Inorganic Chemistry
Article
Preparation of Salen Ligand: General Method B. To a solution
of diazide in THF/H2O (10/1; v/v) (0.02−0.3 M) was added
triphenylphosphine (2.4 equiv). The reaction mixture was stirred at 60
°C until the reduction was completed (monitored by TLC), then
diluted with 1 M HCl and washed with CH2Cl2. The aqueous layer
was concentrated and the residue was purified by cation exchange
column chromatography to give the desired diamine. A mixture of
diamine (1 equiv) and o-vanillin (2 equiv) in MeOH (0.02−0.6 M)
was stirred at room temperature. The reaction mixture was
concentrated and purified by silica gel column chromatography or
GPC to give the desired Salen ligand.
Synthesis of 6a. Compound 6a was prepared from 5a (27.8 mg,
106 μmol) according to general method A as a yellow solid (32.4 mg,
67.9 μmol, 64%). This compound was used for the next step without
further purification: 1H NMR (DMSO-d6, 400 MHz): δ 2.17−2.24 (m,
2H), 2.38−2.45 (m, 2H), 3.20−3.27 (m, 1H), 3.73 (s, 6H), 4.04−4.09
(m, 2H), 6.71 (s, 2H), 6.79 (t, 2H, J = 7.9 Hz), 7.00 (d, 4H, J = 7.9
Hz), 8.54 (s, 2H), 12.38 (brs, 2H); 13C NMR (DMSO-d6, 125 MHz):
δ 35.3, 40.7, 55.5, 71.4, 114.5, 117.8, 118.3, 123.2, 141.0, 147.8, 151.0,
165.4, 172.8; MS (EI): m/z 477 (M); HRMS (EI) calcd for
C25H27N5O5 477.2012 (M); found: 477.2004.
148.2, 151.6, 152.3, 164.9, 172.5; MS (FAB, NBA): m/z 532 (M+1);
HRMS (FAB, NBA) calcd for C29H34N5O5 532.2560 (M+1); found:
532.2553.
Synthesis of 6f. Compound 6f was prepared from 5f (61.7 mg,
227 μmol) according to general method A and purified by preparative
TLC. Crude Salen ligand 6f was further purified by recrystallization
from CHCl3 as yellow needles (24.4 mg, 50.0 μmol, 22%): IR (KBr): ν
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253, 1530, 1627, 1674, 2937, 3310, 3444 cm−1; H NMR (CD3OD,
400 MHz): δ 2.39−2.53 (m, 4H), 3.24−3.26 (m, 1H), 3.77 (s, 6H),
4.09−4.11 (m, 2H), 6.73 (t, 2H, J = 7.9 Hz), 6.91 (dd, 2H, J = 1.3, 7.9
Hz), 6.94 (dd, 2H, J = 1.3, 7.9 Hz), 7.06 (brt, 1H, J = 7.7 Hz), 7.28
(brt, 2H, J = 7.7 Hz), 7.58 (brd, 2H, J = 7.7 Hz), 8.42 (s, 2H); 13C
NMR (CD3OD, 125 MHz): δ 36.5, 43.7, 56.5, 73.0, 115.9, 118.8,
119.6, 121.3, 124.9, 1124.9, 129.7, 149.9, 154.5, 159.3, 166.7, 175.2;
MS (FAB, NBA): m/z 488 (M+H); HRMS (FAB, NBA) calcd for
C28H30N3O5 488.2185 (M+1), found: 488.2191.
Synthesis of 6g. Compound 6g was prepared from 5g (112 mg,
410 μmol) according to general method B as a yellow solid (47.7 mg,
97.6 μmol, 24%). This compound was used for the next step without
further purification: IR (neat): ν 1254, 1632, 1669, 2936, 3368 cm−1;
1H NMR (CDCl3, 400 MHz): δ 2.04−2.12 (m, 2H), 2.70−2.77 (m,
2H), 3.85 (s, 1H), 4.03−4.08 (m, 2H), 4.79−4.89 (m, 1H), 6.78 (t,
2H, J = 7.8 Hz), 6.86 (dd, 2H, J = 1.7, 7.8 Hz), 6.88 (dd, 2H, J = 1.7,
7.8 Hz), 7.40 (ddd, 1H, J = 1.2, 4.9, 7.8 Hz), 7.82 (dt, 1H, J = 1.7, 7.8
Hz), 8.15 (dt, 1H, J = 1.2, 7.8 Hz), 8.32−8.35 (m, 3H), 8.56 (ddd, 1H,
J = 1.2, 1.7, 4.9 Hz); 13C NMR (CDCl3, 125 MHz): δ 38.7, 46.9, 56.0,
71.1, 114.2, 118.0, 118.4, 121.9, 123.2, 126.1, 137.1, 148.2, 149.4,
151.2, 152.6, 164.1, 164.9; MS (FAB,NBA): m/z 489 (M+1); HRMS
(EI) calcd for C27H29N4O5 488.2060 (M), found: 488.2056.
