Syntheses, spectral and thermal analyses of heteronuclear aqua(2-methylpyrazine)metal(II) complexes with tetracyanonickelate ion and crystal structure of supramolecular [Cd(H2O)(2mpz)Ni(μ-CN)4] n complex

Abstract

Polymeric tetracyanonickelate complexes of the type [M(H 2 O)(2mpz)Ni(l-CN) 4 ] n (2mpz = 2-methylpyrazine, M = Mn(II) (1) or Cd(II) (2)) have been prepared and characterized by FT-IR, Raman spectroscopy, thermal, and elemental analyses. The crystal structure of supramolecular [Cd(H 2 O)(2mpz)Ni(CN) 4 ] n complex has been determined by X-ray single crystal diffraction. It crystallizes in the orthorhombic system, space group Pnma. The structure consists of corrugated and cyanide-bridged polymeric two-dimensional networks. In the Hofmann-type complexes, the coordination environment of the M(II) ions can be described as distorted octahedral geometry, whereas around the Ni(II) center has square planar geometry. The spectral features suggest that the 2mpz is coordinated to metal ions of the adjacent layers of [M-Ni(CN) 4 ] n as monodentate ligand. The thermal decomposition of these complexes takes place in three stages: (i) dehydration, (ii) decomposition of the 2-methylpyrazine ligands, and (iii) release of the CN groups and burning of organic residue.

Syntheses, spectroscopic and thermal analyses of the hofmann-type metal(II) tetra- cyanonickelate(II) pyridazine complexes: {[M(pdz)Ni(CN)4]∙H2O}n (M = Zn(II) or Cd(II))

“…Vibration modes of the pdz molecule have upward and downward shifts in wavenumber when compared with the free pdz molecule. Analogous shifts on coordination were observed in pyridine [5], 4,4'-bipridyl [20] and 2-methylpyrazine [11,12] complexes. These shifts were explained as the coupling of the internal modes of the aromatic molecule with the M-N vibrations [5,[20][21][22].…”

“…In previous studies, FT-IR, Raman and thermal studies of Hofmann-type host complexes and Hofmann-type clathrates of 2-methylpyrazine (2mpz) were reported [11,12]. The vibrational spectra [12][13][14] and tetracyanometallate clathrates [15][16][17] of pyrazines have been extensively studied by several authors; however, to the best knowledge, neither crystallographic nor spectroscopic data have been so far would explicity tell the structural analyses of the pyridazine (pdz) complexes of tetracyanonickelate(II) ions.…”

Crystallography of Representative MOFs Based on Pillared Cyanonickelate (PICNIC) Architecture

“…The Ni3 and Ni4 have a square planar arrangement, and the mean Ni-C (1.860 Å) and C≡N (1.153 Å) bond lengths agree with the values reported for other tetracyanonickelate salts [86]. The Ni-N distances (range from 2.0168(13) Å to 2.099 (2) Å) are substantially longer than the Ni-C distances (1.856(2) Å to 1.865(2) Å), which also conform to the literature values [87]. The six-coordination Ni are of high spin configuration because nitrogen is acting as a weak-field ligand.…”

Synthesis of Hetero- and Homo-multinuclear Complexes with a Tetracyanonickelate Anion: Structural Characterization [Cu(bcen)Ni(CN)4]2

“…The complex K 2 [Ni(CN) 4 ] · H 2 O was prepared according to the literature procedure by mixing stoichiometric amounts of nickel(II) chloride hexahydrate (2.00 mmol, 0.475 g) in H 2 O (10 mL) with potassium cyanide (8.00 mmol, 0.521 g) in 10 mL of water. 23 The diamine-diamide ligand 4,7-diazadecanediamide (bcen) was prepared as previously reported from ethylendiamine and acrylamide in acetonitrile by heating the mixture under reflux. [24][25][26] The white powder was re-crystallized from CHCl 3 .…”