metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2053-2296

{Tris[4-(1H-pyrazol-3-yl)-3-azabut-3-enyl]­amine}­iron(II) diperchlorate monohydrate

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aSchool of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, England
*Correspondence e-mail: m.a.halcrow@chem.leeds.ac.uk

(Received 29 January 2004; accepted 20 February 2004; online 20 March 2004)

In the title complex, [Fe(C18H24N10)](ClO4)2·H2O, the com­plex cation adopts a capped trigonal antiprismatic stereochemistry, with a long Fe–amine interaction [2.7468 (16) Å]. The Fe centre in the asymmetric unit is fully high-spin at 100 K. Hydro­gen bonding assembles dimeric units, which are then linked by further hydrogen bonding into chains running parallel to the crystallographic a axis.

Comment

We have been interested for some time in the spin-state transitions shown by iron(II) complexes of polydentate pyrazole-containing ligands (Holland et al., 2001[Holland, J. M., McAllister, J. A., Lu, Z., Kilner, C. A., Thornton-Pett, M. & Halcrow, M. A. (2001). Chem. Commun. pp. 577-578.]; Holland, Barrett et al., 2002[Holland, J. M., Barrett, S. A., Kilner, C. A. & Halcrow, M. A. (2002). Inorg. Chem. Commun. 5, 328-332.]; Holland, McAllister et al., 2002[Holland, J. M., McAllister, J. A., Kilner, C. A., Thornton-Pett, M., Bridgeman, A. J. & Halcrow, M. A. (2002). J. Chem. Soc. Dalton Trans. pp. 548-554.]; Elhaïk et al., 2003[Elhaïk, J., Money, V. A., Barrett, S. A., Kilner, C. A., Radosavljevic Evans, I. & & Halcrow, M. A. (2003). Dalton Trans. pp. 2053-2060.]; Money et al., 2003[Money, V. A., Radosavljevic Evans, I., Halcrow, M. A., Goeta, A. E. & Howard, J. A. K. (2003). Chem. Commun. pp. 158-159.], 2004[Money, V. A., Elhaïk, J., Radosavljevic Evans, I., Halcrow, M. A. & Howard, J. A. K. (2004). Dalton Trans. pp. 65-69.]; Smithson et al., 2003[Smithson, R. J., Kilner, C. A., Brough, A. R. & Halcrow, M. A. (2003). Polyhedron, 22, 725-733.]). During this work, we noted that both iron(II) and iron(III) complexes of tris[4-(imidazol-2-yl)-3-aza-3-butenyl]­amine, the Schiff base derived from the reaction of tris(2-amino­ethyl)­amine (tren) with three equivalents of imidazole-2-carb­aldehyde, and closely related derivatives exhibit interesting spin-state transitions (Nagasato et al., 2001[Nagasato, S., Katsuki, I., Motoda, Y., Sunatsuki, Y., Matsumoto, N. & Kojima, M. (2001). Inorg. Chem. 40, 2534-2540.]; Sunatsuki et al., 2001[Sunatsuki, Y., Sakata, M., Matsuzaki, S., Matsumoto, N. & Kojima, M. (2001). Chem. Lett. pp. 1254-1255.]; Ikuta et al., 2003[Ikuta, Y., Ooidemizu, M., Yamahata, Y., Yamada, M., Osa, S., Matsumoto, N., Iijima, S., Sunatsuki, Y., Kojima, M., Dahan, F. & Tuchagues, J.-P. (2003). Inorg. Chem. 42, 7001-7017.]; Yamada et al., 2003[Yamada, M., Ooidemizu, M., Ikuta, Y., Osa, S., Matsumoto, N., Iijima, S., Kojima, M., Dahan, F. & Tuchagues, J.-P. (2003). Inorg. Chem. 42, 8406-8416.]; Yukinari et al., 2003[Yukinari, S., Ikuta, Y., Matsumoto, N., Ohta, H., Kojima, M., Iijima, S., Hayami, S., Maeda, Y., Kaizaki, S., Dahan, F. & Tuchagues, J.-P. (2003). Angew. Chem. Int. Ed. 42, 1614-1618.]). We therefore decided to investigate the iron chemistry of the pyrazole-containing analogue tris[4-(1H-pyrazol-3-yl)-3-aza-3-butenyl]­amine. We found that reactions of this ligand with hydrated Fe(ClO4)3 in MeOH yielded a dark-brown precipitate. Some of this material proved soluble on extraction with acetone, giving a dark-orange solution that afforded orange crystals of the title compound, (I[link]), following diffusion of diethyl ether vapour into the mixture. Presumably, partial reduction of the FeIII content of the mixture by the MeOH solvent took place during the reaction. Compound (I[link]) was subsequently synthesized in higher yield by direct treatment of the same ligand with Fe(ClO4)2·6H2O. No complexes of tris[4-(1H-pyrazol-3-yl)-3-aza-3-butenyl]­amine have been reported before, although NiII and CoIII complexes of its tri­methyl­ated derivative, tris[4-(5-methyl-1H-­pyrazol-3-yl)-3-aza-3-butenyl]amine, have been structurally characterized (Paul et al., 2000[Paul, S., Barik, A. K., Butcher, R. J. & Kar, S. K. (2000). Polyhedron, 19, 2661-2666.], 2002[Paul, S., Barik, A. K., Peng, S. M. & Kar, S. K. (2002). Inorg. Chem. 41, 5803-5809.]).

