Inorganic Chemistry
Article
1
.41 (s, 9H, t-Bu), 3.79 (s, 3H, O−CH ), 7.55 (d, 1H, aryl−H, 2.50
2.2.2. Preparation of the Complexes. 2.2.2.1. Complex 1. First,
3
1
3
Hz), 7.59 (d, 1H, aryl−H, 2.5 Hz). C NMR (500 MHz, CDCl ) δ
3
1
for C H NO : C, 67.88; H, 8.75; N, 5.28. Found: C, 68.13; H, 8.97;
N, 5.17.
.2.1.3. 3,5-Di-tert-butyl-2-methoxy-aniline. First, 12.42 g (46.8
m mol) of 1,5-di-tert-butyl-2-methoxy-3-nitro-benzene was solubilized
in 200 mL of EtOH, and 1.25 g of 10% mol palladium on charcoal is
added. The mixture is then vigorously stirred under H atmosphere
for 3 days at room temperature. The catalyst is filtered over Celite,
and the filtrate was evaporated, affording 3,5-di-tert-butyl-2-methoxy-
0.12 mL (0.86 mmol) of triethylamine was added to a solution of 80.1
3
2 2
C O
0.67, 31.32, 34.90, 35.95, 61.43, 120.49, 128.64, 143.93, 144.55,
mg (0.111 mmol) of H
4
L
Br and 28.6 mg (0.115 mmol) of
2
+
45.90, 150.96. MS (HRMS): m/z= 266.18 [M + H] . Anal. Calcd
nickel(II) acetate tetrahydrate in 10 mL of MeOH under argon
atmosphere. The mixture is heated at 55 °C and stirred overnight, and
15
23
3
the precipitated pale yellow powder is collected and washed with
1
2
MeOH (49.7 mg, 73%). H NMR (400 MHz, DMSO-d
6
) δ 1.29 (s,
18H, t-Bu), 1.43 (s, 18H, t-Bu), 6.13 (s, 2H, CH
), 7.00 (d, 2H, aryl−
2
Hx or aryl−Hy, 2.12 Hz) 7.39 (d, 2H, aryl−Hx or aryl−Hy, 2.04 Hz),
7.74 (s, 2H, aryl−Hx or aryl−Hy, 1.96 Hz) 8.34 (s, 2H, aryl−Hx or
2
1
3
aryl−Hy, 2.04 Hz). C NMR (500 MHz, DMSO-d
) δ 30.16, 31.68,
6
3
1
3.82, 35.61, 60.44, 111.88, 118.11, 119.96, 121.45, 124.27, 133.21,
+
1
38.77, 152.09, 153.65. MS (HRMS): m/z = 612.30 [NiL] . Anal.
aniline as an orange solid (10.83 g, 98%). H NMR (400 MHz,
CDCl ) δ 1.27 (s, 9H, t-Bu), 1.39 (s, 9H, t-Bu), 3.60 (s, 2H, NH ),
Calcd for C H NiN O 1/3 CH OH: C, 67.99; H, 7.64; N, 8.98.
35 46
4
2
3
3
2
Found: C, 67.56; H, 7.81; N, 9.13.
3
.79 (s, 3H, O−CH ), 6.67 (s, 1H, aryl−H), 6.76 (s, 1H, aryl−H).
3
13
2.2.2.2. Complex 2. First, 65 μL (0.46 mmol) of triethyl amine was
C NMR (500 MHz, CDCl ) δ 31.25, 31.64, 34.58, 35.34, 59.20,
3
2 2
C O
added to a solution of 81.5 mg (0.113 mmol) of H4L
Br and 25.6
2
1
2
5
12.36, 114.50, 139.73, 142.02, 144.82, 146.41. MS (HRMS): m/z=
+
mg (0.115 mmol) of palladium(II) acetate in 10 mL of MeOH under
36.30 [M + H] . Anal. Calcd for C H NO: C, 76.53; H, 10.73; N,
1
5
25
argon atmosphere. The mixture is heated at 60 °C and stirred for 4 h,
.95. Found: C, 76.63; H, 10.76; N, 4.94.
