metal-organic compounds
A mixed iron(III)/lithium alkoxide
aWestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, Scotland
*Correspondence e-mail: a.r.kennedy@strath.ac.uk
The heterometallic alkoxide catena-poly[[tetra-μ2-tert-butoxo-1:2κ4O:O;1:3κ4O:O-bis(tetrahydrofuran)-2κO,3κO-iron(III)dilithium(I)]-μ-bromo], [FeLi2Br(C4H9O)4(C4H8O)2]n, forms a one-dimensional chain through an a-glide. This conformation is achieved through the formation of FeIII/O/Li/O rings and Li—Br—Li bridges.
Comment
Currently, our group is investigating the synthetic and structural synergic effects that can be harnessed by mixing an alkali metal and magnesium in the same molecular amide environment [for pertinent recent examples, see Hevia et al. (2005) and Andrikopoulos et al. (2004)]. One possible outcome of this mixed-metal-induced synergy is to generate `inverse crown' ring systems in which Lewis acidic polymetallic cationic host rings surround Lewis basic anionic cores, as recently described for the oxo-centred 2,2,6,6-tetramethylpiperidinide (TMP) inverse crown `ether' [Na2Mg2O(TMP)4] (Kennedy et al., 2003). Germane to the work reported here, another type of inverse crown motif involves a chair-shaped octagonal ring that is face-capped on opposite sides of the chair by, for example, alkoxide ligands, as demonstrated by the mixed lithium–magnesium diisopropylamideoctoxide [{LiMg[N(iPr)2]2nOctO}2] (Drewette et al., 2002). This motif bears a
close similarity to that of the mixed sodium–iron(II) butoxide [{(THF)NaFe(tBuO)3}2] (THF is tetrahydrofuran) reported by Gun'ko et al. (2002), which, in our terminology, could be regarded as an all-alkoxide inverse crown. Wishing to pursue this structural analogy further, we attempted to prepare the lithium congener [{(THF)xLiFe(tBuO)3}2] by carrying out a metathetical reaction between FeBr2 and three molar equivalents of tBuOLi in THF solution. This attempt failed as the metathesis did not go to completion and the iron in the product oxidized to FeIII, presumably as a result of the strong oxidizing nature of alkoxide ligands. The product obtained was the bromide-containing compound [{(THF)2Li2Fe(tBuO)4Br}∞], (I). Such heterometallic alkoxide compounds are of interest as precursors to oxide-based materials (Bradley, 1989; Bradley et al., 2001).The (Fig. 1) consists of a central FeIII atom bonded to four tBuO ligands that bridge two Li atoms. The coordination about atom Fe1 is considerably distorted from tetrahedral geometry [O—Fe1—O = 89.60 (5)–121.60 (5)°; Table 1], the narrowest angles, as expected, being those internal to the Fe/O/Li/O rings. The Fe—O bond lengths span a tight range [1.8616 (11)–1.8687 (11) Å], and are significantly shorter than those that bridge Fe atoms in [(tBuO)2Fe(μ-tBuO)2Fe(tBuO)2] (1.958–1.961 Å; Spandl et al., 2003). This difference presumably reflects greater competition for the O-atom electron density between two Fe atoms as opposed to between an Fe and an Li atom. In (I), the Li—OBu distances [1.958 (3)–1.991 (3) Å] are greater than the Fe—OBu distances. This configuration contrasts with that of one of the few known structures featuring bridging between FeIII and Li atoms. In [(Bu2CHO)2Fe(μ-Bu2CHO)2Li(Bu2CHOH)] (Bochmann et al., 1980), the situation is reversed, with Fe—O bridges of 1.908 and 1.934 Å, and Li—O distances of 1.870 and 1.874 Å; the difference appears to be that lithium is three-coordinate in this complex and four-coordinate in (I). In (I), the bonding at each Li atom is completed by complexation of a THF molecule and of a Br atom, thus forming an Li—Br—Li bridge that extends (I) into a one-dimensional polymer, propagating through an a-glide (Fig. 2).
of (I)Experimental
FeBr2 (1.078 g, 5 mmol) and Li(tBuO) (1.20 g, 15 mmol) were weighed out in a glove-box and transferred to a Schlenk tube filled with dry argon. The tube was placed on a vacuum line and cooled to 273 K in an ice bath. THF (20 ml) was added via syringe and the brown mixture was stirred at room temperature overnight. The next day, the mixture was filtered through Celite to remove LiBr and washed with THF (10 ml). The solution was reduced in volume under vacuum and left to stand overnight. A large crop of crystals formed in the dark-brown solution. The crystals were not single, and so were redissolved by gentle heating and placed in a water bath to cool slowly. Overnight, suitable higher-quality crystals of (I) formed (yield 18.15%). Microanalysis expected: C 49.17, H 8.94%; found: C 48.36, H 8.60%.
Crystal data
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Refinement
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All H atoms were constrained to an idealized geometry using a riding model [for CH3, Uiso(H) = 1.5Ueq(C) and C—H = 0.98 Å; for CH2, Uiso(H) = 1.2Ueq(C) and C—H = 0.99 Å].
Data collection: DENZO (Hooft, 1988) and COLLECT (Otwinowski & Minor, 1997); cell DENZO and COLLECT; data reduction: DENZO; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.
Supporting information
10.1107/S0108270105017555/sf1003sup1.cif
contains datablocks I, g137. DOI:Structure factors: contains datablock I7. DOI: 10.1107/S0108270105017555/sf1003Isup2.hkl
FeBr2 (1.078 g, 5 mmol) and Li(tBuO) (1.20 g, 15 mmol) were weighed out in a
and transferred to a Schlenk tube filled with dry argon. The tube was placed on the vacuum line and cooled to 273 K in an ice bath. THF (20 ml) was added by syringe and the brown mixture was stirred at room temperature overnight. The next day the mixture was filtered through celite to remove LiBr and washed with THF (10 ml). The solution was reduced in volume under vacuum and left to stand overnight. A large crop of crystals formed in the dark-brown solution. The crystals were not single and so were redissolved by gentle heating and placed in a water bath to cool slowly. Overnight, suitable higher quality crystals of (I) formed (yield 18.15%). Microanalysis expected: C 49.17, H 8.94%; found: C 48.36, H 8.60%.All H atoms were constrained to an idealized geometry with a riding model [for CH3, Uiso(H) = 1.5Ueq(C) and C—H = 0.98 Å; for CH2, Uiso(H) = 1.2Ueq(C) and C—H = 0.99 Å].
