Rare-Earth-Metal Alkyl Species Bearing 1,3-Bis(2-Pyridylimino)isoindoline Ancillary Ligands: Synthesis, Characterizationand Catalysis Toward Highly Cis-1,4-Selective Polymerizations Of Conjugated Dienes

In recent years, main group and transition metal compound bearing isoindole ligands has been widely used in organic synthesis and polymer synthesis research field. However, synthesis of the corresponding rare earth metal compound seems rare and its catalytic role in the field of polymer synthesis is almost none. We synthesized four new alkyl compounds bearing 1,3-bis（2-pyridyl imine） isoindole, whose central metals are Sc, Lu, Y, Dy and other metals(wherein the substituents on the pyridine is methyl, a chlorineatom; the substituent on the metal is trimethylsilylmethyl（-CH₂SiMe₃）. Here, we use NMR, X- ray diffraction and elemental analysis to characterize the structures of these compounds in detail. As the polymerization results show, with various cocatalysts such as fluoro borate([PhMe₂NH][B（C₆F₅）₄] or（[Ph₃C][B（C₆F₅）₄]）, boric acid（B（C₆F₅）₃） or Al R₃（R=Me, iBu） activation, our 1,3-bis（2-pyridyl imine） isoindole Sc, Lu metal compound can catalyze isoprene coordination polymerization reaction ffectively, the catalytic activity is up to 1.9 × 10⁶kg PIP/（mol Sc. h）. The resulting polymer molecular weight Mn = 6.08 × 10⁵g/mol, the molecular weight distribution Mw/Mn = 1.26-2-29. All above results suggest that 1, 3-bis（2-pyridyl imine） isoindoline Sc, Lu metal compound synthesis catalyst system is simple, easy to prepare, high catalytic activity for the polymerization of conjugated diene, whose region and stereo selectivity is very good, has great potential for industrial applications.