Potential Group IV olefin polymerization catalysts that contain a diamido ligand substituted with hexaisopropylterphenyl groups

The diamine rac-H2[HIPTN2] (HIPTN2 = (N-hexa-iso-propyl-3,5-terphenyl)diaminobinaphthalene) has been prepared through palladium-catalyzed N-aryl coupling of diaminobinaphthalene and 3,5-bis(2,4,6-triisopropylphenyl)bromobenzene. The reaction between H2[HIPTN2] and M(NMe2)4 (M = Ti, Zr, and Hf) yields [HIPTN2] M(NMe2)2 complexes. Other complexes of [HIPTN2]2− that have been prepared include [HIPTN2]ZrCl2, [HIPTN2]ZrMe2, [HIPTN2]Zr(CH2CMe3)2, [HIPTN2]HfCl2, [HIPTN2]HfMe2, and [HIPTN2]Hf(CH2CHMe2)2. Activation of [HIPTN2]ZrMe2 with a variety of Lewis acids gives rise to different species depending on the nature of the activator employed. For example, [HIPTN2]ZrMe2 reacts with [Ph3C][B(C6F5)4] to give a cationic complex that is active toward oligomerization of 1-hexene, while activation with B(C6F5)3 leads to formation of [HIPTN2]Zr(C6F5)2. No polymerization of 1-hexene by activated complexes was observed.

Graphical abstractThe diamido ligand, [HIPTN2]2− (HIPTN2 = (N-hexa-iso-propyl-3,5-terphenyl)diaminobinaphthalene), has been prepared and shown to support a variety of Group IV complexes. Several Zr and Hf alkyls of the ligand have been synthesized as potential olefin polymerization catalysts. Activation of [HIPTN2]ZrMe2 with a variety of Lewis acids gives rise to different species depending on the nature of the activator employed.Figure optionsDownload full-size imageDownload as PowerPoint slide