Data collection: DENZO (Hooft, 1988) and COLLECT (Otwinowski & Minor, 1997); cell
DENZO and COLLECT; data reduction: DENZO; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.Fig. 1. The asymmetric unit of (I), with 50% probability displacement ellipsoids. H atoms have been omitted for clarity. | |
Fig. 2. A view of (I), showing the propagation in the a direction to form a polymeric chain. |
[FeLi2(C4H9O)4(C4H8O)2Br] | F(000) = 1244 |
Mr = 586.30 | Dx = 1.243 Mg m−3 |
Monoclinic, P21/a | Mo Kα radiation, λ = 0.71073 Å |
a = 18.4449 (5) Å | Cell parameters from 34588 reflections |
b = 9.0987 (3) Å | θ = 1.0–27.5° |
c = 18.6750 (5) Å | µ = 1.79 mm−1 |
β = 90.535 (2)° | T = 123 K |
V = 3133.99 (16) Å3 | Prism, pale yellow |
Z = 4 | 0.50 × 0.45 × 0.40 mm |
Nonius KappaCCD diffractometer | 7143 independent reflections |
Radiation source: fine-focus sealed tube | 5934 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.039 |
ω and ϕ scans | θmax = 27.5°, θmin = 2.2° |
Absorption correction: multi-scan (SORTAV; Blessing, 1997) | h = −23→23 |
Tmin = 0.460, Tmax = 0.497 | k = −11→11 |
35132 measured reflections | l = −24→24 |
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)] = 0.029 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.070 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0243P)2 + 1.8098P] where P = (Fo2 + 2Fc2)/3 |
7143 reflections | (Δ/σ)max = 0.001 |
319 parameters | Δρmax = 0.50 e Å−3 |
0 restraints | Δρmin = −0.59 e Å−3 |
[FeLi2(C4H9O)4(C4H8O)2Br] | V = 3133.99 (16) Å3 |
Mr = 586.30 | Z = 4 |
Monoclinic, P21/a | Mo Kα radiation |
a = 18.4449 (5) Å | µ = 1.79 mm−1 |
b = 9.0987 (3) Å | T = 123 K |
c = 18.6750 (5) Å | 0.50 × 0.45 × 0.40 mm |
β = 90.535 (2)° |
Nonius KappaCCD diffractometer | 7143 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1997) | 5934 reflections with I > 2σ(I) |
Tmin = 0.460, Tmax = 0.497 | Rint = 0.039 |
35132 measured reflections |
R[F2 > 2σ(F2)] = 0.029 | 0 restraints |
wR(F2) = 0.070 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.50 e Å−3 |
7143 reflections | Δρmin = −0.59 e Å−3 |
319 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Fe1 | 0.004391 (11) | 0.62290 (2) | 0.252100 (12) | 0.01628 (6) | |
Br1 | −0.246920 (10) | 0.76341 (3) | 0.272467 (11) | 0.04186 (7) | |
C1 | 0.11111 (9) | 0.39475 (18) | 0.31172 (9) | 0.0217 (3) | |
C10 | −0.03391 (11) | 0.7477 (2) | 0.45656 (10) | 0.0351 (4) | |
C11 | 0.05598 (9) | 0.8653 (2) | 0.37460 (10) | 0.0291 (4) | |
C12 | −0.07361 (11) | 0.9495 (2) | 0.37392 (11) | 0.0367 (5) | |
C13 | −0.10691 (9) | 0.42806 (19) | 0.17431 (9) | 0.0235 (4) | |
C14 | −0.16164 (11) | 0.5067 (2) | 0.12615 (10) | 0.0369 (5) | |
C15 | −0.14285 (11) | 0.2996 (2) | 0.21295 (10) | 0.0348 (4) | |
C16 | −0.04334 (10) | 0.3735 (2) | 0.13026 (10) | 0.0314 (4) | |
C17 | 0.14965 (10) | 0.4358 (2) | 0.08254 (10) | 0.0336 (4) | |
C18 | 0.20745 (11) | 0.3271 (2) | 0.06097 (11) | 0.0387 (5) | |
C19 | 0.27246 (10) | 0.4255 (2) | 0.04821 (10) | 0.0365 (5) | |
C2 | 0.13224 (12) | 0.4638 (2) | 0.38322 (10) | 0.0368 (5) | |
C20 | 0.26455 (10) | 0.5416 (2) | 0.10565 (11) | 0.0355 (4) | |
C21 | −0.13519 (10) | 0.3753 (2) | 0.41428 (10) | 0.0336 (4) | |
C22 | −0.19103 (11) | 0.2821 (2) | 0.45153 (12) | 0.0388 (5) | |
C23 | −0.25324 (10) | 0.3881 (2) | 0.46549 (10) | 0.0339 (4) | |
C24 | −0.23548 (13) | 0.5219 (3) | 0.42235 (13) | 0.0508 (6) | |
C3 | 0.05064 (11) | 0.2840 (2) | 0.32207 (13) | 0.0417 (5) | |
C4 | 0.17671 (10) | 0.3205 (2) | 0.27845 (10) | 0.0345 (4) | |
C5 | 0.03529 (9) | 0.85518 (19) | 0.13741 (9) | 0.0255 (4) | |
C6 | −0.03792 (12) | 0.9190 (3) | 0.15602 (13) | 0.0483 (6) | |
