S. D. Reid, C. Wilson, C. I. De Matteis, J. B. Love
FULL PAPER
minimisation of each of the 2401 conformations arising. ESFF par-
tial atomic charges and atom types were assigned; in particular the
NH atom type was assigned for the pyrrole nitrogen atom. Mini-
misations were carried out using steepest descents, followed by con-
jugate gradient and Newton–Raphson methods, until the conver-
gence criterion (maximum derivative = 0.001) was reached.
heated at 80 °C for 24 h, after which the mixture was filtered, and
the red filtrate concentrated to dryness under reduced pressure. The
resultant orange solid was extracted into Et2O (5 mL) and cooled
to –20 °C to deposit 276 mg, 48% of [Fe2(L2)2] as an orange crys-
talline solid. Crystals suitable for X-ray diffraction were grown by
slow cooling a hexane solution to –30 °C. C50H76Fe2N8 (900.90):
calcd. C 66.65, H 8.52, N 12.44, found C 66.46, H 8.52, N 12.29.
1H NMR (C6D6, 298 K): δ = 58.7 (s, 2 H) = 48.2 (s, 2 H), 8.6 (s,
2 H), 6.5 (br. s, 6 H), 4.8 (s, 6 H), –0.9 (s, 2 H), –2.4 (s, 18 H), –3.8
Synthesis of H2L2: (–)-(R)-3,3-Dimethyl-2-butylamine (4.83 g,
47.7 mmol) and K2CO3 (5.00 g) were added to a stirred solution of
1 (5.00 g, 21.7 mmol) in EtOH (100 mL). The resulting slurry was
stirred for 24 h, after which the mixture was filtered and the pre-
cipitate washed once with EtOH (10 mL). The combined filtrate
and washings were dried at reduced pressure, the resulting viscous
red oil extracted with CH2Cl2 (10 mL) and transferred to a subli-
mation tube. The oil was sublimed twice at 130 °C/10–2 mbar to
yield H2L2 as a pale yellow oil, 6.46 g, 75%. 1H NMR (C6D6,
298 K): δ = 9.81 (br. s, 2 H, NH), 7.76 (s, 2 H, CH=N), 6.31 (d, J
= 3.6 Hz, 2 H, pyrrole H), 5.95 (d, J = 3.6 Hz, 2 H, pyrrole H),
2.75 (q, J = 6.5 Hz, 2 H, chiral CH), 1.08 (s, 6 H, meso CH3), 1.04
(d, J = 7.7 Hz, 6 H, chiral CH3), 0.92 (s, 18 H, chiral CMe3) ppm.
13C{1H} NMR (C6D6, 298 K): δ = 149.7 (s, CH=N), 142.5 (s, Cq),
130.6 (s, Cq), 114.1 (s, CH), 106.8 (s, CH), 75.7 (s, chiral CH), 36.1
(s, Cq), 34.7 (s, Cq), 28.8 (s, meso CH3), 27.2 (s, chiral CMe3), 18.2
(s, chiral CH3) ppm. ESMS: m/z (%) = 397 (100) [M+].
(s, 18 H) ppm. EIMS: m/z (%) = 900 (21) [M+], 843 (11) [M+
tBu], 396 (48) [L2], 339 (100) [L2 – tBu]. µeff (C6D6) = 7.28 µB.
–
Synthesis of [Zn2(L2)2]·(CH2Cl2): A solution of ZnMe2 (2.0 ) in
toluene (1 mL) was added to a stirred solution of H2L2 (574 mg,
1.45 mmol) in toluene (15 mL). Effervescence occurred immedi-
ately and the solution turned pale orange. The reaction mixture
was heated at 80 °C under reduced pressure for 24 h, after which
the solvents were evaporated under reduced pressure and the resi-
dues extracted with CH2Cl2 (2 mL). Pentane (10 mL) was then
added until cloud point, and the solution was cooled, resulting in
the deposition of 352 mg, 53% of [Zn2(L2)2]·(CH2Cl2) as a pale
yellow, crystalline solid. Crystals suitable for X-ray diffraction were
grown by diffusion of pentane into
a CH2Cl2 solution.
C50H76N8Zn2·CH2Cl2 (1004.9): calcd. C 60.96, H 7.82, N 11.15;
Synthesis of H2L3: (+)-(R)-Phenylethylamine (5.06 mL, 39.6 mmol)
and p-toluenesulfonic acid (342 mg, 1.80 mmol) were added to a
stirred solution of 1 (4.15 g, 18.0 mmol) in MeOH (100 mL). The
resulting orange solution was stirred for 1 h and then concentrated
to dryness at reduced pressure. The orange residues were extracted
with hot hexanes (15 mL), filtered though a plug of Celite and the
volatiles removed at low pressure for 24 h to yield H2L3 as a viscous
orange oil, 5.02 g, 64%. C29H32N4 (436.59): calcd. C 79.76, H 7.40,
N 12.83; found C 79.68, H 7.87, N 12.57. 1H NMR (C6D6, 298 K):
δ = 8.87 (br. s, 2 H, NH), 7.78 (s, 2 H, CH=N), 7.38 (d, J = 7.1 Hz,
4 H, phenyl H), 7.10 (m, 6 H, phenyl H), 6.27 (s, J = 3.6 Hz, 2 H,
pyrrole H), 5.91 (s, J = 3.6 Hz, 2 H, pyrrole H), 4.23 (q, J = 6.6 Hz,
2 H, chiral CH), 1.49 (d, J = 6.6 Hz, 6 H, chiral CH3), 1.07 (s, 6
H, meso CH3) ppm. 13C{1H} NMR (C6D6, 298 K): δ = 150.0 (s,
CH=N), 145.9 (s, Cq), 142.6 (s, Cq), 130.2 (s, Cq), 128.6 (s, CH),
127.1 (s, CH), 127.0 (s, CH), 114.6 (s, CH), 106.6 (s, CH), 69.5 (s,
chiral CH), 35.7 (s, Cq), 28.2 (s, meso CH3), 24.9 (s, chiral CH3)
ppm.
