Structural and theoretical studies of 4,4 '-[1,4-phenylene-bis(azanediyl)]dipent-3-en-2-one: evidence of a pi-delocalized keto-enamine

Abstract

In this work we present the synthesis of 4,4'-[1,4-phenylene-bis(azanediyl)]dipent-3-en-2-one. Evidence is proposed for the presence of various tautomers of this molecule which are complemented with theoretical density functional theory (DFT)-B3LYP/6-31G* calculations to characterize the potential energy surface of these species. The experimentally observed 3b isomer crystallizes as an orthorhombic Pbcn structure; a = 10.8412(10) angstrom, b = 8.9205(7) angstrom, c = 14.9949(13) angstrom, V = 1450.1(2) angstrom(3), Z = 4 with a final R value is 0.038. From our X-Ray crystallographic analysis an intramolecular hydrogen N-H center dot center dot center dot O interaction is observed.