C7 | 0.03414 (15) | 0.7930 (3) | 0.06182 (11) | 0.0499 (6) | |
C8 | 0.09395 (13) | 0.9719 (3) | 0.14379 (14) | 0.0519 (6) | |
C9 | −0.02279 (9) | 0.81807 (19) | 0.38293 (9) | 0.0232 (3) | |
Li1 | 0.14693 (15) | 0.6409 (3) | 0.20543 (15) | 0.0251 (6) | |
Li2 | −0.13684 (15) | 0.6223 (3) | 0.30454 (15) | 0.0253 (6) | |
O1 | 0.08740 (6) | 0.50801 (12) | 0.26390 (6) | 0.0203 (2) | |
O2 | 0.05346 (6) | 0.73899 (13) | 0.18572 (6) | 0.0222 (2) | |
O3 | −0.04130 (6) | 0.71087 (13) | 0.32999 (6) | 0.0212 (2) | |
O4 | −0.08204 (6) | 0.52915 (13) | 0.22755 (6) | 0.0212 (2) | |
O5 | 0.18755 (6) | 0.55285 (15) | 0.11866 (6) | 0.0303 (3) | |
O6 | −0.17497 (6) | 0.48943 (15) | 0.37917 (6) | 0.0306 (3) | |
H10A | −0.0020 | 0.6621 | 0.4616 | 0.053* | |
H10B | −0.0845 | 0.7164 | 0.4610 | 0.053* | |
H10C | −0.0223 | 0.8194 | 0.4941 | 0.053* | |
H11A | 0.0625 | 0.9101 | 0.3274 | 0.044* | |
H11B | 0.0876 | 0.7792 | 0.3792 | 0.044* | |
H11C | 0.0685 | 0.9370 | 0.4119 | 0.044* | |
H12A | −0.1240 | 0.9161 | 0.3762 | 0.055* | |
H12B | −0.0651 | 0.9962 | 0.3275 | 0.055* | |
H12C | −0.0643 | 1.0207 | 0.4123 | 0.055* | |
H14A | −0.1381 | 0.5902 | 0.1028 | 0.055* | |
H14B | −0.2021 | 0.5422 | 0.1551 | 0.055* | |
H14C | −0.1799 | 0.4384 | 0.0897 | 0.055* | |
H15A | −0.1830 | 0.3363 | 0.2419 | 0.052* | |
H15B | −0.1071 | 0.2510 | 0.2441 | 0.052* | |
H15C | −0.1614 | 0.2291 | 0.1776 | 0.052* | |
H16A | −0.0082 | 0.3244 | 0.1618 | 0.047* | |
H16B | −0.0200 | 0.4570 | 0.1067 | 0.047* | |
H16C | −0.0609 | 0.3039 | 0.0940 | 0.047* | |
H17A | 0.1235 | 0.4736 | 0.0398 | 0.040* | |
H17B | 0.1143 | 0.3891 | 0.1149 | 0.040* | |
H18A | 0.1933 | 0.2735 | 0.0169 | 0.046* | |
H18B | 0.2174 | 0.2553 | 0.0997 | 0.046* | |
H19A | 0.3185 | 0.3705 | 0.0541 | 0.044* | |
H19B | 0.2706 | 0.4695 | −0.0002 | 0.044* | |
H20A | 0.2908 | 0.5121 | 0.1499 | 0.043* | |
H20B | 0.2841 | 0.6369 | 0.0891 | 0.043* | |
H21A | −0.1004 | 0.4171 | 0.4494 | 0.040* | |
H21B | −0.1081 | 0.3160 | 0.3791 | 0.040* | |
H22A | −0.1714 | 0.2418 | 0.4970 | 0.047* | |
H22B | −0.2071 | 0.1997 | 0.4206 | 0.047* | |
H23A | −0.3000 | 0.3451 | 0.4497 | 0.041* | |
H23B | −0.2561 | 0.4124 | 0.5171 | 0.041* | |
H24A | −0.2775 | 0.5495 | 0.3918 | 0.061* | |
H24B | −0.2241 | 0.6053 | 0.4546 | 0.061* | |
H2A | 0.1700 | 0.5377 | 0.3757 | 0.055* | |
H2B | 0.1506 | 0.3874 | 0.4156 | 0.055* | |
H2C | 0.0897 | 0.5106 | 0.4044 | 0.055* | |
H3A | 0.0077 | 0.3341 | 0.3406 | 0.062* | |
H3B | 0.0665 | 0.2085 | 0.3562 | 0.062* | |
H3C | 0.0387 | 0.2378 | 0.2761 | 0.062* | |
H4A | 0.1631 | 0.2799 | 0.2316 | 0.052* | |
H4B | 0.1936 | 0.2410 | 0.3098 | 0.052* | |
H4C | 0.2156 | 0.3928 | 0.2725 | 0.052* | |
H6A | −0.0746 | 0.8412 | 0.1545 | 0.072* | |
H6B | −0.0508 | 0.9958 | 0.1214 | 0.072* | |
H6C | −0.0358 | 0.9615 | 0.2042 | 0.072* | |
H7A | 0.0810 | 0.7472 | 0.0517 | 0.075* | |
H7B | 0.0250 | 0.8725 | 0.0275 | 0.075* | |
H7C | −0.0044 | 0.7192 | 0.0576 | 0.075* | |
H8A | 0.0957 | 1.0093 | 0.1930 | 0.078* | |
H8B | 0.0830 | 1.0528 | 0.1108 | 0.078* | |
H8C | 0.1410 | 0.9288 | 0.1317 | 0.078* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.02757 (11) | 0.05601 (15) | 0.04197 (12) | 0.01880 (9) | −0.00044 (8) | 0.00995 (10) |
C1 | 0.0213 (8) | 0.0207 (8) | 0.0232 (8) | 0.0047 (7) | 0.0009 (6) | 0.0039 (7) |
C10 | 0.0437 (11) | 0.0400 (11) | 0.0217 (9) | −0.0065 (9) | 0.0033 (8) | −0.0052 (8) |
C11 | 0.0276 (9) | 0.0255 (9) | 0.0341 (10) | −0.0036 (7) | −0.0004 (7) | −0.0064 (8) |
C12 | 0.0362 (11) | 0.0298 (11) | 0.0440 (11) | 0.0083 (8) | −0.0021 (9) | −0.0111 (9) |
C13 | 0.0215 (8) | 0.0264 (9) | 0.0224 (8) | −0.0049 (7) | −0.0023 (6) | −0.0051 (7) |