Synthesis of 6h. Compound 6h was prepared from 5h (48.2 mg,
177 μmol) according to general method B as a yellow solid (26.0 mg,
53.2 μmol, 30%). This compound was used for the next step without
further purification: IR (KBr): ν 1254, 1626, 1649, 2956, 3378 cm−1;
1H NMR (CDCl3, 400 MHz): δ 2.06−2.10 (m, 2H), 2.69−2.76 (m,
2H), 3.84 (s, 6H), 4.01−4.04 (m, 2H), 4.86−4.95 (m, 1H), 6.77−6.81
(m, 3H), 6.87 (dd, 2H, J = 1.5, 8.0 Hz), 6.90 (dd, 2H, J = 1.5, 8.0 Hz),
7.30 (dd, 1H, J = 4.9, 7.8 Hz), 8.15 (dt, 1H, J = 2.0, 7.8 Hz), 8.38 (s,
2H), 8.68 (dd, 1H, J = 1.5, 4.9 Hz), 9.06 (d, 1H, J = 2.0 Hz); 13C
NMR (CDCl3, 125 MHz): δ 39.4, 47.7, 56.0, 71.5, 114.4, 117.8, 118.4,
119.5, 123.2, 129.6, 134.6, 148.2, 148.7, 151.6, 152.1, 165.2, 165.3; MS
(FAB, NBA): m/z 489 (M+H); HRMS (EI) calcd for C27H29N4O5
488.2060 (M), found: 488.2055
Synthesis of 6b. Compound 6b was prepared from 5b (261 mg,
959 μmol) according to general method A as a yellow solid (350 mg,
716 μmol, 75%). This compound was used for the next step without
1
further purification: IR (KBr): ν 3464, 3327, 1688, 1631 cm−1; H
NMR (CDCl3, 400 MHz): δ 2.33−2.40 (m, 2H), 2.46−2.52 (m, 2H),
3.35−3.43 (m, 1H), 3.87 (s, 6H), 4.16 (quin, 2H, J = 4.5 Hz), 6.79 (t,
2H, J = 7.9 Hz), 6.87 (dd, 2H, J = 1.6, 7.9 Hz), 6.90 (dd, 2H, J = 1.6,
7.9 Hz), 7.05 (ddd, 1H, J = 0.99, 4.9, 7.2 Hz), 7.71 (ddd, 1H, J = 1.6,
7.2, 8.7 Hz), 7.93 (s, 1H), 8.20 (brd, 1H, J = 8.7 Hz), 8.29 (ddd, 1H, J
= 0.99, 1.6, 4.9 Hz), 8.39 (s, 2H); 13C NMR (CDCl3, 125 MHz): δ
35.4, 42.8, 56.1, 72.7, 114.0, 114.2, 118.1, 118.5, 120.0, 123.2, 138.4,
147.9, 148.3, 151.3, 151.3, 165.3, 174.3; MS (FAB, NBA): m/z 490 (M
+H); HRMS (FAB, NBA) calcd for C27H29N4O5 489.2138 (M+1);
found: 489.2147.
Synthesis of 6c. Compound 6c was prepared from 5c (119 mg,
437 μmol) according to general method A as a yellow solid (129 mg,
264 μmol, 60%). This compound was used for the next step without
further purification: IR (KBr): ν 1254, 1628, 1692, 2936, 3342 cm−1;
1H NMR (DMSO-d6, 400 MHz): δ 2.13−2.20 (m, 2H), 2.33−2.39
(m, 2H), 3.00 (brs, 1H), 3.47−3.51 (m, 1H), 3.75 (s, 6H), 3.45−3.53
(m, 2H), 6.81 (t, 2H, J = 7.9 Hz), 7.01 (dd, 2H, J = 1.3, 7.9 Hz), 7.03
(dd, 2H, J = 1.3, 7.9 Hz), 7.34 (dd, 1H, J = 4.7, 8.3 Hz), 8.07 (ddd, 1H,
J = 1.5, 2.5, 8.3 Hz), 8.26 (dd, 1H, J = 1.5, 4.7 Hz), 8.61 (s, 2H), 8.77
(d, 1H, J = 2.5 Hz), 10.3 (s, 1H); 13C NMR (DMSO-d6, 125 MHz): δ
35.4, 41.4, 55.7, 71.4, 115.2, 117.4, 118.4, 123.0, 123.1, 135.6, 140.7,
140.8, 147.7, 151.1, 165.4, 165.5, 173.9; MS (FAB, NBA): m/z 489 (M
+H); HRMS (FAB, NBA) calcd for C27H29N4O5 489.2138 (M+1),
found: 489.2130.
