cyclo-Tetra-μ-fluorido-1:2κ2F;2:3κ2F;3:4κ2F;1:4κ2F-octa­nitrato-1κ8O,O′;3κ8O,O′-tetra­kis­(1,10-phenanthroline)-2κ4N,N′;4κ4N,N′-2,4-dichromium(III)-1,3-dineodymium(III) methanol tetra­solvate monohydrate

Birk, T.; Schau-Magnussen, M.; Weyhermüller, T.; Bendix, J.

doi:10.1107/S1600536811042383

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 67| Part 11| November 2011| Pages m1561-m1562

doi:10.1107/S1600536811042383

Open

access

cyclo-Tetra-μ-fluorido-1:2κ²F;2:3κ²F;3:4κ²F;1:4κ²F-octanitrato-1κ⁸O,O′;3κ⁸O,O′-tetrakis(1,10-phenanthroline)-2κ⁴N,N′;4κ⁴N,N′-2,4-dichromium(III)-1,3-dineodymium(III) methanol tetrasolvate monohydrate

Torben Birk,^a Magnus Schau-Magnussen,^a Thomas Weyhermüller ^b and Jesper Bendix ^a ^*

^aDepartment of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark, and ^bMPI für Bioanorganische Chemie, Stiftstrasse 34–36, PO Box 101365, D-45413 Mülheim an der Ruhr, Germany
^*Correspondence e-mail: bendix@kiku.dk

(Received 30 September 2011; accepted 13 October 2011; online 22 October 2011)

In the title compound, [Cr₂Nd₂F₄(NO₂)₈(C₁₂H₈N₂)₄]·4CH₃OH·H₂O, two cis-difluoridobis(1,10-phenanthroline)chromium(III) fragments containing octahedrally coordinated chromium(III) bridge via fluoride ions to two tetranitratoneodymate(III) fragments, forming an uncharged tetranuclear square-like core. The fluoride bridges are fairly linear, with Cr—F—Nd angles of 168.74 (8)°. Cr—F bond lengths are 1.8815 (15) Å, slightly elongated compared to those of the parent chromium(III) complex, which has bond lengths ranging from 1.8444 (10) to 1.8621 (10) Å. The tetranuclear complex is centered at a fourfold rotoinversion axis, with the Cr and Nd atoms situated on two perpendicular twofold rotation axes. The uncoordinated water molecule resides on a fourfold rotation axis. The four methanol solvent molecules are located around this axis, forming a cyclic hydrogen-bonded arrangement. The title compound is the first structurally characterized example of unsupported fluoride bridges between lanthanide and transition metal ions.

Related literature

For related structures of second sphere interactions with robust chromium(III) fluoride complexes, see: Birk et al. (2010 ); Terasaki et al. (1999 ); Kaizaki & Takemoto (1990 ). For other examples of fluoride bridges between 3d and 4f metal atoms, see: Pevec et al. (2003 ); McRobbie et al. (2011 ). For the structure of the cationic chromium precursor complex, see: Birk et al. (2008 ). For the synthesis of the precursor, see: Glerup et al. (1970 ). For importance of the title compound in the context of magnetic materials, see: Kahn (1985 , 1987 ); Sessoli & Powell (2009 ). For crystallographic background, see: Coppens (1970 ).

Experimental

Crystal data

[Cr₂Nd₂F₄(NO₂)₈(C₁₂H₈N₂)₄]·4CH₄O·H₂O
M_r = 1831.56
Tetragonal, P 4/n c c
a = 17.632 (4) Å
c = 20.955 (3) Å
V = 6515 (2) Å³
Z = 4
Mo Kα radiation
μ = 2.01 mm⁻¹
T = 122 K
0.35 × 0.29 × 0.24 mm

Data collection

Nonius KappaCCD area-detector diffractometer
Absorption correction: integration (Gaussian; Coppens, 1970) T_min = 0.601, T_max = 0.718
339826 measured reflections
10126 independent reflections
6979 reflections with I > 2σ(I)
R_int = 0.047

Refinement

R[F² > 2σ(F²)] = 0.036
wR(F²) = 0.102
S = 1.27
10126 reflections
239 parameters
H-atom parameters constrained
Δρ_max = 2.41 e Å⁻³
Δρ_min = −1.78 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O20—H20⋯O20ⁱ	0.84	1.89	2.700 (4)	161
Symmetry code: (i) $[y, -x+{\script{1\over 2}}, z]$ .

