Research of nickel(II) complexes with aroyl hydrazones of 5,5-dimethyl-2,4-dioxogexane acid ethyl ester ergashov Mansur Yarashovich

RESEARCH OF NICKEL(II) COMPLEXES WITH AROYL HYDRAZONES OF 5,5-DIMETHYL-2,4-DIOXOGEXANE ACID ETHYL ESTER
Ergashov Mansur Yarashovich¹,
Professor of the Department of Organic and Physicolloid Chemistry, Bukhara State University, Ph.D., Professor,
Tursunov Murod Amonovich,
Professor of the Department of Organic and Physicolloid Chemistry, Bukhara State University, Ph.D., Professor,
Savriyeva Nigina Qahramon qizi³,
Second-year master's student of Bukhara State University
[e-mail]
Abstract
The necessary organic compounds H₂L¹-H₂L⁶ for the synthesis of complex compounds have been obtained by the interaction of 5,5-dimethyl-2,4-dioxohexanoic acid ethyl ester with the corresponding para-substituted aroyl hydrazides, the composition and structure of which were established and identified by elemental analysis, IR and NMR–¹H spectroscopy. Since IR spectroscopy does not allow to indicate the regional direction of the condensation reaction for the carbonyl group of the adjacent –C(CH₃)₃ or –COOC₂H₅ fragment of the molecule, the results are contradictory for the benzoylhydrazone of ethyl 5,5-dimethyl-2,4-dioxohexanoic acid deciphering the crystal structure of the grown single crystals of C₁₇H₂₂N₂O₄ (H₂L⁴) was held. In the interaction of alcohol solutions of the isolated organic compounds (H₂L¹–H₂L⁶) with an aqueous ammonia solution of nickel(II) acetate in an equimolar ratio, coordination compounds (NiLⁿ∙NH₃, where n=16) have been synthesized. Using elemental analysis, infrared and NMR–¹H spectroscopy, as well as X-ray diffraction analysis for the NiL⁴∙NH₃ compound the composition, structure, and crystal structure of NiL¹∙NH₃–NiL⁶NH₃ complex compounds were established. A correlation has been found between the parameters of infrared spectroscopy and NMR-¹H spectroscopy, depending on the nature of the substituents in the para position of the benzene ring of the hydrazide part of the ligand molecules. It has been found that upon dissolution of the ammonia complexes of these ligands in polar solvents of the DMSO-d₆ type ligands transform into a linear enhydrazine form with time. When studying the effect of donor solvents on the structure of complex compounds, it has been determined that when pyridine is gradually added to the solution of ammonia complexes in chloroform, ammonia is first replaced with pyridine, and later the coordination environment of the complexing ion changes from a square-to-octahedral ion through a square-pyramidal configuration. A complete set of X-ray diffraction data has been deposited with the Cambridge Structural Data Bank (CCDC Depositor No. 1911468) and can be freely obtained upon request at www.ccdc.cam.ac.uk/data_request/cif.