Bis(alkyl) Sc and Y Complexes Supported by Tri‐ and Tetradentate Amidinate Ligands: Synthesis, Structure, and Catalytic Activity in α‐Olefin and Isoprene Polymerization. Issue 24 (8th June 2021)

• Record Type: Journal Article
• Authors: Rad'kova, Natalia Yu.; Skvortsov, Grigorii G.; Cherkasov, Anton V.; Fukin, Georgy K.; Kovylina, Tatyana A.; Ob'edkov, Anatoly M.; Trifonov, Alexander A.
• Is Part Of: European journal of inorganic chemistry. Issue 24(2021)
• Page Start: 2365
• Page End: 2373
• Publication Date: 2021-06-08
• Subjects: Ligand design -- N ligands -- Olefins -- Polymerization -- Rare earths; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.202100238
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: Bis(alkyl) complexes [(2, 6‐Me2 C6 H3 )NC(tBu)N(C6 H4 −2‐OMe)]M(CH2 C6 H4 −2‐NMe2 )2 (M=Sc (4 ), Y (5 )), [(2‐OMe−C6 H4 N)2 C(tBu)]Y(CH2 SiMe3 )2 (THF)2 (6 ), supported by N, N, O‐tridentate (4, 5 ) and N, N, O, O‐tetradentate (6 ) amidinate ligands were synthesized by the alkane elimination approach reacting tris(alkyl) rare‐earth species M(R)3 Xn (R=Me3 SiCH2, X=THF, n=2; R=CH2 C6 H4 −2‐NMe2, n=0) with one equivalent of amidine (2, 6‐Me2 C6 H3 )N=C(tBu)−NH(C6 H4 −2‐OMe) (1 ) or (2‐MeO−C6 H4 )N=C(tBu)−NH(C6 H4 −2‐OMe) (2 ). The reaction of amidine 2 with equimolar amount of Y(CH2 C6 H4 −2‐NMe2 )3 in toluene unexpectedly results in the addition of N, N‐dimethylaminobenzyl group to C=N bond of one amidinate fragment, ligand disproportionation and the formation of novel bis(amide)amidinate complex [(2‐OMe−C6 H4 N)2 C(tBu)CH2 C6 H4 −2‐NMe2 ]Y[(2‐OMe−C6 H4 N)2 C(tBu)] (7 ). Complexes 4 –6 were evaluated as catalysts for α‐olefins and isoprene polymerization. Abstract : The systems 4 /borate/AliBu3 provide quantitative conversion of 500 equiv. of 1‐heptene and 1‐octene into polymers within 48 h at 25 °C with 63–66 % isotacticity. In isoprene polymerization system 5 /borate/AliBu3 perform high activity and 3, 4‐regularity (up to 77 %) while 6 /borate/AliBu3 demonstrates similar activity and provides cis‐1, 4 stereoselectivity up to 96 %.