Potassium, zinc, and magnesium complexes of a bulky OOO-tridentate bis(phenolate) ligand: synthesis, structures, and studies of cyclic ester polymerisation.
Reaction of the OOO-coordinating tridentate bis(phenolate) protio-ligand 2,2'-{oxybis(methylene)}bis{4,6-di(1-methyl-1-phenylethyl)phenol} (L(O3)-H2), with 1 equiv. of KN(SiMe3)2 in toluene or THF yielded [K(L(O3)-H)] (1) or [K(L(O3)-H)(THF)] (2), respectively. Single-crystal X-ray diffraction...
| Main Authors: | , , , , , , |
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| Format: | Journal article |
| Language: | English |
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2013
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| _version_ | 1797070702048706560 |
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| author | Huang, Y Wang, W Lin, C Blake, M Clark, L Schwarz, A Mountford, P |
| author_facet | Huang, Y Wang, W Lin, C Blake, M Clark, L Schwarz, A Mountford, P |
| author_sort | Huang, Y |
| collection | OXFORD |
| description | Reaction of the OOO-coordinating tridentate bis(phenolate) protio-ligand 2,2'-{oxybis(methylene)}bis{4,6-di(1-methyl-1-phenylethyl)phenol} (L(O3)-H2), with 1 equiv. of KN(SiMe3)2 in toluene or THF yielded [K(L(O3)-H)] (1) or [K(L(O3)-H)(THF)] (2), respectively. Single-crystal X-ray diffraction studies of 1 and 2 revealed mononuclear structures with the phenyl rings of the bulky ligand displaying stabilising π-interactions to the potassium centre. L(O3)-H2 also reacts with 1 equiv. of ZnEt2 or Mg(n)Bu2 to give [M2(L(O3))2] (M = Zn (3) or Mg (4)) in good yield. The molecular structures of complex 3 and 4 reveal dinuclear species in which the metal centres are tetra-coordinated to the three oxygen atoms of one L(O3) ligand, and to the bridging oxygen atom of one phenolate group of another. Complexes 1-4 are catalysts for ring-opening polymerisation of ε-caprolactone and L- and rac-lactide in the presence of benzyl alcohol (BnOH) and also other initiators to give the corresponding polyesters. Kinetic studies for the ROP of ε-caprolactone using 3 and BnOH gives an unusual rate expression R(p) = -d[CL]/dt = k(p)[BnOH]0[3]0(0.5) for which a tentative kinetic model is proposed. |
| first_indexed | 2024-03-06T22:42:44Z |
| format | Journal article |
| id | oxford-uuid:5c24be95-44fd-456a-aa1f-f86ba8b4ad9d |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T22:42:44Z |
| publishDate | 2013 |
| record_format | dspace |
| spelling | oxford-uuid:5c24be95-44fd-456a-aa1f-f86ba8b4ad9d2022-03-26T17:26:21ZPotassium, zinc, and magnesium complexes of a bulky OOO-tridentate bis(phenolate) ligand: synthesis, structures, and studies of cyclic ester polymerisation.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:5c24be95-44fd-456a-aa1f-f86ba8b4ad9dEnglishSymplectic Elements at Oxford2013Huang, YWang, WLin, CBlake, MClark, LSchwarz, AMountford, PReaction of the OOO-coordinating tridentate bis(phenolate) protio-ligand 2,2'-{oxybis(methylene)}bis{4,6-di(1-methyl-1-phenylethyl)phenol} (L(O3)-H2), with 1 equiv. of KN(SiMe3)2 in toluene or THF yielded [K(L(O3)-H)] (1) or [K(L(O3)-H)(THF)] (2), respectively. Single-crystal X-ray diffraction studies of 1 and 2 revealed mononuclear structures with the phenyl rings of the bulky ligand displaying stabilising π-interactions to the potassium centre. L(O3)-H2 also reacts with 1 equiv. of ZnEt2 or Mg(n)Bu2 to give [M2(L(O3))2] (M = Zn (3) or Mg (4)) in good yield. The molecular structures of complex 3 and 4 reveal dinuclear species in which the metal centres are tetra-coordinated to the three oxygen atoms of one L(O3) ligand, and to the bridging oxygen atom of one phenolate group of another. Complexes 1-4 are catalysts for ring-opening polymerisation of ε-caprolactone and L- and rac-lactide in the presence of benzyl alcohol (BnOH) and also other initiators to give the corresponding polyesters. Kinetic studies for the ROP of ε-caprolactone using 3 and BnOH gives an unusual rate expression R(p) = -d[CL]/dt = k(p)[BnOH]0[3]0(0.5) for which a tentative kinetic model is proposed. |
| spellingShingle | Huang, Y Wang, W Lin, C Blake, M Clark, L Schwarz, A Mountford, P Potassium, zinc, and magnesium complexes of a bulky OOO-tridentate bis(phenolate) ligand: synthesis, structures, and studies of cyclic ester polymerisation. |
| title | Potassium, zinc, and magnesium complexes of a bulky OOO-tridentate bis(phenolate) ligand: synthesis, structures, and studies of cyclic ester polymerisation. |
| title_full | Potassium, zinc, and magnesium complexes of a bulky OOO-tridentate bis(phenolate) ligand: synthesis, structures, and studies of cyclic ester polymerisation. |
| title_fullStr | Potassium, zinc, and magnesium complexes of a bulky OOO-tridentate bis(phenolate) ligand: synthesis, structures, and studies of cyclic ester polymerisation. |
| title_full_unstemmed | Potassium, zinc, and magnesium complexes of a bulky OOO-tridentate bis(phenolate) ligand: synthesis, structures, and studies of cyclic ester polymerisation. |
| title_short | Potassium, zinc, and magnesium complexes of a bulky OOO-tridentate bis(phenolate) ligand: synthesis, structures, and studies of cyclic ester polymerisation. |
| title_sort | potassium zinc and magnesium complexes of a bulky ooo tridentate bis phenolate ligand synthesis structures and studies of cyclic ester polymerisation |
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