Synthesis and Spectral Studies of Bisthiocarbohydrazone and Biscarbohydrazone of Quinoline-2-carbaldehyde: Crystal Structure of Bis(quinoline-2-aldehyde) Thiocarbohydrazone

摘要

Two new ligands, having flexible coordination ability, 1,5-bis(quinoline-2-carbaldehyde) thiocarbohydrazone and 1,5-bis(quinoline-2-carbaldehyde) carbohydrazone were synthesized and characterized by elemental analysis, IR, and UV spectral studies. The compounds exist in the thione/ketone tautomeric forms, as evidenced by IR spectral data. The structure of bis(quinoline-2-aldehyde) thiocarbohydrazone has been solved by single crystal XRD study. The compound C21H16N6S crystallizes in triclinic form with two independent molecules in the asymmetric unit, space group $ {text{P}}overline 1$ , Z = 4, V = 1856.1(6) ?3 with unit cell parameters a = 11.331(2) ?, b = 11.714(2) ?, c = 15.116(3) ?, α = 100.369(4)°, β = 109.512(4)° and γ = 90.134(4)°. Both molecules exist in the thione forms and show a Z–Z configuration about both azomethine bonds, with quinoline nitrogens on opposite sides. The N–N, N–C and the C–S bond distances of the thiocarbohydrazide moiety suggest extensive electron delocalization of the whole thiocarbohydrazone moiety.