Synthesis and structure of para‐toluene sulfonamide lanthanide complexes and their application in the polymerization of ε‐caprolactone

Abstract

A series of para-toluene sulfonamide ligands [TsNHPr-i(HL 1 ), TsNHBu-t(HL 2 ), TsNHPh(HL 3 ), TsNHPhMe-p(HL 4 ), TsNHPhOMe-p(HL 5 )] were synthesized by amidation using para-toluene sulfonyl chloride reacting with different primary amines. A series of homoleptic lanthanide complexes (Ln L 3 , 1-10) (Ln = La, L = L 1 (1), Ln = Gd, L = L 2 (2), Ln = La, L = L 2 (3), Ln = Gd, L = L 2 (4), Ln = La, L = L 3 (5), Ln = Gd, L = L 3 (6), Ln = La, L = L 4 (7), Ln = Gd, L = L 4 (8), Ln = La, L = L 5 (9), Ln = Gd, L = L 5 (10)) were prepared by amine elimination reactions of the ligands with Ln[N(SiMe 3 ) 2 ] 3 (Ln = La, Gd). Complexes 1, 3, 5, 7 and 9 were all characterized by NMR spectra, and the structures of complex 3 was determined by single-crystal X-ray diffraction. Complex 3 crystallizes a binuclear cluster, consisting of two La 3+ and six (TsNBu-t) − anions. Three (TsNBu-t) − anions are chelating to each La 3+ as bidentate model with O and N forming three-membered chelate rings; one of three anions is bridging to another La 3+ via oxygen. All complexes were characterized using elemental analysis and infrared spectra. The catalytic properties of complexes 1-10 for the ring-opening polymerization of εcaprolactone were studied and the results showed that all complexes are efficient initiators for this ring-opening polymerization reaction.

Halogenated β‐diketiminato magnesium complexes: Preparation, characterization, and catalysis for ring‐opening polymerization of aliphatic lactones

“…[1][2][3][4] As a powerful strategy for the preparation of polyester, the organometallicspromoted ring-opening polymerization (ROP) of aliphatic lactones has attracted great attentions. [5][6][7][8] To date, plenty of organometallics have been demonstrated as efficient catalysts for the ROP of lactones, such as alkali metals (Li, 9 K [10][11] ), alkaline-earth metals (Mg, [12][13][14][15][16][17][18] Ca, 19 Ba 20 ), aluminum, [21][22][23][24][25] tin, 26 rare-earth metals [27][28][29][30][31][32][33][34] and some transition metals (Ti, 35 Zr, 36 V, 37 Fe, [38][39] Zn [40][41][42][43] ). Among them, the magnesium-based complex has attracted special attention due to its high activity and low toxicity.…”