Gupta S, Guedes da Silva MFC, Pombeiro AJL. Distinctive coordination behavior of a pyrazole imine-oxime compound towards Co(II) and Ni(II).
Heliyon 2019;
5:e01623. [PMID:
31193104 PMCID:
PMC6517534 DOI:
10.1016/j.heliyon.2019.e01623]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/22/2019] [Accepted: 04/29/2019] [Indexed: 11/29/2022] Open
Abstract
The polytopic Schiff base 5-methyl-1H-pyrazole-3-carboxylic acid 2-(hydroxyimino-1-methyl-propylidene)-hydrazide (H2L)was synthesized by the condensation of 5-methyl pyrazole-3-carbohydrazide and 3-(hydroxyimino)butan-2-one and its coordination ability was tested against cobalt (II) and nickel (II) nitrates. The ligand exhibited two different binding modes to form a unique binuclear triply bridged Co(III) cationic complex [Co2(1κN2:2κN2-L) (1κN3:2κO1-HL)2](NO3)2 (1). With the Ni(II) precursor, H2L was hydrolyzed to N′,N˝-butane-2,3-diylidenebis (5-methyl-1H-pyrazole-3-carbohydrazide) (H2L1) which bound the metal cation in a tetradentate N3O1 fashion leading to the neutral square planar complex [Ni(κN3O1-L1)]·MeOH (2·MeOH). Complexes 1 and 2 were characterized by IR, NMR, UV-Vis and single crystal X-ray crystallography. The probable mechanism for the Ni(II) mediated transformation of H2L into H2L1 has been investigated by ESI-MS.
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