Preparation of Mn(Salen) Complex: General Method C. To a
solution of Salen ligand (1 equiv) in MeOH (0.04−0.13 M) was added
manganese(II) acetate tetrahydrate (1 equiv). The reaction mixture
was stirred at room temperature for 1−2 h, then concentrated, and the
residue was thoroughly washed with acetone to give the desired
Mn(Salen) complex.
Synthesis of 3a. Compound 3a was prepared from 6a (62.0 mg,
130 μmol) according to general method C as a brown solid (69.7 mg,
118 μmol, 91%): IR (KBr): ν 1253, 1551, 1612, 2938, 3412 cm−1; MS
(FAB, NBA): m/z 530 (M-OAc); Anal. Calcd for
C27H28MnN5O7·4H2O: C, 49.02; H, 5.49; N, 10.59. Found: C,
49.32, H, 5.49, N, 10.25.
Synthesis of 3b. Compound 3b was prepared from 6b (336 mg,
687 μmol) according to general method C as a brown solid (357 mg,
594 μmol, 86%): IR (KBr): ν 3414, 1687, 1550 cm−1; MS (FAB,
NBA): m/z 541 (M-OAc); Anal. Calcd for C29H29MnN4O7·2H2O: C,
54.72; H, 5.23; N, 8.80. Found: C, 54.40, H, 5.15, N, 8.81.
Synthesis of 3c. Compound 3c was prepared from 6c (41.8 mg,
85.6 μmol) according to general method C as a brown solid (47.0 mg,
78.3 μmol, 91%): IR (KBr): ν 1254, 1551, 1616, 2937, 3420 cm−1;
FAB-MS (NBA): m/z 541 (M-OAc); Anal. Calcd for
C29H29MnN4O7·2H2O: C, 54.72; H,5.23; N, 8.80. Found: C, 54.78;
H, 5.30; N, 8.85.
Synthesis of 6d. Compound 6d was prepared from 5d (194 mg,
640 μmol) according to general method B as a yellow solid (75.0 mg,
144 μmol, 23%). This compound was used for the next step without
further purification: IR (KBr): ν 1251, 1271, 1568, 1631, 2938, 3310,
1
3521 cm−1; H NMR (CDCl3, 400 MHz): δ 2.40−2.55 (m, 4H),
3.20−3.28 (m, 1H), 3.73 (s, 3H), 3.84 (s, 6H), 4.03−4.08 (m, 2H),
6.42 (d, 1H, J = 7.2 Hz), 6.76 (t, 2H, J = 7.8 Hz), 6.86 (t, 4H, J = 7.8
Hz), 7.24 (dd, 1H, J = 2.0, 7.2 Hz), 8.33 (s, 2H), 8.50 (s, 1H), 8.89 (d,
1H, J = 2.0 Hz), 13.19 (brs, 2H); 13C NMR (CDCl3, 125 MHz): δ
34.4, 42.3, 44.6, 56.0, 72.2, 113.7, 114.1, 117.9, 118.6, 123.4, 128.3,
130.0, 138.1, 148.3, 151.3, 164.7, 169.6, 172.7; MS (EI): m/z 518 (M);
HRMS (EI) calcd for C28H30N4O6 518.2165 (M), found: 518.2163
Synthesis of 6e. Compound 6e was prepared from 5e (112 mg,
355 μmol) according to general method B as a yellow solid (26.8 mg,
50.4 μmol, 14%). This compound was used for the next step without
further purification: IR (KBr): ν 1253, 1627, 1679, 2938, 3253, 3368
1
cm−1; H NMR (CDCl3, 400 MHz): δ 2.52−2.53 (m, 4H), 2.75 (s,
Synthesis of 3d. Compoud 3d was prepared from 6d (60.6 mg,
117 μmol) according to general method C as a brown solid (49.0 mg,
77.7 μmol, 66%): IR (KBr): ν 1224, 1252, 1551, 1612, 2939, 3418
cm−1; MS (FAB, NBA): m/z 571 (M-OAc); Anal. Calcd for
6H), 3.31−3.34 (m, 1H), 3.82 (s, 6H), 4.08 (brs, 2H), 6.76 (t, 2H, J =
7.9 Hz), 6.84−6.87 (m, 5H), 8.14 (s, 1H), 8.22 (d, 1H, J = 5.2 Hz),
8.35 (s, 2H), 9.13 (s, 1H); 13C NMR (CDCl3, 125 MHz): δ 34.7, 34.9,
42.4, 56.0, 71.8, 112.5, 114.3, 117.6, 117.8, 118.4, 123.3, 143.9, 144.8,
H
dx.doi.org/10.1021/ic302101c | Inorg. Chem. XXXX, XXX, XXX−XXX