Data collection: COLLECT (Nonius, 1999 ); cell refinement: COLLECT; data reduction: EVALCCD (Duisenberg et al., 2003 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997 ) and Mercury (Macrae et al., 2006 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811042383/wm2538sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811042383/wm2538Isup2.hkl

checkCIF report

Comment top

The magnetic properties of polynuclear, mixed lanthanoide transition metal complexes have received much attention (Sessoli & Powell, 2009). Since early suggestions by Kahn (1985, 1987) that exchange interactions involving d- and f-electrons were likely to lead to ferromagnetic coupling, due to vanishing orbital overlaps, many such systems have been synthesized and studied structurally and magnetically. Despite the high activity in this field, there are still simple types of bridging ligands, which have not been studied in this context. Thus, fluoride, which is known to bind strongly to lanthanoides has not been known as a bridging ligand between paramagnetic transition metal ions and lanthanoide ions until the very recent introduction of fluoride in heterometallic wheels by McRobbie et al. (2011). However, in those systems, fluoride bridges are always supported by carboxylate groups connecting the same metal ions. Based on those systems it is very difficult or impossible to make deductions concerning the geometric preferences of fluoride as a bridging ion and concerning magnetic exchange over fluoride bridges. This problem is remedied by a system such as the title compound, which is the first example of unsupported fluoride bridges between 3d and 4f metals.

In the title compound the solvate water molecule is located on a proper fourfold axis, whereas the tetranuclear Cr₂Nd₂F₄ fragment is centered on a fourfold rotoinversion axes. Consequently, all the metal ions are required to lie in the same plane perpendicular to the tetragonal axes (Fig. 1). The complexation of the neodymium atom induces a slight elongation of the Cr—F bonds by ca 0.03 Å in comparison with the parent compound (Birk et al., 2008). The neodymium atom is 10-coordinated with its coordination sphere completed by bidentate nitrate ions coordinating with unexceptional bond lengths and bite angles. The uncoordinated water molecule is located on a fourfold axis and has no direct partner for hydrogen bonding (the next nearest atom is C5 in a distance of 3.816 (3) Å), which explains the high thermal displacement parameters for its oxygen atom. Around the same fourfold axis, the methanol solvate molecules form a cyclic tetrameric arrangement held together by hydrogen bonds (Table 1, Fig. 2).

Studies of the magnetic properties of this system and the possible generalization of this route to fluoride-bridged systems are currently being undertaken.

Related structures of second sphere interactions with robust chromium(III) fluoride complexes were presented by Birk et al. (2010); Terasaki et al. (1999); Kaizaki & Takemoto (1990). For other examples of fluoride bridges between 3d and 4f metal atoms, see: Pevec et al. (2003).

Related literature top

For related structures of second sphere interactions with robust chromium(III) fluoride complexes, see: Birk et al. (2010); Terasaki et al. (1999); Kaizaki & Takemoto (1990). For other examples of fluoride bridges between 3d and 4f metal atoms, see: Pevec et al. (2003); McRobbie et al. (2011). For the structure of the cationic chromium precursor complex, see: Birk et al. (2008). For the synthesis of the precursor, see: Glerup et al. (1970). For importance of the title compound in the context of magnetic materials, see: Kahn (1985, 1987); Sessoli & Powell (2009). For crystallographic background, see: Coppens (1970).

Experimental top

trans-[Cr(py)₄F₂]NO₃ is synthesized by the literature method (Glerup et al., 1970). 1,10-phenantroline (Alfa Aesar), Nd(NO₃)₃^.6H₂O (Alfa Aesar; 99.9%), 2-methoxyethanol (Sigma-Aldrich; 99.3+%) and methanol (Lab-Scan; Anhydroscan) were all used as received. The synthesis of cis-[Cr(phen)₂F₂]NO₃ proceeds in many ways analogous to the method described by Glerup et al. (1970) for the synthesis of cis-[Cr(phen)₂F₂]ClO₄. As a result of a significant difference in solubility of the two salts, some modification with respect to solvent volume and isolation procedure has been introduced. It should also be noted that the nitrate can be crystallized with a variable number of crystal water and that this number can change depending on whether the substance is stored in dry or moist air. Elemental analysis for C, H and N was performed with an CE Instrument: FLASH 1112 series EA, at the microanalytic laboratory, University of Copenhagen. Electrospray (ES) mass spectra were recorded on a Micromass Q-TOF apparatus with positive ion detection.

