Synthesis and characterisation of aluminium(III) and tin(II) complexes bearing quinoline-based N,N,O-tridentate ligands and their catalysis in the ring-opening polymerisation of ε-caprolactone.
The synthesis and catalysis in the ring-opening polymerisation (ROP) of ε-caprolactone (ε-CL) of aluminium(iii) and tin(ii) complexes supported by quinoline-based N,N,O-tridentate ligands are reported. Reaction of 8-{RC(O)CH(2)P(Ph(2)) = N}C(9)H(6)N (R = Bu(t), 2; R = Ph, 3) with AlMe(3) gave [Al(Me(2)){OCR = CHP(Ph(2)) = N(8-C(9)H(6)N)}] (R = Bu(t), 4; R = Ph, 5). Treatment of 2 and 3 with Sn[N(SiMe(3))(2)](2) generated tin(ii) complexes [Sn{OC(R) = CHP(Ph(2)) = N(8-C(9)H(6)N)}{N(SiMe(3))(2)}] (R = Bu(t), 6; R = Ph, 7). A similar reaction of AlMe(3) with 8-{MeC(O)CH(2)C(Me) = N}C(9)H(6)N gave [Al(Me(2)){OC(Me) = CHC(Me) = NC(9)H(6)N}] (9). Compounds 2-9 were characterised by NMR spectroscopy and elemental analysis. The molecular structures of complexes 4, 6 and 9 were determined by single crystal X-ray diffraction techniques. Investigation of catalysis of complexes 4-7 and 9 in the ROP of ε-CL revealed that the aluminium complexes, 4, 5 and 9, are much more active than the tin(ii) complexes. The kinetic studies for the polymerisation of ε-CL catalysed by complexes 4, 5 and 9 in the presence of benzyl alcohol (BnOH) indicated that the polymerisations proceed with the first-order dependence on monomer concentration. The polymerisation was well controlled and gave a polymer with narrow molecular weight distribution.
CAS Key Laboratory of Soft Matter Chemistry and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China. zxwang@ustc.edu.cn.
Wen-An
WA
Ma
Zhong-Xia
ZX
Wang
D000535:Aluminum / Q000737:chemistry*; D002208:Caproates / Q000737:chemistry*; D002384:Catalysis; D007783:Lactones / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D009947:Organotin Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D058105:Polymerization; D011804:Quinolines / Q000138:chemical synthesis / Q000737:chemistry*
D002208:Caproates; D007783:Lactones; D008024:Ligands; D009942:Organometallic Compounds; D009947:Organotin Compounds; D011804:Quinolines; C121056:caprolactone; D000535:Aluminum