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accessA tetragonal polymorph of bis[hydrotris(pyrazol-1-yl)borato]iron(II)
aSchool of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, People's Republic of China
*Correspondence e-mail: nizhonghai@cumt.edu.cn
The title compound, [Fe(C9H10BN6)2], is a polymorph of a compound reported previously [Oliver et al. (1980![[Oliver, J. D., Mullica, D. F., Hutchinson, B. B. & Milligan, W. O. (1980). Inorg. Chem. 19, 165-168.]](../../../../../../logos/arrows/e_arr.gif "Oliver, J. D., Mullica, D. F., Hutchinson, B. B. & Milligan, W. O. (1980). Inorg. Chem. 19, 165-168.")
). Inorg. Chem. 19, 165–168]. In the previous report, the compound crystallized in the monoclinic P21/c (Z = 4), whereas the crystal symmetry of the compound reported here is tetragonal (P42/ncm, Z = 4). The molecular structure is comprised of two hydrotris(1-pyrazolyl)borate ligands (Tp−) and a central FeII ion, which is coordinated by six pyrazole N atoms from two two Tp− ligands, yielding a distorted bipyramidal FeN6 geometry. The complete molecule exhibits symmetry 2/m.
Related literature
For the of the other polymorph measured at room temperature, see: Oliver et al. (1980). For iron(II) complexes with the Tp− derivative ligands, see: Janiak et al. (2000); Reger et al. (2005).
![[Scheme 1]](hg5058scheme1.gif)
Experimental
Crystal data
|
Data collection: APEX2 (Bruker, 2004); cell SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP (Sheldrick, 1998); software used to prepare material for publication: XP.
Supporting information
contains datablocks global, I. DOI: 10.1107/S1600536811025839/hg5058sup1.cif
Structure factors: contains datablock I. DOI: 10.1107/S1600536811025839/hg5058Isup2.hkl
The title complex was prepared as following: methanol solution (10 ml) of [FeII(BF4)2].4H2O (30 mg, 0.1 mmol) was added slowly into a MeOH and aqueous solution (20 ml, water and methanol with v/v = 1/1) containing the ligand KTp (50.4 mg, 0.2 mmol). Then, the mixture was carefully filtered and the resulting solution was kept at room temperature for about two days, producing block brown crystals of (I) with yield 50%.
The coordinates of the H atom bound to boron atom was found from difference Fourier maps and refined freely. H atoms bound to C atoms were placed using the HFIX commands in SHELXL-97, with C—H distances of 0.93 Å. All H atoms were allowed for as riding atoms with Uiso(H) = 1.2Ueq(C).
Data collection: APEX2 (Bruker, 2004); cell SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP (Sheldrick, 1998); software used to prepare material for publication: XP (Sheldrick, 1998).
![[Figure 1]](./hg5058fig1thm.gif) | Fig. 1. A view of (I) with the unique atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level. [symmetry code: (A) -x, -y, -z; (B) -y, -x, -z; (C) +y, +x, +z.] |
