magnetic susceptibilities were measured by the Faraday method
using a home-made magnetometer comprising a Mettler ME21
microbalance and Cahn 0.8 T permanent magnet, fitted
with Faraday pole caps, and variable temperature magnetic
data (2–300 K) were obtained using a Quantum Design
MPMS5S SQUID magnetometer using field strengths in the
range 0.1–0.5 T. Background corrections for the sample holder
assembly and diamagnetic components of the complexes were
applied.
Table 1 Summary of crystallographic data for 1 and 2
Compound
1
2
Empirical formula
C H N Ni O
C H B F N -
51 53 3 13 33
Ni O
5
4
48 33
3
33.5
2
10
M
1871.38
Triclinic
P1¯
1685.11
Triclinic
P1¯
Crystal system
Space group
a/Å
b/Å
c/Å
α/Њ
β/Њ
γ/Њ
15.211(3)
15.363(3)
19.525(4)
111.999(2)
91.168(3)
109.541(2)
3931.1(14)
1.581
12.5079(17)
14.952(2)
19.463(3)
96.740(2)
96.966(2)
108.259(2)
3384.2(8)
1.654
Synthesis of ligands and complexes
Pd2am. The methyl ester of iminopicolinic acid was prepared
in situ by reaction of 2-cyanopyridine (5.21 g, 50.0 mmol) with
sodium methoxide solution, produced by dissolving sodium
metal (0.11 g, 5.0 mmol) in dry methanol (100 mL). 3,6-
Pyridazinedicarboxylic acid hydrazide (4.90 g, 25.0 mmol)
3
U/Å
Ϫ3
D /g cm
c
T /K
Z
µ/mm
150(2)
2
0.819
100(2)
2
0.67
Ϫ1
(
prepared from the reaction of dimethyl-3,6-pyridazine
dicarboxylate with hydrazine hydrate in methanol) was added
to the above solution and the mixture refluxed for 24 h. A
yellow powder was obtained, which was filtered off, washed
with water (2 × 100 mL), methanol (2 × 100 mL), and then
Reflections collected:
total, independent, R
48465, 13820, 0.0569 33715, 15434,
0.0274
int
a
Final R , wR
0.0566, 0.1463
0.0560, 0.1485
1
2
a
2
2
2
2
R
= Σ||F
| Ϫ |F
||/Σ|F
|, wR
= [Σw(|F
| Ϫ |F
| ) /Σw|F
| .
1
o
c
o
2
o
c
o
diethyl ether (2 × 100 mL) and dried under vacuum. Yield
1
(
7.82 g, 77%), mp > 250 ЊC. H NMR (300 MHz, DMSO-d ,
6
2
8
4
5 ЊC): δ 11.0 (br s, 2H, OH), 8.64 (d, 2H, Ar), 8.39 (s, 2H, Ar),
.23 (d, 2H, Ar), 7.94 (dd, 2H, Ar), 7.53 (dd, 2H, Ar), 7.21 (br s,
H, NH ). Mass spectrum (major mass peaks, m/z): 368
2
Ϫ1
(
M Ϫ 2H O), 340, 311, 224, 104, 78. IR/cm (Nujol): 3374,
2
3
307, 3183 (νNH); 1677 (νC᎐O); 1604 νC᎐N); 997 (νpy). Anal.
᎐ ᎐
calc. for C H N O ؒH O: C, 51.18; H, 4.30; N, 33.16. Found:
18
16 10
2
2
C, 51.62; H, 4.01; N, 33.08%.
2
Pzoap. 2,6-Pyridinedicarboxylic acid dihydrazide (3.9 g,
.020 mol) was added to a dry methanolic solution (100 mL) of
the methyl ester of iminopyrazine-2-carboxylic acid (5.2 g,
.050 mol), prepared in situ from 2-cyanopyrazine and sodium
0
0
metal (stirred at room temperature for 12 h) and the mixture
refluxed for 24 h with the formation of a yellow powder. The
solid was filtered off washed with water, methanol and ether
and dried under vacuum. Yield (6.3 g, 79%), mp 259 ЊC
Fig. 1 Structural representation of the trinuclear cation in [Ni3-
(
pd2am-H) (H O)](NO ) ؒ2H O 1.
3 2 3 3 2
1
655 (νC᎐O); 1565 (vC᎐N). λ/nm (Nujol): 899, 560 sh, 460 sh.
