8738 J. Am. Chem. Soc., Vol. 121, No. 38, 1999
BritoVsek et al.
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3
in 76% yield. H NMR (CDCl3): δ 8.42 (d, 2H, J(HH) 7.8, Py-Hm),
7.94 (t, 1H, Py-Hp), 7.44, 7.21, 7.09, and 6.56 (m, 8H, Ar-H), 2.43 (s,
6H, NdCMe), 1.39 (s, 18H, CMe). 13C NMR (CDCl3,1H gated
decoupled): δ 165.32 (NdC), 155.61 (Py-Co), 149.66 (Ar-Cip), 139.77
(Ar-C), 136.86 (Ar-Co), 126.41 (Py-Cm), 123.75, 122.26 and 119.75
(Ar-C), 29.61 (CMe), 16.88 (NdC-Me). EI mass spectrum, m/z 425
[M+]. Anal. (C29H35N3) calcd: C, 81.84; H, 8.29; N, 9.87. Found: C,
81.03; H, 8.29; N, 9.75.
are observed in each case): δ 86.2 (2H, Py-Hm), 39.6 (1H, Py-Hp),
16.3 (4H, Ar-Hm), 13.4 (12H, Ar-Me), -11.3 (2H, Ar-Hp), -17.0 (6H,
NdC(Me)). FAB mass spectrum, m/z 496 [M+], 461 [M+-Cl], 425 [M+-
2Cl]. Anal. (C25H27N3FeCl2) calcd: C, 60.48; H, 5.44; N, 8.47.
Found: C, 60.11; H, 5.10; N, 8.01. µeff (Evans Balance): 5.31 BM.
5.3.3. Preparation of (2,6-Diacetylpyridinebis(2,4,6-trimethyl-
anil))FeCl2 (11). The procedure as above in (5.3.1) using 3 and FeCl2
gave 11 as a blue powder in 64% yield. 1H NMR (CD2Cl2, broad
singlets are observed in each case): δ 83.7 (2H, Py-Hm), 40.1 (1H,
Py-Hp), 21.8 (6H, Ar-Mep), 15.7 (4H, Ar-Hm), 13.0 (12H, Ar-Meo),
-21.3 (6H, NdC(Me)). FAB mass spectrum, m/z 523 [M+], 488 [M+-
Cl], 453 [M+-2Cl]. Anal. (C27H31N3FeCl2‚1.5H2O) calcd: C, 58.82;
H, 6.22; N, 7.62. Found: C, 58.63; H, 6.20; N, 6.88. µeff (Evans
Balance): 5.25 BM.
5.2.5. 2,6-Diformylpyridinebis(2,6-diisopropylanil) (5). To a solu-
tion of 2,6-pyridinedicarboxaldehyde (0.101 g, 0.75 mmol) in absolute
ethanol (20 mL), were successively added 2,6-diisopropylaniline (2.1
equiv, 1.57 mmol, 0.26 mL) and one drop of glacial acetic acid, and
the resulting mixture was refluxed for 24 h. Upon cooling, yellow
crystalline 5 was obtained in high yield (0.270 g, 80%). 1H NMR
3
(CDCl3): δ 8.44 (s, 2H, NdCH), 8.40 (d, 2H, J(HH) 7.6, Py-Hm),
8.00 (t, 1H, Py-Hp), 7.23 (m, 6H, Ar-H), 3.01 (sept, 4H, J(HH) 6.9,
5.3.4. Preparation of (2,6-Diacetylpyridinebis(2,4,6-trimethyl-
anil))FeBr2 (12). The procedure as above in (5.3.1) using 3 and FeBr2
gave 12 as a blue powder in 61% yield. 1H NMR (CD2Cl2, broad
singlets are observed in each case): δ 80.4 (2H, Py-Hm), 39.7 (1H,
Py-Hp), 22.3 (6H, Ar-Mep), 15.6 (16H, Ar-Hm, Ar-Meo), -18.5 (6H,
NdC(Me)). FAB mass spectrum, m/z 613 [M+], 533 [M+-Br], 453 [M+-
2Br]. Anal. (C27H31N3FeBr2) calcd: C, 52.88; H, 5.10; N, 6.85.
Found: C, 52.82; H, 5.42; N, 6.51. µeff (Evans Balance): 4.71 BM.
5.3.5. Preparation of (2,6-Diacetylpyridinebis(2-tert-butylanil))-
FeCl2 (13). The procedure as above in (5.3.1) using 4 and FeCl2 gave
3
CHMe2), 1.21 (d, 24H, CHMe2). 13C NMR (CDCl3,1H gated de-
coupled): δ 162.70 (NdC), 154.43 (Py-Co), 148.30 (Ar-Cip), 137.14
(Ar-Co), 124.54 (Ar-Cp), 123.05 (Py-Cp), 122.90 (Ar-Cm), 122.76 (Py-
Cm), 28.00 (CHMe2), 23.44 (CHMe2). CI mass spectrum, m/z 454
[(M+H)+]. Anal. (C31H39N3) calcd: C, 82.07; H, 8.66; N, 9.26.
