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

Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296
Volume 62| Part 9| September 2006| Pages m437-m439
doi:10.1107/S0108270106028903

An unusual example of a linearly coordinated acetone ligand in a six-coordinate iron(II) complex

CROSSMARK_Color_square_no_text.svg
Colin A. Kilnera and Malcolm A. Halcrowa*

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

(Received 12 July 2006; accepted 25 July 2006; online 31 August 2006)

The title compound, acetonediaqua[2,6-bis­(3-tert-butyl­pyrazol-1-yl)pyridine]iron(II) bis­(tetra­fluoro­borate) acetone disolvate, [Fe(C19H25N5)(C3H6O)(H2O)2](BF4)2·2C3H6O, contains a C2-symmetric six-coordinate complex dication, with an acetone ligand in its equatorial plane that is linearly coordinated by symmetry (Fe—O=CMe2 = 180°). This is a consequence of close steric contacts between the coordinated carbonyl group and the two distal tert-butyl substituents on the tridentate ligand.

Comment

We are studying the chemistry of homoleptic iron(II) complexes of 2,6-dipyrazol­ylpyridine and 2,6-dipyrazol­yl­pyrazine derivatives (Halcrow, 2005[Halcrow, M. A. (2005). Coord. Chem. Rev. 249, 2880-2908.]). Compounds of this type sometimes exhibit an unusual angular Jahn–Teller distortion, in which the metal coordination is severely twisted from its ideal near-octa­hedral geometry (Holland 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., 2005[Elhaïk, J., Evans, D. J., Kilner, C. A. & Halcrow, M. A. (2005). Dalton Trans. pp. 1693-1700.], 2006[Elhaïk, J., Kilner, C. A. & Halcrow, M. A. (2006). Dalton Trans. pp. 823-830.]; Kilner & Halcrow, 2006[Kilner, C. A. & Halcrow, M. A. (2006). Polyhedron, 25, 235-240.]). We have been looking for more examples of this phenomenon and decided to examine the iron(II) chemistry of 2,6-bis(3-tert-butyl­pyrazol-1-yl)pyridine (L) to determine if the bulky ligand substituents might enforce a structural distortion onto an [FeL2]2+ centre. In fact, as we had already observed in its copper chemistry (Solanki et al., 2002[Solanki, N. K., McInnes, E. J. L., Collison, D., Kilner, C. A., Davies, J. E. & Halcrow, M. A. (2002). J. Chem. Soc. Dalton Trans. pp. 1625-1630.]), L proved too bulky to allow [FeL2]2+ to form. Hence, when hydrated Fe(BF4)2 and two molar equivalents of L were reacted in MeOH, MeCN or MeNO2, the resulting yellow solutions only yielded single crystals of unreacted L (Halcrow, 2005[Halcrow, M. A. (2005). Coord. Chem. Rev. 249, 2880-2908.]) and/or small amounts of intractable powder when layered with Et2O. A pure iron-containing product was only obtained when these reactions were performed in acetone, giving near-colourless crystals of trans-[FeL(OH2)2(OCMe2)](BF4)2·2Me2CO, (I)[link]. This compound was obtained in pure form when Fe(BF4)2·6H2O and L were reacted in a 1:1 molar ratio under the same conditions.

The complex dication in (I)[link] spans a crystallographic C2 axis passing through atoms Fe1, N2, C5, O16 and C17 (Fig. 1[link]). The bond lengths to Fe1 are in the range expected for a high-spin iron(II) centre (but see below), while the bond angles are close to those of an ideal octa­hedron, except for the restricted

[Scheme 1]
74.50 (4)° bite angle of the L ligand (Table 1[link]). The metal coordination is completed by an acetone ligand occupying the fourth equatorial coordination site and by two axial water ligands. Notably, the acetone ligand is coordinated in a linear fashion, the Fe1—O16—C17 angle being 180° by symmetry. Linear, rather than bent, coordination of a terminal monodentate dialkyl or alkyl aryl ketone ligand is unusual, particularly in compounds where a significant degree of d-orbital metal–ligand covalency might be expected (Fig. 2[link]). The five previous examples with an Fe—O=CR2 angle greater than 170° (Fig. 2[link]) in d-block chemistry involve d0 ZrIV (Sun et al., 1997[Sun, Y., Piers, W. E. & Yap, G. P. A. (1997). Organometallics, 16, 2509-2513.]) or d10 CuI (Munakata et al., 1994[Munakata, M., Kuroda-Sowa, T., Maekawa, M., Nakamura, M., Akiyama, S. & Kitagawa, S. (1994). Inorg. Chem. 33, 1284-1291.]) and HgII (Lee et al., 2001[Lee, H., Knobler, C. B. & Hawthorne, M. F. (2001). J. Am. Chem. Soc. 123, 8543-8549.]) metal ions, or weak apical or axial inter­actions to tetra­gonal copper(II) centres (Scott & Holm, 1994[Scott, M. J. & Holm, R. H. (1994). J. Am. Chem. Soc. 116, 11357-11367.]; Akitsu & Einaga, 2004[Akitsu, T. & Einaga, Y. (2004). Acta Cryst. C60, m162-m164.]). Of particular relevance is trans-[RhCl2(Phebox)(OCMe2)] [HPhebox is 1,3-bis­(4-methyl­oxazolin-2-yl)benzene], which is isoelectronic with and stereochemically similar to (I)[link] but contains a bent acetone ligand with an Rh—O=C angle of 137 (1)° (Motoyama et al., 2001[Motoyama, Y., Okano, M., Narusawa, H., Makihara, N., Aoki, K. & Nishiyama, H. (2001). Organometallics, 20, 1580-1591.]).

