. Materials
All reagents (A.R.) were purchased from Merck or Aldrich and
were used without further purification, except for solvents, which
were treated according to standard methods.
2.2. Preparation of the organometallic functionalized nanosize
SiO2–Al2O3 mixed-oxides
ASNPs was used as the support. This support was prepared by
sol–gel method as follow; Aluminum tri-sec-butylate (97%) and
tetraethyl orthosilicate (98%) were used as the precursors, and
2,4-pentandione (H-acac) as the complexing agent. Appropriate
amounts of aluminum tri-sec-butylate and tetraethyl orthosilicate
were dissolved in n-butanol. The solution was heated to 60 C. The
components were thoroughly mixed, then it was cooled down to
room temperature, and then H-acac was added. The produced clear
solution was hydrolyzed with deionized water (11.0 mol H2O/mol
alkoxide). The solution was left overnight to hydrolyze the alkoxides,
yielding transparent gel. The transparent gel was dried at
110 C to remove water and any solvent, and then it was calcined
at 500 C for 5 h to remove the organic materials. The support is
denoted as ASNPs. ASNPs-supported 3-aminopropyl (Scheme 1)
was prepared by refluxing 5.2 g SiO2–Al2O3 (1:1) that had been
activated at 550 C for 6 h under air with 3.5 mL (0.0195 mol) of
3-aminopropyl-trimethoxysilane in dry dichloromethane
(100 mL) for 24 h. The solid was filtered and washed off with
methanol, dichloromethane and dried at 100 C under vacuum
for 6 h. The functionalized ASNPs is identified here after by Si/Alpr-NH2.
Then, ferrocenecarboxaldehyde (FCA) was added to a suspended
solution of Si/Al-pr-NH2, in dry methanol. The mixture was
refluxed for 48 h to prepare an organometallic compound (Si/Al-prN
= ferrocene, here after is identified by Si/Al–Fe) (vide Scheme 1)
on the surface of the ASNPs. Then, the resulting material (dirty
red powder) was filtered off, washed with copious of ethanol and
methanol, and finally it dried in a vacuum at 60 C.
2.3.