1
found C 61.19, H 8.09, N 11.04. H NMR (C6D6, 298 K): δ = 7.55
(s, 1 H, CH=N), 7.33 (s, 1 H, CH=N), 6.95 (d, J = 3.6 Hz, 1 H,
pyrrole H), 6.86 (d, J = 3.8 Hz, 2 H, pyrrole H), 6.73 (d, J = 3.7 Hz,
1 H, pyrrole H), 4.24 (s, 1 H, CH2Cl2), 2.97 (q, J = 6.8 Hz, 1 H,
CH), 2.64 (q, J = 6.6 Hz, 1 H, CH), 2.34 (s, 3 H, meso CH3), 2.04
(s, 3 H, meso CH3), 1.00 (d, J = 6.8 Hz, 3 H, CH3), 0.87 (d, J =
6.6 Hz, 3 H, CH3), 0.67 (s, 9 H, CMe3), 0.56 (s, 9 H, CMe3) ppm.
13C{1H} NMR (C6D6, 298 K): δ = 159.5 (s, CH) = 158.3 (s, Cq),
158.2 (s, Cq), 158.0 (s, CH), 134.2 (s, Cq), 120.4 (s, CH), 120.1 (s,
CH), 113.1 (s, CH), 112.5 (s, CH), 72.8 (s, CH), 68.3 (s, CH), 53.1
(s, CH2Cl2), 39.1 (s, Cq), 34.8 (s, Cq) ppm. 34.7 (s, Cq), 31.9 (s, meso
CH3), 26.8 (s, CMe3), 26.7 (s, CMe3), 23.3 (s, meso CH3), 16.6 (s,
CH3), 15.8 (s, CH3). EIMS: m/z (%) = 918 (8) [M+], 863 (26) [M+
tBu], 49 (100) [tBu – 8 H].
–
Synthesis of [Zn2(L3)2]: A solution of ZnMe2 (2.0 ) in toluene
(0.5 mL) was added dropwise to a stirred solution of H2L3 (393 mg,
0.9 mmol) in toluene (10 mL). Gas evolved immediately and the
resulting yellow-brown solution was heated at 80 °C for 24 h, after
which the orange-yellow solution was dried at reduced pressure and
the pale yellow solids inspected by 1H NMR spectroscopy. 1H
NMR (C6D6, 298 K): δ = 7.60 (s, 2 H, CH=N), 7.34 (s, 2 H,
CH=N), 7.3–6.7 (m, 20 H, phenyl H), 6.68 (d, J = 3.5 Hz, 2 H,
pyrrole H), 6.63 (d, J = 3.5 Hz, 2 H, pyrrole H), 6.51 (d, J = 3.5 Hz,
2 H, pyrrole H), 6.36 (d, J = 3.5 Hz, 2 H, pyrrole H), 4.22 (q, J =
7.1 Hz, 2 H, chiral CH), 3.92 (q, J = 6.2 Hz, 2 H, chiral CH), 1.93
(s, 6 H, meso CH3), 1.80 (s, 6 H, meso CH3), 1.19 (d, J = 7.0 Hz,
6 H, chiral CH3), 1.08 (d, J = 7.0 Hz, 6 H, chiral CH3) ppm. The
yellow solids were then extracted into Et2O (5 mL) and cooled. The
resulting slurry was filtered and the liquors concentrated to dryness
to yield 112 mg, 25%, of [Zn2(L3)2] as yellow solids. C58H60N8Zn2
(999.93): calcd. C 69.67, H 6.05, N 11.21; found C 69.54, H 6.15,
N 11.15.
Synthesis of [Mn2(L2)2]: A solution of H2L2 (586 mg, 1.48 mmol)
in THF (10 mL) was added to a stirred slurry of KH (178 mg,
4.43 mmol) in THF (10 mL). Effervescence occurred immediately
and the resulting slurry was stirred for 1 h, after which the ligand
salt was added dropwise to a slurry of MnCl2 (186 mg, 1.48 mmol)
in THF (10 mL). The resultant yellow slurry was heated at 80 °C
for 24 h, after which the mixture was filtered though Celite, and
the yellow filtrate concentrated to dryness under reduced pressure.
The yellow solid was extracted into hexanes (5 mL) and cooled to
deposit 109 mg, 16% of [Mn2(L2)2] as a yellow crystalline solid.
Crystals suitable for X-ray diffraction were grown by slow cooling
a hexane solution to –30 °C. C50H76Mn2N8 (899.08): calcd. C
67.31, H 8.54, N 12.46; found C 67.39, H 8.42, N 12.45. EIMS:
m/z (%) = 898 (14) [M+], 841 (53) [M+ – tBu], 450 (43) [MnL2], 43
(100) [tBu – Me]. µeff (C6D6) = 8.06 µB.
Synthesis of [Fe2(L2)2]: To a stirred slurry of KH (154 mg,
3.83 mmol) in THF (10 mL) was added a solution of H2L2 (507 mg,
1.28 mmol) in THF (10 mL). Effervescence occurred immediately
and the resulting slurry was stirred for 1 h, after which the ligand
salt was added dropwise to a stirred slurry of FeBr2 (291 mg,
1.35 mmol) in THF (10 mL). The resultant red-brown slurry was
Acknowledgments
The authors thank the EPSRC (UK), The Royal Society, and the
Universities of Nottingham and Edinburgh for their support.
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Eur. J. Inorg. Chem. 2007, 5286–5293