[Scheme 1]

The coordination geometry about the Fe centre in (I[link]) (Fig. 1[link]) is best described as a capped trigonal antiprism. There are six Fe—N bonds of 2.1563 (16)–2.2547 (16) Å (Table 1[link]) to the imine and pyrazole N-atoms donors, these lengths being typical of a high-spin FeII centre. Amine atom N2 lies at a much longer distance [2.7468 (16) Å] from the metal atom, at a position approximately central above the triangular face formed by atoms N5, N14 and N23. This distance is at the lower end of the range of capping Fe—N distances seen for high-spin FeII complexes of related heptadentate tripodal ligands. As can be seen from Table 3[link], there is an approximate positive correlation in this class of compound (for the ligands shown in the scheme[link] below) between contraction of this capping Fe—N bond and an opening out of the capped face of the trigonal antiprism, indicated by an increase in the Nimine—Fe—Nimine angles [N5—Fe1—N14, N5—Fe1—N23 and N14—Fe1—N23 in (I[link])]. However, there is no apparent relation between these structural parameters and whether or not these compounds undergo spin-crossover upon cooling. Although the helical ligand conformation about each Fe atom is chiral, (I[link]) crystallizes as a racemate in the centrosymmetric space group P21/n.

[Scheme 2]

Two of the three pyrazole NH groups in (I[link]) are hydrogen bonded to two different lattice water mol­ecules, forming N9—H9⋯O40 and N18—H18⋯O40i interactions [symmetry code: (i) 1 − x, 1 − y, 1 − z; Table 2[link]]. The third NH group (N27—H27) hydrogen bonds to atom O31 in one of the two independent ClO4 anions. This same anion accepts a hydrogen bond from water atom H40Aii [symmetry code: (ii) x − 1, y, z]. The other water H atom (H40B) hydrogen bonds to the other ClO4 ion in the asymmetric unit. The net effect of these interactions is to assemble two formula units into a hydrogen-bonded dimer about the inversion centre at ([1 \over 2], [1 \over 2], [1 \over 2]) (Fig. 2[link]). These dimers are in turn linked into chains running parallel to the crystallographic a direction through the Cl30/O34 anion, which accepts hydrogen bonds from two different dimer moieties.

[Figure 1]
Figure 1
The molecular structure of the complex cation in the crystal structure of (I[link]), showing 50% probability displacement ellipsoids and the atom-numbering scheme. All C-bound H atoms have been omitted for clarity.
[Figure 2]
Figure 2
A partial packing diagram of (I[link]), showing the centrosymmetric hydrogen-bonded dimerization of the formula units in the structure. [Symmetry codes: (i) 1 − x, 1 − y, 1 − z; (ii) x − 1, y, z.]

Experimental

A solution of the tris[4-(1H-pyrazol-3-yl)-3-aza-3-butenyl]­amine ligand was prepared by refluxing a mixture of pyrazole-3-carb­aldehyde (1.00 g, 10.4 mmol) and tris(2-amino­ethyl)­amine (0.51 g, 3.47 mmol) in MeOH (100 ml) until all of the solid had dissolved. Fe(ClO4)2·6H2O (1.26 g, 3.47 mmol) was then added to the mixture, yielding a dark-yellow solution. The volume was reduced to ∼10 ml by evaporation, and then an excess of diethyl ether was added to yield a yellow–orange precipitate (yield 1.23 g, 56%). Recrystallization of the crude product from undried acetone gave orange monohydrated crystals, which lost their water of crystallization upon drying in vacuo over P2O5. Analysis found: C 34.0, H 3.9, N 22.2%; calculated for C18H24Cl2FeN10O8: C 34.0, H 3.8, N 22.1%.

Crystal data
  • [Fe(C18H24N10)](ClO4)2·H2O

  • Mr = 653.24

  • Monoclinic, P21/n

  • a = 9.4086 (1) Å

  • b = 22.5317 (4) Å

  • c = 12.7279 (2) Å

  • β = 101.9858 (6)°

  • V = 2639.38 (7) Å3

  • Z = 4

  • Dx = 1.644 Mg m−3

  • Mo Kα radiation

  • Cell parameters from 25 327 reflections

  • θ = 1.8–27.5°

  • μ = 0.84 mm−1

  • T = 100 (2) K

  • Rectangular prism, orange

  • 0.33 × 0.23 × 0.20 mm

Data collection
  • Nonius KappaCCD area-detector diffractometer

  • ω scans

  • Absorption correction: multi-scan (SORTAV; Blessing, 1995[Blessing, R. H. (1995). Acta Cryst. A51, 33-38.]) Tmin = 0.769, Tmax = 0.850

  • 25 327 measured reflections

  • 6004 independent reflections

  • 4724 reflections with I > 2σ(I)

  • Rint = 0.066

  • θmax = 27.5°

  • h = −12 → 12

  • k = −29 → 29

  • l = −16 → 16

Refinement
  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.037

  • wR(F2) = 0.099

  • S = 1.04

  • 6004 reflections

  • 370 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • w = 1/[σ2(Fo2) + (0.047P)2 + 1.086P] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max = 0.001

  • Δρmax = 0.34 e Å−3

  • Δρmin = −0.51 e Å−3

Table 1
Selected geometric parameters (Å, °)

Fe1—N2 2.7468 (17)
Fe1—N5 2.1563 (16)
Fe1—N8 2.2547 (16)
Fe1—N14 2.1575 (17)
Fe1—N17 2.2413 (17)
Fe1—N23 2.1628 (17)
Fe1—N26 2.2457 (16)
N2—Fe1—N5 67.23 (5)
N2—Fe1—N8 128.69 (5)
N2—Fe1—N14 68.49 (6)
N2—Fe1—N17 126.82 (6)
N2—Fe1—N23 68.08 (6)
N2—Fe1—N26 126.16 (5)
N5—Fe1—N8 74.02 (6)
N5—Fe1—N14 109.45 (6)
N5—Fe1—N17 92.64 (6)
N5—Fe1—N23 104.25 (6)
N5—Fe1—N26 161.14 (6)
N8—Fe1—N14 159.82 (6)
N8—Fe1—N17 86.13 (6)
N8—Fe1—N23 91.34 (6)
N8—Fe1—N26 87.25 (6)
N14—Fe1—N17 73.95 (6)
N14—Fe1—N23 106.51 (6)
N14—Fe1—N26 88.90 (6)
N17—Fe1—N23 161.53 (7)
N17—Fe1—N26 88.21 (6)
N23—Fe1—N26 73.39 (6)

Table 2
Hydrogen-bonding geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N9—H9⋯O40 0.88 2.00 2.848 (2) 160
N18—H18⋯O40i 0.88 1.97 2.833 (2) 168
N27—H27⋯O31 0.88 2.03 2.848 (2) 155
O40—H40A⋯O32ii 0.854 (19) 2.04 (2) 2.728 (2) 137.1 (16)
O40—H40B⋯O36 0.84 (2) 2.07 (2) 2.832 (2) 149 (2)
Symmetry codes: (i) 1-x,1-y,1-z; (ii) x-1,y,z.