The linear Fe1—O16—C17 angle in (I)[link] is probably sterically imposed by the surrounding tert-butyl groups (Fig. 3[link]), since atom O16 is in close contact with one H atom from each of the C12 and C13 methyl groups, with C12⋯O16 = 3.528 (3) Å and C13⋯O16 = 3.362 (3) Å. For comparison, the sum of the van der Waals radii of an O atom and a methyl group is 3.4 Å (Pauling, 1960[Pauling, L. (1960). The Nature of the Chemical Bond, 3rd ed., pp. 257-264. Ithaca, New York: Cornell University Press.]). This steric influence is also probably why the Fe1—N7 bond is 0.07–0.10 Å longer than we have previously observed in high-spin complexes of 2,6-dipyrazol­ylpyridines with regular six-coordinate structures (Halcrow, 2005[Halcrow, M. A. (2005). Coord. Chem. Rev. 249, 2880-2908.], and references therein). In contrast, the Fe1—O16 bond length is somewhat shorter than those in the only other two known high-spin iron(II) acetone complexes, which have Fe—O distances of 2.113 (2) [Fe—O=CMe2 = 134.91 (18)°] and 2.123 (2) Å [135.9 (2)°] (Costes et al., 2002[Costes, J.-P., Clemente-Juan, J. M., Dahan, F., Dumestre, F. & Tuchagues, J.-P. (2002). Inorg. Chem. 41, 2886-2891.]). Unfortunately, this sample is too small to determine whether a meaningful correlation exists between the Fe—O distance and Fe—O=CR2 angle in these complexes. One more iron(II) acetone complex is known (Hamon et al., 1994[Hamon, P., Toupet, L., Hamon, J. R. & Lapinte, C. (1994). J. Chem. Soc. Chem. Commun. pp. 931-932.]), but since it contains an inter­mediate-spin iron centre it is not strictly comparable with (I)[link].

The O15 water ligand hydrogen bonds to one F atom of the disordered BF4− anion in the asymmetric unit of (I)[link] through H15A, and to the acetone solvent mol­ecule through H15B (Fig. 1[link] and Table 2[link]). Therefore, (I)[link] exists as discrete [FeL(OH2)2(OCMe2)](BF4)2·2Me2CO supra­molecules, which associate with each other through van der Waals contacts only.

[Figure 1]
Figure 1
The mol­ecular structure of the components of (I)[link], showing the atom-numbering scheme employed. All C-bound H atoms, and the minor anion disorder orientation (B19B/F20B–F23B) have been omitted for clarity. Displacement ellipsoids are shown at the 50% probability level, except for H atoms, which have arbitrary radii. [Symmetry code: (i) −x, y, −z + [{1\over 2}].]
[Figure 2]
Figure 2
The distribution of M—O=CR2 angles in d- and f-block metal complexes of acetone, and other monodentate dialkyl and alkyl aryl ketones in the Cambridge Structural Database (July 2006 Version; Allen, 2002[Allen, F. H. (2002). Acta Cryst. B58, 380-388.]).
[Figure 3]
Figure 3
An alternative view of the complex dication in (I)[link], showing the close approach of the tert-butyl methyl groups to the coordinated acetone ligand. Displacement ellipsoids are at the 50% probability level, except for H atoms, which have arbitrary radii. The view is approximately parallel to the O15—Fe1—O15i vector, with Fe1 and O15 hidden behind O15i. [Symmetry code: (i) −x, y, −z + [{1\over 2}].]

Experimental

A solution of L (0.25 g, 7.7 × 10 −4 mol) (Jameson & Goldsby, 1990[Jameson, D. L. & Goldsby, K. A. (1990). J. Org. Chem. 55, 4992-4994.]) and Fe(BF4)2·6H2O (0.13 g, 3.9 × 10 −4 mol) in acetone (30 ml) was stirred at room temperature in air until all the solid had dissolved. The colourless solution was concentrated in vacuo to ca 5 ml and filtered. Slow diffusion of diethyl ether vapour into the solution yielded colourless crystals of (I)[link] (yield 0.19 g, 64%). The crystals decompose to a very pale-green powder following exposure to air for a period of minutes. Analysis of the dried material implied that all the acetone solvent had been lost and about half of the coordinated acetone in the solid had been replaced with water from atmospheric moisture. The stoichiometry of acetone in the final product was confirmed by IR analysis and by the acetone methyl 1H NMR peak listed below, which only integrates to ca 3.5H relative to the other peaks in the spectrum [the complex mol­ecule in crystalline (I)[link] would give an acetone peak integrating to 6H]. Analysis found: C 38.7, H 5.1, N 10.9%; calculated for [Fe(C19H25N5)(C3H6O)0.5(H2O)2.5](BF4)2: C 39.3, H 5.3, N 11.2%. IR (nujol): 3425 (br, ν O—H), 1692 (m, ν C=O), 1642 (br, δ H—O—H), 1070 (vs, ν B—F) cm−1. 1H NMR (250.1 MHz, CD3NO2, 293 K): δ 69.0, 65.0, 31.9 (all 2H, py H3/5 + pz H4 and H5), 2.0 [3.5H, (CH3)2CO], −0.2 [18H, C(CH3)3], −2.9 (1H, py H4).

Crystal data

  • [Fe(C19H25N5)(C3H6O)(H2O)2](BF4)2·2C3H6O

  • Mr = 763.18

  • Monoclinic, C 2/c

  • a = 24.4575 (4) Å

  • b = 12.7827 (1) Å

  • c = 14.5598 (4) Å

  • β = 126.323 (1)°

  • V = 3667.40 (12) Å3

  • Z = 4

  • Dx = 1.382 Mg m−3

  • Mo Kα radiation

  • μ = 0.49 mm−1

  • T = 150 (2) K

  • Rectangular prism, colourless

  • 0.46 × 0.33 × 0.26 mm
Data collection

  • Nonius KappaCCD area-detector diffractometer

  • ω and φ scans

  • Absorption correction: multi-scan (SORTAV; Blessing, 1995[Blessing, R. H. (1995). Acta Cryst. A51, 33-38.]) Tmin = 0.745, Tmax = 0.981 (expected range = 0.668–0.879)

