Chemoselectivity diversity in the reaction of LiNC6F 5SiMe3 with nitriles and the synthesis, structure, and reactivity of zirconium mono-and tris[2-(2-pyridyl)tetrafluorobenzimidazolate] complexes

Sinai Aharonovich, Mark Botoshansky, Robert M. Waymouth, Moris S. Eisen

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Unlike the reaction of LiNTMS2· TMEDA (TMS = SiMe 3; TMEDA = tetramethylethylenediamine) with 2-cyanopyridine, which results in the nearly exclusive formation of the amidinate, (Me 3SiNC6F5)Li · TMEDA (1) reacts with 2-cyanopyridine in toluene to yield quantitatively the lithium pyridyltetrafluorobenzimidazolate complex [C6F4N 2C(2-C5H4N)]Li · TMEDA (3). In this work, the reactivity of complex 1 toward aromatic nitriles Ar-CN (Ar = Ph, o-OMeC6H4, C6F5, 2-pyridyl) was examined. Whereas complex 1 fails to react with o-methoxybenzonitrile, its reaction with benzonitrile or pentafluorobenzonitrile gives triphenyl-1,3,5- triazine (4) or the hexacoordinate lithium polymer [LiN(4-NCC6F 4)(C6F5) · THF · TMEDA] n (7), respectively. When 1 is reacted with 2-cyanopyridine in tetrahydrofuran (THF), the benzimidazolate coordination polymer {[C 6F4N2C(2-C5H4N)]Li · THF}n (5) is obtained. Herein we discuss how this diverse chemoselectivity in the reaction of the examined lithium N-silylated amides LiNRTMS · TMEDA (R = TMS, C6F5) with nitriles is influenced by the electronic properties of the nitrile or amide substituents and by the ability of these substituents to interact with the lithium or silicon atoms. Further, we present the syntheses and structures of zirconium tris(pyridyltetrafluorobenzimidazolate) chloride (10) and zirconium bis(dimethylamido)(pyridyltetrafluorobenzimidazolate) chloride · THF (11) complexes. These complexes, the first prepared zirconium mono-and tris(benzimidazolate)s, were crystallographically characterized and examined in the polymerization of propylene with methyl aluminoxane (1:1000 Zr/Al molar ratio).

Original languageEnglish
Pages (from-to)9217-9229
Number of pages13
JournalInorganic Chemistry
Volume49
Issue number20
DOIs
StatePublished - 18 Oct 2010
Externally publishedYes

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