i) Syntesis of the starting material cis-[Cr(phen)₂F₂]NO₃

trans-[Cr(py)₄F₂]NO₃ + 1,10-phenantroline = cis-[Cr(phen)₂F₂]NO₃ + 4py

trans-[Cr(py)₄F₂]NO₃ (36.7 g; 0.078 mol) and 1,10-phenantroline (34.8 g; 0.19 mol) were placed in a conical flask (500 ml) with 2-methxyethanol (250 ml). The mixture was heated to boiling temperature, whereby a violet solution formed, followed shortly by precipitation of a red-violet solid. The heating was continued for 1 h followed by cooling to room temperature before a purple red product was isolated. The raw product was washed with ethanol (2x100 ml) and dried by suction.

Yield of raw product: 31.7 g (79.0% of theoretical based on Cr^III). Analysis: Calcd. for H₁₇C₂₄N₅O₄F₂Cr₁: H, 3.29%; C, 55.28%; N, 13.43%. Found: H, 3.16%; C, 55.25%; N, 13.30% (sesqui hydrat). TOF MS ES⁺ (MeOH): m/z: 450.5 ([Cr(phen)₂F₂]⁺)

ii) Syntesis of the title compound {[Cr(phen)₂(µ-F)₂][Nd(NO₃)₄]}₂^.CH₃OH^.H₂O

2 cis-[Cr(phen)₂F₂]NO₃ + 2 Nd(NO₃)₃ = {[Cr(phen)₂(µ-F)₂][Nd(NO₃)₄]}₂

The title compound was prepared by reaction of a methanolic solution of cis-[Cr(phen)₂F₂](NO₃) (210 mg, 0.41 mmol in 10 ml) with a methanolic solution of Nd(NO₃)₃^.6H₂O (175 mg, 0.40 mmol in 5 ml). Before combination, both solutions were filtered through filters with pore size 0.45 µm. Crystals formed over a period of 2–12 h. The yield was 284 mg (82% based on Nd). Crystals suitable for single-crystal X-ray diffraction were obtained directly using the concentrations given above. Upon drying, the crystals loose solvent and deteriorate. For the diffraction experiment, a crystal was taken from the mother liquor, covered with paraffin oil and cooled directly.

Computing details top

Data collection: COLLECT (Nonius, 1999); cell refinement: COLLECT (Nonius, 1999); data reduction: EVALCCD (Duisenberg et al., 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. A view of the tetranuclear molecular structure of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. Solvent methanol and water molecules were omitted.
	Fig. 2. A packing diagram in projection along [001] showing hydrogen bonds between the methanol solvent molecules (dotted lines).

cyclo-Tetra-µ-fluorido-1:2κ²F;2:3κ²F; 3:4κ²F;1:4κ²F-octanitrato-1κ⁸O,O'; 3κ⁸O,O'-tetrakis(1,10-phenanthroline)- 2κ⁴N,N';4κ⁴N,N'-2,4-dichromium(III)- 1,3-dineodymium(III) methanol tetrasolvate monohydrate top

Crystal data top

[Cr₂Nd₂F₄(NO₂)₈(C₁₂H₈N₂)₄]·4CH₄O·H₂O	D_x = 1.867 Mg m⁻³
M_r = 1831.56	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4/ncc	Cell parameters from 120466 reflections
Hall symbol: -P 4a 2ac	θ = 2.3–40.1°
a = 17.632 (4) Å	µ = 2.01 mm⁻¹
c = 20.955 (3) Å	T = 122 K
V = 6515 (2) Å³	Prism, pink
Z = 4	0.35 × 0.29 × 0.24 mm
F(000) = 3640

Data collection top

Nonius KappaCCD area-detector diffractometer	10126 independent reflections
Radiation source: fine-focus sealed tube	6979 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.047
ω and ϕ scans	θ_max = 40.1°, θ_min = 2.3°
Absorption correction: integration (Gaussian; Coppens, 1970)	h = −31→31
T_min = 0.601, T_max = 0.718	k = −29→31
339826 measured reflections	l = −37→37