  • 36356 measured reflections

  • 4190 independent reflections

  • 3718 reflections with I > 2σ(I)

  • Rint = 0.131

  • θmax = 27.5°
Refinement

  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.046

  • wR(F2) = 0.125

  • S = 1.04

  • 4190 reflections

  • 259 parameters

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

  • w = 1/[σ2(Fo2) + (0.062P)2 + 2.6971P] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.45 e Å−3

  • Δρmin = −0.68 e Å−3

  • Extinction correction: SHELXL97

  • Extinction coefficient: 0.0057 (7)

Table 1
Selected geometric parameters (Å, °)

Fe1—N2 2.112 (2)
Fe1—N7 2.2739 (15)
Fe1—O15 2.0857 (14)
Fe1—O16 2.0676 (17)
N2—Fe1—N7 74.50 (4) 
N2—Fe1—O15 91.35 (4)
N2—Fe1—O16 180
N7—Fe1—N7i 149.00 (7)
N7—Fe1—O15 89.41 (6)
N7—Fe1—O15i 91.31 (6)
N7—Fe1—O16 105.50 (4)
O15—Fe1—O15i 177.30 (8)
O15—Fe1—O16 88.65 (4)
Symmetry code: (i) [-x, y, -z+{\script{1\over 2}}].

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
O15—H15A⋯F21A 0.80 (3) 1.99 (3) 2.771 (3) 164 (3)
O15—H15A⋯F20B 0.80 (3) 2.01 (3) 2.715 (5) 147 (3)
O15—H15B⋯O24 0.79 (3) 1.92 (3) 2.689 (2) 165 (3)

The high value of Rint is not a consequence of weak high-angle diffraction, since this parameter does not decrease significantly if only low-angle data are merged. Rather, it may be a consequence of the absorption correction applied, or it may simply reflect the high redundancy in the data collection (ca nine reflections collected for every unique reflection).

The structure was originally solved and refined in the triclinic space group P[\overline{1}], with the complex dication lying on a general crystallographic position (i.e. Z = 2). However, a check for higher symmetry following this initial refinement, using the ADDSYM routine in PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]), suggested that the higher-symmetry space group C2/c might be more appropriate. The data were transformed into C2/c and the structure was then solved again and refined, leading to the final model described here.

The asymmetric unit contains half a complex dication, lying on the crystallographic C2 axis [0, y, [1\over4]], which passes through atoms Fe1, N2, C5, H5, O16 and C17, and one BF4− anion and an acetone solvent mol­ecule lying on general positions. The BF4− ion B19/F20–F23 is disordered over two orientations, labelled A (refined occupancy 0.65) and B (0.35). All B—F bonds were restrained to 1.38 (2) Å during refinement, and all F⋯F distances within a given disorder orientation to 2.25 (2) Å. All non-H atoms, except for the minor anion disorder site, were refine anisotropically. All C-bound H atoms were placed in calculated positions and refined using a riding model with the methyl group torsion angles allowed to refine freely [C—H = 0.95 Å and Uiso(H) = 1.2Ueq(C) for aryl, and C—H = 0.98 Å and Uiso(H) = 1.5Ueq(C) for methyl H atoms]. The water H atoms H15A and H15B were located in a difference map and allowed to refine freely with a common Uiso parameter, which refined to 0.063 (6) Å2. The refined O15—H distances are 0.79 (3) and 0.80 (3) Å, while the H15A—O15—H15B angle is 105 (3)°.

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

Crystal structure: contains datablocks I, global. DOI: 10.1107/S0108270106028903/gg3033sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S0108270106028903/gg3033Isup2.hkl


Comment top

We are studying the chemistry of homoleptic iron(II) complexes of 2,6-di(pyrazolyl)pyridine and 2,6-di(pyrazolyl)pyrazine derivatives (Halcrow, 2005\). Compounds of this type sometimes exhibit an unusual angular Jahn–Teller distortion, in which the metal coordination is severely twisted from its ideal near-octahedral geometry (Holland et al., 2002\; Elhaïk et al., 2005\, 2006\; Kilner & Halcrow, 2006\). We have been looking for more examples of this phenomenon and decided to examine the iron(II) chemistry of 2,6-di(3-tertbutylpyrazol-1-yl)pyridine (L), to determine if the bulky ligand substituents might enforce a structural distortion onto an [FeL2]2+ centre. In fact, as we had already observed in its copper chemistry (Solanki et al., 2002\), L proved too bulky to allow [FeL2]2+ to form. Hence, when hydrated Fe[BF4]2 and two molar equivalents of L were reacted in MeOH, MeCN or MeNO2, the resulting yellow solutions only yielded single crystals of unreacted L (Halcrow, 2005\) and/or small amounts of intractable powder when layered with Et2O. A pure iron-containing product was only obtained when these reactions were performed in acetone, giving near-colourless crystals of trans-[FeL(OH2)2(OC{CH3}2)][BF4]2·2(CH3)2CO, (I). This compound was obtained in pure form when Fe[BF4]2·6H2O and L were reacted in a 1:1 molar ratio under the same conditions.

The complex dication in (I) spans a crystallographic C2 axis passing through atoms Fe1, N2, C5, O16 and C17 (Fig. 1). The bond lengths to Fe1 are in the range expected for a high-spin iron(II) centre (but see below), while the bond angles are close to those of an ideal octahedron, except for the restricted 74.50 (4)° bite angle of the L ligand. The metal coordination is completed by an acetone ligand occupying the fourth equatorial coordination site and by two axial water ligands. Notably, the acetone ligand is coordinated in a linear fashion, the Fe1—O16—C17 angle being 180° by symmetry. Linear, rather than bent, coordination of a terminal monodentate dialkyl or (alkyl)(aryl)ketone ligand is unusual, particularly in compounds where a significant degree of d-orbital metal–ligand covalency might be expected (Fig. 2). The five previous examples with Fe—O═CR2 > 170° (Fig. 2) in d-block chemistry involve d0 ZrIV (Sun et al., 1997\) or d10 CuI (Munakata et al., 1994\) and HgII (Lee et al., 2001\) metal ions, or weak apical or axial interactions to tetragonal copper(II) centres (Scott & Holm, 1994\; Akitsu & Einaga, 2004\). Of particular relevance is trans-[RhCl2(Phebox)(OC{CH3}2)] (HPhebox = 1,3-bis{4-methyloxazolin-2-yl}benzene), which is isoelectronic with and stereochemically similar to (I) but contains a bent acetone ligand with Rh—O═C = 137 (1)° (Motoyama et al., 2001\).