C14 | 0.0345 (10) | 0.0450 (12) | 0.0310 (10) | 0.0006 (9) | −0.0110 (8) | −0.0057 (9) |
C15 | 0.0369 (10) | 0.0357 (11) | 0.0317 (10) | −0.0143 (9) | 0.0000 (8) | −0.0043 (8) |
C16 | 0.0309 (9) | 0.0349 (10) | 0.0285 (9) | −0.0027 (8) | 0.0021 (7) | −0.0089 (8) |
C17 | 0.0287 (10) | 0.0426 (12) | 0.0293 (10) | 0.0043 (9) | −0.0019 (7) | −0.0060 (8) |
C18 | 0.0430 (11) | 0.0392 (12) | 0.0339 (11) | 0.0096 (9) | −0.0037 (9) | −0.0091 (9) |
C19 | 0.0324 (10) | 0.0515 (13) | 0.0258 (9) | 0.0158 (9) | 0.0066 (8) | 0.0042 (9) |
C2 | 0.0551 (13) | 0.0321 (11) | 0.0232 (9) | 0.0098 (9) | −0.0058 (8) | 0.0014 (8) |
C20 | 0.0273 (9) | 0.0383 (11) | 0.0412 (11) | 0.0024 (8) | 0.0125 (8) | 0.0036 (9) |
C21 | 0.0275 (9) | 0.0398 (11) | 0.0334 (10) | 0.0035 (8) | 0.0027 (8) | 0.0108 (9) |
C22 | 0.0370 (11) | 0.0360 (11) | 0.0436 (12) | −0.0038 (9) | 0.0012 (9) | 0.0111 (9) |
C23 | 0.0316 (10) | 0.0398 (11) | 0.0304 (10) | −0.0095 (8) | 0.0079 (8) | −0.0019 (8) |
C24 | 0.0483 (13) | 0.0441 (13) | 0.0606 (15) | 0.0150 (11) | 0.0362 (11) | 0.0140 (11) |
C3 | 0.0369 (11) | 0.0329 (11) | 0.0552 (13) | −0.0037 (9) | −0.0008 (10) | 0.0183 (10) |
C4 | 0.0354 (10) | 0.0369 (11) | 0.0311 (10) | 0.0160 (9) | 0.0044 (8) | 0.0050 (8) |
C5 | 0.0306 (9) | 0.0218 (9) | 0.0243 (9) | 0.0029 (7) | 0.0041 (7) | 0.0070 (7) |
C6 | 0.0440 (12) | 0.0474 (13) | 0.0537 (14) | 0.0218 (11) | 0.0125 (10) | 0.0224 (11) |
C7 | 0.0855 (18) | 0.0385 (13) | 0.0257 (10) | 0.0135 (12) | −0.0029 (11) | 0.0055 (9) |
C8 | 0.0556 (14) | 0.0361 (12) | 0.0638 (15) | −0.0154 (11) | −0.0040 (12) | 0.0199 (11) |
C9 | 0.0257 (8) | 0.0219 (8) | 0.0220 (8) | −0.0001 (7) | 0.0007 (6) | −0.0059 (7) |
Fe1 | 0.01494 (11) | 0.01688 (11) | 0.01703 (11) | −0.00004 (9) | 0.00068 (8) | −0.00048 (9) |
Li1 | 0.0204 (14) | 0.0299 (16) | 0.0248 (14) | −0.0012 (12) | 0.0014 (11) | −0.0023 (12) |
Li2 | 0.0214 (14) | 0.0309 (16) | 0.0236 (14) | 0.0005 (12) | 0.0028 (11) | 0.0024 (12) |
O1 | 0.0168 (5) | 0.0215 (6) | 0.0227 (6) | 0.0022 (5) | −0.0001 (4) | 0.0034 (5) |
O2 | 0.0215 (6) | 0.0224 (6) | 0.0227 (6) | 0.0024 (5) | 0.0029 (4) | 0.0053 (5) |
O3 | 0.0208 (6) | 0.0222 (6) | 0.0207 (6) | −0.0010 (5) | 0.0020 (4) | −0.0046 (5) |
O4 | 0.0168 (5) | 0.0244 (6) | 0.0222 (6) | −0.0022 (5) | −0.0010 (4) | −0.0050 (5) |
O5 | 0.0232 (6) | 0.0390 (8) | 0.0288 (7) | 0.0044 (6) | 0.0036 (5) | −0.0059 (6) |
O6 | 0.0242 (6) | 0.0380 (8) | 0.0298 (7) | 0.0048 (5) | 0.0084 (5) | 0.0101 (6) |
Fe1—O4 | 1.8616 (11) | C4—H4A | 0.9800 |
Fe1—O1 | 1.8653 (11) | C4—H4B | 0.9800 |
Fe1—O3 | 1.8680 (11) | C4—H4C | 0.9800 |
Fe1—O2 | 1.8687 (11) | C22—C21 | 1.509 (3) |
Fe1—Li1 | 2.782 (3) | C22—H22A | 0.9900 |
Fe1—Li2 | 2.792 (3) | C22—H22B | 0.9900 |
Br1—Li2 | 2.471 (3) | C19—C20 | 1.514 (3) |
Br1—Li1i | 2.472 (3) | C19—C18 | 1.517 (3) |
O2—C5 | 1.4277 (19) | C19—H19A | 0.9900 |
O2—Li1 | 1.973 (3) | C19—H19B | 0.9900 |
O1—C1 | 1.4295 (19) | C21—H21A | 0.9900 |
O1—Li1 | 1.970 (3) | C21—H21B | 0.9900 |
O4—C13 | 1.4271 (19) | C15—H15A | 0.9800 |
O4—Li2 | 1.958 (3) | C15—H15B | 0.9800 |
O3—C9 | 1.4279 (19) | C15—H15C | 0.9800 |
O3—Li2 | 1.991 (3) | C14—H14A | 0.9800 |
O5—C17 | 1.438 (2) | C14—H14B | 0.9800 |
O5—C20 | 1.447 (2) | C14—H14C | 0.9800 |
O5—Li1 | 1.963 (3) | C20—H20A | 0.9900 |
O6—C24 | 1.414 (2) | C20—H20B | 0.9900 |
O6—C21 | 1.428 (2) | C10—H10A | 0.9800 |
O6—Li2 | 1.979 (3) | C10—H10B | 0.9800 |
C9—C11 | 1.525 (2) | C10—H10C | 0.9800 |
C9—C12 | 1.528 (2) | C3—H3A | 0.9800 |
C9—C10 | 1.533 (2) | C3—H3B | 0.9800 |
C5—C6 | 1.513 (3) | C3—H3C | 0.9800 |
C5—C8 | 1.520 (3) | C17—C18 | 1.512 (3) |
C5—C7 | 1.521 (3) | C17—H17A | 0.9900 |
C1—C3 | 1.517 (2) | C17—H17B | 0.9900 |
