Molecular structure of isopropyl 1-phenyl-4-phenylhydrazono-5-oxo-3-pyrazolecarboxylate

Abstract

The new azopyrazolone dye has been synthesized and its crystal structure has been investigated. Crystals of C₁₉H₁₈N₄O₃ are triclinic:$P\bar 1$,a=7.484(1),b=10.646 (1),c=11.897(1) Å, α=82.28(1), β=72.86(1), γ=86.83(1)°,Z=2. The structure has been solved by direct methods and refined by full-matrix least-squares techniques toR=0.050 for 2622 unique reflections. The tautomeric form of the molecules has been determined as a hydrazo form. Delocalization of the C5=O3 and C4=N3 π-electrons and delocalization of the lone-pair electrons of N1, N3, and N4 atoms has been observed. The intramolecular N−H...O hydrogen bond forms the six-membered ring C₂N₂H...O condensed with the pyrazolone ring. The molecules are connected by intramolecular C−H...O hydrogen bonds.