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.102	H-atom parameters constrained
S = 1.27	w = 1/[σ²(F_o²) + (0.0144P)² + 22.4316P] where P = (F_o² + 2F_c²)/3
10126 reflections	(Δ/σ)_max = 0.002
239 parameters	Δρ_max = 2.41 e Å⁻³
0 restraints	Δρ_min = −1.78 e Å⁻³

Crystal data top

[Cr₂Nd₂F₄(NO₂)₈(C₁₂H₈N₂)₄]·4CH₄O·H₂O	Z = 4
M_r = 1831.56	Mo Kα radiation
Tetragonal, P4/ncc	µ = 2.01 mm⁻¹
a = 17.632 (4) Å	T = 122 K
c = 20.955 (3) Å	0.35 × 0.29 × 0.24 mm
V = 6515 (2) Å³

Data collection top

Nonius KappaCCD area-detector diffractometer	10126 independent reflections
Absorption correction: integration (Gaussian; Coppens, 1970)	6979 reflections with I > 2σ(I)
T_min = 0.601, T_max = 0.718	R_int = 0.047
339826 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.036	0 restraints
wR(F²) = 0.102	H-atom parameters constrained
S = 1.27	w = 1/[σ²(F_o²) + (0.0144P)² + 22.4316P] where P = (F_o² + 2F_c²)/3
10126 reflections	Δρ_max = 2.41 e Å⁻³
239 parameters	Δρ_min = −1.78 e Å⁻³

