Triketiminate bis(borohydride) complexes of rare-earth metals [(2,6-Me{sub 2}C{sub 6}H{sub 3}N=CMe){sub 2}C(2,6-Me{sub 2}C{sub 6}H{sub 3}N=CBu{sup t})]Ln(BH{sub 4}){sub 2}(THF){sub 2} (Ln = Y, Nd): synthesis, structure, and catalytic activity in polymerization of rac-lactide, ε-caprolactone, and isoprene
A new triketimine (2,6-Me{sub 2}C{sub 6}H{sub 3}N=CMe){sub 2}CH(2,6-Me{sub 2}C{sub 6}H{sub 3}N=CBu{sup t}) (1) was synthesized by the reaction of imidoyl chloride 2,6-Me{sub 2}C{sub 6}H{sub 3}N=CClBu{sup t} with lithium diketiminate (2,6-Me{sub 2}C{sub 6}H{sub 3}N=CMe){sub 2}CHLi. In the crystalline state, compound 1 exists in the diimineenamine form; in solution, in the triimine form. The metalation of triketimine 1 with n-butyllithium in THF at 0 °C produced lithium triketiminate [(2,6-Me{sub 2}C{sub 6}H{sub 3}N=CMe){sub 2}C(2,6-Me{sub 2}C{sub 6}H{sub 3}N=CBu{sup t})]Li(THF){sub 2} (2). The metathesis reactions of Ln(BH{sub 4}){sub 3}(THF){sub 3} (Ln = Y, Nd) with compound 2 (1: 1 molar ratio, THF) gave the neutral triketiminate bis(borohydride) complexes [(2,6-Me{sub 2}C{sub 6}H{sub 3}N=CMe){sub 2}C(2,6-Me{sub 2}C{sub 6}H{sub 3}N=CBu{sup t})]Ln(BH{sub 4}){sub 2}(THF){sub 2} (Ln = Y (3), Nd (4)). As opposed to the complexes with neutral triketimine, the monoanionic triketiminate ligand is coordinated to Li and Y or Nd cations in a bidentate fashion. Complexes 3 and 4 catalyze the polymerization of rac-lactide and ε-caprolactone; in combination with [Ph{sub 3}C][B(C{sub 6}F{sub 5}){sub 4}] and AlBu{sub 3}{sup i} (1 : 1 : 10 molar ratio), these compounds exhibit catalytic activity in the polymerization of isoprene.
- OSTI ID:
- 22863510
- Journal Information:
- Russian Chemical Bulletin, Journal Name: Russian Chemical Bulletin Journal Issue: 9 Vol. 66; ISSN RCBUEY; ISSN 1066-5285
- Country of Publication:
- United States
- Language:
- English
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