyphenyl)-por -m-xylene [10,11]. In this contribution, we focus on bis(imido) molybdenum(VI) complexes and report on their ability to ring open polymerize ε-caprolactone.…”