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Nd1	0.120550 (5)	0.879450 (5)	0.2500	0.01191 (3)
Cr1	0.142468 (17)	0.642468 (17)	0.2500	0.01199 (6)
F1	0.14142 (8)	0.74891 (8)	0.24362 (7)	0.0179 (2)
N1	0.14262 (10)	0.52607 (10)	0.24070 (8)	0.0148 (3)
N2	0.13452 (11)	0.63381 (11)	0.15243 (8)	0.0154 (3)
N3	0.05724 (12)	0.80814 (11)	0.36783 (10)	0.0194 (3)
N4	−0.00247 (12)	0.89135 (13)	0.15390 (10)	0.0200 (3)
O1	0.12382 (11)	0.83605 (11)	0.36641 (9)	0.0224 (3)
O2	0.01948 (10)	0.81071 (10)	0.31637 (8)	0.0194 (3)
O3	0.03125 (13)	0.77993 (12)	0.41658 (9)	0.0280 (4)
O4	0.02408 (11)	0.94903 (11)	0.18224 (10)	0.0237 (3)
O5	0.01769 (11)	0.82711 (11)	0.17550 (9)	0.0227 (3)
O6	−0.04596 (12)	0.89763 (14)	0.10853 (9)	0.0297 (4)
C1	0.15642 (14)	0.47330 (13)	0.28428 (11)	0.0186 (3)
H1	0.1678	0.4886	0.3267	0.022*
C2	0.15473 (15)	0.39539 (14)	0.26990 (12)	0.0222 (4)
H2	0.1663	0.3590	0.3019	0.027*
C3	0.13624 (15)	0.37223 (13)	0.20931 (12)	0.0217 (4)
H3	0.1327	0.3197	0.1996	0.026*
C4	0.12255 (14)	0.42689 (13)	0.16182 (11)	0.0193 (4)
C5	0.10393 (16)	0.40922 (15)	0.09673 (12)	0.0248 (4)
H5	0.0975	0.3577	0.0845	0.030*
C6	0.09540 (17)	0.46455 (16)	0.05244 (12)	0.0258 (5)
H6	0.0818	0.4514	0.0100	0.031*
C7	0.10658 (14)	0.54258 (14)	0.06875 (11)	0.0203 (4)
C8	0.10612 (16)	0.60257 (16)	0.02423 (11)	0.0235 (4)
H8	0.0953	0.5929	−0.0194	0.028*
C9	0.12147 (16)	0.67492 (16)	0.04442 (12)	0.0250 (4)
H9	0.1227	0.7154	0.0145	0.030*
C10	0.13538 (15)	0.68919 (14)	0.10924 (11)	0.0206 (4)
H10	0.1457	0.7396	0.1226	0.025*
C11	0.12150 (12)	0.56114 (12)	0.13254 (10)	0.0159 (3)
C12	0.12809 (12)	0.50311 (12)	0.17959 (10)	0.0150 (3)
O20	0.14380 (18)	0.22887 (17)	0.41608 (17)	0.0543 (8)
H20	0.1608	0.2733	0.4185	0.081*
C20	0.07522 (19)	0.22365 (18)	0.45093 (15)	0.0315 (6)
H20A	0.0838	0.2404	0.4949	0.047*
H20B	0.0576	0.1709	0.4510	0.047*
H20C	0.0367	0.2560	0.4310	0.047*
O30	0.2500	0.2500	0.0863 (5)	0.225 (9)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Nd1	0.01150 (4)	0.01150 (4)	0.01274 (5)	0.00073 (4)	−0.00057 (3)	−0.00057 (3)
Cr1	0.01221 (9)	0.01221 (9)	0.01155 (14)	−0.00036 (12)	0.00017 (10)	−0.00017 (10)
F1	0.0179 (5)	0.0122 (5)	0.0237 (6)	0.0010 (4)	0.0006 (5)	−0.0002 (5)
N1	0.0151 (7)	0.0146 (6)	0.0147 (7)	−0.0010 (5)	0.0001 (5)	0.0003 (5)
N2	0.0189 (8)	0.0152 (7)	0.0120 (5)	−0.0002 (5)	0.0008 (6)	0.0010 (5)
N3	0.0232 (9)	0.0175 (8)	0.0176 (7)	0.0015 (6)	0.0030 (6)	−0.0008 (6)
N4	0.0179 (8)	0.0260 (9)	0.0160 (7)	0.0005 (7)	−0.0011 (6)	−0.0001 (6)
O1	0.0222 (8)	0.0268 (8)	0.0181 (7)	−0.0014 (6)	−0.0026 (6)	0.0010 (6)
O2	0.0188 (7)	0.0216 (7)	0.0178 (7)	−0.0028 (6)	0.0004 (5)	0.0008 (6)
O3	0.0395 (11)	0.0260 (9)	0.0183 (7)	−0.0027 (8)	0.0073 (7)	0.0043 (6)
O4	0.0230 (8)	0.0207 (7)	0.0274 (8)	0.0029 (6)	−0.0073 (7)	−0.0023 (6)
O5	0.0242 (8)	0.0210 (8)	0.0229 (8)	−0.0026 (6)	−0.0054 (6)	0.0011 (6)
O6	0.0282 (9)	0.0411 (12)	0.0198 (8)	0.0035 (8)	−0.0104 (7)	0.0011 (8)
C1	0.0219 (9)	0.0178 (8)	0.0161 (8)	0.0003 (7)	0.0010 (7)	0.0025 (7)
C2	0.0267 (11)	0.0171 (9)	0.0229 (9)	0.0001 (8)	0.0008 (8)	0.0056 (8)
C3	0.0255 (10)	0.0157 (8)	0.0238 (9)	−0.0012 (7)	0.0013 (8)	0.0002 (7)
C4	0.0208 (9)	0.0171 (8)	0.0201 (9)	−0.0022 (7)	−0.0002 (7)	−0.0029 (7)
C5	0.0307 (12)	0.0221 (10)	0.0214 (9)	−0.0049 (9)	0.0002 (9)	−0.0072 (8)
C6	0.0333 (13)	0.0273 (11)	0.0167 (9)	−0.0052 (10)	−0.0022 (8)	−0.0059 (8)
C7	0.0228 (10)	0.0236 (10)	0.0144 (8)	−0.0009 (8)	−0.0010 (7)	−0.0028 (7)
C8	0.0281 (11)	0.0293 (12)	0.0131 (7)	0.0006 (8)	−0.0008 (8)	0.0000 (8)
C9	0.0319 (12)	0.0269 (11)	0.0161 (8)	0.0014 (9)	−0.0001 (8)	0.0049 (8)
C10	0.0253 (10)	0.0197 (9)	0.0168 (8)	0.0007 (8)	0.0014 (7)	0.0029 (7)
C11	0.0165 (8)	0.0179 (8)	0.0134 (7)	−0.0003 (6)	0.0013 (6)	−0.0006 (6)
C12	0.0147 (7)	0.0156 (8)	0.0149 (7)	−0.0006 (6)	0.0012 (6)	−0.0008 (6)
O20	0.0445 (16)	0.0375 (14)	0.081 (2)	−0.0003 (12)	0.0101 (16)	−0.0038 (15)
C20	0.0370 (15)	0.0287 (13)	0.0288 (12)	0.0012 (11)	0.0023 (11)	0.0038 (10)
O30	0.317 (15)	0.317 (15)	0.040 (5)	0.000	0.000	0.000

