21
Tip: Degassing the mixture with the aid of bath sonication and
a vacuum pump, followed by flushing with hydrogen gas, will
enhance the hydrogen adsorption in the porous catalyst. The
reaction mixture was stirred under hydrogen atmosphere for
24 h. The catalyst was removed by filtration on Celite
®
, the
filter pad was washed excessively with DCM and the filtrate
was evaporated under reduced pressure to furnish the BOCprotected aniline derivative in 91% yield. Tip: It is suggested
to prepare fresh BOC-protected aniline derivatives.
3. Alternatively, microwave irradiation can be employed for
reducing reaction time and amount of solvents, especially
when reaction is performed at larger scale. In a typical procedure, add pristine CNHs (30 mg), BOC aniline derivative
(350 mg, 0.95 mmol), and oDCB (2 mL) in a glass vial under
an inert nitrogen atmosphere and bath-sonicate for 15 min.
Then, add isoamyl nitrite (5.7 mmol), seal the vial with a septum cap, heat at 150 °C, and apply microwave irradiation with
100 Watts for 60 min.
4. Filtration over PTFE membrane filter with the particular
0.2 μm or smaller pore size allows retaining covalently functionalized CNHs on top of the filter. If PTFE filter with bigger
pore size is employed, modified CNHs shall pass through the
filter or block/chock the pores.
5. Washing modified CNHs onto the PTFE filter allows to completely remove organic material physisorbed onto the surface
of CNHs. Furthermore, examination of the filtrate via UV-Vis
allows monitoring the purification.
6. Removal of the BOC-protecting group with gaseous HCl
yields a cleaner material as compared to the one obtained upon
the corresponding cleavage of BOC with trifluoroacetic acid
(TFA). Caution: Work with gaseous HCl only in a wellventilated fume hood.
7. During the evaporation of the solvent the dissolved HCl gas
will also be released.
8. A conventional 500 W halogen (or Xe) lamp is sufficient.
9. This treatment will convert the carboxylic acids to the corresponding acyl chlorides allowing the subsequent reaction of
the modified CNHs with hydroxyl- and amino-terminated
drugs/biomolecules.
10. The objective is to remove the traces of SOCl 2 . The use of dry
solvent and nitrogen atmosphere is essential for the stability of
the acyl chlorides, since they are susceptible to hydrolysis by
traces of moisture. Caution: Work with SOCl 2 only in a wellventilated fume hood. Contact of SOCl 2 with moisture results
in hydrolysis affording SO x and HCl gas. Do not store the acyl
chloride-modified CNHs and use them instantly.
Functionalized Carbon Nanohorns
Tip: Degassing the mixture with the aid of bath sonication and
a vacuum pump, followed by flushing with hydrogen gas, will
enhance the hydrogen adsorption in the porous catalyst. The
reaction mixture was stirred under hydrogen atmosphere for
24 h. The catalyst was removed by filtration on Celite
®
, the
filter pad was washed excessively with DCM and the filtrate
was evaporated under reduced pressure to furnish the BOCprotected aniline derivative in 91% yield. Tip: It is suggested
to prepare fresh BOC-protected aniline derivatives.
3. Alternatively, microwave irradiation can be employed for
reducing reaction time and amount of solvents, especially
when reaction is performed at larger scale. In a typical procedure, add pristine CNHs (30 mg), BOC aniline derivative
(350 mg, 0.95 mmol), and oDCB (2 mL) in a glass vial under
an inert nitrogen atmosphere and bath-sonicate for 15 min.
Then, add isoamyl nitrite (5.7 mmol), seal the vial with a septum cap, heat at 150 °C, and apply microwave irradiation with
100 Watts for 60 min.
4. Filtration over PTFE membrane filter with the particular
0.2 μm or smaller pore size allows retaining covalently functionalized CNHs on top of the filter. If PTFE filter with bigger
pore size is employed, modified CNHs shall pass through the
filter or block/chock the pores.
5. Washing modified CNHs onto the PTFE filter allows to completely remove organic material physisorbed onto the surface
of CNHs. Furthermore, examination of the filtrate via UV-Vis
allows monitoring the purification.
6. Removal of the BOC-protecting group with gaseous HCl
yields a cleaner material as compared to the one obtained upon
the corresponding cleavage of BOC with trifluoroacetic acid
(TFA). Caution: Work with gaseous HCl only in a wellventilated fume hood.
7. During the evaporation of the solvent the dissolved HCl gas
will also be released.
8. A conventional 500 W halogen (or Xe) lamp is sufficient.
9. This treatment will convert the carboxylic acids to the corresponding acyl chlorides allowing the subsequent reaction of
the modified CNHs with hydroxyl- and amino-terminated
drugs/biomolecules.
10. The objective is to remove the traces of SOCl 2 . The use of dry
solvent and nitrogen atmosphere is essential for the stability of
the acyl chlorides, since they are susceptible to hydrolysis by
traces of moisture. Caution: Work with SOCl 2 only in a wellventilated fume hood. Contact of SOCl 2 with moisture results
in hydrolysis affording SO x and HCl gas. Do not store the acyl
chloride-modified CNHs and use them instantly.
Functionalized Carbon Nanohorns