Infrared spectra and stability of Hofmann-type dioxane clathrates

Exploring the geometric, magnetic and electronic properties of Hofmann MOFs for drug delivery

The geometric, magnetic, and electronic properties and the drug capturing abilities of Hofmann-type metal organic frameworks (MOFs) were examined using theoretical calculations. The detailed theoretical calculations predicted that the Hofmann sheet can have two different conformations, planar and twisted. The Ni-Co sheet was the most stable among the systems studied, whereas the Ni-Fe sheet was the least stable. All of the sheets were magnetic spin semiconductors, having Dirac-like and dispersionless bands, which give rise to a major spatial separation between the charge carriers upon excitation. After treatment with bidentate ligands, such as pyrazine and bipyridine, these sheets produce a three dimensional cage-like structure, which is efficient for capturing small drug molecules, e.g., fluorouracil and niacin. This study shows that the magnetic metal atom and ligand structure have a significant effect on the drug capturing abilities of these systems. Therefore, these systems may be a tunable host system for drug delivery.

Synthesis and vibrational spectroscopic analysis of some Hofmann type clathrates

New Hofmann type clathrates in the form of M(pp)(2)Ni(CN)(4)·2G (where pp = 1-phenylpiperazine, G = 1,4-dioxane and M = Ni, Co or Cd) have been prepared in powder form and their FT-IR and FT-Raman spectra are reported. The results suggest that the present compounds are similar in structure to the Hofmann type clathrates and their structures consist of conjugated polymeric layers of |M-Ni(CN)(4)|(∞) with the pp bound to the metal (M) atom.

Vibrational spectroscopic study on some Hofmann-Td type clathrates: Ni(4-phenylpyridine)2M(CN)4·2G (M=Cd or Hg, G=1,4-dioxane)

New Hofmann-T(d) type clathrates in the form of Ni(4-Phpy)(2)M(CN)(4)·2G (where 4-Phpy=4-phenylpyridine, M=Cd or Hg and G=1,4-dioxane) have been prepared in powder form and their FT-IR and Raman spectra have been reported. The results suggest that these compounds are similar in structure to the Hofmann-T(d) type clathrates.

FT-IR spectroscopic investigation of some Hofmann type complexes: M(1-phenylpiperazine)2Ni(CN)4 (M=Ni, Co, Cd, Pd or Mn)

New Hofmann type complexes in the form of M(pp)(2)Ni(CN)(4) (where pp=1-phenylpiperazine and M=Ni, Co, Cd, Pd or Mn) have been prepared in powder form and their infrared spectra have been reported in the range of (4000-400) cm(-1). The thermal behaviours of these complexes have been investigated by differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA). Ni(pp)(2)Ni(CN)(4) complex has been examined via transmission electron microscope (TEM). The results suggest that these compounds are similar in structure to Hofmann type complexes and their structures consist of polymeric layers |M-Ni(CN)(4)|(infinity) with the pp molecule bounded to the metal atom (M).