Synthesis, Structural Characterization and Chromotropism of a Ni(II) and a Co(II) Compound with Acesulfamate as a Ligand

Abstract

The novel bis(acesulfamato-O)tetraaquanickel(II) and bis(acesulfamato-N)tetraaquacobalt(II) complexes have been synthesized and characterized by elemental analyses, magnetic measurements, u.v.-vis and FT-IR spectra. The thermal behavior of the complexes was also studied by simultaneous TG, DTG and DTA methods in a static air atmosphere. The crystal structure of bis(acesulfamato-O)tetraaquanickel(II) complex has been identified by singlecrystal X-ray diffraction analyses. The acesulfamate ligand (acs) acts as an O-donor through the carbonyl oxygen as a monodentate ligand in the Ni(II) complex. The Ni(II) ion structure resides on a two-fold axis and is coordinated by four aqua ligands defining the basal plane, and by two monodentate acesulfamate ligands occupying the axial positions. The chromotropism of both complexes has been studied using thermal and spectral analysis. The bis(acesulfamato-N)tetraaquacobalt(II)complex is found to be very soluble in water and organic solvents and exhibits a reversible thermochromism from pink to violet depending on deaquation, which occurs in two steps, in the solid state. The bis(acesulfamato-O)tetraaquanickel(II) complex has shown two thermochromic properties one of which is a reversible and changes the color from green to yellow by an endothermic effect, whereas the other one is irreversible and changes from yellow to brown depending on deaquation, in the solid state. The bis(acesulfamato-N)tetraaquacobalt(II) complex exhibits solvatochromism in solvents with different donor number and ionochromism in the presence of various cations in solution.

Crystal Structure, Thermal Analysis, Spectroscopic Studies and DFT Calculations on Hexaaquamagnesium(II) Acesulfamate

“…The vibrational frequencies belong to magnesium complex show some deviation from other reported crystal structures [4], because of different molecular geometry. The reason of difference between theoretical and experimental values may be hydrogen bonds and different geometric parameters between experimental and theoretical structure.…”

Synthesis, structural and spectroscopic characterization of thallium(I) acesulfamate

“…The study of this ligand constituted, during many years, one of the main research activities of Gligor Jovanovski, which can be considered as a central figure in the development of this peculiar field of chemistry and coordination chemistry. Similar to saccharinate, the acesulfamate anion presents different potential coordination sites: the iminic nitrogen, the carbonylic oxygen and the two sulfonyl oxygen atoms, and it can act as a monodentate, bidentate or bridging ligand, in the same way as saccharinate [6], as demonstrated by a number of acesulfamato metal complexes reported during the last years [7][8][9][10][11][12][13][14].…”

Experimental and theoretical (DFT) studies on poly[octa-μ3-acesulfamato-O,O:N,Oʹ;Oʹ,N:O,O-tetraaquatetrabarium(II)] and poly[octa-μ3-acesulfamato-O,O:N,Oʹ;Oʹ,N:O,O-tetraaquatetrastrontium(II)] complexes

“…While some ammonium-acesulfame compounds display acute oral toxicities, deterrent activity and skin irritation [2], choline acesulfamate is known having low toxicity [3]. In addition to biological importance of acesulfame, its coordination properties are important because acesulfame has potential donor atoms forming coordination bonds with metal ions [4].…”

“…Barium sulfate, which is an insoluble salt, is used as an enteric contrast agent for magnetic resonance studies [14,15]. Strontium is also an alkaline earth metal, which in nature appears mainly as SrSO 4 or SrCO 3 [13]. Both, BaSO 4 and SrSO 4 , exist also as biominerals in some marine species [16].…”

“…Strontium is also an alkaline earth metal, which in nature appears mainly as SrSO 4 or SrCO 3 [13]. Both, BaSO 4 and SrSO 4 , exist also as biominerals in some marine species [16]. Besides, low doses of stable strontium have beneficial effect for treatment of osteoporosis [17][18].…”