Table 3
Selected structural parameters for high-spin FeII complexes of the ligands shown the second scheme[link] in the Comment

a is the distance between the Fe and bridgehead N atoms [Fe1—N2 in (I)], θ is the average of the three Nimine—Fe—Nimine angles, and ω is the average of the three Nheterocycle—Fe—Nheterocycle angles.

Compound a (Å) θ (°) ω (°) Spin-crossover on cooling
[Fe(L1)](ClO4)2 2.504 (6) 112.7 (2) 86.1 (2) No
[Fe(L2)](PF6)2 2.724 (4) 106.6 (3) 86.6 (3) N/a
(I)§ 2.7468 (16) 106.73 (10) 87.20 (10) N/a
[Fe(L4)](PF6)2 2.753 (8) N/a N/a Yes
[Fe(L3)](PF6)2 3.004 (8) 100.2 (7) 98.0 (6) No
[{Fe(L5)}2H3]NO3†† 3.122 (6) 97.93 (13) 93.13 (13) Yes
  3.169 (9) 98.30 (12) 92.95 (12) Yes
[{Fe(L5)}2H3]PF6‡‡ 3.198 (8) 97.14 (13) 94.41 (13) Yes
  3.215 (8) 97.18 (14) 94.47 (13) Yes
[Fe(L6)](PF6)2§§ 3.261 (5) 96.5 (3) 97.7 (5) No
[Fe(L7)](ClO4)2¶¶ 3.280 (3) 91.5 (2) 102.1 (2) No
†Morgenstern-Badarau et al. (2000[Morgenstern-Badarau, I., Lambert, F., Renault, J.-P., Cesario, M., Marechal, J.-D. & Maseras, F. (2000). Inorg. Chim. Acta, 297, 338-350.]).
‡Yang et al. (2001[Yang, S.-P., Tong, Y.-X., Zhu, H.-L., Cao, H., Chen, X.-M. & Ji, L.-N. (2001). Polyhedron, 20, 223-229.]).
§This work; the compound does not undergo spin-crossover above 100 K.
¶Morgenstern-Badarau et al. (1998[Morgenstern-Badarau, I., Lambert, F., Deroche, A., Cesario, M., Guilhem, J., Keita, B. & Nadjo, L. (1998). Inorg. Chim. Acta, pp. 234-241, 275-276.]).
††Ikuta et al. (2003[Ikuta, Y., Ooidemizu, M., Yamahata, Y., Yamada, M., Osa, S., Matsumoto, N., Iijima, S., Sunatsuki, Y., Kojima, M., Dahan, F. & Tuchagues, J.-P. (2003). Inorg. Chem. 42, 7001-7017.]).
‡‡Yamada et al. (2003[Yamada, M., Ooidemizu, M., Ikuta, Y., Osa, S., Matsumoto, N., Iijima, S., Kojima, M., Dahan, F. & Tuchagues, J.-P. (2003). Inorg. Chem. 42, 8406-8416.]).
§§Nagasato et al. (2001[Nagasato, S., Katsuki, I., Motoda, Y., Sunatsuki, Y., Matsumoto, N. & Kojima, M. (2001). Inorg. Chem. 40, 2534-2540.]).
¶¶Deeney et al. (1998[Deeney, F. A., Harding, C. J., Morgan, G. G., McKee, V., Nelson, J., Teat, S. J. & Clegg, W. (1998). J. Chem. Soc. Dalton Trans. pp. 1837-1844.]).

The data set used for the refinement is 99.3% complete to 2θ = 50°. All H atoms in the complex dication were placed in calculated positions and treated using a riding model, with Csp2—H distances of 0.95 Å, Csp3—H distances of 0.99 Å and N—H distances of 0.88 Å, and all Uiso(H) parameters were fixed at 1.2Ueq(C,N). Water atoms H40A and H40B were located in a difference map and included in the refinement with O—H distances restrained to 0.84 (1) Å and H⋯H distances restrained to 1.37 (1) Å. An antibumping restraint was also applied between atoms H9 and H40A. In the refined water mol­ecule, the O40—H40A distance is 0.854 (19) Å, the O40—H40B distance is 0.84 (2) Å and the H40A—O40—H40B angle is 106.0 (15)°.

Data collection: COLLECT (Nonius, 1999[Nonius (1999). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: DENZO–SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); molecular graphics: ORTEX (McArdle, 1995[McArdle, P. (1995). J. Appl. Cryst. 28, 65.]); software used to prepare material for publication: local program.

Supporting information


Comment top

We have been interested for some time in the spin-state transitions shown by iron(II) complexes of polydentate pyrazole-containing ligands (Holland et al., 2001; Holland, Barrett et al., 2002; Holland, McAllister et al., 2002; Money et al., 2003; Money et al., 2004; Elhaïk et al., 2003; Smithson et al., 2003). During this work, we noted that both iron(II) and iron(III) complexes of tris-(4-{imidazol-2-yl}-3-aza-3-butenyl)amine, the Schiff base derived from the reaction of tris(2-aminoethyl)amine (tren) with three equivalents of imidazol-2-carbaldehyde, and closely related derivatives exhibit interesting spin-state transitions (Sunatsuki et al., 2001; Nagasato et al., 2001; Ikuta et al., 2003; Yamada et al., 2003; Yukinari et al., 2003). We therefore decided to investigate the iron chemistry of the pyrazole-containing analogue, tris-(4-{pyrazol-3-yl}-3-aza-3-butenyl)amine. We found that reactions of this ligand with hydrated Fe(ClO4)3 in MeOH yielded a dark-brown precipitate. Some of this material proved soluble on extraction with acetone, giving a dark-orange solution that afforded orange crystals of the title compound, (I), following diffusion of diethyl ether vapour into the mixture. Presumably, partial reduction of the FeIII content of the mixture by the MeOH solvent took place during the reaction. Compound (I) was subsequently synthesized in higher yield by direct treatment of the same ligand with Fe(ClO4)2·6H2O. No complexes of tris-(4-{pyrazol-3-yl}-3-aza-3-butenyl)amine have been reported before, although NiII and CoIII complexes of its trimethylated derivative tris-(4-{5-methylpyrazol-3-yl}-3-aza-3-butenyl)amine have been structurally characterized (Paul et al., 2000; Paul et al., 2002).

