Zinc anilido-oxazolinate complexes as initiators for ring opening polymerization

Abstract

Three new anilido-oxazolines, ortho-C(6)H(4)(NHAr')(4,4-dimethyl-2-oxazoline) [Ar'=2,4,6-trimethylphenyl, HNPh(TriMe)Oxa (1); 2,6-diisopropylphenyl, HNPh(DiiPr)Oxa (2); 2-methoxyphenyl, HNPh(OMe)Oxa (3)], have been prepared. Reactions of 1 or 2 with one molar equivalent of ZnEt(2) in tetrahydrofuran or hexane solution give the zinc ethyl complexes (NPh(TriMe)Oxa)ZnEt (4) and (NPh(DiiPr)Oxa)ZnEt (5). The dinuclear zinc benzyloxide complexes, [(NAr'Oxa)Zn(mu-OBn)](2), [Ar'=2,4,6-trimethylphenyl, (6); 2-methoxyphenyl, (7)], were synthesized by the reaction of 4 with one molar equivalent of benzyl alcohol in tetrahydrofuran solution (for 6) or by treatment of with 3 one molar equivalent of ZnEt(2) in tetrahydrofuran solution followed by the addition of one molar equivalent of benzyl alcohol (for 7). The molecular structures are reported for compounds 6 and 7. Their catalytic activities toward the ring opening polymerization reactions are under investigation.

Synthesis, Characterization, and Catalytic Application of Aluminum Anilido‐Oxazolinate Complexes

“…Complexes 1 – 5 were synthesized by an alkane elimination reaction in moderate to high yields. Treatment of ligand precursors HNPh TriMe Oxa,5k HNPh Di i Pr Oxa,5k HNPh OMe Oxa,5k HNPh SMe Oxa, or HNPhOxa with AlMe 3 in toluene yields the desired anilido‐oxazolinate aluminum dimethyl complexes 1 – 5 . Complexes 1 – 5 were all characterized by NMR spectroscopy and elemental analyses.…”

“…Pd(OAc) 2 (Acros), AlMe 3 (Aldrich, 2.0 M in toluene), NaO t Bu (TCI), 2‐methylthioaniline (Lancaster), L ‐proline (Lancaster), K 3 PO 4 (Alfa), iodobenzene (Acros), and bis[2‐(diphenylphosphanyl)phenyl] ether (DPEPhos, Strem) were used as supplied. 2‐(2‐Bromophenyl)‐4,4‐dimethyl‐2‐oxazoline,7a 2‐(4,4‐dimethyl‐4,5‐dihydro‐oxazol‐2‐yl)‐phenylamine,7b HNPh TriMe Oxa,5k HNPh Di i Pr Oxa,5k and HNPh OMe Oxa5k were prepared according to the literature. Benzyl alcohol was dried with magnesium sulfate and distilled before use.…”

“…Therefore some metal complexes bearing structurally related ligands with similar chelating systems and isoelectronic features were synthesized and some of their catalytic activities in ring‐opening polymerization have been examined 5. According to our previous catalytic studies on the zinc anilido‐oxazolinate complexes5k and the catalytic activities demonstrated by some aluminum complexes bearing β‐diketiminate or anilido‐imino ligands in ring‐opening polymerization,4,5k–5m aluminum anilido‐oxazolinate complexes are expected to be efficient initiators/catalysts in ring‐opening polymerization. In this paper, several ligand precursors and their aluminum dimethyl complexes have been synthesized.…”

Synthesis and crystal structures of tetrameric [2-(4,4-dimethyl-2-oxazolin-2-yl)anilido]sodium and tris[2-(4,4-dimethyl-2-oxazolin-2-yl)anilido]ytterbium(III)

“…There are 68 structure in the CSD (version 5.39, update of November, 2018;Groom et al, 2016) containing a substituted anilido-oxazoline ligand (R-L1 À ) coordinated to a transition or main group metal. [COZFIH (Coeffard et al, 2009); DEJHIK (Cabeza et al, 2006); EDEBOG (Niwa & Nakada, 2012); EFICON (Bian et al, 2014); FONYAI (Mikami et al, 1999); GIWYES (Chen et al, 2014); GUTTOF (Inagaki et al, 2010); ISEWAG (Abbina et al, 2016); LUNGOS (Bauer et al, 2015a); LUNHAF (Bauer et al, 2015a); MALVUS, MALWAZ and MALWED (Kieltsch et al, 2010); MICTID, MICTOJ, MICTUP, MICVAX and MICVEB (Lu et al, 2013); MUQNAN and MUQNER (Wan et al, 2002); NANFEP, NANFIT, NANFOZ, NANFUF, NANGAM, NANGEQ, NANGIU and NANGOA (Peng & Chen, 2011); OCIHOX, OCIHUD and OCIJAL (Cabaleiro et al, 2001); PUDKUV, PUDLAC, PUDLEG and PUDLIK (Chen et al, 2009a); QIFFES and QIFFIW (Abbina & Du, 2012); RAKTAA (McKeon et al, 2011); RAMFIW, RAMFOC, RAMFUI, RAMGAP and RAMGET ; RAMKEY (Huang et al, 2017); ROGWAM (Nakada & Inoue, 2007); SELVIQ (Nixon & Ward, 2012); SUYQOS, SUYQUY, SUYRAF and SUYREJ (Castro et al, 2001); TIMLIL and TIMLOR (Chen et al, 2007); VOZZOB, VOZZUH and VUBBAX (Bauer et al, 2015b); VUQZAK (O'Reilly et al, 2015); WUGQOF, WUGQUL, WUGRAS and WUGREW (Chen et al, 2009b); XIGYEU (Wu et al, 2018); XOQVEG and XOQVIK (He et al, 2014); XOYVOW, XOYVUC, XOYWAJ, XOYWEN and XOYWIR (Castro et al, 2002)]. In contrast, there is only one structure of an unsubstituted anilido-oxazoline ligand (H-L1 À ) coordinated to a transition metal (Cabeza et al, 2006) and there are no structures of this type with a lanthanide metal.…”

Synthesis, Structure, and Ring‐Opening Polymerization Catalysis of Zinc Complexes Containing Amido Phosphinimine Ligands

“…[a] Data represent one of two independent molecules found in the asymmetric unit. [a] 100.80 (19) 136.5(2) 122.7 (2) [a] Data represent one of two independent molecules found in the asymmetric unit.…”