TY - JOUR
T1 - Iron(III) and Zinc(II) calixarene complexes
T2 - Synthesis, structural studies, and use as procatalysts for ε-caprolactone polymerization
AU - Arbaoui, Abdessamad
AU - Redshaw, Carl
AU - Elsegood, Mark R.J.
AU - Wright, Victoria E.
AU - Yoshizawa, Akina
AU - Yamato, Takehiko
PY - 2010/3/1
Y1 - 2010/3/1
N2 - Treatment of the heterobimetallic iron(II) alkoxides [(THF)MFe(OtBu) 3]2 with p-tert-butylcalix[4]areneH4 (L 1H4) affords the oxo-bridged diiron(III) complexes {Fe[M(NCMe)x]2L1}2(μ-O), M=Na, x=2 1·8(CH3CN), M=K, x=3 2·3.5(CH3CN); similar use of p-tert-butylcalix[6]areneH6 (L2H 6) afforded [{Fe2(μ-O)Na2(OH 2)(NCMe)2L2}2][{Fe 2(μ-O)Na(OH2)(NCMe)6L2} 2]2-[Na(NCMe)5]22+ 3·9.46(CH3CN) and [{Fe2(μ-O)L 2(K(NCMe)2)2}2] 4·10.8(MeCN), respectively. In the case of 4, a minor product {(L2 2Fe8O8)[K(NCMe)1.5K(H 2O)(NCMe)2.5]2} 5·6(CH3CN), which is comprised of chains of (L22Fe8O 8) clusters bridged by K/MeCN fragments, is also isolated. Use of p-tert-butylcalix[8]areneH8 (L3H8) and two equivalents of [(THF)KFe(OtBu)3]2 affords [(K 2(μ-NCCH3)4(μ-OH2)) 2(Fe2(μ-O)L3H2) 2(CH3CN)2] 6·9(CH3CN). In the case of p-tert-butyltetrahomodioxacalix[6]areneH6 (L 4H6), reaction with [(THF)MFe(OtBu)3] 2 (two equivalents) leads to isolation of the pseudoisomorphic complexes [M2(CH3CN)4L4Fe 2(μ-O)].4CH3CN M=Na 7·4(CH3CN), M=K 8·2(CH3CN); similar use of p-tert-butylhexahomotrioxacalix[3] areneH3 (L5H3) led to [Na2Fe 2(μ-OH)2(L5)2(CH 3CN)4] 9·2(CH2Cl2). The complex [L4(ZnEt)4Zn2(CH3CN) 4(μ-OEt)2], 10·2(CH3CN), isolated from the reaction of L4H6 and ZnEt2 is also reported. Complexes 1-10 are structurally characterized (partially in the case of 4) and screened (not 5) as catalysts for the ring opening polymerization of ε-caprolactone.
AB - Treatment of the heterobimetallic iron(II) alkoxides [(THF)MFe(OtBu) 3]2 with p-tert-butylcalix[4]areneH4 (L 1H4) affords the oxo-bridged diiron(III) complexes {Fe[M(NCMe)x]2L1}2(μ-O), M=Na, x=2 1·8(CH3CN), M=K, x=3 2·3.5(CH3CN); similar use of p-tert-butylcalix[6]areneH6 (L2H 6) afforded [{Fe2(μ-O)Na2(OH 2)(NCMe)2L2}2][{Fe 2(μ-O)Na(OH2)(NCMe)6L2} 2]2-[Na(NCMe)5]22+ 3·9.46(CH3CN) and [{Fe2(μ-O)L 2(K(NCMe)2)2}2] 4·10.8(MeCN), respectively. In the case of 4, a minor product {(L2 2Fe8O8)[K(NCMe)1.5K(H 2O)(NCMe)2.5]2} 5·6(CH3CN), which is comprised of chains of (L22Fe8O 8) clusters bridged by K/MeCN fragments, is also isolated. Use of p-tert-butylcalix[8]areneH8 (L3H8) and two equivalents of [(THF)KFe(OtBu)3]2 affords [(K 2(μ-NCCH3)4(μ-OH2)) 2(Fe2(μ-O)L3H2) 2(CH3CN)2] 6·9(CH3CN). In the case of p-tert-butyltetrahomodioxacalix[6]areneH6 (L 4H6), reaction with [(THF)MFe(OtBu)3] 2 (two equivalents) leads to isolation of the pseudoisomorphic complexes [M2(CH3CN)4L4Fe 2(μ-O)].4CH3CN M=Na 7·4(CH3CN), M=K 8·2(CH3CN); similar use of p-tert-butylhexahomotrioxacalix[3] areneH3 (L5H3) led to [Na2Fe 2(μ-OH)2(L5)2(CH 3CN)4] 9·2(CH2Cl2). The complex [L4(ZnEt)4Zn2(CH3CN) 4(μ-OEt)2], 10·2(CH3CN), isolated from the reaction of L4H6 and ZnEt2 is also reported. Complexes 1-10 are structurally characterized (partially in the case of 4) and screened (not 5) as catalysts for the ring opening polymerization of ε-caprolactone.
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U2 - 10.1002/asia.200900514
DO - 10.1002/asia.200900514
M3 - Article
C2 - 20108302
AN - SCOPUS:77749339880
SN - 1861-4728
VL - 5
SP - 621
EP - 633
JO - Chemistry - An Asian Journal
JF - Chemistry - An Asian Journal
IS - 3
ER -