5-Amino-3-imino-1,2,6,7-tetracyano-3H-pyrrolizine: synthesis of alkylimino derivatives. X-Ray crystal and molecular structures of the hex-5-enyl, and Langmuir–Blodgett film of the octyl and octadecyl derivatives

Abstract

The alkylimino-substituted derivatives of 5-amino-3-imino-1,2,6,7-tetracyano-3H-pyrrolizine, H₂N–C₇N(CN)₄NR, R = hex-5-enyl (1), octyl (2), octadecyl (3), have been synthesized through a nucleophilic substitution reaction on the amino group of the anion 2-(5-amino-3,4-dicyano-2H-pyrrol-2-ylidene)-1,1,2-tricyanoethanide, C₅N₃–C₄N(CN)₂–NH₂⁻ (L′). A sigmatropic rearrangement via a [1,5]-H shift is involved in this synthesis and also in the deprotonation of 1, leading to the anion C₅N₃–C₄N(CN)₂–NH(CH₂)₄CHCH₂⁻ (1′) isolated as the tetraphenylarsonium salt, AsPh₄·1′. All the new compounds have been characterized by elemental analysis and IR, UV–VIS and ¹H NMR spectroscopy. The X-ray crystal and molecular structure of 1 has been determined. Langmuir–Blodgett (LB) films from 2 and 3 have been deposited and characterized by polarised optical absorption spectroscopy.