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

The alkylimino-substituted derivatives of 5-amino-3-imino-1,2,6,7-tetracyano-3H-pyrrolizine, H2N-C7N(CN)(4)=NR, 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)(4)CH=CH2- (1') isolated as the tetraphenylarsonium salt, AsPh4.1'. All the new compounds have been characterized by elemental analysis and IR, UV-VIS and H-1 NMR spectroscopy. The X-ray crystal and molecular structure of 1 has been determined. Langmuir-Blodgett (LB) lms from 2 and 3 have been deposited and characterized by polarised optical absorption spectroscopy.