H
J. R. Cubanski et al.
resulting in evolution of CO2. The mixture was heated to 608C
for 0.5 h, during which time more CO2 evolved, and the dark red
solution was allowed to cool to room temperature and filtered
through Celite. The filtrate was diluted to 1 L and loaded onto a
Sephadex SP C-25 cation exchange column, and eluted with
0.1 M NaClO4 solution. The main band was collected as a
fraction of 150 mL and concentrated to 20 mL. On standing at
48C, red crystals (0.215 g, 33 %) formed, which were collected
by filtration, washed with isopropanol and diethyl ether and air-
dried. nmax (ATR)/cmꢀ1 3470w, br (H2O), 3116w (pz), 1670s
(CO3), 1086s, br (ClO4), 771s (g pz), 617s (pz). lmax/nm
(e/L molꢀ1 cmꢀ1) 499 (115). dH (CD3CN, 400 MHz) 8.46 (1H,
d, J 2.2, Ha), 8.00 (1H, s, Hg), 7.97 (1H, d, J 2.6, Hc), 7.78 (1H, d,
J 2.5, Hc), 7.41 (3H, m, Hi and Hk), 7.28 (2H, m, Hj), 7.22 (1H, d,
J 1.9, Ha), 6.68 (1H, t, J 2.5, Hb), 6.44 (1H t, J 2.5, Hb), 5.61 (2H,
s, Hh), 5.04 (1H, dt, J 13.9, 6.7, Hd or He), 4.88 (1H, d, J 15.4, Hf),
4.69 (1H, dt, J 15.1, 2.7, Hb), 4.29 (1H, dd, J 15.8, 4.3, Hd or He),
4.17 (1H, d, J 14.7, Hf), 3.64 (1H, dd, J 16.0, 11.0, Hd or He), 3.48
(2H, dd, J 7.2, 2.3, Hd or He), 3.15 (1H, dd, J 14.1, 4.3, Hd or He),
2.77 (1H, dd, J 14.6, 11.9, Hd or He). dC (CD3CN) 145.4, 143.0,
137.2, 136.9, 133.8, 129.1, 129.0, 128.3, 124.9, 108.7, 108.2,
57.6, 57.3, 55.8, 47.4, 45.9. m/z (HRMS ESI; CH3CN) 495.1316
[Co(2a)O2CO]þ requires 495.1298, 451.1421; [Co(2a)O]þ
requires 451.1400. Found: C 41.3, H 4.3, N 18.3. [Co(C20H24N8)
(O2CO)](ClO4)ꢁH2O requires C 41.2, H 4.3, N 18.3 %.
to 100 mL and loaded onto a Sephadex SP C-25 cation exchange
column, and eluted with 0.1 M NaClO4 solution. The main band
was collected as a fraction of 50 mL and concentrated to 5 mL.
On standing at 48C, red crystals (0.054 g, 30 %) formed, which
were collected by filtration, washed with isopropanol and die-
thyl ether, and air-dried. nmax (ATR)/cmꢀ1 3579w, br (H2O),
3134w (Ar–H), 1663s (CO3), 1062s, br (ClO4), 761s (g pz), 618s
(pz). lmax/nm (e/L molꢀ1 cmꢀ1) 497 (131). dH (CD3CN,
400 MHz) 8.83 (1H, s, Hg), 8.58 (1H, ddd, J 4.8, 1.7, 0.9, Hk),
8.54 (1H, d, J 2.2, Ha), 8.08 (2H, m, Hh and Hi), 8.00 (1H, d, J
2.5, Hc), 7.79 (1H, d, J 2.5, Hc), 7.57 (1H, ddd, J 7.1, 4.8, 1.3, Hj),
7.25 (1H, d, J 1.9, Ha), 6.69 (1H, t, J 2.5, Hb), 6.47 (1H, t, J 2.5,
Hb), 5.09 (1H, ddd, J 14.3, 9.9, 3.6, Hd or He), 5.01 (1H, dd, J
14.8, 1.3, Hf), 4.74 (1H, dt, J 15.0, 2.5, Hd or He), 4.32 (2H, m, Hd
or He and Hf), 3.66 (1H, dd, J 16.0, 11.0, Hd or He), 3.54 (2H, m),
3.22 (1H, dd, J 14.0, 4.3, Hd or He), 2.93 (1H, dd, J 13.7, 10.7, Hd
or He). dC (CD3CN) 152.1, 149.0, 146.0, 143.1, 143.0, 140.3,
137.3, 136.9, 125.7, 121.7, 113.9, 108.7, 108.3, 57.6, 57.4, 57.2,
47.4, 46.0. m/z (HRMS ESI; CH3CN) 482.1137; [Co(2c)
(O2CO)]þ requires 482.1094, 438.1255; [Co(2c)(O)]þ requires
438.1201. Found: C 36.9, H 4.0, N 20.2. Co(C24H32N8)(O2CO)]
(ClO4)ꢁ2H2O requires C 36.9, H 4.1, N 20.4 %.