Geometric parameters (Å, º) top

Nd1—F1ⁱ	2.3348 (15)	C1—C2	1.407 (3)
Nd1—F1	2.3348 (15)	C1—H1	0.9500
Nd1—O4	2.5328 (19)	C2—C3	1.373 (4)
Nd1—O4ⁱ	2.5328 (19)	C2—H2	0.9500
Nd1—O1	2.5574 (18)	C3—C4	1.406 (3)
Nd1—O1ⁱ	2.5574 (18)	C3—H3	0.9500
Nd1—O5	2.5648 (19)	C4—C12	1.398 (3)
Nd1—O5ⁱ	2.5648 (19)	C4—C5	1.437 (3)
Nd1—O2	2.5650 (18)	C5—C6	1.355 (4)
Nd1—O2ⁱ	2.5650 (18)	C5—H5	0.9500
Cr1—F1ⁱⁱ	1.8815 (15)	C6—C7	1.431 (4)
Cr1—F1	1.8815 (15)	C6—H6	0.9500
Cr1—N2	2.0551 (17)	C7—C11	1.401 (3)
Cr1—N2ⁱⁱ	2.0551 (17)	C7—C8	1.410 (4)
Cr1—N1	2.0616 (19)	C8—C9	1.371 (4)
Cr1—N1ⁱⁱ	2.0616 (19)	C8—H8	0.9500
N1—C1	1.326 (3)	C9—C10	1.403 (3)
N1—C12	1.367 (3)	C9—H9	0.9500
N2—C10	1.332 (3)	C10—H10	0.9500
N2—C11	1.367 (3)	C11—C12	1.425 (3)
N3—O3	1.225 (3)	O20—C20	1.416 (4)
N3—O2	1.268 (3)	O20—H20	0.8400
N3—O1	1.273 (3)	C20—H20A	0.9800
N4—O6	1.226 (3)	C20—H20B	0.9800
N4—O4	1.267 (3)	C20—H20C	0.9800
N4—O5	1.271 (3)

