Synthesis, Characterization, Interionic Structure, and Self-Aggregation Tendency of Zirconaaziridinium Salts Bearing Long Alkyl Chains

Zirconaaziridinium inner sphere ion pairs (ISIPs) bearing alkyl chains of different lengths, [Cp2Zr(η2-CH2NR1R2)+···X−] (R1 = Me, R2 = C2H5, X− = MeB(C6F5)3−, ZrNC2BN; R1 = Me, R2 = C16H33, X− = MeB(C6F5)3−, ZrNC16BN; R1 = R2 = C18H37, X− = MeB(C6F5)3−, ZrNC18BN; R1 = Me, R2 = Ph, X− = MeB(C6F5)3−, ZrNPhBN; R1 = R2 = C18H37, X− = B(C6F5)4−, ZrNC18BT; R1 = Me, R2 = Ph, X− = B(C6F5)4−, ZrNPhBT), have been synthesized by the reaction of [Cp2ZrMe+···MeB(C6F5)3−] or [Cp2ZrMe+···B(C6F5)4−] with the suitable tertiary amine followed by selective C−H activation of one Me group of the coordinated amine and methane elimination. Subsequent reaction of ISIPs with THF afforded the corresponding outer-sphere ion pairs (OSIPs) ([ZrNC2THF][BN], [ZrNC16THF][BN], [ZrNC18THF][BN], [ZrNPhTHF][BN], [ZrNC18THF][BT], [ZrNPhTHF][BT]) in which the anion has been displaced into the second coordination sphere. The interionic structure in solution (i.e., the relative cation−anion position) and the self-aggregation level of both ISIPs...