C1—C2 | 1.523 (2) | C18—H18A | 0.9900 |
C1—C4 | 1.523 (2) | C18—H18B | 0.9900 |
C23—C24 | 1.498 (3) | C24—H24A | 0.9900 |
C23—C22 | 1.523 (3) | C24—H24B | 0.9900 |
C23—H23A | 0.9900 | C12—H12A | 0.9800 |
C23—H23B | 0.9900 | C12—H12B | 0.9800 |
C13—C16 | 1.522 (2) | C12—H12C | 0.9800 |
C13—C14 | 1.524 (2) | C7—H7A | 0.9800 |
C13—C15 | 1.528 (2) | C7—H7B | 0.9800 |
C11—H11A | 0.9800 | C7—H7C | 0.9800 |
C11—H11B | 0.9800 | C6—H6A | 0.9800 |
C11—H11C | 0.9800 | C6—H6B | 0.9800 |
C2—H2A | 0.9800 | C6—H6C | 0.9800 |
C2—H2B | 0.9800 | C8—H8A | 0.9800 |
C2—H2C | 0.9800 | C8—H8B | 0.9800 |
C16—H16A | 0.9800 | C8—H8C | 0.9800 |
C16—H16B | 0.9800 | Li1—Br1ii | 2.472 (3) |
C16—H16C | 0.9800 | ||
O4—Fe1—O1 | 118.19 (5) | H19A—C19—H19B | 109.1 |
O4—Fe1—O3 | 89.80 (5) | O6—C21—C22 | 105.69 (15) |
O1—Fe1—O3 | 121.60 (5) | O6—C21—H21A | 110.6 |
O4—Fe1—O2 | 120.97 (5) | C22—C21—H21A | 110.6 |
O1—Fe1—O2 | 89.60 (5) | O6—C21—H21B | 110.6 |
O3—Fe1—O2 | 119.94 (5) | C22—C21—H21B | 110.6 |
O4—Fe1—Li1 | 139.41 (7) | H21A—C21—H21B | 108.7 |
O1—Fe1—Li1 | 45.01 (7) | C13—C15—H15A | 109.5 |
O3—Fe1—Li1 | 130.78 (7) | C13—C15—H15B | 109.5 |
O2—Fe1—Li1 | 45.09 (7) | H15A—C15—H15B | 109.5 |
O4—Fe1—Li2 | 44.42 (7) | C13—C15—H15C | 109.5 |
O1—Fe1—Li2 | 136.48 (7) | H15A—C15—H15C | 109.5 |
O3—Fe1—Li2 | 45.44 (7) | H15B—C15—H15C | 109.5 |
O2—Fe1—Li2 | 133.87 (7) | O4—Li2—O6 | 116.21 (16) |
Li1—Fe1—Li2 | 176.03 (9) | O4—Li2—O3 | 83.60 (11) |
Li2—Br1—Li1i | 161.93 (10) | O6—Li2—O3 | 113.49 (15) |
C5—O2—Fe1 | 136.50 (10) | O4—Li2—Br1 | 118.39 (13) |
C5—O2—Li1 | 130.72 (13) | O6—Li2—Br1 | 101.04 (11) |
Fe1—O2—Li1 | 92.77 (10) | O3—Li2—Br1 | 124.83 (14) |
C1—O1—Fe1 | 136.37 (9) | O4—Li2—Fe1 | 41.71 (6) |
C1—O1—Li1 | 128.30 (12) | O6—Li2—Fe1 | 125.94 (13) |
Fe1—O1—Li1 | 92.96 (10) | O3—Li2—Fe1 | 41.95 (6) |
C13—O4—Fe1 | 137.39 (10) | Br1—Li2—Fe1 | 132.95 (11) |
C13—O4—Li2 | 128.74 (13) | C13—C14—H14A | 109.5 |
Fe1—O4—Li2 | 93.87 (10) | C13—C14—H14B | 109.5 |
C9—O3—Fe1 | 136.48 (10) | H14A—C14—H14B | 109.5 |
C9—O3—Li2 | 130.30 (13) | C13—C14—H14C | 109.5 |
Fe1—O3—Li2 | 92.61 (9) | H14A—C14—H14C | 109.5 |
C17—O5—C20 | 110.04 (14) | H14B—C14—H14C | 109.5 |
C17—O5—Li1 | 120.12 (13) | O5—C20—C19 | 105.64 (16) |
C20—O5—Li1 | 123.39 (14) | O5—C20—H20A | 110.6 |
C24—O6—C21 | 107.16 (14) | C19—C20—H20A | 110.6 |
C24—O6—Li2 | 124.16 (15) | O5—C20—H20B | 110.6 |
C21—O6—Li2 | 125.69 (13) | C19—C20—H20B | 110.6 |
O3—C9—C11 | 110.11 (13) | H20A—C20—H20B | 108.7 |
O3—C9—C12 | 108.43 (14) | C9—C10—H10A | 109.5 |
C11—C9—C12 | 110.63 (15) | C9—C10—H10B | 109.5 |
O3—C9—C10 | 107.62 (14) | H10A—C10—H10B | 109.5 |
C11—C9—C10 | 110.17 (15) | C9—C10—H10C | 109.5 |
C12—C9—C10 | 109.81 (15) | H10A—C10—H10C | 109.5 |
O2—C5—C6 | 110.11 (14) | H10B—C10—H10C | 109.5 |
O2—C5—C8 | 107.77 (15) | C1—C3—H3A | 109.5 |
C6—C5—C8 | 110.47 (18) | C1—C3—H3B | 109.5 |
O2—C5—C7 | 108.19 (14) | H3A—C3—H3B | 109.5 |
C6—C5—C7 | 110.57 (18) | C1—C3—H3C | 109.5 |
C8—C5—C7 | 109.66 (18) | H3A—C3—H3C | 109.5 |
O1—C1—C3 | 109.73 (14) | H3B—C3—H3C | 109.5 |
O1—C1—C2 | 108.96 (14) | O5—C17—C18 | 105.58 (15) |
C3—C1—C2 | 110.17 (16) | O5—C17—H17A | 110.6 |
O1—C1—C4 | 107.72 (13) | C18—C17—H17A | 110.6 |
C3—C1—C4 | 110.18 (16) | O5—C17—H17B | 110.6 |
C2—C1—C4 | 110.04 (15) | C18—C17—H17B | 110.6 |
C24—C23—C22 | 104.69 (15) | H17A—C17—H17B | 108.8 |
C24—C23—H23A | 110.8 | C17—C18—C19 | 102.48 (17) |
C22—C23—H23A | 110.8 | C17—C18—H18A | 111.3 |
C24—C23—H23B | 110.8 | C19—C18—H18A | 111.3 |
C22—C23—H23B | 110.8 | C17—C18—H18B | 111.3 |
H23A—C23—H23B | 108.9 | C19—C18—H18B | 111.3 |
O4—C13—C16 | 110.03 (13) | H18A—C18—H18B | 109.2 |
O4—C13—C14 | 108.37 (14) | O6—C24—C23 | 108.35 (17) |