The linear Fe1—O16—C17 angle in (I) is probably sterically imposed by the surrounding tert-butyl groups, since atom O16 is in close contact with one H atom from each of the methyl groups C12 and C13, with C12···O16 = 3.528 (3) Å and C13···O16 = 3.362 (3) Å. For comparison, the sum of the van der Waals radii of an O atom and a methyl group is 3.4 Å (Pauling, 1960\). This steric influence is also probably why the bond Fe1—N7 is 0.07–0.10 Å longer than we have previously observed in high-spin complexes of 2,6-di(pyrazolyl)pyridines with regular six-coordinate structures (Halcrow, 2005\, and references therein). In contrast, the Fe1—O16 bond length of 2.0676 (17) Å is somewhat shorter than in the only other two known high-spin iron(II) acetone complexes, which show Fe—O = 2.113 (2) [Fe—O═CMe2 = 134.91 (18)] and 2.123 (2) [135.9 (2)] (Costes et al., 2002\). Unfortunately, this sample is too small to determine whether a meaningful correlation exists between the Fe—O distance and Fe—O═CR2 angle in these complexes. One more iron(II) acetone complex is known, but it is not strictly comparable with (I) since it contains an intermediate-spin iron centre (Hamon et al., 1994\).

The water ligand O15 hydrogen bonds to one F atom of the disordered BF4- anion in the asymmetric unit of (I), through H15A, and to the acetone solvent molecule through H15B (Fig. 1). Therefore, (I) exists as discrete [FeL(OH2)2(OC{CH3}2)][BF4]2·2(CH3)2CO supramolecules, which associate with each other through van der Waals contacts only.

Experimental top

A solution of L (0.25 g, 7.7 × 10 -4 mol) (Jameson & Goldsby, 1990\) and Fe[BF4]2·6H2O (0.13 g, 3.9 × 10 -4 mol) in acetone (30 ml) was stirred at room temperature in air, until all the solid had dissolved. The colourless solution was concentrated in vacuo to ca 5 ml and filtered. Slow diffusion of diethyl ether vapour into the solution yielded colourless crystals of (I) (yield 0.19 g, 64%). The crystals decompose to a very pale-green powder following exposure to air for a period of minutes. Analysis of the dried material implied that all the acetone solvent had been lost, and about half of the coordinated acetone in the solid had been replaced with water from atmospheric moisture. The stoichiometry of acetone in the final product was confirmed by IR analysis and by the acetone methyl 1H NMR peak listed below, which only integrates to ca 3.5H relative to the other peaks in the spectrum [the complex molecule in crystalline (I) would give an acetone peak integrating to 6H]. Analysis found: C 38.7, H 5.1, N 10.9%; calculated for [Fe(C19H25N5)(H2O)2.5(C3H6O)0.5](BF4)2: C 39.3, H 5.3, N 11.2%. IR (nujol): 3425 br (ν O—H), 1692 m (ν C═O), 1642 br (δ H—O—H), 1070 vs (ν B—F) cm-1. 1H NMR (250.1 MHz, CD3NO2, 293 K, p.p.m.): δ 69.0, 65.0, 31.9 (all 2H, py H3/5 + pz H4 and H5), 2.0 [3.5H, (CH3)2CO], -0.2 [18H, C(CH3)3], -2.9 (1H, py H4).

Refinement top

The high value of Rint is not a consequence of weak high-angle diffraction, since this parameter does not decrease significantly if only low-angle data are merged. Rather, it may be a consequence of the absorption correction applied, or it may simply reflect the high redundancy in the data collection (ca nine reflections collected for every one unique).

The structure was originally solved and refined in the triclinic space group P1, with the complex dication lying on a general crystallographic position (i.e. Z = 2). However, a check for higher symmetry following this initial refinement using the ADDSYM routine in PLATON (Spek, 2003\) suggested that the higher-symmetry space group C2/c might be more appropriate. The data were transformed into C2/c and the structure was then re-solved and refined, leading to the final model described here.

The asymmetric unit contains half a complex dication, lying on the crystallographic C2 axis [0, y, 1/4], which passes through atoms Fe1, N2, C5, H5, O16 and C17, and one BF4- anion and an acetone solvent molecule lying on general positions. The BF4- ion B19/F20–F23 is disordered over two orientations, labelled `A' (refined occupancy 0.65) and `B' (0.35). All B—F bonds were restrained to 1.38 (s.u.?) Å during refinement, and all F···F distances within a given disorder orientation to 2.25 (2) Å. All non-H atoms except for the minor anion disorder site were refined anisotropically. All C-bound H atoms were placed in calculated positions and refined using a riding model with the methyl group torsion angles allowed to refine freely. The fixed bond distances and isotropic dispalcement parameters for the H-atom refinements were C—H(aryl) = 0.95 Å and Uiso(H) = 1.2Ueq(C) (for aryl atoms), and C—H = 0.98 Å and Uiso(H) = 1.5Ueq(C) (for methyl atoms). The water H atoms H15A and H15B were located in a difference map, and allowed to refine freely with a common Uiso parameter, which refined to 0.063 (6) Å2. The refined O15—H distances are 0.79 (3) and 0.80 (3) Å, while the H15A—O15—H15B angle is 105 (3)°.