The coordination geometry about the Fe atom in (I) is best described as a capped trigonal antiprism. There are six Fe—N bonds of 2.1563 (16)–2.2547 (16) Å to the imine and pyrazole N donors, these lengths being typical of a high-spin FeII centre. Amine atom N2 lies at a much longer distance [2.7468 (16) Å] from the metal atom, at a position approximately centrally above the triangular face formed by atoms N5, N14 and N23. This value is at the lower end of the range of capping Fe—N distances seen for high-spin FeII complexes of related heptadentate tripodal ligands (AUTHOR: reference?). As can be seen from Table 3, there is an approximate, positive correlation in this class of compound between contraction of this capping Fe—N bond and an opening out of the capped face of the trigonal antiprism, indicated by an increase in the Nimine—Fe—Nimine angles [N5—Fe1—N14, N5—Fe1—N23 and N14—Fe1—N23 in (I)]. However, there is no apparent relation between these structural parameters and whether or not these compounds undergo spin-crossover upon cooling. Although the helical ligand conformation about each Fe is chiral, (I) crystallizes as a racemate in the centrosymmetric space group P21/n.

Two of the three pyrazole N—H groups in (I) are hydrogen bonded to two different lattice water molecules, forming N9—H9···O40 and N18—H18···O40i interactions [symmetry code: (i) 1 − x, 1 − y, 1 − z]. The third NH group (N27/H27) hydrogen bonds to atom O31 in one of the two independent ClO4 anions. This same anion accepts a hydrogen bond from water atom H40Aii [symmetry code: (ii) −1 + x, y, z]. The other water H atom (H40B) hydrogen bonds to the other ClO4 ion in the asymmetric unit. The net effect of these interactions is to assemble two formula units into a hydrogen-bonded dimer about the inversion centre at (1/2, 1/2, 1/2) (Fig. 2). These dimers are in turn linked into chains running parallel to the crystallographic a direction through the Cl30/O34 anion, which accepts hydrogen bonds from two different dimer moieties.

Experimental top

A solution of the tris-(4-{pyrazol-3-yl}-3-aza-3-butenyl)amine ligand was prepared by refluxing a mixture of pyrazole-3-carbaldehyde (1.00 g, 10.4 mmol) and tris-(2-aminoethyl)amine (0.51 g, 3.47 mmol) in MeOH (100 ml) until all of the solid had dissolved. Fe(ClO4)2·6H2O (1.26 g, 3.47 mmol) was then added to the mixture, yielding a dark-yellow solution. The volume was reduced to ca 10 ml by evaporation, and then an excess of diethyl ether was added to yield a yellow–orange precipitate. Yield 1.23 g, 56%. Recrystallization of the crude product from undried acetone gave orange monohydrated crystals, which lost their water of crystallization upon drying in vacuo over P2O5. Analysis found: C 34.0, H 3.9, N 22.2%; calculated for C18H24Cl2FeN10O8: C 34.0, H 3.8, N 22.1%.

Refinement top

The data set used for the refinement is 99.3% complete to 2θ = 50°. All H atoms in the complex dication were placed in calculated positions and refined using a riding model, with Csp2—H distances of 0.95, Csp3—H distances of 0.99 Å and N—H distances of 0.88 Å, and all Uiso(H) parameters fixed at 1.2Ueq(C,N). Water atoms H40A and H40B were located in a difference map and allowed to refine with O—H distances restrained to 0.84 (1) Å and H···H distances restrained to 1.37 (1) Å. An antibumping restraint was also applied between atoms H9 and H40A. In the refined water molecule, the O40—H40A distance is 0.854 (19) Å, the O40—H40B distance is 0.84 (2) Å and the H40A—O40—H40B angle is 106.0 (15)°. Table 3. Selected structural parameters for high-spin Fe(II) complexes of the ligands shown in Fig. 3. 'a' is the distance between the Fe and bridgehead N atoms [Fe1—N2 in I]; 'θ' is the average of the three N{imine}—Fe—N{imine} angles; and 'ω' is the average of the three N{heterocycle}—Fe—N{heterocycle} angles.

Computing details top

Data collection: COLLECT (Nonius, 1999); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997); data reduction: DENZO–SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEX (McArdle, 1995); software used to prepare material for publication: local program.

Figures top
[Figure 1]
[Figure 2]
Fig. 1. The molecular structure of the complex cation in the crystal structure of (I), showing 50% probability displacement ellipsoids and the atom-numbering scheme. All C-bound H atoms have been omitted for clarity.

Fig. 2. A partial packing diagram of (I), showing the centrosymmetric hydrogen-bonded dimerization of the formula units in the structure.