C16—C13—C14 | 110.10 (15) | O6—C24—H24A | 110.0 |
O4—C13—C15 | 107.58 (13) | C23—C24—H24A | 110.0 |
C16—C13—C15 | 110.21 (16) | O6—C24—H24B | 110.0 |
C14—C13—C15 | 110.50 (15) | C23—C24—H24B | 110.0 |
C9—C11—H11A | 109.5 | H24A—C24—H24B | 108.4 |
C9—C11—H11B | 109.5 | C9—C12—H12A | 109.5 |
H11A—C11—H11B | 109.5 | C9—C12—H12B | 109.5 |
C9—C11—H11C | 109.5 | H12A—C12—H12B | 109.5 |
H11A—C11—H11C | 109.5 | C9—C12—H12C | 109.5 |
H11B—C11—H11C | 109.5 | H12A—C12—H12C | 109.5 |
C1—C2—H2A | 109.5 | H12B—C12—H12C | 109.5 |
C1—C2—H2B | 109.5 | C5—C7—H7A | 109.5 |
H2A—C2—H2B | 109.5 | C5—C7—H7B | 109.5 |
C1—C2—H2C | 109.5 | H7A—C7—H7B | 109.5 |
H2A—C2—H2C | 109.5 | C5—C7—H7C | 109.5 |
H2B—C2—H2C | 109.5 | H7A—C7—H7C | 109.5 |
C13—C16—H16A | 109.5 | H7B—C7—H7C | 109.5 |
C13—C16—H16B | 109.5 | C5—C6—H6A | 109.5 |
H16A—C16—H16B | 109.5 | C5—C6—H6B | 109.5 |
C13—C16—H16C | 109.5 | H6A—C6—H6B | 109.5 |
H16A—C16—H16C | 109.5 | C5—C6—H6C | 109.5 |
H16B—C16—H16C | 109.5 | H6A—C6—H6C | 109.5 |
C1—C4—H4A | 109.5 | H6B—C6—H6C | 109.5 |
C1—C4—H4B | 109.5 | C5—C8—H8A | 109.5 |
H4A—C4—H4B | 109.5 | C5—C8—H8B | 109.5 |
C1—C4—H4C | 109.5 | H8A—C8—H8B | 109.5 |
H4A—C4—H4C | 109.5 | C5—C8—H8C | 109.5 |
H4B—C4—H4C | 109.5 | H8A—C8—H8C | 109.5 |
C21—C22—C23 | 103.98 (16) | H8B—C8—H8C | 109.5 |
C21—C22—H22A | 111.0 | O5—Li1—O1 | 115.21 (15) |
C23—C22—H22A | 111.0 | O5—Li1—O2 | 111.73 (15) |
C21—C22—H22B | 111.0 | O1—Li1—O2 | 83.71 (11) |
C23—C22—H22B | 111.0 | O5—Li1—Br1ii | 104.79 (12) |
H22A—C22—H22B | 109.0 | O1—Li1—Br1ii | 112.23 (13) |
C20—C19—C18 | 102.66 (15) | O2—Li1—Br1ii | 128.44 (14) |
C20—C19—H19A | 111.2 | O5—Li1—Fe1 | 127.14 (13) |
C18—C19—H19A | 111.2 | O1—Li1—Fe1 | 42.03 (6) |
C20—C19—H19B | 111.2 | O2—Li1—Fe1 | 42.13 (6) |
C18—C19—H19B | 111.2 | Br1ii—Li1—Fe1 | 127.47 (11) |
O4—Fe1—O2—C5 | 49.28 (17) | C24—O6—Li2—Br1 | −26.2 (2) |
O1—Fe1—O2—C5 | 172.43 (15) | C21—O6—Li2—Br1 | 175.94 (14) |
O3—Fe1—O2—C5 | −60.66 (16) | C24—O6—Li2—Fe1 | 156.45 (18) |
Li1—Fe1—O2—C5 | 180.0 (2) | C21—O6—Li2—Fe1 | −1.4 (3) |
Li2—Fe1—O2—C5 | −5.4 (2) | C9—O3—Li2—O4 | 174.56 (14) |
O4—Fe1—O2—Li1 | −130.71 (10) | Fe1—O3—Li2—O4 | 2.45 (9) |
O1—Fe1—O2—Li1 | −7.57 (10) | C9—O3—Li2—O6 | −69.6 (2) |
O3—Fe1—O2—Li1 | 119.35 (10) | Fe1—O3—Li2—O6 | 118.29 (14) |
Li2—Fe1—O2—Li1 | 174.63 (12) | C9—O3—Li2—Br1 | 54.2 (2) |
O4—Fe1—O1—C1 | −64.48 (15) | Fe1—O3—Li2—Br1 | −117.88 (14) |
O3—Fe1—O1—C1 | 44.50 (16) | C9—O3—Li2—Fe1 | 172.11 (17) |
O2—Fe1—O1—C1 | 170.07 (15) | Li1i—Br1—Li2—O4 | 18.0 (4) |
Li1—Fe1—O1—C1 | 162.49 (19) | Li1i—Br1—Li2—O6 | −110.1 (3) |
Li2—Fe1—O1—C1 | −12.24 (19) | Li1i—Br1—Li2—O3 | 120.8 (3) |
O4—Fe1—O1—Li1 | 133.04 (10) | Li1i—Br1—Li2—Fe1 | 67.0 (4) |
O3—Fe1—O1—Li1 | −117.99 (10) | O1—Fe1—Li2—O4 | −84.58 (12) |
O2—Fe1—O1—Li1 | 7.58 (10) | O3—Fe1—Li2—O4 | −176.34 (14) |
Li2—Fe1—O1—Li1 | −174.73 (12) | O2—Fe1—Li2—O4 | 92.22 (11) |
O1—Fe1—O4—C13 | −51.89 (16) | O4—Fe1—Li2—O6 | 90.36 (18) |
O3—Fe1—O4—C13 | −178.23 (16) | O1—Fe1—Li2—O6 | 5.8 (2) |
O2—Fe1—O4—C13 | 56.32 (17) | O3—Fe1—Li2—O6 | −85.98 (17) |
Li1—Fe1—O4—C13 | 0.7 (2) | O2—Fe1—Li2—O6 | −177.41 (12) |
Li2—Fe1—O4—C13 | 179.2 (2) | O4—Fe1—Li2—O3 | 176.34 (14) |
O1—Fe1—O4—Li2 | 128.95 (10) | O1—Fe1—Li2—O3 | 91.76 (11) |
O3—Fe1—O4—Li2 | 2.61 (10) | O2—Fe1—Li2—O3 | −91.44 (11) |
O2—Fe1—O4—Li2 | −122.85 (10) | O4—Fe1—Li2—Br1 | −86.10 (17) |
Li1—Fe1—O4—Li2 | −178.45 (13) | O1—Fe1—Li2—Br1 | −170.67 (10) |
O4—Fe1—O3—C9 | −173.82 (15) | O3—Fe1—Li2—Br1 | 97.56 (18) |
O1—Fe1—O3—C9 | 62.65 (16) | O2—Fe1—Li2—Br1 | 6.1 (2) |
O2—Fe1—O3—C9 | −47.53 (16) | C17—O5—C20—C19 | 9.7 (2) |
Li1—Fe1—O3—C9 | 7.09 (19) | Li1—O5—C20—C19 | 161.34 (16) |