F1ⁱ—Nd1—F1	72.09 (7)	Cr1—F1—Nd1	168.74 (8)
F1ⁱ—Nd1—O4	140.40 (6)	C1—N1—C12	118.15 (19)
F1—Nd1—O4	123.46 (5)	C1—N1—Cr1	129.31 (15)
F1ⁱ—Nd1—O4ⁱ	123.46 (5)	C12—N1—Cr1	112.52 (14)
F1—Nd1—O4ⁱ	140.40 (6)	C10—N2—C11	118.83 (19)
O4—Nd1—O4ⁱ	70.35 (9)	C10—N2—Cr1	128.39 (16)
F1ⁱ—Nd1—O1	82.88 (5)	C11—N2—Cr1	112.61 (13)
F1—Nd1—O1	75.88 (6)	O3—N3—O2	121.8 (2)
O4—Nd1—O1	134.02 (6)	O3—N3—O1	121.4 (2)
O4ⁱ—Nd1—O1	71.16 (7)	O2—N3—O1	116.77 (19)
F1ⁱ—Nd1—O1ⁱ	75.88 (6)	O6—N4—O4	121.5 (2)
F1—Nd1—O1ⁱ	82.87 (5)	O6—N4—O5	122.1 (2)
O4—Nd1—O1ⁱ	71.16 (7)	O4—N4—O5	116.4 (2)
O4ⁱ—Nd1—O1ⁱ	134.02 (6)	N3—O1—Nd1	96.72 (13)
O1—Nd1—O1ⁱ	153.69 (9)	N3—O2—Nd1	96.50 (13)
F1ⁱ—Nd1—O5	132.47 (6)	N4—O4—Nd1	97.01 (14)
F1—Nd1—O5	73.85 (5)	N4—O5—Nd1	95.39 (13)
O4—Nd1—O5	50.07 (6)	N1—C1—C2	122.3 (2)
O4ⁱ—Nd1—O5	103.91 (6)	N1—C1—H1	118.9
O1—Nd1—O5	119.27 (6)	C2—C1—H1	118.9
O1ⁱ—Nd1—O5	67.84 (6)	C3—C2—C1	119.6 (2)
F1ⁱ—Nd1—O5ⁱ	73.85 (5)	C3—C2—H2	120.2
F1—Nd1—O5ⁱ	132.47 (6)	C1—C2—H2	120.2
O4—Nd1—O5ⁱ	103.91 (6)	C2—C3—C4	119.4 (2)
O4ⁱ—Nd1—O5ⁱ	50.07 (6)	C2—C3—H3	120.3
O1—Nd1—O5ⁱ	67.84 (6)	C4—C3—H3	120.3
O1ⁱ—Nd1—O5ⁱ	119.27 (6)	C12—C4—C3	117.3 (2)
O5—Nd1—O5ⁱ	151.57 (9)	C12—C4—C5	118.5 (2)
F1ⁱ—Nd1—O2	125.40 (5)	C3—C4—C5	124.2 (2)
F1—Nd1—O2	71.02 (5)	C6—C5—C4	121.3 (2)
O4—Nd1—O2	93.81 (6)	C6—C5—H5	119.4
O4ⁱ—Nd1—O2	71.14 (6)	C4—C5—H5	119.4
O1—Nd1—O2	49.98 (6)	C5—C6—C7	120.9 (2)
O1ⁱ—Nd1—O2	135.60 (6)	C5—C6—H6	119.6
O5—Nd1—O2	70.66 (6)	C7—C6—H6	119.6
O5ⁱ—Nd1—O2	104.72 (6)	C11—C7—C8	117.2 (2)
F1ⁱ—Nd1—O2ⁱ	71.02 (5)	C11—C7—C6	118.6 (2)
F1—Nd1—O2ⁱ	125.40 (5)	C8—C7—C6	124.2 (2)
O4—Nd1—O2ⁱ	71.14 (6)	C9—C8—C7	119.5 (2)
O4ⁱ—Nd1—O2ⁱ	93.81 (6)	C9—C8—H8	120.2
O1—Nd1—O2ⁱ	135.60 (6)	C7—C8—H8	120.2
O1ⁱ—Nd1—O2ⁱ	49.98 (6)	C8—C9—C10	120.0 (2)
O5—Nd1—O2ⁱ	104.72 (6)	C8—C9—H9	120.0
O5ⁱ—Nd1—O2ⁱ	70.66 (6)	C10—C9—H9	120.0
O2—Nd1—O2ⁱ	161.92 (8)	N2—C10—C9	121.6 (2)
F1ⁱⁱ—Cr1—F1	91.41 (8)	N2—C10—H10	119.2
F1ⁱⁱ—Cr1—N2	97.93 (7)	C9—C10—H10	119.2
F1—Cr1—N2	90.16 (7)	N2—C11—C7	122.8 (2)
F1ⁱⁱ—Cr1—N2ⁱⁱ	90.16 (7)	N2—C11—C12	116.64 (18)
F1—Cr1—N2ⁱⁱ	97.93 (7)	C7—C11—C12	120.5 (2)
N2—Cr1—N2ⁱⁱ	168.43 (10)	N1—C12—C4	123.2 (2)
F1ⁱⁱ—Cr1—N1	89.75 (7)	N1—C12—C11	116.78 (19)
F1—Cr1—N1	170.49 (6)	C4—C12—C11	120.0 (2)
N2—Cr1—N1	80.33 (7)	C20—O20—H20	109.5
N2ⁱⁱ—Cr1—N1	91.51 (7)	O20—C20—H20A	109.5
F1ⁱⁱ—Cr1—N1ⁱⁱ	170.49 (6)	O20—C20—H20B	109.5
F1—Cr1—N1ⁱⁱ	89.75 (7)	H20A—C20—H20B	109.5
N2—Cr1—N1ⁱⁱ	91.50 (7)	O20—C20—H20C	109.5
N2ⁱⁱ—Cr1—N1ⁱⁱ	80.33 (7)	H20A—C20—H20C	109.5
N1—Cr1—N1ⁱⁱ	90.66 (10)	H20B—C20—H20C	109.5

Symmetry codes: (i) −y+1, −x+1, −z+1/2; (ii) y−1/2, x+1/2, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O20—H20···O20ⁱⁱⁱ	0.84	1.89	2.700 (4)	161

Symmetry code: (iii) y, −x+1/2, z.

