1900
M. Ulusoy et al. / Journal of Organometallic Chemistry 693 (2008) 1895–1902
157.92 (CH@N); 140.71; 138.25; 137.34; 136.65; 130.17;
127.52; 126.58; 125.42; 122.28; 120.95; 117.85; 56.21 (CH2–
C6H2(CH3)3); 48.80 (–CH@N–CH2–); 48.15 (im–N–CH2–);
35.19 (CH2–CH2–CH2); 34.36 (C6H2-5-C(CH3)3); 31.69
(C6H2-5-C(CH3)3); 31.29 (C6H2-3-C(CH3)3); 29.61 (C6H2-
3-C(CH3)3); 21.22 (C6H2-p-CH3); 20.06 (C6H2-o-(CH3)2).
6.17 (d, J = 14.8 Hz, 1H, –CH02–C6H5); 6.84 (d,
J = 2.0 Hz, 1H, N–CH@CH–N); 6.88 (d, J = 2.0 Hz, 1H,
N–CH@CH–N); 6.95 (d, J = 2.8 Hz, 1H; 6-C6H2); 7.30–
7.35 (m, 3H, o,p-C6H5); 7.43 (d, J = 2.4 Hz, 1H, 4-C6H02);
7.47–7.49 (dd, J = 1.6, 1.6 Hz, 2H, m-C6H5); 7.60 (s, 1H,
CH@N).13C NMR (100.56 MHz, CDCl3, d ppm) 164.4
(CH@N); 163.9 (2-C6H2); 157.7 (Pd–C); 141.2 (3-C6H2);
136.7 (4-C6H2); 135.5 (1-C6H5); 130.7 (5-C6H2); 129.1 (o-
C6H5); 128.9 (m-C6H5); 128.6 (p-C6H5); 127.8 (6-C6H2);
122.7 (N-CH@CH–N); 120.9 (N–CH@CH–N); 117.9
(1-C6H2); 62.6 (–CH@N–CH2–); 54.9 (CH2–C6H5); 45.8
(im–N–CH2–); 35.9 (C6H2-3-C(CH3)3); 34.0 (C6H2-5-
C(CH3)3); 32.7 (CH2–CH2–CH2); 31.6 (C6H2-3-C(CH3)3);
29.8 (C6H2-5-C(CH3)3).
5.4. Synthesis of 1-[3-(3,5-di-tert-butyl-2-
hydroxyphenyl)propylimino]-3-(2,3,4,5,6-
pentamethylbenzyl)imidazolium bromide (2c)
Compound 2c was prepared in the same way as 2a
from N-[1-(3-aminopropyl)imidazole]-3,5-di-tert-butylsali-
cylaldimine (1) (341 mg, 1.0 mmol) and 2,3,4,5,6-pentam-
ethylbenzyl bromide (241 mg, 1.0 mmol) to give pale
1
yellow crystals. 86% yield (501 mg). M.p. 170–172 °C. H
5.6. Synthesis of 1-[3-(3,5-di-tert-butyl-2-oxophenyl)
propyliminato]-3-(2,4,6- trimethylbenzyl)
imidazol-2-ylidenebromopalladium(II) (3b)
NMR (400 MHz, CDCl3, d ppm) 1.26 (s, 9H, C6H2-5-
C(CH3)3); 1.36 (s, 9H, C6H2-3-C(CH3)3); 2.13 (s, 6H,
C6H0-o-(CH3)2); 2.16 (s, 6H, C6H0-m-(CH3)2); 2.20 (s, 3H,
C6H0-p-CH3); 2.38 (m, 2H, CH2–CH2–CH2); 3.76 (t,
J = 6.4 Hz, 2H, im–N–CH2–); 4.56 (t, J = 7.2 Hz, 2H,
CH@N–CH2); 5.50 (s, 2H, –CH2–C6H0(CH3)5); 6.86 (t,
J = 1.6 Hz, 1H, C6H2-p-CH); 7.12 (s, 1H, C6H2-o-CH);
7.35 (d, J = 2.4 Hz, 1H, N–CH@CH–N); 7.49 (d,
J = 1.6 Hz, 1H, N–CH@CH–N); 8.47 (s, 1H, –CH@N);
10.19 (s, 1H, N–CH–N); 13.31 (s, 1H, –OH). 13C NMR
(100.56 MHz, CDCl3, d ppm) 167.90 (N–CH–N); 158.0
(CH@N); 140.7; 137.5; 136.7; 136.7; 134.0; 133.7; 127.5;
126.5; 125.5; 122.4; 121.2; 117.9; 56.2 (CH2–C6H0
(CH3)5); 49.3 (–CH@N–CH2–); 48.7 (im–N–CH2–); 35.2
(CH2–CH2–CH2); 34.4 (C6H2-5-C(CH3)3); 31.7 (C6H2-5-
C(CH3)3); 31.4 (C6H2-3-C(CH3)3); 29.5 (C6H2-3-C(CH3)3);
17.4 (C6H0-p-CH3); 17.1 (C6H0-o-(CH3)2); 17.0 (C6H0-m-
(CH3)2).