᎐ ᎐
(
(
decomp.). Mass spectrum (major mass peaks, m/z): 369
Anal. calc. for [Ni (C H N O ) F](BF ) ؒ8.5H O: C, 34.68;
2
17 15 11
2
3
4
3
2
M Ϫ 2H O), 341, 340, 312, 262, 250, 207, 168, 130, 79. IR/
2
H, 3.52; N, 26.17. Found: C, 34.66; H, 3.06; N, 26.16%.
Ϫ1
cm (Nujol): 3413 (νOH); 3317, 3156 (νNH); 1685 (νC᎐O);
1
4
632, 1610 (νC᎐N). Anal. calc. for C H N O ؒ0.5H O: C,
᎐
17 15 11 2 2
Crystallographic data collection and refinement of the structures
9.27; H, 3.89; N, 37.18. Found: C, 49.19; H, 3.66; N, 37.08%.
Ni (pd2am-H) (H O)](NO ) ؒ2H O 1. pd2am (0.40 g,
Data collections for 1 and 2 were made using graphite mono-
chromatised Mo-Kα X-radiation using a Bruker SMART CCD
[
3
3
2
3
3
2
18
1
mmol) was added to a hot solution of Ni(NO ) ؒ6H O
detector diffractometer equipped with a Cryostream N flow
3
2
2
2
(
0.29 g, 1 mmol) in water (25 mL). The resulting suspension
cooling device. Series of narrow ω scans (0.3Њ) were performed
at several ꢀ-settings in such a way as to cover a hemisphere or a
full sphere of data to a maximum resolution of 0.7 Å. Cell
was stirred with heating until complete dissolution of the ligand
occurred. The dark red solution was allowed to cool to room
temperature and was filtered to remove any undissolved ligand.
Red crystals suitable for X-ray diffraction formed from the
19
parameters were determined and refined within SMART
using the centroid values of approximately 1000 selected reflec-
tions with 2θ values between 20 and 45Њ. Raw frame data were
Ϫ1
filtrate after standing for 1 week (yield 0.41 g, 78%). IR/cm
20
(
Nujol): 3395 (νH O); 3299 (νNH); 1693 (νC᎐O); 1093 (νpy).
integrated using the SAINT program. The data were corrected
2
᎐
Ϫ1
Ϫ1
21
λ/nm (Nujol): 796, 912; λ/nm (H O): (ε/M cm ) 821 (114),
for absorption using SADABS. The structures were solved
2
9
4
16 (86). Anal. calc. for [Ni (C H N O ) ](NO ) ؒ2H O: C,
0.33; H, 3.07; N, 28.74. Found: C, 40.47; H, 2.97; N, 28.91%.
Repeated attempts to introduce a fourth metal into the
using direct methods and refined by full-matrix, least squares
on F .
Abbreviated crystal data for 1 and 2 are given in Table 1.
3
18 15 10
2
3
3
3
2
2
21
complex failed, even with a large excess of metal salt, and each
time the trinuclear derivative was obtained.
CCDC reference numbers 162087 and 149292.
See http://www.rsc.org/suppdata/dt/b1/b102344f/ for crystal-
lographic data in CIF or other electronic format.
[
Ni (2pzoap) F](BF ) ؒ8.5H O 2. 2pzoap (0.41 g, 1.0 mmol)
2 3 4 3 2
was added to a solution of Ni(BF ) ؒ6H O (2.05 g, 6.0 mmol)
4
2
2
in MeOH–H O (5 : 3 mL) with the formation of a yellow–
Results and discussion
2
orange powder, which was filtered off and recrystallized
from DMF–diethyl ether to give the nona-nuclear complex
Structures
17
[
Ni (C H N O ) ](BF ) ؒ12H O (0.51 g, 82%). The yellow
[Ni (pd2am-H) (H O)](NO ) ؒ2H O 1. The structural
9
17 13 11
2
6
4
6
2
3
3
2
3
3
2
coloured original mother liquor produced a small quantity of
representation of the trinuclear cation is shown in Fig. 1, and
important bond distances and angles are listed in Table 2. A
view of the trinuclear core is shown in Fig. 2. Three ligands bind
orange crystals of 2 (0.072 g, 12%) upon standing at room
Ϫ1
temperature. IR/cm (Nujol): 3422 (νH O); 3339 (νNH); 1676,
2
J. Chem. Soc., Dalton Trans., 2001, 2258–2262
2259