TY - JOUR
T1 - Efficient ring-opening polymerization (ROP) of ϵ-caprolactone catalysed by isomeric pyridyl β-diketonate iron(III) complexes
AU - Lee, Sze Ling
AU - Hu, Fei Long
AU - Shang, Xiu Juan
AU - Shi, Yi Xiang
AU - Tan, Ai Ling
AU - Mizera, Jens
AU - Clegg, Jack K.
AU - Zhang, Wen Hua
AU - Young, David J.
AU - Lang, Jian Ping
PY - 2017/12/7
Y1 - 2017/12/7
N2 - A series of Fe(iii) complexes of β-diketonate ligands, 1-(2-pyridyl)-3-(3-pyridyl)-1,3-propanedione (L1), 1-(2-pyridyl)-3-(2-pyridyl)-1,3-propanedione (L2), 1-(2-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L3), 1-(3-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L4), 1-(3-pyridyl)-3-(3-pyridyl)-1,3-propanedione (L5) and 1-(4-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L6), viz. [Fe(L1)3] (1), [Fe(L2)3] (2), [Fe(L3)3] (3), [Fe(L4)3] (4), [Fe(L5)3] (5) and [Fe(L6)3] (6) have been structurally characterized. All but one complex (1) catalyzed the ring-opening polymerization (ROP) of ϵ-caprolactone (ϵ-CL) in near quantitative yield at 110 °C to give polymers with relatively narrow polydispersities (PDI). The comparison of in situ reaction and a reaction with preformed 1 indicated that the latter was a better catalyst, giving a higher molecular weight. Complex 2 catalyzed this reaction in a more modest yield reflecting its greater thermal stability, shorter Fe-O bonds and minimal distortion in fold angle among the isomeric complexes, suggesting that ligand dissociation is important for catalytic activity.
AB - A series of Fe(iii) complexes of β-diketonate ligands, 1-(2-pyridyl)-3-(3-pyridyl)-1,3-propanedione (L1), 1-(2-pyridyl)-3-(2-pyridyl)-1,3-propanedione (L2), 1-(2-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L3), 1-(3-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L4), 1-(3-pyridyl)-3-(3-pyridyl)-1,3-propanedione (L5) and 1-(4-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L6), viz. [Fe(L1)3] (1), [Fe(L2)3] (2), [Fe(L3)3] (3), [Fe(L4)3] (4), [Fe(L5)3] (5) and [Fe(L6)3] (6) have been structurally characterized. All but one complex (1) catalyzed the ring-opening polymerization (ROP) of ϵ-caprolactone (ϵ-CL) in near quantitative yield at 110 °C to give polymers with relatively narrow polydispersities (PDI). The comparison of in situ reaction and a reaction with preformed 1 indicated that the latter was a better catalyst, giving a higher molecular weight. Complex 2 catalyzed this reaction in a more modest yield reflecting its greater thermal stability, shorter Fe-O bonds and minimal distortion in fold angle among the isomeric complexes, suggesting that ligand dissociation is important for catalytic activity.
UR - http://www.scopus.com/inward/record.url?scp=85034851218&partnerID=8YFLogxK
U2 - 10.1039/c7nj03571c
DO - 10.1039/c7nj03571c
M3 - Article
AN - SCOPUS:85034851218
VL - 41
SP - 14457
EP - 14465
JO - New Journal of Chemistry
JF - New Journal of Chemistry
SN - 1144-0546
IS - 23
ER -