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, 1997\); 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] Fig. 1. The molecular structure of the [FeL(OH2)2(OC{CH3}2)][BF4]2·2(CH3)2CO moiety in (I), showing the atom-numbering scheme employed. All C-bound H atoms, and the minor anion disorder orientation B19B/F20B–F23B, have been omitted for clarity. Displacement ellipsoids are shown at the 50% probability level, except for H atoms, which have arbitrary radii. [Symmetry code: (i) -x, y, -z + 1/2.]
[Figure 2] Fig. 2. The distribution of M—O═CR2 angles in d- and f-block metal complexes of acetone, and other monodentate dialkyl and alkyl–aryl ketones, in the Cambridge Crystallographic Database (Allen, 2002\) in July 2006.
[Figure 3] Fig. 3. An alternative view of the complex dication in (I), showing the close approach of the tert-butyl methyl groups to the coordinated acetone ligand. Displacement ellipsoids are at the 50% probability level, except for H atoms, which have arbitrary radii. The view is approximately parallel to the O15—Fe1—O15i vector, with Fe1 and O15 hidden behind O15i. [Symmetry code: (i) -x, y, -z + 1/2.]
diaqua(diethyl ether)[2,6-bis(3-tert-butylpyrazol-1-yl)pyridine]iron(II) bis(tetrafluoroborate) diethyl ether disolvate top
Crystal data top
[Fe(C19H25N5)(C3H6O)(H2O)2](BF4)2·2C3H6OF(000) = 1592
Mr = 763.18Dx = 1.382 Mg m−3
MonoclinicC2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 36356 reflections
a = 24.4575 (4) Åθ = 2.8–27.5°
b = 12.7827 (1) ŵ = 0.49 mm−1
c = 14.5598 (4) ÅT = 150 K
β = 126.323 (1)°Rectangular prism, colourless
V = 3667.40 (12) Å30.46 × 0.33 × 0.26 mm
Z = 4
Data collection top
Nonius KappaCCD area-detector
diffractometer		4190 independent reflections
Radiation source: fine-focus sealed tube3718 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.131
Detector resolution: 9.091 pixels mm-1θmax = 27.5°, θmin = 2.8°
ω and φ scansh = −31→31
Absorption correction: multi-scan
Using multiple and symmetry-related data measurements via the program SORTAV See R.H. Blessing (1995), Acta Cryst. A51, 33-38		k = −16→16
Tmin = 0.745, Tmax = 0.981l = −18→18
36356 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.046H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.125 w = 1/[σ2(Fo2) + (0.062P)2 + 2.6971P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max < 0.001
4190 reflectionsΔρmax = 0.45 e Å−3
259 parametersΔρmin = −0.68 e Å−3
20 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0057 (7)
Crystal data top
[Fe(C19H25N5)(C3H6O)(H2O)2](BF4)2·2C3H6OV = 3667.40 (12) Å3
Mr = 763.18Z = 4
MonoclinicC2/cMo Kα radiation
a = 24.4575 (4) ŵ = 0.49 mm−1
b = 12.7827 (1) ÅT = 150 K
c = 14.5598 (4) Å0.46 × 0.33 × 0.26 mm
β = 126.323 (1)°
Data collection top
Nonius KappaCCD area-detector
diffractometer		4190 independent reflections
Absorption correction: multi-scan
Using multiple and symmetry-related data measurements via the program SORTAV See R.H. Blessing (1995), Acta Cryst. A51, 33-38		3718 reflections with I > 2σ(I)
Tmin = 0.745, Tmax = 0.981Rint = 0.131
36356 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.04620 restraints
wR(F2) = 0.125H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.45 e Å−3
4190 reflectionsΔρmin = −0.68 e Å−3
259 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

The high value of Rint reflects the very high redundancy in the data collection (ca 9 reflections collected for every 1 unique).

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. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

The structure was originally solved and refined in the triclinic space group P-1, with the complex dication lying on a general crystallographic position (i.e Z = 2). However, a check for higher symmetry following this initial refinement using the ADSYMM routine in PLATON (Spek, 2003) suggested that the higher symmetry space group C2/c might be more appropriate. The data were transformed into C2/c and the structure was then re-solved and refined, leading to the final model described here.