| [Fe(C9H10BN6)2] | Dx = 1.492 Mg m−3 |
| Mr = 481.93 | Mo Kα radiation, λ = 0.71073 Å |
| Tetragonal, P42/ncm | Cell parameters from 1210 reflections |
| Hall symbol: -P 4ac 2ac | θ = 2.4–27.1° |
| a = 17.017 (3) Å | µ = 0.74 mm−1 |
| c = 7.4099 (15) Å | T = 123 K |
| V = 2145.7 (7) Å3 | Block, brown |
| Z = 4 | 0.2 × 0.15 × 0.12 mm |
| F(000) = 992 |
| Bruker APEXII CCD area-detector diffractometer | 1099 independent reflections |
| Radiation source: fine-focus sealed tube | 1095 reflections with I > 2σ(I) |
| Graphite monochromator | Rint = 0.034 |
| ϕ and ω scans | θmax = 26.0°, θmin = 3.4° |
| Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | h = −20→20 |
| Tmin = 0.867, Tmax = 0.916 | k = −20→16 |
| 14091 measured reflections | l = −9→8 |
| 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)] = 0.037 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.123 | H-atom parameters not refined |
| S = 0.95 | w = 1/[σ2(Fo2) + (0.0908P)2 + 2.7074P] where P = (Fo2 + 2Fc2)/3 |
| 1099 reflections | (Δ/σ)max < 0.001 |
| 87 parameters | Δρmax = 0.43 e Å−3 |
| 0 restraints | Δρmin = −0.39 e Å−3 |
| [Fe(C9H10BN6)2] | Z = 4 |
| Mr = 481.93 | Mo Kα radiation |
| Tetragonal, P42/ncm | µ = 0.74 mm−1 |
| a = 17.017 (3) Å | T = 123 K |
| c = 7.4099 (15) Å | 0.2 × 0.15 × 0.12 mm |
| V = 2145.7 (7) Å3 |
| Bruker APEXII CCD area-detector diffractometer | 1099 independent reflections |
| Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 1095 reflections with I > 2σ(I) |
| Tmin = 0.867, Tmax = 0.916 | Rint = 0.034 |
| 14091 measured reflections |
| R[F2 > 2σ(F2)] = 0.037 | 0 restraints |
| wR(F2) = 0.123 | H-atom parameters not refined |
| S = 0.95 | Δρmax = 0.43 e Å−3 |
| 1099 reflections | Δρmin = −0.39 e Å−3 |
| 87 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 | 0 | 0 | 0.0125 (3) | |
| B1 | 0.11871 (13) | 0.11871 (13) | 0.1589 (4) | 0.0150 (6) | |
| H1A | 0.1588 (14) | 0.1588 (14) | 0.211 (4) | 0.013 (7)* | |
| C1 | 0.19598 (12) | 0.00348 (11) | 0.3210 (3) | 0.0173 (5) | |
| H1 | 0.2365 | 0.0317 | 0.3749 | 0.021* | |
| C2 | 0.18477 (12) | −0.07653 (13) | 0.3322 (3) | 0.0218 (5) | |
| H2 | 0.2154 | −0.1127 | 0.3947 | 0.026* | |
| C3 | 0.11737 (12) | −0.09163 (12) | 0.2293 (3) | 0.0201 (5) | |
| H3 | 0.0954 | −0.1411 | 0.2117 | 0.024* | |
| C4 | 0.08225 (9) | 0.08225 (9) | −0.3162 (3) | 0.0176 (6) | |
| H4 | 0.0562 | 0.0562 | −0.4090 | 0.021* | |
| C5 | 0.13997 (9) | 0.13996 (9) | −0.3405 (3) | 0.0196 (6) | |
| H5 | 0.1594 | 0.1594 | −0.4491 | 0.024* | |
| C6 | 0.16160 (12) | 0.16160 (12) | −0.1690 (4) | 0.0179 (6) | |
| H6 | 0.1992 | 0.1992 | −0.1401 | 0.021* | |
| N1 | 0.13791 (9) | 0.03379 (9) | 0.2180 (2) | 0.0157 (4) | |
| N2 | 0.08928 (10) | −0.02509 (10) | 0.1603 (2) | 0.0162 (4) | |
| N3 | 0.11954 (9) | 0.11954 (9) | −0.0499 (3) | 0.0148 (5) | |
