the solution, with an air-tight, argon-filled syringe, transferred to
argon-flushed EPR tubes, frozen and stored in liquid nitrogen.
were measured at a fixed field of 1 kOe, and field dependence of
molar longitudinal moment was measured at 2 K.
X-Ray crystallography†
Acknowledgements
Crystal data for 1: [(C40H44N8O4)Mn2]3(ClO4)6, (C120H132Cl6-
This work was supported by grants from the Swedish En-
ergy Agency, Knut and Alice Wallenberg Foundation and the
EU/Energy Network project SOLAR-H2 (FP7 contract no.
212508).
Mn6N24O36), white needles, Fw = 3028.84, tetragonal, space group
P42/n, a = 26.7119(3) A, c = 24.2013(5) A, V = 17268.2(5) A , dc =
3
˚
˚
˚
-3
-1
˚
1.165 g cm , Z = 4, T = 100(2) K, m(l = 0.90769 A) = 1.140 mm ,
Rint = 0.0542, Nmeasured = 29 388, Nunique = 13 671, wR2 = 0.4092 (all
13 671 data) and R1 = 0.1532 (7708 data with I ≥ 2 s(I)).
The diffraction data were collected on beam-line I911-5 at
the Swedish synchrotron facility MaxLab, Lund. The data was
obtained with a MARCCD 165 detector using f-scans.
Notes and references
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Due to the large amount of solvent accessible voids (approx-
3
˚
imately 5400 A ) in the structure of (1·(ClO4)6) the data were
subjected to the SQUEEZE procedure available in PLATON
to remove contributions to the diffraction data from disordered
solvent. One of the perchlorate ions was modelled as disordered
over two positions. The structure analysis was done with direct
methods using SHELXD32 and refined with full-matrix least-
square calculations using SHELXH97.32 Anomalous dispersion
˚
correction terms for the used wavelength (0.9083 A) obtained from
WCROMER.33,34
Crystal data for 2: [(C36H42N8)Mn2(C2H3O2)Cl] (ClO4)2,
(C38H45Cl3Mn2N8O10), colourless plates, Fw = 990.05, monoclinic,
8 C. Baffert, M. N. Collomb, A. Deronzier, S. Kjærgaard-Knudsen, J. M.
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˚
˚
space group C2/c, a = 19.2617(9) A, b = 14.0395(7) A, c =
◦
3
-3
˚
˚
36.5344(16) A, b = 93.564(4) , V = 9860.7(8) A , d = 1.334 g cm ,
Z = 8, T = 293(2) K, m(Mo-Ka) = 0.732 mm-1, Rint = 0.0694,
Nmeasured = 59 669, Nunique = 10 048, wR2 = 0.1640 (all 10048 data)
and R1 = 0.0482 (5617 data with I ≥ 2 s(I)).
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The diffraction data was collected on an Excalibur-II k diffrac-
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square calculations using SHELXL97.32
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EPR spectroscopy
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21 It should be noted that chloride oxidation has been observed in a
manganese(II) chloride complex at about the same potential as the first
oxidation of 2.22 We cannot distinguish direct oxidation of a manganese
ion from the case where a chloride bridge in 2 is oxidised and the then
formed radical proceeds to oxidise manganese.
EPR spectra were recorded at X-band range using Bruker
ELEXSYS-E500 spectrometer equipped with an ER0601SHQE
resonator or a DM9807 resonator. Liquid helium temperature
controller Oxford ITC503 and ESR900 cryostat were used for
III,IV
temperature control. Quantification of Mn2
EPR signals were
made by double integration of the signals recorded at 20 K using
a microwave power of 20 mW. The size of the signal was compared
to the size of the doubly integrated Mn2III,IV EPR signal of [Mn2(m-
O)2(H2O)2(tpy)2]3+ (1 mM)35 measured under the same conditions.
This quantification gives an approximate accuracy of 5%.
Magnetic susceptibility
22 G. Berggren, P. Huang, L. Eriksson and M. F. Anderlund, Appl. Magn.
Magnetic susceptibilities of 1 and 2 were measured on a Quantum
Design MPMS SQUID susceptometer equipped with a supercon-
ducting magnet operating in 7 T and a continuous temperature
controller operating in 1.9–400 K range. Samples of 1 and 2 were
kept in a sample bucket with lid. Data were recorded using RSO
(reciprocating sample option) detecting mode and background
subtraction option. No further corrections were made in the data
analysis. Temperature dependence of mol susceptibility of 1 and 2
Reson., 2009, 36, 9–24.
23 S. Groni, C. Hureau, R. Guillot, G. Blondin, G. Blain and E.
Anxolabe´he`re-Mallart, Inorg. Chem., 2008, 47, 11783–11797.
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A. Deronzier, Phys. Chem. Chem. Phys., 2005, 7, 202–210.
26 G. Eilers, C. Zettersten, L. Nyholm, L. Hammarstro¨m and R. Lomoth,
Dalton Trans., 2005, 1033–1041.
This journal is
The Royal Society of Chemistry 2010
Dalton Trans., 2010, 39, 11035–11044 | 11043
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