Amidine Production by the Addition of NH₃ to Nitrile(s) Bound to and Activated by the Lewis Acidic [Re₆(μ₃-Se)₈]²⁺ Cluster Core

Abstract

Acetonitrile bound to and activated by the Lewis acidic [Re(μ-Se)] cluster core was transformed into acetamidine in quantitative yield using NH as the nucleophile at room temperature. The amidine ligand was removed by treating the cluster-acetamidine complexes with trifluoroacetic acid in CHCN, affording amidinium trifluoroacetate and the starting acetonitrile complexes.

Piperidine and piperazine analogs in action: zinc(ii)-mediated formation of amidines

“…By analogy to our system, the in situ formed acetamidine coordinated to the transition metal ion used. [35][36][37][38][39][40][41][42][43] The reaction described in Scheme 3 implies the presence of ammonia in the reaction systems. The formation of ammonia has been observed previously.…”

[ReH3(PPh3)4] – A Key Compound in the Rhenium Hydride Chemistry

“…The adjacent C1À C2 bond is a 'normal' CÀ C single bond with a length of 1.44(1) Å. Additionally, the ReÀ N1À C1 bond angle is perfectly linear, while the N1À C1À C2 bond angle is clearly bent suggesting double bonds between Re and N1 and N1 and C1. The observed bonding features, particularly the linear ReÀ NÀ C unit, [48][49][50][51][52][53][54][55][56][57][58][59][60] strongly favor the assignment of compound 4 a as an azavinylidene over an interpretation as an amido complex, which would require a bent unit. [61] Recently, we observed the formation of a similar product as result of a nucleophilic attack of a fluorinated aryl lithium reagent, [62] where the obtained azavinylidene complex shows similar geometric features as discussed for 4 a.…”