The asymmetric unit contains half a complex dication, lying on the crystallographic C2 axis [0, y, 1/4], which passes through Fe1, N2, C5, H5, O16 and C17, and one BF4- anion and acetone solvent molecule lying on general positions. The BF4- ion is disordered over two orientations, labelled 'A' (refined occupancy 0.65) and 'B' (0.35). All B—F bonds were restrained to 1.38 Å during refinement, and all F···F distances within a given disorder orientation to 2.25 (2) Å. All non-H atoms except for the minor anion disorder site were refined anisotropically. All C-bound H atoms were placed in calculated positions and refined using a riding model with the methyl group torsions allowed to refine freely. The water H atoms were located in the difference map, and allowed to refine freely with a common Ueq thermal parameter. The refined O15—H distances are 0.79 (3) and 0.80 (3) Å, while the H15A—O15—H15B angle is 105 (3)°.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Fe10.00000.30658 (2)0.25000.02901 (14)
N20.00000.47179 (15)0.25000.0323 (4)
C30.02961 (9)0.52457 (13)0.21176 (14)0.0346 (4)
C40.03140 (10)0.63327 (14)0.20994 (17)0.0431 (4)
H40.05310.66950.18260.052*
C50.00000.68583 (19)0.25000.0467 (7)
H50.00000.76010.25000.056*
N60.05990 (8)0.46157 (11)0.17439 (13)0.0355 (3)
N70.06095 (7)0.35412 (11)0.18478 (12)0.0326 (3)
C80.09541 (9)0.31925 (14)0.14600 (15)0.0340 (4)
C90.11584 (11)0.40403 (16)0.11037 (18)0.0455 (5)
H90.14060.40020.07910.055*
C100.09313 (11)0.49174 (15)0.12972 (18)0.0449 (5)
H100.09920.56150.11490.054*
C110.10866 (9)0.20394 (14)0.14358 (16)0.0363 (4)
C120.14913 (10)0.15894 (16)0.26494 (17)0.0437 (4)
H12A0.19430.19110.31150.066*
H12B0.15380.08310.26210.066*
H12C0.12520.17390.29860.066*
C130.04054 (9)0.14670 (15)0.06605 (16)0.0403 (4)
H13A0.01360.15680.09520.060*
H13B0.04880.07180.06490.060*
H13C0.01570.1749−0.01150.060*
C140.14970 (11)0.18863 (17)0.0962 (2)0.0484 (5)
H14A0.12460.21810.01910.073*
H14B0.15720.11380.09330.073*
H14C0.19350.22420.14560.073*
O150.08949 (7)0.30274 (11)0.41547 (12)0.0420 (3)
H15A0.1007 (14)0.267 (2)0.469 (3)0.063 (6)*
H15B0.1146 (15)0.351 (2)0.441 (2)0.063 (6)*
O160.00000.14483 (13)0.25000.0447 (5)
C170.00000.04961 (18)0.25000.0322 (5)
C180.05461 (11)−0.01097 (17)0.34977 (16)0.0470 (5)
H18A0.0818−0.04690.33020.071*
H18B0.0344−0.06270.37120.071*
H18C0.08370.03660.41390.071*
B19A0.1530 (4)0.1692 (5)0.6886 (5)0.0332 (14)0.65
F20A0.16075 (12)0.27801 (15)0.6986 (2)0.0612 (6)0.65
F21A0.12620 (10)0.14616 (16)0.57387 (14)0.0493 (4)0.65
F22A0.21371 (10)0.1205 (2)0.76035 (19)0.0547 (6)0.65
F23A0.1030 (2)0.1382 (4)0.7047 (4)0.0624 (9)0.65
B19B0.1408 (6)0.1662 (10)0.6793 (11)0.037 (4)*0.35
F20B0.1244 (2)0.2604 (3)0.6267 (4)0.0604 (10)*0.35
F21B0.1284 (2)0.0865 (4)0.6080 (4)0.0618 (10)*0.35
F22B0.2102 (4)0.1638 (5)0.7691 (6)0.086 (2)*0.35
F23B0.1117 (4)0.1530 (7)0.7312 (6)0.056 (2)*0.35
O240.16066 (8)0.47987 (12)0.46096 (14)0.0504 (4)
C250.20620 (10)0.50368 (16)0.45374 (16)0.0423 (4)
C260.24263 (12)0.4236 (2)0.4346 (2)0.0601 (6)
H26A0.22320.35440.42740.090*
H26B0.29080.42350.49920.090*
H26C0.23790.44000.36440.090*
C270.22717 (14)0.61492 (19)0.4639 (2)0.0624 (6)
H27A0.19760.65960.47170.094*
H27B0.22350.63520.39550.094*
H27C0.27430.62310.53120.094*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Fe10.0367 (2)0.0227 (2)0.0289 (2)0.0000.02004 (16)0.000
N20.0415 (10)0.0238 (9)0.0314 (10)0.0000.0215 (9)0.000
C30.0431 (9)0.0262 (8)0.0324 (8)−0.0010 (7)0.0212 (7)0.0009 (6)
C40.0562 (11)0.0278 (8)0.0461 (10)−0.0026 (8)0.0308 (9)0.0034 (7)
C50.0636 (18)0.0226 (11)0.0525 (16)0.0000.0337 (15)0.000
N60.0468 (8)0.0280 (7)0.0361 (7)−0.0025 (6)0.0270 (7)0.0023 (6)
N70.0411 (7)0.0264 (7)0.0319 (7)−0.0021 (6)0.0225 (6)−0.0003 (5)
C80.0364 (8)0.0374 (9)0.0304 (8)−0.0050 (7)0.0209 (7)−0.0047 (6)
C90.0569 (11)0.0441 (10)0.0511 (11)−0.0087 (9)0.0406 (10)−0.0041 (8)
C100.0585 (11)0.0381 (10)0.0490 (11)−0.0066 (8)0.0378 (10)0.0039 (8)
C110.0371 (9)0.0365 (9)0.0379 (9)−0.0057 (7)0.0237 (8)−0.0091 (7)
C120.0444 (10)0.0385 (10)0.0423 (10)0.0034 (8)0.0225 (8)−0.0035 (8)