[Co2(2d)(O2CO)2](ClO4)2 (3d)
Ligand 2d (0.553 g, 0.814 mmol) was dissolved in H2O (10 mL)
which had been adjusted to pH ,1 with concentrated HCl.
Na3[Co(CO3)3]ꢁ3H2O (0.742 g, 2.05 mmol) was added, result-
ing in evolution of CO2. The mixture was heated to 608C for
0.5 h, during which time more CO2 evolved, and the dark red
solution was allowed to cool to room temperature and filtered
through Celite. The filtrate was diluted to 800 mL and loaded
onto a Sephadex SP C-25 cation exchange column, and washed
with 0.1 M NaClO4 solution. The collected pink band was dis-
carded, and the main fraction was eluted with 0.15 M NaClO4.
A fraction of 120 mL was collected and concentrated to 20 mL.
On standing at 48C, a red powder (0.104 g, 12 %) formed, which
was collected by filtration, washed with isopropanol and diethyl
ether, and air-dried. nmax (ATR)/cmꢀ1 3560w, br (H2O), 3121w
(pz), 1658s (CO3), 1070s, br (ClO4), 750s (g pz), 622s (pz).
[Co(2b)(O2CO)]ClO4 (3b)
Ligand 2b (0.134 g, 0.370 mmol) and Co(ClO4)2ꢁ6H2O
(0.156 g, 0.426 mmol) were dissolved in CH3CN (10 mL). Then,
30 % H2O2 (0.076 mL, 0.74 mmol) and NaHCO3 (0.033 g,
0.39 mmol) were added and the red solution was stirred over-
night at room temperature. The solution was filtered through
Celite, diluted to 1 L with H2O, and loaded onto a Sephadex SP
C-25 cation exchange column. Elution with 0.1 M aqueous
NaClO4 resulted in collection of a red band (150 mL), which was
concentrated to 10 mL. Standing at 48C overnight resulted in
crystals (0.106 g, 42 %), suitable for X-ray diffraction, and were
isolated by filtration and washed with isopropanol and diethyl
ether and air-dried. nmax (ATR)/cmꢀ1 3591w, br (H2O), 3119w
(pz), 1674s (CO3), 1088s, br (ClO4), 767s (g pz), 621s (pz).
