Mesoporous silica SBA-15 functionalized by nickel–phosphonic units: Raman and magnetic analysis

• SBA-15 silica functionalized with propyl-nickel phosphonate units was synthesized.
• Efficiency of synthesis was examined by Raman study supported with DFT simulations.
• Concentration of nickel ions in the matrix was determined by magnetic measurements.
• Homogenous distribution of nickel–phosphonate active units was proved.

In the present work we present mesoporous silica SBA-15 containing propyl-nickel phosphonate study towards confirmation of synthesis procedure correctness. The structure of mesoporous sample was tested by TEM microscopy, N2 sorption tests and X-ray scattering. To probe bounding between nickel atoms and phosphonic units the Raman spectroscopy was carried out. As a support of Raman scattering, the theoretical calculations were made based on density functional theory, with the B3LYP method. By comparison of the calculated vibrational spectra of the molecule with experimental results, distribution of the active units inside silica matrix has been determined. Magnetic measurements were carried out to find nickel ions concentration inside the mesoporous matrix, and also to determine nickel ions environment. Both magnetic and Raman study confirm the efficiency of the synthesis and corroborate the homogenous distribution of nickel–phosphonate active units in silica matrix.

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