.2.1.4. 1-(3,5-Di-tert-butyl-2-methoxy-phenyl)imidazole. First,
.52 mL (4.55 mmol) of glyoxal 10 wt % in H O was added to a
and the precipitated pale gray powder is collected and washed with
2
1
MeOH (42.5 mg, 57%). H NMR (400 MHz, DMSO-d ) δ 1.30 (s,
6
0
2
1
8H, t-Bu), 1.48 (s, 18H, t-Bu), 6.33 (s, 2H, CH ), 7.08 (d, 2H, aryl−
2
solution of 1.06 g (4.51 mmol) of 3,5-di-tert-butyl-2-methoxy-aniline
in 25 mL of EtOH. The mixture is stirred overnight at room
temperature before adding 482 mg (9.01 mmol) of ammonium
chloride and 0.68 mL of formaldehyde 37 wt % in H O. The mixture
is heated to reflux for 2 h, and 0.74 mL of H PO 85 wt % in H O was
added. The mixture is maintained at reflux for a further 12 h. The
crude mixture is evaporated and treated with a potassium hydroxide
solution (40% in water) until pH 9 is reached. The aqueous phase is
extracted with CH Cl (3 × 30 mL), and the combined organic
phases are washed with H O (50 mL) and brine (2 × 50 mL), dried
over Na SO , and evaporated. The crude brown solid is purified on
H, 1.60 Hz) 7.40 (s, 2H, aryl−H), 7.81 (d, 2H, aryl−H, 1.64 Hz) 8.39
1
3
(
3
1
d, 2H, aryl−H, 1.84 Hz). C NMR (500 MHz, DMSO-d ) δ 29.90,
6
1.69, 33.83, 35.77, 62.15, 113.51, 118.07, 120.79, 121.25, 125.04,
2
32.98, 139.61, 153.84, 154.52. MS (HRMS): m/z= 661.27 [PdL +
3
4
2
+
H] . Anal. Calcd for C H N O Pd: C, 63.57; H,7.03; N, 8.47.
3
5
46
4
2
Found: C, 63.18; H, 6.84; N, 8.03.
.2.2.3. Complex 3. First, 0.06 mL (0.43 mmol) of triethyl amine
2
C O
2
2
was added to a solution of 76.0 mg (0.106 mmol) of H4L Br and
2
2
2
4
8.8 mg (0.116 mmol) of cis-dichlorobis(dimethyl sulfoxide)-
platinum(II) in 12 mL of EtOH under argon atmosphere. The
2
2
4
mixture is heated at 100 °C and stirred for 5 h then overnight at 60
silica chromatography with a pentane/ethyl acetate 40/60 eluent
affording 1-(3,5-di-tert-butyl-2-methoxy-phenyl)imidazole as a pale
white solid (788 mg, 61%). H NMR (400 MHz, CDCl ) δ 1.32 (s,
9
°
C. The precipitated white powder is collected and washed with cold
1
EtOH (58.0 mg, 73%). H NMR (400 MHz, DMSO-d ) δ 1.30 (s,
1
6
3
1
8H, t-Bu), 1.48 (s, 18H, t-Bu), 6.28 (s, 2H, CH ), 7.11 (s, 2H, aryl−
2
H, t-Bu), 1.41 (s, 9H, t-Bu), 3.20 (s, 3H, O−CH ), 7.11 (d, 1H,
3
H) 7.43 (s, 2H, aryl−H), 7.68 (s, 2H, aryl−H) 8.37 (s, 2H, aryl−H).
aryl−H, 2.36 Hz), 7.22 (s, 1H, aryl−H), 7.23 (s, 1H, aryl−H) 7.37 (d,
13
C NMR (500 MHz, DMSO-d ) δ 29.94, 31.66, 33.90, 35.88, 62.07,
1
3
6
1
H, aryl−H, 2.32 Hz), 7.76 (s, 1H, aryl−H). C NMR (500 MHz,
1
1
13.24, 116.74, 120.46, 120.87, 125.34, 134.29, 139.50, 140.04,
CDCl ) δ 30.78, 31.51, 34.77, 35.66, 59.72, 120.42, 121.60, 123.95,
+
3
51.76. MS (HRMS): m/z = 749.33 [PdL] . Anal. Calcd for
1
2
9
29.72, 130.52, 137.71, 143.74, 146.58, 151.07. MS (HRMS): m/z =
87.21 [M + H] . Anal. Calcd for C H N O: C, 75.47; H, 9.17; N,
.78. Found: C, 74.20; H, 9.86; N, 9.78.
C H N O Pt·1/3CH OH: C, 55.80; H, 6.27; N, 7.37. Found: C,
+
35 46
4
2
3
1
8
26
2
5
5.40; H, 6.64; N, 7.39.