Found: C, 82.02; H, 8.90; N, 9.54.
5.2.6. 2,6-Diformylpyridinebis(2,6-dimethylanil) (6). By using the
procedure described in (5.2.5) above, we obtained 6 as a yellow powder
in 82% yield. 1H NMR (CDCl3): δ 8.43 (s, 2H, NdCH), 8.40 (d, 2H,
3J(HH) 7.6, Py-Hm), 8.00 (t, 1H, Py-Hp), 7.10 (d, 4H, 3J(HH) 7.4, Ar-
Hm), 6.99 (t, 2H, Ar-Hp), 2.20 (s, 12H, Ar-Me). 13C NMR (CDCl3,1H
gated decoupled): δ 163.16 (NdC), 154.45 (Py-Co), 150.26 (Ar-Cip),
137.32 (Ar-Co), 128.16 (Py-Cp), 126.77 (Py-Cm), 124.16 (Ar-Cp), 122.69
(Ar-Cm), 18.31 (Ar-Meo). CI mass spectrum, m/z 342 [(M+H)+]. Anal.
(C23H23N3) calcd: C, 80.94; H, 6.74; N, 12.32. Found: C, 80.62; H,
6.44; N, 12.29.
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13 as a blue powder in 85% yield. H NMR (CD2Cl2, broad singlets
are observed in each case): δ 78.7 (2H, Py-Hm), 68.15 (1H, Py-Hp),
17.0 (2H, Ar-H), 1.70 (2H, Ar-H), -2.32 (18H, CMe), -14.3 (2H,
Ar-H), -24.1 (6H, NCCH3), -45.2 (2H, Ar-H). FAB mass spectrum,
m/z 551 [M+], 516 [M+-Cl], 426 [M+-FeCl2]. Anal. (C29H35N3FeCl2)
calcd: C, 63.06; H, 6.39; N, 7.61. Found: C, 63.09; H, 6.69; N, 7.35.
µeff (Evans NMR Method): 5.11 BM.
5.3.6. Preparation of (2,6-Diacetylpyridinebis(2,6-diisopropyl-
5.2.7. 2,6-Diformylpyridinebis(2,6-diethylanil) (7). By using the
procedure described in (5.2.5) above, we obtained 7 as a yellow powder
in 75% yield. 1H NMR (CDCl3): δ 8.44 (s, 2H, NdCH), 8.40 (d, 2H,
3J(HH) 7.6, Py-Hm), 8.00 (t, 1H, Py-Hp), 7.25 (m, 6H, Ar-H), 2.55 (q,
anil))CoCl2 (14). The procedure as above in (5.3.1) using 1 and CoCl2
gave 14 as a light brown powder in 67% yield. H NMR (CD2Cl2,
1
broad singlets are observed in each case): δ 117.1 (2H, Py-Hm), 49.91
(1H, Py-Hp), 10.07 (4H, Ar-Hm), 4.56 (6H, NdCCH3), -8.75 (2H, Ar-
Hp), -17.51 (12H, iPr-Me), -18.51 (12H, iPr-Me), -84.36 (6H, iPr-
CH). FAB mass spectrum, m/z 575 [M+-Cl]. µeff (Evans NMR
Method): 4.55 BM.
5.3.7. Preparation of (2,6-Diacetylpyridinebis(2,4,6-trimethyl-
anil))CoCl2 (15). The procedure as above in (5.3.1) using 3 and CoCl2
gave 15 as a green powder in 94% yield. The product was recrystalized
from hot 1,1,2,2-tetrachloroethane to give green needles. 1H NMR (CD2-
Cl2, broad singlets are observed in each case): δ 111.4 (2H, Py-Hm),
36.14 (1H, Py-Hp), 16.92 (6H, p-CH3), 6.33 (4H, Ar-Hm), -0.65 (6H,
NdC-CH3), -26.83 (12H, o-CH3). Anal. (C27H31N3CoCl2‚0.5H2O)
calcd: C, 60.46; H, 6.01; N, 7.83. Found: C, 60.58; H, 5.79; N, 7.79.
µeff (Evans Balance): 4.55 BM.
3
8H, J(HH) 7.5, Ar-CH2Me), 1.61 (t, 12H, Ar-CH2Me). 13C NMR
(CDCl3,1H gated decoupled): δ 162.79 (NdC), 154.45 (Py-Co), 149.52
(Ar-Cip), 137.33 (Ar-Co), 132.69 (Py-Cp), 126.27 (Py-Cm), 124.36 (Ar-
Cp), 122.62 (Ar-Cm), 24.68 (CH2Me), 14.58 (CH2Me). CI mass
spectrum, m/z 398 [(M+H)+]. Anal. (C27H31N3) calcd: C, 81.57; H,
7.86; N, 10.57. Found: C, 81.65; H, 7.69; N, 10.71.