l
max/nm (e/L molꢀ1 cmꢀ1) 499 (224). dH (CD3CN, 400 MHz)
max/nm (e/L molꢀ1 cmꢀ1) 498 (135). dH (CD3CN, 400 MHz)
8.42 (1H, d, J 2.4, Ha), 8.40 (1H, m, Ha), 8.05 (2H, m, Hg), 7.97
(2H, d, J 2.4, Hc), 7.84 (1H, dd, J 2.5, 0.7, Hc), 7.82 (1H, dd,
J 2.5, 0.7, Hc), 7.22 (6H, dd, J 16.4, 0.5, Ha and Hi), 6.69 (1H, td,
J 2.5, 0.5, Hb), 6.65 (1H, td, J 2.5, 0.6, Hb), 6.44 (2H, tt, J 2.6, 0.6,
Hb), 5.59 (4H, m, Hh), 5.01 (2H, m, Hd or He), 4.85 (2H, m, Hf),
4.69 (2H, m, Hd or He), 4.34 (2H, d, J 15.8, Hd or He), 4.19 (2H,
dd, J 14.8, 4.3, Hd or He), 3.62 (2H, ddd, J 16.6, 11.0, 6.2, Hd or
He), 3.49 (4H, m, Hd or He), 3.16 (2H, dd, J 14.2, 4.4, Hd or He),
2.75 (2H, m, Hd or He). dC (CD3CN) 145.5, 143.1, 143.0, 137.2,
137.0, 134.8, 128.8, 128.7, 128.3, 125.2, 108.7, 108.2, 57.6,
57.3, 57.7, 57.4, 57.3, 55.2, 47.4, 45.9. Diffusion coefficient
l
8.51 (1H, d, J 2.3, Ha), 8.48 (1H, s, Hg), 8.00 (1H, d, J 2.6, Hc),
7.80 (1H, d, J 2.5, Hc), 7.74 (2H, dd, J 8.3, 1.6, Hi), 7.63 (3H, m,
Hh and Hj), 7.25 (1H, d, J 2.1, Ha), 6.68 (1H, t, J 2.5, Hb), 6.46
(1H, t, J 2.5, Hb), 5.09 (1H, ddd, J 14.3, 8.4, 5.3, Hd or He), 4.99
(1H, d, J 14.7, Hf), 4.73 (1H, dt, J 15.1, 2.7, Hd or He), 4.32 (2H,
m, Hd or He and Hf), 3.66 (1H, dd, J 15.9, 11.0, Hd or He), 3.54
(2H, m, Hd or He), 3.21 (1H, dd, J 14.1, 4.3, Hd or He), 2.94 (1H,
dd, J 14.5, 11.6, Hd or He). dC (CD3CN) 146.0, 143.1, 143.0,
137.2, 136.9, 130.5, 130.1, 123.2, 121.0, 108.7, 108.2, 57.5,
57.4, 57.2, 47.4, 46.0. m/z (HRMS ESI; CH3CN) 481.1123;
[Co(2b)O2CO]þ requires 481.1141, 437.1222; [Co(2b)O]þ
requires 437.1249. Found: C 39.6, H 3.9, N 18.5. [Co(C24H32N8)
(O2CO)](ClO4)ꢁ1.5H2O requires C 39.5, H 4.2, N 18.4 %.
(CD3CN): 8 ꢃ 10ꢀ10 m2 sꢀ1
. m/z (HRMS ESI; CH3CN)
1011.1577; {[Co2(2d)(O2CO)2](ClO4)}þ requires 1011.1617.
Found: C 35.8, H 4.2, N 18.6. [(C34H42N16)Co2(O2CO)2]
(ClO4)2ꢁ5H2O requires C 36.0, H 4.4, N 18.9 %.
[Co(2c)(O2CO)]ClO4 (3c)
[Co3(2e)(O2CO)3](ClO4)3 (3e)
Ligand 2c (0.104 g, 0.285 mmol) was dissolved in H2O (5 mL)
which had been adjusted to pH ,1 with concentrated HCl.
Na3[Co(CO3)3]ꢁ3H2O (0.110 g, 0.304 mmol) was added. The
mixture was heated to 608C for 0.5 h, resulting in evolution of
CO2, and the dark red solution was allowed to cool to room
temperature and filtered through Celite. The filtrate was diluted
Ligand 2e (0.428 g, 0.440 mmol) was dissolved in H2O (25 mL)
which had been adjusted to pH ,1 with concentrated HCl.
Na3[Co(CO3)3]ꢁ3H2O (1.45 g, 4.01 mmol) was added, resulting
in evolution of CO2. The mixture was heated to 608C for 0.5 h,
during which time more CO2 evolved, and the dark red solution