Li2—Fe1—O3—C9 | −171.25 (19) | C18—C19—C20—O5 | −28.93 (19) |
O4—Fe1—O3—Li2 | −2.56 (10) | C20—O5—C17—C18 | 13.8 (2) |
O1—Fe1—O3—Li2 | −126.10 (10) | Li1—O5—C17—C18 | −138.90 (16) |
O2—Fe1—O3—Li2 | 123.73 (10) | O5—C17—C18—C19 | −31.41 (19) |
Li1—Fe1—O3—Li2 | 178.34 (12) | C20—C19—C18—C17 | 36.50 (19) |
Fe1—O3—C9—C11 | −3.7 (2) | C21—O6—C24—C23 | −25.7 (2) |
Li2—O3—C9—C11 | −172.23 (15) | Li2—O6—C24—C23 | 172.98 (16) |
Fe1—O3—C9—C12 | 117.46 (15) | C22—C23—C24—O6 | 7.9 (3) |
Li2—O3—C9—C12 | −51.1 (2) | C17—O5—Li1—O1 | 29.8 (2) |
Fe1—O3—C9—C10 | −123.82 (15) | C20—O5—Li1—O1 | −119.18 (17) |
Li2—O3—C9—C10 | 67.7 (2) | C17—O5—Li1—O2 | −63.5 (2) |
Fe1—O2—C5—C6 | 15.3 (2) | C20—O5—Li1—O2 | 147.54 (15) |
Li1—O2—C5—C6 | −164.72 (17) | C17—O5—Li1—Br1ii | 153.62 (13) |
Fe1—O2—C5—C8 | 135.86 (16) | C20—O5—Li1—Br1ii | 4.7 (2) |
Li1—O2—C5—C8 | −44.1 (2) | C17—O5—Li1—Fe1 | −17.9 (2) |
Fe1—O2—C5—C7 | −105.65 (18) | C20—O5—Li1—Fe1 | −166.85 (15) |
Li1—O2—C5—C7 | 74.3 (2) | C1—O1—Li1—O5 | 77.0 (2) |
Fe1—O1—C1—C3 | 44.8 (2) | Fe1—O1—Li1—O5 | −118.31 (14) |
Li1—O1—C1—C3 | −157.67 (16) | C1—O1—Li1—O2 | −171.88 (13) |
Fe1—O1—C1—C2 | −75.85 (18) | Fe1—O1—Li1—O2 | −7.22 (9) |
Li1—O1—C1—C2 | 81.63 (19) | C1—O1—Li1—Br1ii | −42.8 (2) |
Fe1—O1—C1—C4 | 164.80 (12) | Fe1—O1—Li1—Br1ii | 121.88 (11) |
Li1—O1—C1—C4 | −37.7 (2) | C1—O1—Li1—Fe1 | −164.66 (16) |
Fe1—O4—C13—C16 | 6.7 (2) | C5—O2—Li1—O5 | −58.1 (2) |
Li2—O4—C13—C16 | −174.41 (16) | Fe1—O2—Li1—O5 | 121.88 (13) |
Fe1—O4—C13—C14 | −113.77 (16) | C5—O2—Li1—O1 | −172.79 (14) |
Li2—O4—C13—C14 | 65.2 (2) | Fe1—O2—Li1—O1 | 7.21 (9) |
Fe1—O4—C13—C15 | 126.74 (15) | C5—O2—Li1—Br1ii | 73.7 (2) |
Li2—O4—C13—C15 | −54.3 (2) | Fe1—O2—Li1—Br1ii | −106.27 (15) |
C24—C23—C22—C21 | 11.6 (2) | C5—O2—Li1—Fe1 | 180.00 (18) |
C24—O6—C21—C22 | 33.0 (2) | O4—Fe1—Li1—O5 | 5.6 (2) |
Li2—O6—C21—C22 | −165.99 (17) | O1—Fe1—Li1—O5 | 87.59 (18) |
C23—C22—C21—O6 | −27.0 (2) | O3—Fe1—Li1—O5 | −175.74 (12) |
C13—O4—Li2—O6 | 65.2 (2) | O2—Fe1—Li1—O5 | −81.67 (17) |
Fe1—O4—Li2—O6 | −115.53 (14) | O4—Fe1—Li1—O1 | −81.94 (12) |
C13—O4—Li2—O3 | 178.26 (13) | O3—Fe1—Li1—O1 | 96.67 (10) |
Fe1—O4—Li2—O3 | −2.46 (9) | O2—Fe1—Li1—O1 | −169.27 (14) |
C13—O4—Li2—Br1 | −55.4 (2) | O4—Fe1—Li1—O2 | 87.32 (12) |
Fe1—O4—Li2—Br1 | 123.89 (13) | O1—Fe1—Li1—O2 | 169.27 (14) |
C13—O4—Li2—Fe1 | −179.27 (17) | O3—Fe1—Li1—O2 | −94.07 (10) |
C24—O6—Li2—O4 | −155.69 (19) | O4—Fe1—Li1—Br1ii | −163.99 (9) |
C21—O6—Li2—O4 | 46.4 (2) | O1—Fe1—Li1—Br1ii | −82.05 (15) |
C24—O6—Li2—O3 | 109.8 (2) | O3—Fe1—Li1—Br1ii | 14.6 (2) |
C21—O6—Li2—O3 | −48.1 (2) | O2—Fe1—Li1—Br1ii | 108.69 (17) |
Symmetry codes: (i) x−1/2, −y+3/2, z; (ii) x+1/2, −y+3/2, z. |
Experimental details
Crystal data | |
Chemical formula | [FeLi2(C4H9O)4(C4H8O)2Br] |
Mr | 586.30 |
Crystal system, space group | Monoclinic, P21/a |
Temperature (K) | 123 |
a, b, c (Å) | 18.4449 (5), 9.0987 (3), 18.6750 (5) |
β (°) | 90.535 (2) |
V (Å3) | 3133.99 (16) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 1.79 |
Crystal size (mm) | 0.50 × 0.45 × 0.40 |
Data collection | |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | Multi-scan (SORTAV; Blessing, 1997) |
Tmin, Tmax | 0.460, 0.497 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 35132, 7143, 5934 |
Rint | 0.039 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.029, 0.070, 1.03 |
No. of reflections | 7143 |
No. of parameters | 319 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.50, −0.59 |
Computer programs: DENZO (Hooft, 1988) and COLLECT (Otwinowski & Minor, 1997), DENZO and COLLECT, DENZO, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEPII (Johnson, 1976), SHELXL97.