Fig. 3. The ligands referred to in Table 3. ############ Should this be a Scheme? ################################
[Tris-(4-{pyrazol-3-yl}-3-aza-3-butenyl)amine]iron(II) diperchlorate hydrate top
Crystal data top
C18H24FeN10·2(ClO4)·H2OF(000) = 1344
Mr = 653.24Dx = 1.644 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 9.4086 (1) ÅCell parameters from 25327 reflections
b = 22.5317 (4) Åθ = 1.8–27.5°
c = 12.7279 (2) ŵ = 0.84 mm1
β = 101.9858 (6)°T = 100 K
V = 2639.38 (7) Å3Rectangular prism, yellow
Z = 40.33 × 0.23 × 0.20 mm
Data collection top
Nonius KappaCCD area-detector
diffractometer
6004 independent reflections
Radiation source: fine-focus sealed tube4724 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.066
Detector resolution: 9.091 pixels mm-1θmax = 27.5°, θmin = 1.8°
Area detector scansh = 1212
Absorption correction: multi-scan
(SORTAV; Blessing, 1995)
k = 2929
Tmin = 0.769, Tmax = 0.850l = 1616
25327 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.037Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.099H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.047P)2 + 1.086P]
where P = (Fo2 + 2Fc2)/3
6004 reflections(Δ/σ)max = 0.001
370 parametersΔρmax = 0.34 e Å3
4 restraintsΔρmin = 0.51 e Å3
Crystal data top
C18H24FeN10·2(ClO4)·H2OV = 2639.38 (7) Å3
Mr = 653.24Z = 4
Monoclinic, P21/nMo Kα radiation
a = 9.4086 (1) ŵ = 0.84 mm1
b = 22.5317 (4) ÅT = 100 K
c = 12.7279 (2) Å0.33 × 0.23 × 0.20 mm
β = 101.9858 (6)°
Data collection top
Nonius KappaCCD area-detector
diffractometer
6004 independent reflections
Absorption correction: multi-scan
(SORTAV; Blessing, 1995)
4724 reflections with I > 2σ(I)
Tmin = 0.769, Tmax = 0.850Rint = 0.066
25327 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0374 restraints
wR(F2) = 0.099H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.34 e Å3
6004 reflectionsΔρmin = 0.51 e Å3
370 parameters
Special details top

Experimental. Detector set at 30 mm from sample with different 2theta offsets 1 degree phi exposures for chi=0 degree settings 1 degree omega exposures for chi=90 degree settings