C130.0417 (9)0.0408 (10)0.0417 (10)−0.0085 (8)0.0265 (8)−0.0108 (8)
C140.0488 (11)0.0503 (12)0.0591 (13)−0.0105 (9)0.0392 (10)−0.0180 (9)
O150.0429 (7)0.0415 (8)0.0318 (7)−0.0085 (6)0.0168 (6)0.0014 (5)
O160.0665 (12)0.0229 (8)0.0677 (13)0.0000.0523 (11)0.000
C170.0425 (12)0.0274 (11)0.0337 (11)0.0000.0264 (10)0.000
C180.0538 (11)0.0454 (11)0.0348 (9)0.0091 (9)0.0223 (9)0.0031 (8)
B19A0.026 (2)0.037 (2)0.023 (2)0.0050 (17)0.0072 (17)0.0005 (12)
F20A0.0697 (13)0.0347 (10)0.0724 (15)−0.0012 (9)0.0383 (12)−0.0085 (9)
F21A0.0558 (11)0.0558 (11)0.0305 (8)0.0039 (9)0.0224 (8)−0.0028 (8)
F22A0.0386 (10)0.0605 (14)0.0410 (10)0.0170 (10)0.0103 (8)0.0088 (10)
F23A0.0652 (18)0.073 (2)0.0506 (19)−0.0043 (15)0.0353 (17)0.0109 (18)
O240.0524 (8)0.0494 (8)0.0563 (9)−0.0147 (6)0.0360 (7)−0.0127 (7)
C250.0435 (9)0.0481 (11)0.0322 (9)−0.0088 (8)0.0208 (8)−0.0073 (7)
C260.0542 (12)0.0686 (15)0.0563 (13)0.0015 (11)0.0320 (11)−0.0099 (11)
C270.0763 (16)0.0543 (13)0.0762 (16)−0.0187 (12)0.0559 (14)−0.0118 (12)
Geometric parameters (Å, º) top
Fe1—N22.112 (2)C14—H14A0.9800
Fe1—N72.2739 (15)C14—H14B0.9800
Fe1—O152.0857 (14)C14—H14C0.9800
Fe1—O162.0676 (17)O15—H15A0.80 (3)
N2—C31.329 (2)O15—H15B0.79 (3)
C3—C41.391 (2)O16—C171.217 (3)
C3—N61.404 (2)C17—C181.482 (2)
C4—C51.383 (2)C18—H18A0.9800
C4—H40.9500C18—H18B0.9800
C5—H50.9500C18—H18C0.9800
N6—C101.363 (2)B19A—F22A1.358 (6)
N6—N71.3803 (19)B19A—F20A1.400 (6)
N7—C81.338 (2)B19A—F21A1.418 (6)
C8—C91.414 (3)B19A—F23A1.431 (8)
C8—C111.514 (2)B19B—F23B1.322 (14)
C9—C101.353 (3)B19B—F21B1.355 (13)
C9—H90.9500B19B—F20B1.355 (13)
C10—H100.9500B19B—F22B1.400 (12)
C11—C141.531 (3)O24—C251.218 (2)
C11—C131.535 (2)C25—C261.488 (3)
C11—C121.536 (3)C25—C271.489 (3)
C12—H12A0.9800C26—H26A0.9800
C12—H12B0.9800C26—H26B0.9800
C12—H12C0.9800C26—H26C0.9800
C13—H13A0.9800C27—H27A0.9800
C13—H13B0.9800C27—H27B0.9800
C13—H13C0.9800C27—H27C0.9800
N2—Fe1—N774.50 (4)C11—C13—H13C109.5
N2—Fe1—O1591.35 (4)H13A—C13—H13C109.5
N2—Fe1—O16180H13B—C13—H13C109.5
N7—Fe1—N7i149.00 (7)C11—C14—H14A109.5
N7—Fe1—O1589.41 (6)C11—C14—H14B109.5
N7—Fe1—O15i91.31 (6)H14A—C14—H14B109.5
N7—Fe1—O16105.50 (4)C11—C14—H14C109.5
O15—Fe1—O15i177.30 (8)H14A—C14—H14C109.5
O15—Fe1—O1688.65 (4)H14B—C14—H14C109.5
C3i—N2—C3119.0 (2)Fe1—O15—H15A131 (2)
C3—N2—Fe1120.50 (10)Fe1—O15—H15B121 (2)
N2—C3—C4123.10 (18)H15A—O15—H15B105 (3)
N2—C3—N6114.49 (15)C17—O16—Fe1180
C4—C3—N6122.40 (17)O16—C17—C18121.51 (12)
C5—C4—C3116.47 (19)C18i—C17—C18117.0 (2)
C5—C4—H4121.8C17—C18—H18A109.5
C3—C4—H4121.8C17—C18—H18B109.5
C4—C5—C4i121.9 (2)H18A—C18—H18B109.5
C4—C5—H5119.1C17—C18—H18C109.5
C10—N6—N7110.86 (15)H18A—C18—H18C109.5
C10—N6—C3128.55 (16)H18B—C18—H18C109.5
N7—N6—C3120.54 (14)F22A—B19A—F20A110.9 (5)
C8—N7—N6105.11 (14)F22A—B19A—F21A110.1 (4)
C8—N7—Fe1145.04 (12)F20A—B19A—F21A105.6 (4)
N6—N7—Fe1109.72 (10)F22A—B19A—F23A113.5 (5)
N7—C8—C9110.31 (16)F20A—B19A—F23A109.5 (5)
N7—C8—C11122.06 (16)F21A—B19A—F23A107.0 (5)
C9—C8—C11127.62 (17)F23B—B19B—F21B113.0 (10)
C10—C9—C8106.30 (17)F23B—B19B—F20B110.9 (10)
C10—C9—H9126.8F21B—B19B—F20B112.3 (10)
C8—C9—H9126.8F23B—B19B—F22B103.3 (10)
C9—C10—N6107.41 (17)F21B—B19B—F22B107.3 (9)
C9—C10—H10126.3F20B—B19B—F22B109.7 (9)
N6—C10—H10126.3O24—C25—C26121.6 (2)
C8—C11—C14109.96 (16)O24—C25—C27120.6 (2)
C8—C11—C13109.10 (15)C26—C25—C27117.8 (2)
C14—C11—C13108.86 (15)C25—C26—H26A109.5
C8—C11—C12109.79 (15)C25—C26—H26B109.5
C14—C11—C12108.84 (17)H26A—C26—H26B109.5
C13—C11—C12110.28 (16)C25—C26—H26C109.5
C11—C12—H12A109.5H26A—C26—H26C109.5
C11—C12—H12B109.5H26B—C26—H26C109.5
H12A—C12—H12B109.5C25—C27—H27A109.5
C11—C12—H12C109.5C25—C27—H27B109.5
H12A—C12—H12C109.5H27A—C27—H27B109.5
H12B—C12—H12C109.5C25—C27—H27C109.5
C11—C13—H13A109.5H27A—C27—H27C109.5
C11—C13—H13B109.5H27B—C27—H27C109.5
H13A—C13—H13B109.5
Symmetry code: (i) −x, y, −z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O15—H15A···F21A0.80 (3)1.99 (3)2.771 (3)164 (3)
O15—H15A···F20B0.80 (3)2.01 (3)2.715 (5)147 (3)
O15—H15B···O240.79 (3)1.92 (3)2.689 (2)165 (3)

