136
E. Kim et al. / Polyhedron 42 (2012) 135–141
purification. Elemental analyses (C, H, N) of the prepared com-
plexes were carried out on an elemental analyzer (EA 1108; Car-
lo-Erba, Milan, Italy). 1H NMR (400 MHz, 600 MHz) and 13C NMR
(75.46 MHz, 150.85 MHz operating, respectively) were recorded
on Bruker Advance Digital 400 and 600 NMR spectrometers and
the chemical shifts were recorded in ppm units using SiMe4 as
an internal standard. Electronic absorption spectra were obtained
on an Ocean Optics USB4000 spectrophotometer (Ocean Optics,
Dunedin, FL). The molecular weight and molecular weight distribu-
tion of the obtained PMMA were determined using gel permeation
chromatography (GPC) (CHCl3, Alliance e2695; Waters Corp., Mil-
ford, MA). The glass transition temperature (Tg) was determined
using a thermal analyzer (Q2000; TA Instruments, New Castle, DE).
7.03 (d, 2H, J = 8.4 Hz), 6.28 (t, 2H, J = 1.2 Hz), 5.88 (s, 4H).
13C{1H} NMR (DMSO-d6, 600 MHz) d: 156.02 13C(19F)} (d,
J = 236 Hz), 142.43 (s), 139.59 (d, J = 184 Hz), 130.13 (d,
J = 186 Hz), 116.52 (d, J = 153 Hz), 115.82 (d, J = 174 Hz), 106.08
(d, J = 167 Hz), 66.72 (t, J = 153 Hz). UV–vis: kmax (nm) and emax
(MÀ1 cmÀ1) in DMF: 260 and 1421, and 293 and 1706.
{
2.2.5. N,N-bis(3,5-dimethyl-1H-pyrazolyl-1-methyl)aniline (L4)
L4 was prepared by an analogous method as described for L1,
except utilizing 3,5-dimethyl-1H-pyrazolyl-1-methanol. A white
solid product was obtained (4.20 g, 68.0%). 1H NMR (DMSO-d6,
600 MHz) d: 7.20 (t, 2H, J = 7.2 Hz), 7.12 (d, 2H, J = 7.8 Hz), 6.82
(t, 1H, J = 7.2 Hz), 5.78 (s, 2H), 5.64 (s, 4H), 2.16 (s, 6H), 2.08 (s,
6H). 13C{1H} NMR (DMSO-d6, 600 MHz) d: 146.34 (s), 139.30 (s),
129.07 (s), 120.47 (d, J = 161 Hz), 117.34 (d, J = 157 Hz), 113.12
(d, J = 155 Hz), 106.18 (d, J = 175 Hz), 63.49 (t, J = 147 Hz), 13.47
(q, J = 126 Hz), 10.69 (q, J = 129 Hz). UV–vis: kmax (nm) and emax
(MÀ1 cmÀ1) in DMF: 269 and 1199, and 284 and 1231.
