Infrared spectra and stability of Hofmann-type dioxane clathrates

<b>Vibrational spectroscopic investigation of some Hofmann type clathrates: M(4-phenylpyridine)₂Ni(CN)₄.2G (M = Ni, Co and Cd, G = 1,4-dioxane) </b>

“…The observed shifts of the vibrational frequencies are consistent with previously reported Hofmann type complexes of 4-Phpy [6]. These shifts in frequencies have been explained in terms of coupling of the internal vibration of 4-Phpy molecule with M-N vibrations [3][4][5][6][10][11][12].…”

“…The assignments and frequencies of the vibrational bands for 1,4-dioxane of clathrates are given in Table 4 along with the frequencies of 1,4-dioxane in the liquid phase [14]. The vibrational frequencies of 1,4-dioxane in the IR spectra of clathrates closely correspond in frequency to those in the IR spectrum of liquid dioxane and to the Hofmann type dioxane clathrates reported previously [11,12,16]. It can be said that 1,4-dioxane molecules in the clathrates are most likely in a chair conformation [11,12,16].…”

“…The assigned infrared and Raman wavenumbers for Ni(CN) 4 group in the compounds studied appear to be much higher than those for isolated Ni(CN) 4 units (Table 3, Figures 1, 2). Such frequency shifts have been observed for other Hofmann type [3][4][5] and Hofmann type dioxane [10][11][12] clathrates and are attributed to the mechanical coupling of the internal modes of Ni(CN) 4 with the M-NC vibrations. The characteristic frequencies of Ni(CN) 4 group are found to be similar to those of the Hofmann type clathrates suggesting that coordination around the Ni atom is square planar, and that |M-Ni(CN) 4 | ∞ layers have been preserved.…”

“…As well as the strong shifts, another spectral feature caused by coordination is the small frequency shifts resulting from the environmental changes of 4-Phpy [3][4][5][6][10][11][12]. Hence the observed small frequency shifts for the B 1 and B 2 classes of the ligand molecule are resulting from the environmental changes caused by 4-Phpy on coordination.…”

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))

“…The square-planar [Ni(CN) 4 ] 2-moiety may take a number of catenation modes to build up multidimensional structures. Based on this structure, metal(II) tetracyanonickelate(II) complexes have been developed using Ndonor ligands such as ammonia [4], pyridine [5], O-donor ligands such as water [6], dioxane [7] and S-donor ligands as N,N-dimethylthioformamide [8].…”