5.2.8. 2,6-diformylpyridinebis(2,4,6-trimethylanil) (8). By using
the procedure described in (5.2.5) above, we obtained 8 as a yellow
powder in 80% yield. 1H NMR (CDCl3): δ 8.42 (s, 2H, NdCH), 8.40
3
(s, 2H, Py-Hm), 8.0 (t, 1H, J(HH) 8, Py-Hp), 7.0 (s, 4H, Ar-H), 2.33
(s, 6H, Ar-Mep), 2.19 (s, 12H, Ar-Meo). 13C NMR (CDCl3,1H gated
decoupled): δ 163.14 (NdC), 154.57 (Py-Co), 147.84 (Ar-Cip), 137.24
(Ar-Co), 133.52 (Ar-Cp), 128.86 (Py-Cp), 126.80, (Py-Cm) 122.57 (Ar-
Cm), 20.79 (Ar-Mep), 18.27 (Ar-Meo). EI mass spectrum, m/z 369 [M+].
Anal. (C25H27N3) calcd: C, 81.30; H, 7.32; N, 11.38. Found: C, 81.69;
H, 7.51; N, 11.11.
5.3.8. Preparation of (2,6-Diacetylpyridinebis(2-tert-butylanil))-
CoCl2 (16). The procedure as above in (5.3.1) using 4 and CoCl2 gave
1
16 as a golden-brown powder in 83% yield. H NMR (CD2Cl2, broad
singlets are observed in each case): δ 111.8 (2H, Py-Hm), 50.4 (1H,
Py-Hp), 12.6 (2H, Ar-H), 10.4 (6H, NCCH3), 1.92 (2H, Ar-H), -11.7
(2H, Ar-H), -25.7 (18H, CMe), -85.4 (2H, Ar-H). FAB mass
spectrum, m/z 519 [M+-Cl], 484 [M+-2Cl]. µeff (Evans NMR Method):
4.71 BM.
5.3. Complexation with MX2 (M ) Fe, Co; X ) Cl, Br). 5.3.1.
Preparation of (2,6-Diacetylpyridinebis(2,6-diisopropylanil))FeCl2
(9). A suspension of 1 (0.92 g; 1.89 mmol) in n-butanol was added
dropwise at 80 °C to a solution of FeCl2 (0.24 g; 1.89 mmol) in
n-butanol (20 mL) to yield a blue solution. After being stirred at 80 °C
for 15 min, the reaction was allowed to cool to room temperature. The
reaction volume was concentrated, and diethyl ether (30 mL) was added
to precipitate the product as a blue powder, which was subsequently
washed with diethyl ether (3 × 10 mL), filtered, and dried to afford
5.3.9. Preparation of (2,6-Diformylpyridinebis(2,6-diisopropyl-
anil))FeCl2 (17). A suspension of 5 (0.245 g, 0.55 mmol, 1 equiv) in
n-butanol (10 mL) was added dropwise at 80 °C to a solution of FeCl2
(0.070 g, 0.55 mmol) in n-butanol (40 mL) to yield a dark green
solution. After being stirred for 15 min at 80 °C, the mixture was
allowed to cool to room temperature and was then stirred for a further
12 h. The solvent volume was reduced to ∼1 mL and the reaction
mixture washed with diethyl ether (3 × 40 mL) to yield a dark green
1
0.93 g (81%) of 9. H NMR (CD2Cl2, broad singlets are observed in
each case): δ 81.7 (2H, Py-Hm), 81.1 (1H, Py-Hp), 14.9 (4H, Ar-Hm),
-5.3 (12H, i-Pr-Me), -6.3 (12H, i-Pr-Me), -10.9 (2H, Ar-Hp), -22.4
(4H, i-Pr-CH), -37.1 (6H, NdC(Me)). FAB mass spectrum, m/z 607
[M+], 572 [M+-Cl], 482 [M+-FeCl2]. Anal. (C33H43N3FeCl2‚0.5H2O)
calcd: C, 64.19; H, 7.18; N, 6.80. Found: C, 64.19; H, 6.90; N, 6.70.
µeff (Evans Balance): 5.34 BM.
1
powder of 17 (0.205 g, 65%). H NMR (CD2Cl2, broad singlets are
observed in each case): δ 61.5 (2H, Py-Hm), 16.8 (1H, Py-Hp), 14.1
(4H, Ar-Hm), 2.1 (2H, Ar-Hp), 1.4 (4H, i-Pr-CH), 0.6 (24H, i-Pr-Me),
-5.5 (2H, NdC-H). FAB mass spectrum: m/z 576 [M+], 544 [M+-
Cl], 454 [M+-FeCl2]. Anal. (C31H39N3FeCl2‚H2O) calcd: C, 62.22; H,
6.91; N, 7.02. Found: C, 62.18; H, 6.73; N, 6.92. µeff (Evans
Balance): 5.51 BM.
5.3.2. Preparation of (2,6-Diacetylpyridinebis(2,6-dimethylanil))-
FeCl2 (10). The procedure as above in (5.3.1) using 2 and FeCl2 gave
1
10 as a blue powder in 78% yield. H NMR (CD2Cl2, broad singlets