Three novel nickel(II) complexes based on acetate and pyridinecarboxamide ligands were synthesized and characterized magnetically, structurally and spectrally where different position of amido ...substituents enables distinct supramolecular associations. Display omitted
•Three novel coordination compounds of nickel(II) acetate with pyridinecarboxamides were synthesized.•The complexes consist of six coordinated central Ni2+ ion with pyridinecarboxamides, acetate ligands and/or water molecules.•Magnetic measurements reveal the 2+ ionic state of nickel and paramagnetic behaviour.•IR spectral studies show differences in CONH2 stretching region and COO− stretching vibrations.
Three new mononuclear complexes of nickel(II) pyridinecarboxamides (picolinamide – pia, nicotinamide – nia, isonicotinamide – isn), Ni(OCOCH3)(pia)2(H2O)·(CH3COO)·2H2O (1), Ni(nia)2(H2O)4(CH3COO)2·2H2O (2) and Ni(OCOCH3)2(isn)2(H2O)·C3H7NO (3) have been synthesized. The turquoise (1) and green (2, 3) crystals of the compounds were prepared by the reaction of nickel(II) acetate tetrahydrate and pyridinecarboxamides in different solvents by standard method under reflux (1) and by solvothermal method (2, 3). The compounds were characterized structurally by single-crystal X-ray diffraction analysis, magnetically and spectrally by FT-IR spectroscopy. All complexes consist of six coordinated central Ni2+ ion with pyridinecarboxamides, acetate ligands and/or water molecules. The interactions between building units in the crystal structures include intra- and intermolecular hydrogen bonds in all compounds and π–π interactions in complexes 1 and 2. Magnetic properties of the compounds were measured between 2K and 300K giving the results: μeff=3.0BM for compound 1, μeff=2.8BM for 2 and 2.6BM for compound 3 in paramagnetic region. Experimental values of the IR spectra are comparable with literature data and are in good agreement with results of the structural analysis.
The synthesis and characterization of two new nickel(II) coordination compounds with 3- and 4-aminopyridine are reported. They were obtained after dissolving Ni(CH
3
COO)
2
·4H
2
O in different ...solutions of 3- and 4-aminopyridine. The products were characterized magnetically, structurally by single-crystal X-ray diffraction analysis, and spectrally by FT-IR spectroscopy. Dark green crystals of the polymeric coordination complex {Ni(O
2
CCH
3
)
2
(3-apy)
2
·H
2
O}
n
were synthesized by the reaction of Ni(CH
3
COO)
2
·4H
2
O and 3-aminopyridine (3-apy). The molecular structure of this complex consists of a zigzag chain in which nickel(II) ions are connected by bridging 3-aminopyridine ligands. The Ni(II) ion is six-coordinated by three oxygen atoms from two acetate ligands, one chelating and one monodenate, and by three nitrogen atoms from three 3-aminopyridine ligands, one terminal and two bridging ones. The blue crystals obtained by the reaction of Ni(CH
3
COO)
2
·4H
2
O with 4-aminopyridine (4-apy) consist of the monomeric complex Ni(O
2
CCH
3
)
2
(4-apy)
2
(H
2
O)
2
, in which the ligands possess
trans
geometry around the Ni(II) ion. The interactions including intra- and intermolecular hydrogen bonds in the crystal structures of both complexes are discussed. Magnetic properties of both compounds were studied between 2 and 300 K giving the result of
μ
eff
= 3.1 BM in the paramagnetic region.
Graphical abstract
