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Neodymium dihalide complexes with a tridentate amidinate phosphine oxide ligand: synthesis, structure, and catalytic activity in isoprene polymerization

Journal Article · · Russian Chemical Bulletin
The deprotonation of amidine 2-[Ph{sub 2}P(O)]C{sub 6}H{sub 4}NHC(Bu{sup t})=N(2,6-Me{sub 2}C{sub 6}H{sub 3}) (1) with BunLi affords lithium amidinate {2-[Ph_2P(O)]C_6H_4NLiC(Bu"t)=N(2,6-Me_2C_6H_3)}2 (2) having a dimeric structure, as demonstrated by X-ray diffraction. New amidinate dihalide complexes {2-[Ph_2P(O)]C_6H_4NC(Bu"t)N(2,6-Me_2C_6H_3)}NdHal{sub 2}(THF){sub 2} (Hal = I (3), Cl (4)) were synthesized by exchange reactions of lithium and potassium amidinates with anhydrous neodymium halides NdHal{sub 3}(THF){sub n} (Hal = I, n = 3.5; Cl, n = 0). The X-ray diffraction studies showed that the new compounds are monomeric and the amidinate ligand is tridentate. Chloride complex 4 involved in the three- and four-component catalyst systems 4–AlR{sub 3}–[Ph3C] [B(C{sub 6}F{sub 5}){sub 4}] (1: 10: 1; AlR{sub 3} = AlBu{sup i} 3, AlMe{sub 3}), 4–AlR{sub 3}–Pr{sup i}OH (1: 10: 10; AlR{sub 3} = AlBu{sup i}{sub 3}, AlMe{sub 3}), and 4–AlR{sub 3}–[Ph{sub 3}C][B(C{sub 6}F{sub 5}){sub 4}]–Pr{sup i}OH (1: 10: 1: 10; AlR{sub 3} = AlBu{sup i}{sub 3}, AlMe{sub 3}) exhibits activity in stereospecific isoprene polymerization and allows the preparation of high-molecular-weight polyisoprene samples with exceptionally high cis-1,4-unit content (up to 99.4%).
OSTI ID:
22943306
Journal Information:
Russian Chemical Bulletin, Journal Name: Russian Chemical Bulletin Journal Issue: 1 Vol. 68; ISSN RCBUEY; ISSN 1066-5285
Country of Publication:
United States
Language:
English