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. No disorder was detected during refinement and no restraints were applied. All non-H atoms were refined anisotropically. All H atoms in the complex dication were placed in calculated positions and refined using a riding model. The two water H atoms [H40A and H40B] were located in the difference map and allowed to refine with the restraints O—H = 0.84 (1) Å and H···H = 1.37 (1) Å. An anti-bumping restraint was also applied between H9 and H40A.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Fe10.50212 (3)0.366591 (12)0.25044 (2)0.01882 (9)
N20.42530 (18)0.26732 (7)0.12636 (12)0.0219 (4)
C30.4007 (2)0.21984 (9)0.19870 (15)0.0248 (4)
H3A0.42670.18120.17080.030*
H3B0.29650.21860.20190.030*
C40.4919 (2)0.22993 (9)0.31113 (15)0.0240 (4)
H4A0.46480.20090.36210.029*
H4B0.59630.22490.31090.029*
N50.46352 (18)0.29044 (7)0.34325 (12)0.0209 (4)
C60.4015 (2)0.29873 (9)0.42240 (15)0.0219 (4)
H60.37600.26620.46220.026*
C70.3711 (2)0.35947 (9)0.44990 (15)0.0207 (4)
N80.40373 (18)0.40215 (7)0.38485 (13)0.0206 (4)
N90.36715 (18)0.45327 (7)0.42674 (13)0.0222 (4)
H90.37790.48850.39970.027*
C100.3121 (2)0.44404 (9)0.51509 (16)0.0238 (4)
H100.27860.47370.55710.029*
C110.3131 (2)0.38397 (9)0.53324 (15)0.0228 (4)
H110.28160.36360.58960.027*
C120.5505 (2)0.25584 (9)0.07622 (16)0.0262 (5)
H12A0.51750.23450.00750.031*
H12B0.62180.23040.12410.031*
C130.6227 (2)0.31409 (9)0.05553 (15)0.0245 (4)
H13A0.70980.30620.02550.029*
H13B0.55430.33870.00370.029*
N140.66354 (18)0.34474 (7)0.15855 (13)0.0216 (4)
C150.7954 (2)0.35771 (9)0.19791 (16)0.0237 (4)
H150.86910.35230.15780.028*
C160.8291 (2)0.38135 (9)0.30735 (16)0.0220 (4)
N170.71804 (18)0.38498 (7)0.35824 (13)0.0216 (4)
N180.77857 (18)0.40390 (7)0.45793 (13)0.0231 (4)
H180.72950.41030.50860.028*
C190.9228 (2)0.41179 (9)0.47085 (17)0.0268 (5)
H190.98710.42460.53450.032*
C200.9602 (2)0.39783 (10)0.37475 (17)0.0269 (5)
H201.05390.39910.35800.032*
C210.2919 (2)0.28376 (9)0.04891 (16)0.0254 (5)
H21A0.23250.24790.02690.030*
H21B0.31760.30130.01600.030*
C220.2045 (2)0.32831 (9)0.09948 (16)0.0259 (5)
H22A0.11800.34140.04620.031*
H22B0.17140.31000.16100.031*
N230.29967 (18)0.37886 (7)0.13586 (13)0.0219 (4)
C240.2685 (2)0.43029 (9)0.09623 (16)0.0236 (4)
H240.17770.43820.04960.028*
C250.3778 (2)0.47649 (9)0.12542 (15)0.0216 (4)
N260.50237 (18)0.46036 (7)0.19068 (13)0.0218 (4)
N270.58740 (19)0.50866 (7)0.19898 (13)0.0239 (4)
H270.67630.51030.23800.029*
C280.5205 (2)0.55426 (9)0.14045 (17)0.0274 (5)
H280.56040.59250.13390.033*
C290.3841 (2)0.53545 (9)0.09208 (17)0.0282 (5)
H290.31020.55750.04620.034*
Cl300.96490 (6)0.53235 (2)0.20209 (4)0.02860 (13)
O310.87955 (18)0.54411 (8)0.28247 (13)0.0412 (4)
O321.10489 (18)0.51063 (8)0.25561 (15)0.0435 (4)
O330.89253 (18)0.48819 (7)0.12910 (12)0.0345 (4)
O340.9830 (2)0.58560 (8)0.14540 (15)0.0525 (5)
Cl350.50340 (5)0.71869 (2)0.23985 (4)0.02391 (12)
O360.40823 (18)0.66807 (7)0.23031 (15)0.0403 (4)
O370.62998 (17)0.70271 (8)0.19977 (13)0.0378 (4)
O380.5450 (2)0.73624 (8)0.35028 (12)0.0420 (4)
O390.42776 (18)0.76658 (7)0.17823 (12)0.0338 (4)
O400.34003 (17)0.57388 (7)0.35871 (12)0.0265 (3)
H40A0.260 (2)0.5725 (9)0.3126 (18)0.048 (8)*
H40B0.391 (3)0.5997 (13)0.336 (2)0.075 (11)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Fe10.01900 (17)0.02036 (16)0.01707 (15)0.00015 (11)0.00369 (11)0.00102 (11)
N20.0245 (9)0.0242 (9)0.0168 (8)0.0015 (7)0.0040 (7)0.0002 (7)
C30.0328 (12)0.0208 (10)0.0212 (10)0.0048 (9)0.0063 (9)0.0016 (8)
C40.0330 (12)0.0191 (10)0.0200 (10)0.0027 (9)0.0056 (9)0.0001 (8)
N50.0235 (9)0.0215 (8)0.0169 (8)0.0011 (7)0.0022 (7)0.0005 (6)
C60.0250 (10)0.0225 (10)0.0172 (9)0.0027 (8)0.0022 (8)0.0029 (8)
C70.0182 (10)0.0247 (10)0.0185 (9)0.0002 (8)0.0023 (8)0.0017 (8)
N80.0212 (9)0.0209 (8)0.0196 (8)0.0008 (7)0.0038 (7)0.0008 (7)
N90.0237 (9)0.0200 (8)0.0225 (8)0.0006 (7)0.0042 (7)0.0014 (7)
C100.0234 (11)0.0267 (11)0.0222 (10)0.0017 (9)0.0065 (8)0.0025 (8)
C110.0222 (10)0.0277 (11)0.0187 (9)0.0010 (9)0.0047 (8)0.0002 (8)
C120.0336 (12)0.0248 (11)0.0211 (10)0.0022 (9)0.0076 (9)0.0040 (8)
C130.0260 (11)0.0292 (11)0.0185 (9)0.0007 (9)0.0052 (8)0.0041 (8)
N140.0245 (9)0.0222 (9)0.0181 (8)0.0001 (7)0.0043 (7)0.0003 (6)
C150.0235 (11)0.0248 (10)0.0243 (10)0.0010 (9)0.0081 (9)0.0004 (8)
C160.0218 (10)0.0218 (10)0.0219 (10)0.0013 (8)0.0031 (8)0.0000 (8)
N170.0232 (9)0.0225 (9)0.0181 (8)0.0001 (7)0.0022 (7)0.0022 (7)
N180.0260 (9)0.0248 (9)0.0179 (8)0.0024 (7)0.0029 (7)0.0030 (7)
C190.0250 (11)0.0280 (11)0.0246 (10)0.0022 (9)0.0010 (8)0.0028 (8)
C200.0205 (10)0.0307 (11)0.0288 (11)0.0003 (9)0.0035 (9)0.0021 (9)
C210.0265 (11)0.0275 (11)0.0202 (10)0.0064 (9)0.0002 (8)0.0012 (8)
C220.0234 (11)0.0289 (11)0.0235 (10)0.0041 (9)0.0005 (8)0.0026 (8)
N230.0215 (9)0.0249 (9)0.0190 (8)0.0036 (7)0.0037 (7)0.0010 (7)
C240.0217 (10)0.0282 (11)0.0202 (10)0.0028 (9)0.0028 (8)0.0031 (8)
C250.0229 (10)0.0233 (10)0.0193 (9)0.0004 (8)0.0058 (8)0.0002 (8)
N260.0228 (9)0.0228 (9)0.0200 (8)0.0029 (7)0.0051 (7)0.0005 (7)
N270.0234 (9)0.0255 (9)0.0229 (9)0.0044 (7)0.0052 (7)0.0018 (7)