Experimental details

Crystal data
Chemical formula	[Cr₂Nd₂F₄(NO₂)₈(C₁₂H₈N₂)₄]·4CH₄O·H₂O
M_r	1831.56
Crystal system, space group	Tetragonal, P4/ncc
Temperature (K)	122
a, c (Å)	17.632 (4), 20.955 (3)
V (Å³)	6515 (2)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	2.01
Crystal size (mm)	0.35 × 0.29 × 0.24

Data collection
Diffractometer	Nonius KappaCCD area-detector diffractometer
Absorption correction	Integration (Gaussian; Coppens, 1970)
T_min, T_max	0.601, 0.718
No. of measured, independent and observed [I > 2σ(I)] reflections	339826, 10126, 6979
R_int	0.047
(sin θ/λ)_max (Å⁻¹)	0.906

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.102, 1.27
No. of reflections	10126
No. of parameters	239
H-atom treatment	H-atom parameters constrained
	w = 1/[σ²(F_o²) + (0.0144P)² + 22.4316P] where P = (F_o² + 2F_c²)/3
Δρ_max, Δρ_min (e Å⁻³)	2.41, −1.78

Computer programs: COLLECT (Nonius, 1999), EVALCCD (Duisenberg et al., 2003), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2006).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O20—H20···O20ⁱ	0.84	1.89	2.700 (4)	160.8

Symmetry code: (i) y, −x+1/2, z.

Acknowledgements

JB thanks the Danish Research Council (FNU) for financial support (grant No. 272–08–0491).

References

Birk, T., Bendix, J. & Weihe, H. (2008). Acta Cryst. E64, m369–m370. Web of Science CSD CrossRef IUCr Journals Google Scholar
Birk, T., Magnussen, M. J., Piligkos, S., Weihe, H., Holten, A. & Bendix, J. (2010). J. Fluorine Chem. 131, 898–906. Web of Science CSD CrossRef CAS Google Scholar
Coppens, P. (1970). Crystallographic Computing, edited by F. R. Ahmed, S. R. Hall & C. P. Huber, pp. 255–270. Copenhagen: Munksgaard. Google Scholar
Duisenberg, A. J. M., Kroon-Batenburg, L. M. J. & Schreurs, A. M. M. (2003). J. Appl. Cryst. 36, 220–229. Web of Science CrossRef CAS IUCr Journals Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Glerup, J., Josephsen, J., Michelsen, K., Pedersen, E. & Schäffer, C. E. (1970). Acta Chem. Scand. 24, 247–254. CrossRef CAS Web of Science Google Scholar
Kahn, O. (1985). Angew. Chem. Int. Ed. 24, 834–850. CrossRef Google Scholar
Kahn, O. (1987). Struct. Bond. 68, 89–167. CrossRef CAS Google Scholar
Kaizaki, S. & Takemoto, H. (1990). Inorg. Chem. 29, 4960–4964. CrossRef CAS Web of Science Google Scholar
Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457. Web of Science CrossRef CAS IUCr Journals Google Scholar
McRobbie, A., Sarwar, A. R., Yeninas, S., Nowell, H., Baker, M. L., Allan, D., Luban, M., Muryn, C. A., Pritchard, R. G., Prozorov, R., Timco, G. A., Tuna, F., Whitehead, G. F. & Winpenny, R. E. (2011). Chem. Commun. 47, 6251–6253. Web of Science CSD CrossRef CAS Google Scholar
Nonius (1999). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
Pevec, A., Mrak, M., Demsar, A., Petricek, S. & Roesky, H. W. (2003). Polyhedron, 22, 575–579. Web of Science CSD CrossRef CAS Google Scholar
Sessoli, R. & Powell, A. K. (2009). Coord. Chem. Rev. 253, 2328–2341. Web of Science CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Terasaki, Y., Fujihara, T., Schönherr, T. & Kaizaki, S. (1999). Inorg. Chim. Acta, 259, 84–90. Web of Science CrossRef Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.