2.2. Preparation of the ligands and the Zn(II) complexes
2.2.1. 1H-pyrazolyl-1-methanol and 3,5-dimethyl-1H-pyrazolyl-1-
methanol
1H-pyrazolyl-1-methanol and 3,5-dimethyl-1H-pyrazolyl-1-
methanol, as starting materials, were prepared in processes de-
scribed elsewhere [8]. A CH2Cl2 solution (100 mL) of pyrazole
(20.4 g, 0.30 mol) or 3,5-dimethylpyrazole (28.8 g, 0.30 mol) was
2.2.6. N,N-bis(1H-pyrazolyl-1-methyl)aniline zinc(II) chloride
(L1ZnCl2)
A solution of L1 (0.253 g, 1.00 mmol) in dried ethanol (10.0 mL)
was added to a solution of anhydrous ZnCl2 (0.136 g, 1.00 mmol) in
dried ethanol (10.0 mL) at room temperature. Precipitation of a
white material occurred while stirring at room temperature for
12 h. The white powder was filtered and washed with ethanol
(50.0 mL), followed by washing with diethyl ether (50.0 mL)
(0.28 g, 72%). X-ray quality crystals of L1ZnCl2 were obtained with-
in 5 days from diethyl ether (10.0 mL) diffusion into an acetone
solution (10.0 mL) of L1ZnCl2 (0.10 g). Anal. Calc. for
added to
a CH2Cl2 solution (100 mL) of para-formaldehyde
(9.00 g, 0.30 mol). The solution was refluxed for 5 days and the fil-
trate solvent was removed under reduced pressure to give a white
powder (28.5 g, 98.0% for 1H-pyrazolyl-1-methanol and 36.3 g,
96.0% for 3,5-dimethyl-1H-pyrazolyl-1-methanol). 1H NMR (CDCl3,
400 MHz) for 1H-pyrazolyl-1-methanol d: 7.71 (s, 1H), 7.59 (d, 1H,
J = 2.24 Hz), 7.56 (d, 1H, J = 1.48 Hz), 6.29 (t, 1H, J = 1.8 Hz), 5.51 (s,
2H); 3,5-dimethyl-1H-pyrazolyl-1-methanol d: 7.81(s, 1H), 5.83 (s,
1H), 5.40 (s, 2H), 2.34 (s, 3H), 2.20 (s, 3H).
C14H15Cl2N5Zn: C, 43.16; H, 3.88; N, 17.98. Found: C, 43.01; H,
3.94; N, 18.16%. 1H NMR (DMSO-d6, 600 MHz) d: 7.85 (d, 2H,
J = 2.4 Hz), 7.52 (d, 2H, J = 1.4 Hz), 7.20 (d, 2H, J = 9.0 Hz), 7.17 (d,
2H, J = 9.0 Hz), 6.79 (t, 2H, J = 6.6 Hz), 6.27 (t, 2H, J = 2.4 Hz),
5.92 (s, 4H). 13C{1H} NMR (DMSO-d6, 600 MHz) d: 145.66 (s),
139.58 (d, J = 184 Hz), 130.17 (d, J = 188 Hz), 129.43 (d,
J = 159 Hz), 119.85 (d, J = 161 Hz), 114.58 (d, J = 157 Hz), 106.04
(d, J = 176 Hz), 66.38 (t, J = 157 Hz). UV–Vis: kmax (nm) and emax
(MÀ1 cmÀ1) in DMF: 269 and 734, and 284 and 817.
2.2.2. N,N-bis(1H-pyrazolyl-1-methyl)aniline (L1)
L1 was prepared by a similar procedure as described in the lit-
erature [30–32]. A CH2Cl2 solution (10.0 mL) of aniline (1.86 g,
0.020 mol) was added to a CH2Cl2 solution (30.0 mL) of 1H-1-pyr-
azolyl-1-methanol (3.92 g, 0.040 mol). The reaction solution was
dried over MgSO4 after stirring the reaction mixture at room tem-
perature for 3 days. The filtrate solvent was removed under re-
duced pressure to give a bright yellow oil (3.54 g, 70.0%). 1H
NMR (DMSO-d6, 600 MHz) d: 7.83 (d, 2H, J = 2.4 Hz), 7.50 (t, 2H,
J = 1.2 Hz), 7.17 (d, 2H, J = 5.4 Hz), 7.16 (d, 2H, J = 2.4 Hz), 6.77 (t,
2H, J = 7.2 Hz), 6.25 (t, 2H, J = 1.8 Hz), 5.91 (s, 4H). 13C{1H} NMR
(DMSO-d6, 600 MHz) d: 145.48 (s), 139.50 (d, J = 178 Hz),
130.27(d, J = 114 Hz), 129.16 (d, J = 84 Hz), 119.78 (d, J = 164 Hz),
114.53 (d, J = 160 Hz), 106.09 (d, J = 176 Hz), 66.37 (t, J = 153 Hz).
UV–Vis: kmax (nm) and emax (MÀ1 cmÀ1) in DMF: 269 and 1052,
and 283 and 1232.