+
2
.3. Crystal Structure Analysis. Single crystals of 1, 2, 3, and 1 ·
OMe
2
.2.1.5. H4L Br . A mixture of 1 mL (14.25 mmol) of
−
2
SbF6 were coated with perfluoropolyether, picked up with nylon
loops, and mounted in the nitrogen cold stream of the diffractometer.
Mo Kα radiation (λ = 0.71073 Å) from a Mo-target rotating-anode X-
ray source equipped with INCOATEC Helios mirror optics was used.
Final cell constants were obtained from least-squares fits of several
thousand strong reflections. Intensity data were corrected for
absorption using intensities of redundant reflections with the program
dibromomethane and 103.1 mg (0.36 mmol) of 1-(3,5-di-tert-butyl-
-methoxy-phenyl)imidazole is sealed in a tube and stirred overnight
2
at 100 °C. The resulting white precipitate is collected and washed
with cold acetone giving the pure product as a white solid (88.0 mg,
1
6
5%). H NMR (400 MHz, DMSO-d ) δ 1.31 (s, 18H, t-Bu), 1.42 (s,
6
1
8H, t-Bu), 3.35 (s, 6H, O−CH ), 6.90 (s, 2H, CH ), 7.47 (d, 2H,
3
2
aryl−H, 2.00 Hz) 7.54 (d, 2H, aryl−H, 2.08 Hz), 8.26 (s, 2H, aryl−
75
SADABS. The structures were readily solved by charge-flipping
1
3
H) 8.34 (s, 2H, aryl−H), 9.96 (s, 2H, aryl−H). C NMR (500 MHz,
methods and subsequent difference Fourier techniques. The OLEX
DMSO-d ) δ 30.51, 30.97, 34.62, 35.27, 58.72, 61.04, 121.95, 122.62,
76
6
software was used for the refinement. All non-hydrogen atoms were
1
24.10, 125.86, 128.20, 139.04, 143.57, 146.81, 150.21. MS (HRMS):
anisotropically refined, and hydrogen atoms were placed at calculated
2
+
m/z = 293.21 [M − 2Br] . Anal. Calcd for C H N O .2Br: C,
3
7
54
4
2
5
9.51; H, 7.30; N, 7.50. Found: C, 59.30; H, 7.71; N, 7.21.
2 2
C
O
+
−
2
.2.1.6. H4L
Br . First, 0.36 mL (3.54 mmol) of boron tribomide
2
is added dropwise to a solution of 434.2 mg (0.58 mmol) of
H4L
solution is stirred overnight then quenched by successive additions
and evaporations of MeOH (4 × 20 mL). The resulting white solid is
collected and washed with cold acetone (377.6 mg, 90%). H NMR
OMe
Br in 15 mL of dry CH Cl under argon atmosphere. The
2
2
2
2
.4. Computational Details. Full geometry optimizations were
77
78,79
82
performed with the Gaussian 9 program, by using the B3LYP,
B3LYP-D3, or CAM-B3LYP functionals. The 6-31g* basis set
was used for the C, H, N, and O atoms. For the metal ion in 1 , we
1
80 81
+
(
400 MHz, DMSO-d ) δ 1.29 (s, 18H, t-Bu), 1.42 (s, 18H, t-Bu), 6.93
6
(
2
s, 2H, CH ), 7.32 (d, 2H, aryl−H, 2.40 Hz) 7.45 (d, 2H, aryl−H,
tested both the 6-31g* basis set and a pseudo-potential based on the
2
83
+
+
.35 Hz), 8.14 (t, 2H, aryl−H, 1.77 Hz) 8.27 (t, 2H, aryl−H, 1.72
LANL2Dz basis set. For 2 and 3 , we used only the pseudo-
potential for the metal center. Frequency calculations were system-
atically performed in order to ensure that the optimized structure
corresponds to a minimum and not a saddle point. Optical properties
were computed by using time-dependent density functional theory
1
3
Hz), 9.19 (s, 2H, aryl−H), 9.89 (s, 2H, aryl−H). C NMR (500
MHz, DMSO-d ) δ 29.54, 31.10, 34.22, 35.19, 58.08, 121.09, 122.28,
6
1
24.37, 124.92, 125.58, 139.10, 139.81, 142.67, 146.94. MS (HRMS):
2
+
m/z = 279.20 [M − 2Br] . Anal. Calcd for C H N O ·2Br: C,
5
3
5
50
4
2
84
8.49; H, 7.03; N, 7.80. Found: C, 57.31; H, 7.26; N, 7.23.
(TD-DFT) with the same basis set as for optimization. The solvent
C
Inorg. Chem. XXXX, XXX, XXX−XXX