Supporting Information

Multi walled carbon nanotubes supported N-heterocyclic carbene

cobalt (ΙΙ) as a novel, efficient and inexpensive catalyst for the

Mizoroki–Heck reaction

Abdol R. Hajipoura,b* and Zahra Khorsandia

a Pharmaceutical Research Laboratory, Department of Chemistry ,Isfahan University of

Technology, Isfahan 84156, Islamic Republic of Iran

b Department of Neuroscience, University of Wisconsin, Medical School, Madison,

WI53706-1532, USA.

Experimental

Instrumentation and analysis

Analysis of 1H and 13C NMR spectra were taken on a Bruker-avance 400 MHz spectrometer

in CDCl3. The FT-IR spectra was recorded on a Jasco-680 (Japan) spectrophotometer in KBr

pellets and reported in cm−1. The X-ray diffraction (XRD) patterns were collected using a

broker, D8 Advanced (Germany) diffractometer with a copper target at the wavelength λ

CuKα = 1.54˚A and a tube voltage of 40 KV. The metal content of the complex was

measured using inductively coupled plasma (ICP; Varian vista-mpx), TGA curve was

obtained with a heating rate of 10 ºC/min on a STA503 win TA (Bahr-Thermoanalyse

GmbH, Hüllhorst, Germany). The transmission electron microscopy (TEM) images were

obtained using an EM208S micro-scope with an accelerating voltage of 100 KV.

General procedure for preparation Co-NHC@MWCNTs

Multi-walled carbon nanotubes (MWCNTs) were functionalized according to the procedure

described by Dyke and Tour [1]. In a typical experiment (see Scheme 1), MWCNTs (60 mg)

and 1,4-benzenediamine (54 mg, 0.5 mmol) were added to a flask equipped with a reflux

condenser and a magnetic stir bar, then sodium nitrite (55 mg, 0.8 mmol) was added in small

portion, under heating (60 °C) and vigorous stirred (magnetic stir bar) conditions. After 8 h,

the resulted solid was diluted with DMF and filtered, the solid was washed with DMF and

dispersing in DMF by sonication to afford the purified functionalized nanotubes.

For preparation of imidazolinium salts [2,3], on MWCNTs, aniline@MWCNTs 1 (58 mg,

0.13 mmol aniline) was dispersed in ethanol (25 mL) and glyoxal (10 μL, 0.22 mmol, 40 %

aq. solution), aniline (0.5 mmol, 45 μL) and a catalytic amount of formic acid were also

added. The mixture was stirred at 60 ºC for 24 h. Next, a solution of 37% aq. formaldehyde

(2 mL, 25 mmol) and ZnCl2 (5.5 mg, 0.04 mmol) in HCl (36%, 26.6 mL, 0.87 mmol) were

added dropwise. The reaction was stirred overnight at 60 ºC. Then, the solution was cooled,

diluted with CH2Cl2 (5 mL) and washed with 2 M HCl (3× 5 mL). The resulted brown

powder of 2 was washed with ether and ethanol to removed unreacted materials.

Finally, anhydrous cobalt (II) chloride (9 mg, 0.07 mmol) was dissolved in THF (1.0 mL) and

added to imidazolium@MWCNTs 2 (45 mg,) and pyridine (57 μL, 0.7 mmol) which

dispersed in THF (2mL). The reaction mixture was stirred for 2h [4], and the solvent was

removed under reduced pressure and the obtained solid was washed with ethanol (3 × 10 mL)

to remove the unreacted cobalt chlorides. The desired catalyst 4 was dried in a vacuum oven

(65 °C) overnight to give the product in 65 % yield (36 mg).

General procedure for the Heck reaction

In a round-bottom flask equipped with a magnetic stirring bar, to a mixture of Li2CO3 (4

mmol), olefin (1.5 mmol) and aryl halide (1 mmol) in poly ethylene glycol (PEG) (3 mL) was

added 10 mg of catalyst 4 and equipped with a condenser for refluxing. The above mixture

was heated at 80 ºC in an oil bath, and the progress of the reaction was monitored by TLC

(hexane/EtOAc, 80 : 20) and gas chromatography (GC). After completion of the reaction, the

mixture was diluted with dichloromethane and water. The organic layer was washed with

brine, dried over anhydrous MgSO4, and concentrated under reduced pressure. The residue

was purified by recrystallization from ethanol and water. The products were characterized by

comparing their physical properties m.p., IR, 1H and 13C NMR spectra with those found in the

literature [5-7].

Characterization of catalyst

Fig. S1 XRD pattern of the the catalyst (Co-NHC@MWCNTs (4))

Fig. S2 The TGA of pure MWCNT (a) and Co-NHC@MWCNTs (4))

Fig. S3 SEM images of a) pure- MWCNTs and b) Co-NHC@MWCNTs

Fig. S4. The FT-IR spectra of fresh catalyst Co-NHC@MWCNTs (1) and recovered after

eigth run (2)

Fig. S5. TEM image of Co-NHC@MWCNTs recovered after eigth run

References:

[1] C. A. Dyke and J. M. Tour, J. Am. Chem. Soc., 125 (2003) 1156-1157.

[2] Z. Wang, Y. Yu, Y. X. Zhang, S. Z. Li, H. Qian, Z. Y. Lin, Green Chem., 17 (2015) 413-

420.

[3] S. G. Weber, C. Loos, F. Rominger, Bernd F. Straub, ARKIVOC (2012) 226-242.

[4] K. Matsubara, A. Kumamoto, H. Yamamoto, Y. Koga, S. Kawata, J. Organomet. Chem.,

727 (2013) 44-49.

[5] A. R. Hajipour and G. Azizi, Synlett, 24 (2013) 254-258.

[6] A. R. Hajipour and G. Azizi, RSC Adv. 4 (2014) 20704-20708.

[7] A. R. Hajipour and G. Azizi, Appl. Organomet. Chem., 29 (2015) 247-253.