C280.0328 (12)0.0211 (10)0.0295 (11)0.0004 (9)0.0093 (9)0.0013 (8)
C290.0300 (12)0.0241 (11)0.0296 (11)0.0024 (9)0.0046 (9)0.0024 (9)
Cl300.0260 (3)0.0301 (3)0.0283 (3)0.0040 (2)0.0023 (2)0.0015 (2)
O310.0294 (9)0.0597 (12)0.0342 (9)0.0028 (8)0.0063 (7)0.0178 (8)
O320.0253 (9)0.0500 (11)0.0510 (11)0.0012 (8)0.0018 (8)0.0030 (9)
O330.0373 (9)0.0349 (9)0.0300 (8)0.0085 (7)0.0042 (7)0.0078 (7)
O340.0712 (14)0.0317 (10)0.0505 (11)0.0119 (9)0.0036 (10)0.0095 (8)
Cl350.0304 (3)0.0218 (2)0.0210 (2)0.0003 (2)0.0089 (2)0.00018 (18)
O360.0387 (10)0.0283 (9)0.0586 (11)0.0065 (7)0.0206 (8)0.0012 (8)
O370.0300 (9)0.0482 (10)0.0395 (9)0.0008 (8)0.0168 (7)0.0046 (8)
O380.0658 (12)0.0397 (10)0.0182 (8)0.0187 (9)0.0033 (8)0.0022 (7)
O390.0468 (10)0.0296 (8)0.0234 (8)0.0057 (7)0.0041 (7)0.0062 (6)
O400.0264 (8)0.0281 (8)0.0252 (8)0.0032 (7)0.0054 (7)0.0011 (6)
Geometric parameters (Å, º) top
Fe1—N22.7468 (17)C16—N171.341 (3)
Fe1—N52.1563 (16)C16—C201.398 (3)
Fe1—N82.2547 (16)N17—N181.348 (2)
Fe1—N142.1575 (17)N18—C191.344 (3)
Fe1—N172.2413 (17)N18—H180.8800
Fe1—N232.1628 (17)C19—C201.377 (3)
Fe1—N262.2457 (16)C19—H190.9500
N2—C31.461 (2)C20—H200.9500
N2—C211.473 (3)C21—C221.522 (3)
N2—C121.475 (3)C21—H21A0.9900
C3—C41.525 (3)C21—H21B0.9900
C3—H3A0.9900C22—N231.463 (3)
C3—H3B0.9900C22—H22A0.9900
C4—N51.464 (2)C22—H22B0.9900
C4—H4A0.9900N23—C241.273 (3)
C4—H4B0.9900C24—C251.456 (3)
N5—C61.278 (3)C24—H240.9500
C6—C71.456 (3)C25—N261.339 (3)
C6—H60.9500C25—C291.400 (3)
C7—N81.345 (2)N26—N271.342 (2)
C7—C111.403 (3)N27—C281.346 (3)
N8—N91.344 (2)N27—H270.8800
N9—C101.349 (3)C28—C291.370 (3)
N9—H90.8800C28—H280.9500
C10—C111.373 (3)C29—H290.9500
C10—H100.9500Cl30—O341.4282 (17)
C11—H110.9500Cl30—O331.4332 (15)
C12—C131.526 (3)Cl30—O321.4372 (17)
C12—H12A0.9900Cl30—O311.4502 (17)
C12—H12B0.9900Cl35—O391.4332 (15)
C13—N141.461 (2)Cl35—O381.4341 (16)
C13—H13A0.9900Cl35—O371.4355 (16)
C13—H13B0.9900Cl35—O361.4394 (16)
N14—C151.272 (3)O40—H40A0.854 (19)
C15—C161.463 (3)O40—H40B0.84 (2)
C15—H150.9500
N2—Fe1—N567.23 (5)C12—C13—H13B110.3
N2—Fe1—N8128.69 (5)H13A—C13—H13B108.5
N2—Fe1—N1468.49 (6)C15—N14—C13121.04 (18)
N2—Fe1—N17126.82 (6)C15—N14—Fe1118.23 (14)
N2—Fe1—N2368.08 (6)C13—N14—Fe1120.70 (13)
N2—Fe1—N26126.16 (5)N14—C15—C16117.34 (19)
N5—Fe1—N874.02 (6)N14—C15—H15121.3
N5—Fe1—N14109.45 (6)C16—C15—H15121.3
N5—Fe1—N1792.64 (6)N17—C16—C20111.33 (18)
N5—Fe1—N23104.25 (6)N17—C16—C15116.45 (18)
N5—Fe1—N26161.14 (6)C20—C16—C15132.05 (19)
N8—Fe1—N14159.82 (6)C16—N17—N18104.75 (16)
N8—Fe1—N1786.13 (6)C16—N17—Fe1113.02 (12)
N8—Fe1—N2391.34 (6)N18—N17—Fe1141.91 (13)
N8—Fe1—N2687.25 (6)C19—N18—N17112.05 (17)
N14—Fe1—N1773.95 (6)C19—N18—H18124.0
N14—Fe1—N23106.51 (6)N17—N18—H18124.0
N14—Fe1—N2688.90 (6)N18—C19—C20107.36 (18)
N17—Fe1—N23161.53 (7)N18—C19—H19126.3
N17—Fe1—N2688.21 (6)C20—C19—H19126.3
N23—Fe1—N2673.39 (6)C19—C20—C16104.49 (19)
C3—N2—C21112.40 (16)C19—C20—H20127.8
C3—N2—C12112.93 (16)C16—C20—H20127.8
C21—N2—C12113.64 (15)N2—C21—C22110.05 (16)
C3—N2—Fe1106.93 (11)N2—C21—H21A109.7
C21—N2—Fe1105.42 (12)C22—C21—H21A109.7
C12—N2—Fe1104.67 (11)N2—C21—H21B109.7
N2—C3—C4110.50 (16)C22—C21—H21B109.7
N2—C3—H3A109.5H21A—C21—H21B108.2
C4—C3—H3A109.5N23—C22—C21107.35 (16)
N2—C3—H3B109.5N23—C22—H22A110.2
C4—C3—H3B109.5C21—C22—H22A110.2
H3A—C3—H3B108.1N23—C22—H22B110.2
N5—C4—C3107.54 (16)C21—C22—H22B110.2
N5—C4—H4A110.2H22A—C22—H22B108.5
C3—C4—H4A110.2C24—N23—C22120.48 (17)
N5—C4—H4B110.2C24—N23—Fe1118.79 (14)
C3—C4—H4B110.2C22—N23—Fe1120.62 (13)
H4A—C4—H4B108.5N23—C24—C25117.20 (18)
C6—N5—C4119.71 (17)N23—C24—H24121.4
C6—N5—Fe1118.15 (13)C25—C24—H24121.4
C4—N5—Fe1121.81 (12)N26—C25—C29111.04 (18)
N5—C6—C7118.14 (18)N26—C25—C24116.44 (17)
N5—C6—H6120.9C29—C25—C24132.33 (19)
C7—C6—H6120.9C25—N26—N27105.05 (16)
N8—C7—C11111.00 (18)C25—N26—Fe1113.78 (13)
N8—C7—C6116.28 (17)N27—N26—Fe1141.17 (13)
C11—C7—C6132.72 (19)N26—N27—C28111.88 (17)
N9—N8—C7104.99 (15)N26—N27—H27124.1
N9—N8—Fe1141.73 (13)C28—N27—H27124.1
C7—N8—Fe1113.26 (13)N27—C28—C29107.42 (19)
N8—N9—C10111.92 (16)N27—C28—H28126.3
N8—N9—H9124.0C29—C28—H28126.3
C10—N9—H9124.0C28—C29—C25104.61 (19)
N9—C10—C11107.56 (18)C28—C29—H29127.7
N9—C10—H10126.2C25—C29—H29127.7
C11—C10—H10126.2O34—Cl30—O33110.25 (11)
C10—C11—C7104.53 (18)O34—Cl30—O32109.39 (12)
C10—C11—H11127.7O33—Cl30—O32109.64 (10)
C7—C11—H11127.7O34—Cl30—O31110.14 (12)
N2—C12—C13110.35 (17)O33—Cl30—O31109.02 (10)
N2—C12—H12A109.6O32—Cl30—O31108.36 (11)
C13—C12—H12A109.6O39—Cl35—O38109.39 (9)
N2—C12—H12B109.6O39—Cl35—O37110.41 (10)
C13—C12—H12B109.6O38—Cl35—O37109.87 (11)
H12A—C12—H12B108.1O39—Cl35—O36108.72 (10)
N14—C13—C12107.18 (16)O38—Cl35—O36109.84 (11)
N14—C13—H13A110.3O37—Cl35—O36108.59 (10)
C12—C13—H13A110.3H40A—O40—H40B106.0 (15)
N14—C13—H13B110.3
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N9—H9···O400.882.002.848 (2)160
N18—H18···O40i0.881.972.833 (2)168
N27—H27···O310.882.032.848 (2)155
O40—H40A···O32ii0.85 (2)2.04 (2)2.728 (2)137 (2)
O40—H40B···O360.84 (2)2.07 (2)2.832 (2)149 (2)
Symmetry codes: (i) x+1, y+1, z+1; (ii) x1, y, z.