2.2.7. N,N-bis(1H-pyrazolyl-1-methyl)-p-methoxyaniline zinc(II)
chloride (L2ZnCl2)
L2ZnCl2 was prepared according to a similar procedure as de-
scribed for L1ZnCl2. The white powder was filtered and washed
with ethanol (50.0 mL), followed by washing with diethyl ether
(50.0 mL) (0.32 g, 76%). X-ray quality crystals of L2ZnCl2 were ob-
tained within five days from diethyl ether (10.0 mL) diffusion into
an acetone solution (10.0 mL) of L2ZnCl2 (0.10 g). Anal. Calc. for
C15H17Cl2N5Zn: C, 42.93; H, 4.08; N, 16.69. Found: C, 42.96; H,
2.2.3. N,N-bis(1H-pyrazolyl-1-methyl)-p-methoxyaniline (L2)
4.08; N, 17.03%. 1H NMR (DMSO-d6, 600 MHz) d: 7.77 (d, 2H,
J = 1.8 Hz), 7.49 (d, 2H, J = 1.8 Hz), 7.05 (d, 2H, J = 7.2 Hz), 6.78 (d,
2H, J = 6.0 Hz), 6.24 (t, 2H, J = 1.8 Hz), 5.81 (s, 4H), 3.63 (s, 3H).
13C{1H} NMR (DMSO-d6, 600 MHz) d: 153.54 (s), 139.17 (s),
139.26 (d, J = 184 Hz), 129.99 (d, J = 188 Hz), 116.80 (d,
J = 159 Hz), 114.65 (d, J = 154 Hz), 105.90 (d, J = 176 Hz), 66.91 (t,
J = 153 Hz), 55.47 (q, J = 144 Hz). UV–vis: kmax (nm) and emax
(MÀ1 cmÀ1) in DMF: 268 and 672, and 303 and 1308.
L2 was prepared by an analogous method as described for L1,
except utilizing p-methoxyaniline. The product was obtained as a
dark brown oil (4.30 g, 76.0%). 1H NMR (DMSO-d6, 600 MHz) d:
7.79 (d, 2H, J = 1.8 Hz), 7.51 (d, 2H, J = 1.2 Hz), 7.09 (d, 2H,
J = 9.6 Hz), 6.79 (d, 2H, J = 9.0 Hz), 6.25 (t, 2H, J = 1.8 Hz), 5.83 (s,
4H), 3.65 (s, 3H). 13C{1H} NMR (DMSO-d6, 600 MHz) d: 153.67
(s), 139.54 (s), 139.45 (d, J = 186 Hz), 130.00 (d, 2C, J = 187 Hz),
116.91 (d, J = 158 Hz), 114.84 (d, J = 158 Hz), 105.95 (d,
J = 176 Hz), 67.03 (t, J = 152 Hz), 55.65 (q, J = 144 Hz). UV–Vis: kmax
2.2.8. N,N-bis(1H-pyrazolyl-1-methyl)-p-fluoroaniline zinc(II)
chloride (L3ZnCl2)
(nm) and e
max (MÀ1 cmÀ1) in DMF: 268 and 684, and 298 and 1389.
L3ZnCl2 was prepared according to a similar procedure as de-
scribed for L1ZnCl2. The white powder was filtered and washed
with ethanol (50.0 mL), followed by washing with diethyl ether
(50.0 mL) (0.38 g, 83.0%). X-ray quality crystals of L3ZnCl2 were ob-
tained within five days from diethyl ether (10.0 mL) diffusion into
an acetone solution (10.0 mL) of L3ZnCl2 (0.10 g). Anal. Calc. for
2.2.4. N,N-bis(1H-pyrazolyl-1-methyl)-p-fluoroaniline (L3)
L3 was prepared by an analogous method as described for L1,
except utilizing p-fluoroaniline. A bright yellow oil product was
obtained (4.34 g, 80.0%). 1H NMR (DMSO-d6, 600 MHz) d: 7.84 (d,
2H, J = 1.8 Hz), 7.53 (d, 2H, J = 1.8 Hz), 7.21 (d, 2H, J = 4.8 Hz),