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

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, N-2 asorption 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. (C) 2014 Elsevier Inc. All rights reserved.