Experimental details

Crystal data
Chemical formula[Fe(C19H25N5)(C3H6O)(H2O)2](BF4)2·2C3H6O
Mr763.18
Crystal system, space groupMonoclinicC2/c
Temperature (K)150
a, b, c (Å)24.4575 (4), 12.7827 (1), 14.5598 (4)
β (°) 126.323 (1)
V (Å3)3667.40 (12)
Z4
Radiation typeMo Kα
µ (mm−1)0.49
Crystal size (mm)0.46 × 0.33 × 0.26
Data collection
DiffractometerNonius KappaCCD area-detector
diffractometer
Absorption correctionMulti-scan
Using multiple and symmetry-related data measurements via the program SORTAV See R.H. Blessing (1995), Acta Cryst. A51, 33-38
Tmin, Tmax0.745, 0.981
No. of measured, independent and
observed [I > 2σ(I)] reflections		36356, 4190, 3718
Rint0.131
(sin θ/λ)max (Å−1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.125, 1.04
No. of reflections4190
No. of parameters259
No. of restraints20
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.45, −0.68

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

Selected geometric parameters (Å, º) top
Fe1—N22.112 (2)Fe1—O152.0857 (14)
Fe1—N72.2739 (15)Fe1—O162.0676 (17)
N2—Fe1—N774.50 (4)N7—Fe1—O15i91.31 (6)
N2—Fe1—O1591.35 (4)N7—Fe1—O16105.50 (4)
N2—Fe1—O16180O15—Fe1—O15i177.30 (8)
N7—Fe1—N7i149.00 (7)O15—Fe1—O1688.65 (4)
N7—Fe1—O1589.41 (6)
Symmetry code: (i) −x, y, −z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O15—H15A···F21A0.80 (3)1.99 (3)2.771 (3)164 (3)
O15—H15A···F20B0.80 (3)2.01 (3)2.715 (5)147 (3)
O15—H15B···O240.79 (3)1.92 (3)2.689 (2)165 (3)
 

Acknowledgements

The authors acknowledge the EPSRC and the University of Leeds for funding.

References

First citationAkitsu, T. & Einaga, Y. (2004). Acta Cryst. C60, m162–m164.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
 First citationAllen, F. H. (2002). Acta Cryst. B58, 380–388.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
 First citationBlessing, R. H. (1995). Acta Cryst. A51, 33–38.  CrossRef CAS Web of Science IUCr Journals Google Scholar
 First citationCostes, J.-P., Clemente-Juan, J. M., Dahan, F., Dumestre, F. & Tuchagues, J.-P. (2002). Inorg. Chem. 41, 2886–2891.  Web of Science CSD CrossRef PubMed CAS Google Scholar
 First citationElhaïk, J., Evans, D. J., Kilner, C. A. & Halcrow, M. A. (2005). Dalton Trans. pp. 1693–1700.  Google Scholar
 First citationElhaïk, J., Kilner, C. A. & Halcrow, M. A. (2006). Dalton Trans. pp. 823–830.  Google Scholar
 First citationHalcrow, M. A. (2005). Coord. Chem. Rev. 249, 2880–2908.  Web of Science CSD CrossRef CAS Google Scholar
 First citationHamon, P., Toupet, L., Hamon, J. R. & Lapinte, C. (1994). J. Chem. Soc. Chem. Commun. pp. 931–932.  CrossRef Google Scholar
 First citationHolland, 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.  Web of Science CSD CrossRef Google Scholar
 First citationJameson, D. L. & Goldsby, K. A. (1990). J. Org. Chem. 55, 4992–4994.  CrossRef CAS Web of Science Google Scholar
 First citationKilner, C. A. & Halcrow, M. A. (2006). Polyhedron, 25, 235–240.  Web of Science CSD CrossRef CAS Google Scholar
 First citationLee, H., Knobler, C. B. & Hawthorne, M. F. (2001). J. Am. Chem. Soc. 123, 8543–8549.  Web of Science CSD CrossRef PubMed CAS Google Scholar
 First citationMcArdle, P. (1995). J. Appl. Cryst. 28, 65.  CrossRef IUCr Journals Google Scholar
 First citationMotoyama, Y., Okano, M., Narusawa, H., Makihara, N., Aoki, K. & Nishiyama, H. (2001). Organometallics, 20, 1580–1591.  Web of Science CSD CrossRef CAS Google Scholar
 First citationMunakata, M., Kuroda-Sowa, T., Maekawa, M., Nakamura, M., Akiyama, S. & Kitagawa, S. (1994). Inorg. Chem. 33, 1284–1291.  CSD CrossRef CAS Web of Science Google Scholar
 First citationNonius (1999). COLLECT. Nonius BV, Delft, The Netherlands.  Google Scholar
 First citationOtwinowski, 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.  Google Scholar
 First citationPauling, L. (1960). The Nature of the Chemical Bond, 3rd ed., pp. 257–264. Ithaca, New York: Cornell University Press.  Google Scholar
 First citationScott, M. J. & Holm, R. H. (1994). J. Am. Chem. Soc. 116, 11357–11367.  CSD CrossRef CAS Web of Science Google Scholar
 First citationSheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.  Google Scholar
 First citationSolanki, N. K., McInnes, E. J. L., Collison, D., Kilner, C. A., Davies, J. E. & Halcrow, M. A. (2002). J. Chem. Soc. Dalton Trans. pp. 1625–1630.  Web of Science CSD CrossRef Google Scholar
 First citationSpek, A. L. (2003). J. Appl. Cryst. 36, 7–13.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationSun, Y., Piers, W. E. & Yap, G. P. A. (1997). Organometallics, 16, 2509–2513.  CSD CrossRef CAS Web of Science Google Scholar

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CHEMISTRY
ISSN: 2053-2296
Volume 62| Part 9| September 2006| Pages m437-m439
doi:10.1107/S0108270106028903
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