Fe1—O4 | 1.8616 (11) | O2—Li1 | 1.973 (3) |
Fe1—O1 | 1.8653 (11) | O1—Li1 | 1.970 (3) |
Fe1—O3 | 1.8680 (11) | O4—Li2 | 1.958 (3) |
Fe1—O2 | 1.8687 (11) | O3—Li2 | 1.991 (3) |
Br1—Li2 | 2.471 (3) | O5—Li1 | 1.963 (3) |
Br1—Li1i | 2.472 (3) | O6—Li2 | 1.979 (3) |
O4—Fe1—O1 | 118.19 (5) | O4—Li2—O3 | 83.60 (11) |
O4—Fe1—O3 | 89.80 (5) | O6—Li2—O3 | 113.49 (15) |
O1—Fe1—O3 | 121.60 (5) | O4—Li2—Br1 | 118.39 (13) |
O4—Fe1—O2 | 120.97 (5) | O6—Li2—Br1 | 101.04 (11) |
O1—Fe1—O2 | 89.60 (5) | O3—Li2—Br1 | 124.83 (14) |
O3—Fe1—O2 | 119.94 (5) | O5—Li1—O1 | 115.21 (15) |
Li2—Br1—Li1i | 161.93 (10) | O5—Li1—O2 | 111.73 (15) |
Fe1—O2—Li1 | 92.77 (10) | O1—Li1—O2 | 83.71 (11) |
Fe1—O1—Li1 | 92.96 (10) | O5—Li1—Br1ii | 104.79 (12) |
Fe1—O4—Li2 | 93.87 (10) | O1—Li1—Br1ii | 112.23 (13) |
Fe1—O3—Li2 | 92.61 (9) | O2—Li1—Br1ii | 128.44 (14) |
O4—Li2—O6 | 116.21 (16) |
Symmetry codes: (i) x−1/2, −y+3/2, z; (ii) x+1/2, −y+3/2, z. |
References
Andrikopoulos, P. C., Armstrong, D. R., Clegg, W., Gilfillan, C. J., Hevia, E., Kennedy, A. R., Mulvey, R. E., O'Hara, C. T., Parkinson, J. A. & Tooke, D. M. (2004). J. Am. Chem. Soc. 126, 11612–11620. Web of Science CSD CrossRef PubMed CAS Google Scholar
Blessing, R. H. (1997). J. Appl. Cryst. 30, 421–426. CrossRef CAS Web of Science IUCr Journals Google Scholar
Bochmann, M., Wilkinson, G., Young, G. B., Hursthouse, M. B. & Malik, K. M. A. (1980). J. Chem. Soc. Dalton Trans. pp. 1863–1871. CSD CrossRef Web of Science Google Scholar
Bradley, D. C. (1989). Chem. Rev. 89, 1317–1322. CrossRef CAS Web of Science Google Scholar
Bradley, D. C., Mehrotra, R. C., Rothwell, I. P. & Singh, A. (2001). In Alkoxo and Aryloxo Derivatives of Metals. London: Academic Press. Google Scholar
Drewette, K. J., Henderson, K. W., Kennedy, A. R., Mulvey, R. E., O'Hara, C. T. & Rowlings, R. B. (2002). Chem. Commun. pp. 1176–1177. Web of Science CSD CrossRef Google Scholar
Gun'ko, Y. K., Cristmann, U. & Kessler, V. G. (2002). Inorg. Chem. pp. 1029–1031. Google Scholar
Hevia, E., Honeyman, G. W., Kennedy, A. R., Mulvey, R. E. & Sherrington, D. C. (2005). Angew. Chem. Int. Ed. 44, 68–72. Web of Science CSD CrossRef CAS Google Scholar
Hooft, R. (1988). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA. Google Scholar
Kennedy, A. R., MacLellan, J. G. & Mulvey, R. E. (2003). Acta Cryst. C59, m302–m303. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
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. Google Scholar
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany. Google Scholar
Spandl, J., Kusserow, M. & Bradgam, I. (2003). Z. Anorg. Allg. Chem. 629, 968–974. Web of Science CSD CrossRef CAS Google Scholar
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Currently, our group is investigating the synthetic and structural synergic effects that can be harnessed by mixing an alkali metal and magnesium in the same molecular amide environment [for pertinent recent examples, see Hevia et al. (2005) and Andrikopoulos et al. (2004)]. One possible outcome of this mixed-metal-induced synergy is to generate `inverse crown' ring systems, in which Lewis acidic polymetallic cationic host rings surround Lewis basic anionic cores, as recently described for the oxo-centred 2,2,6,6-tetramethylpiperidinido (TMP) inverse crown `ether' [Na2Mg2O(TMP)4] (Kennedy et al., 2003). Germane to the work reported here, another type of inverse crown motif involves a chair-shaped octagonal ring that is face-capped on opposite sides of the chair by, for example, alkoxide ligands, as demonstrated by the mixed lithium–magnesium–diisopropylamideoctoxide [{LiMg[N(iPr)2]2nOctO}2] (Drewette et al., 2002). This motif bears a close similarity to that of the mixed sodium–iron(II) butoxide [{(THF)NaFe(tBuO)3}2] (THF is tetrahydrofuran) reported by Gun'ko et al. (2002), which, in our terminology, could be regarded as an all-alkoxide inverse crown. Wishing to pursue this structural analogy further, we attempted to prepare the lithium congener [{(THF)xLiFe(tBuO)3}2] by carrying out a metathetical reaction between FeBr2 and three molar equivalents of tBuOLi in THF solution. This attempt failed as the metathesis did not go to full completion and the iron in the product oxidized to FeIII, presumably as a result of the strong oxidizing nature of alkoxide ligands. The product obtained was the bromide-containing compound [{(THF)2Li2Fe(tBuO)4Br}∞], (I). Such heterometallic alkoxide compounds are of interest as precursors to oxide-based materials (Bradley, 1989; Bradley et al., 2001).
The asymmetric unit of (I) (Fig. 1) consists of a central FeIII atom bonded to four tBuO ligands that bridge two Li atoms. The coordination about atom Fe1 is considerably distorted from tetrahedral geometry [O—Fe1—O = 89.60 (5)–121.60 (5)°], the narrowest angles, as expected, being those internal to the Fe/O/Li/O rings. The Fe—O bond lengths span a tight range [1.8616 (11)–1.8687 (11) Å], and are significantly shorter than those that bridge between Fe atoms in [(tBuO)2Fe(µ-tBuO)2Fe(tBuO)2] (1.958–1.961 Å; Spandl et al., 2003). This presumably reflects greater competition for the O-atom electron density between two Fe atoms as opposed to between an Fe and an Li atom. In (I), the Li—OBu distances [1.958 (3) to 1.991 (3) Å] are greater than the Fe—OBu distances. This configuration contrasts with that of one of the few known structures featuring alkoxides bridging between FeIII and Li atoms. In [(Bu2CHO)2Fe(µ-Bu2CHO)2Li(Bu2CHOH)] (Bochmann et al., 1980), the situation is reversed, with Fe—O bridges of 1.908 and 1.934 Å, and Li—O distances of 1.870 and 1.874 Å. The difference appears to be that Li is three-coordinate in that complex and four-coordinate in (I). The bonding at each Li atom is completed by complexation of a THF molecule and of a Br atom, thus forming an Li—Br—Li bridge that extends (I) to a one-dimensional polymer, propagating through an a glide (Fig. 2).