Experimental details

Crystal data
Chemical formulaC18H24FeN10·2(ClO4)·H2O
Mr653.24
Crystal system, space groupMonoclinic, P21/n
Temperature (K)100
a, b, c (Å)9.4086 (1), 22.5317 (4), 12.7279 (2)
β (°) 101.9858 (6)
V3)2639.38 (7)
Z4
Radiation typeMo Kα
µ (mm1)0.84
Crystal size (mm)0.33 × 0.23 × 0.20
Data collection
DiffractometerNonius KappaCCD area-detector
diffractometer
Absorption correctionMulti-scan
(SORTAV; Blessing, 1995)
Tmin, Tmax0.769, 0.850
No. of measured, independent and
observed [I > 2σ(I)] reflections
25327, 6004, 4724
Rint0.066
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.099, 1.04
No. of reflections6004
No. of parameters370
No. of restraints4
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.34, 0.51

Computer programs: COLLECT (Nonius, 1999), DENZO–SMN (Otwinowski & Minor, 1997), DENZO–SMN, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ORTEX (McArdle, 1995), local program.

Selected geometric parameters (Å, º) top
Fe1—N22.7468 (17)Fe1—N172.2413 (17)
Fe1—N52.1563 (16)Fe1—N232.1628 (17)
Fe1—N82.2547 (16)Fe1—N262.2457 (16)
Fe1—N142.1575 (17)
N2—Fe1—N567.23 (5)N8—Fe1—N14159.82 (6)
N2—Fe1—N8128.69 (5)N8—Fe1—N1786.13 (6)
N2—Fe1—N1468.49 (6)N8—Fe1—N2391.34 (6)
N2—Fe1—N17126.82 (6)N8—Fe1—N2687.25 (6)
N2—Fe1—N2368.08 (6)N14—Fe1—N1773.95 (6)
N2—Fe1—N26126.16 (5)N14—Fe1—N23106.51 (6)
N5—Fe1—N874.02 (6)N14—Fe1—N2688.90 (6)
N5—Fe1—N14109.45 (6)N17—Fe1—N23161.53 (7)
N5—Fe1—N1792.64 (6)N17—Fe1—N2688.21 (6)
N5—Fe1—N23104.25 (6)N23—Fe1—N2673.39 (6)
N5—Fe1—N26161.14 (6)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N9—H9···O400.882.002.848 (2)160
N18—H18···O40i0.881.972.833 (2)168
N27—H27···O310.882.032.848 (2)155
O40—H40A···O32ii0.854 (19)2.04 (2)2.728 (2)137.1 (16)
O40—H40B···O360.84 (2)2.07 (2)2.832 (2)149 (2)
Symmetry codes: (i) x+1, y+1, z+1; (ii) x1, y, z.
Table 3. Selected structural parameters. top
Compounda, Åθ, °ω, °Spin-crossover
on cooling?
[Fe(L1)][ClO4]2a2.504 (6)112.7 (2)86.1 (2)no
[Fe(L2)][PF6]2b2.724 (4)106.6 (3)86.6 (3)n/a
Ic2.7468 (16)106.73 (10)87.20 (10)n/a
[Fe(L4)][PF6]2a2.753 (8)n/an/ayes
[Fe(L3)][PF6]2d3.004 (8)100.2 (7)98.0 (6)no
[{Fe(L5)}2–3H]NO3e3.122 (6)97.93 (13)93.13 (13)yes
3.169 (9)98.30 (12)92.95 (12)yes
[{Fe(L5)}2–3H]PF6f3.198 (8)97.14 (13)94.41 (13)yes
3.215 (8)97.18 (14)94.47 (13)yes
[Fe(L6)][PF6]2g3.261 (5)96.5 (3)97.7 (5)no
[Fe(L7)][ClO4]2h3.280 (3)91.5 (2)102.1 (2)no
(a) Morgenstern-Badarau et al., 2000. (b) Yang et al., 2001. (c) This work. This compound does not undergo spin-crossover above 100 K. (d) Morgenstern-Badarau et al., 1998. (e) Ikuta et al., 2003. (f) Yamada et al., 2003. (g) Nagasato et al., 2001. (h) Deeney et al., 1998.
 

Acknowledgements

The authors acknowledge the Royal Society of London (for University Research Fellowships to MAH), the EPSRC and the University of Leeds.

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