Compound 3b was prepared in the same way as 3a from
1-[3-(3,5-di-tert-butyl-2-hydroxyphenyl)propylimino]-3-(2,-
4,6- trimethylbenzyl)imidazolium bromide (2b) (277 mg,
0.5 mmol) and Pd(OAc)2 (112 mg, 0.5 mmol) with 12 h
refluxing to give yellow crystals. 89% yield (293 mg). M.p.
1
291–292 °C. H NMR (400 MHz, CDCl3, d ppm) 1.27 (s,
9H, C6H2-5-C(CH3)3); 1.49 (s, 9H, C6H2-3-C(CH3)3);
1.98–2.08 (m, 2H, CH2–CH2–CH2); 2.92 (s, 9H, C6H2–
(CH3)3); 2.35 (s, 1H, im–N–CH2–); 2.92 (t, J = 10.8 Hz,
1H, im–N–CH02–); 3.56 (d, J = 10.4 Hz, 1H, CH@N–CH2);
4.09–4.14 (dd, J = 6.8, 6.0 Hz, 1H, CH@N–CH02); 5.63 (d,
J = 14.8 Hz, 1H, –CH2–C6H2–(CH3)3); 5.83 (d, J =
14.8 Hz, 1H, –CH02–C6H2–(CH3)3); 6.42 (s, 1H, N–
CH@CH–N); 6.83 (s, 1H, N–CH@CH–N); 6.89 (s, 2H;
C6H2–(CH3)3); 6.92 (s, 1H, C6H2-p-CH); 7.43 (s, 1H,
C6H2-o-CH); 7.68 (s, 1H, –CH@N). 13C NMR
(100.56 MHz, CDCl3, d ppm) 164.2 (CH@N); 163.6; 155.9
(Pd–C); 141.2; 138.8; 138.3; 135.4; 130.7; 129.7; 128.5;
128.1; 121.4; 120.7; 117.7; 62.3 (CH2–C6H2(CH3)3); 50.7
(–CH@N–CH2–); 45.8 (im–N–CH2–); 35.9 (CH2–CH2–
CH2); 34.0 (C6H2-5-C(CH3)3); 31.6 (C6H2-5-C(CH3)3);
32.8 (C6H2-3-C(CH3)3); 29.8 (C6H2-3-C(CH3)3); 21.3
(C6H2-p-CH3); 20.1 (C6H2-o-(CH3)2).
5.5. Synthesis of 1-[3-(3,5-di-tert-butyl-2-oxophenyl)
propyliminato]-3(benzyl)imidazol-2-
ylidenechloropalladium(II) (3a)
A solution of the 1-[3-(3,5-di-tert-butyl-2-hydroxy-
phenyl)propylimino]-3-(benzyl)imidazolium chloride (2a)
(234 mg, 0.5 mmol) in toluene (8 mL) and Pd(OAc)2
(112 mg, 0.5 mmol) were heated for 12 h under reflux. The
color of the solution turned from red to yellow. The solu-
tion was evaporated to half of its initial volume in vacuo.
n-Hexane (10 mL) was added in order to precipitate the
product. The precipitated solid was filtered via cannula
and washed several times with Et2O. The desired compound
was recrystallized from CH2Cl2 (3 mL):Et2O (12 mL). 92%
yield (285 mg). M.p. 273–275 °C. 1H NMR (400 MHz,
CDCl3, d ppm)1H NMR (400 MHz, CDCl3, d ppm) 1.27
(s, 9H, C6H2-5-C(CH3)3); 1.48 (s, 9H, C6H2-3-C(CH3)3);
1.94–2.04 (m, 2H, CH2–CH2–CH2); 2.83 (td, J = 3.6, 4.0,
4.0 Hz, 1H, CH@N–CH2–); 3.50–3.54 (dd, J = 3.6,
4.0 Hz, 1H, CH@N–CH02–); 4.09–4.14 (dd, J = 6.8,
6.4 Hz, 1H, im–N–CH2); 5.61 (td, J = 5.2, 4.8, 5.2 Hz,
1H, im–N–CH02); 5.35 (d, J = 14.8 Hz, 1H, –CH2–C6H5);
5.7. Synthesis of 1-[3-(3,5-di-tert-butyl-2-
oxophenyl)propyliminato]-3-(2,3,4,5,6-
pentamethylbenzyl)imidazol-2-ylidenebromopalladium(II)
(3c)
Compound 3c was prepared in the same way as 3a
from 1-[3-(3,5-di-tert-butyl-2-hydroxyphenyl)propylimino]-
3-(2,3,- 4,5,6-pentamethylbenzyl)imidazolium bromide (2c)
(291 mg, 0.5 mmol) and Pd(OAc)2 (112 mg, 0.5 mmol)
to give orange-yellow crystals. 71% yield (207 mg). M.p.
>282 °C (dec.). 1H NMR (400 MHz, CDCl3, d ppm)
1.21 (s, 9H, C6H2-5-C(CH3)3); 1.43 (s, 9H, C6H2-3-
C(CH3)3); 1.89–2.07 (m, 2H, CH2–CH2–CH2); 2.15 (s, 6H,
C6H0-o-(CH3)2); 2.19 (s, 3H, C6H0-p-CH3); 2.20 (s, 6H,