| N4 | 0.07002 (9) | 0.07002 (9) | −0.1405 (3) | 0.0152 (5) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Fe1 | 0.0106 (3) | 0.0106 (3) | 0.0163 (4) | −0.00276 (17) | −0.00002 (13) | −0.00002 (13) |
| B1 | 0.0120 (9) | 0.0120 (9) | 0.0212 (15) | −0.0015 (11) | −0.0007 (8) | −0.0007 (8) |
| C1 | 0.0121 (10) | 0.0198 (11) | 0.0201 (10) | −0.0007 (7) | −0.0028 (8) | 0.0015 (7) |
| C2 | 0.0177 (10) | 0.0192 (10) | 0.0283 (11) | 0.0014 (8) | −0.0013 (8) | 0.0071 (8) |
| C3 | 0.0198 (10) | 0.0135 (9) | 0.0270 (11) | −0.0020 (7) | 0.0006 (8) | 0.0030 (8) |
| C4 | 0.0183 (9) | 0.0183 (9) | 0.0162 (13) | −0.0024 (11) | −0.0005 (7) | −0.0005 (7) |
| C5 | 0.0194 (9) | 0.0194 (9) | 0.0201 (14) | −0.0011 (11) | 0.0032 (8) | 0.0032 (8) |
| C6 | 0.0136 (8) | 0.0136 (8) | 0.0266 (15) | −0.0008 (10) | 0.0027 (8) | 0.0027 (8) |
| N1 | 0.0144 (8) | 0.0131 (9) | 0.0197 (8) | −0.0031 (6) | −0.0012 (6) | −0.0007 (6) |
| N2 | 0.0144 (8) | 0.0128 (8) | 0.0216 (8) | −0.0034 (6) | −0.0004 (6) | −0.0009 (6) |
| N3 | 0.0111 (7) | 0.0111 (7) | 0.0223 (12) | −0.0020 (8) | 0.0001 (6) | 0.0001 (6) |
| N4 | 0.0134 (7) | 0.0134 (7) | 0.0190 (11) | −0.0024 (9) | −0.0006 (6) | −0.0006 (6) |
| Fe1—N2i | 1.9751 (17) | C2—C3 | 1.401 (3) |
| Fe1—N2ii | 1.9751 (17) | C2—H2 | 0.9300 |
| Fe1—N2 | 1.9751 (17) | C3—N2 | 1.331 (3) |
| Fe1—N2iii | 1.9751 (17) | C3—H3 | 0.9300 |
| Fe1—N4iii | 1.981 (2) | C4—N4 | 1.335 (3) |
| Fe1—N4 | 1.981 (2) | C4—C5 | 1.4005 |
| B1—N1ii | 1.545 (2) | C4—H4 | 0.9300 |
| B1—N1 | 1.545 (2) | C5—C6 | 1.374 (4) |
| B1—N3 | 1.547 (4) | C5—H5 | 0.9300 |
| B1—H1A | 1.04 (3) | C6—N3 | 1.343 (4) |
| C1—N1 | 1.351 (3) | C6—H6 | 0.9300 |
| C1—C2 | 1.377 (3) | N1—N2 | 1.368 (2) |
| C1—H1 | 0.9300 | N3—N4 | 1.368 (3) |
| N2i—Fe1—N2ii | 180.00 (6) | C3—C2—H2 | 127.4 |
| N2i—Fe1—N2 | 91.67 (10) | N2—C3—C2 | 110.30 (18) |
| N2ii—Fe1—N2 | 88.33 (10) | N2—C3—H3 | 124.9 |
| N2i—Fe1—N2iii | 88.33 (10) | C2—C3—H3 | 124.9 |
| N2ii—Fe1—N2iii | 91.67 (10) | N4—C4—C5 | 110.13 (13) |
| N2—Fe1—N2iii | 180.00 (14) | N4—C4—H4 | 124.9 |
| N2i—Fe1—N4iii | 89.05 (7) | C5—C4—H4 | 124.9 |
| N2ii—Fe1—N4iii | 90.95 (7) | C6—C5—C4 | 104.89 (14) |
| N2—Fe1—N4iii | 90.95 (7) | C6—C5—H5 | 127.6 |
| N2iii—Fe1—N4iii | 89.05 (7) | C4—C5—H5 | 127.6 |
| N2i—Fe1—N4 | 90.95 (7) | N3—C6—C5 | 108.8 (2) |
| N2ii—Fe1—N4 | 89.05 (7) | N3—C6—H6 | 125.6 |
| N2—Fe1—N4 | 89.05 (7) | C5—C6—H6 | 125.6 |
| N2iii—Fe1—N4 | 90.95 (7) | C1—N1—N2 | 109.85 (16) |
| N4iii—Fe1—N4 | 180.00 (18) | C1—N1—B1 | 132.23 (18) |
| N1ii—B1—N1 | 108.4 (2) | N2—N1—B1 | 117.93 (17) |
| N1ii—B1—N3 | 106.87 (15) | C3—N2—N1 | 106.59 (16) |
| N1—B1—N3 | 106.87 (15) | C3—N2—Fe1 | 133.71 (14) |
| N1ii—B1—H1A | 111.6 (9) | N1—N2—Fe1 | 119.67 (13) |
| N1—B1—H1A | 111.6 (9) | C6—N3—N4 | 109.5 (2) |
| N3—B1—H1A | 111.2 (17) | C6—N3—B1 | 131.8 (2) |
| N1—C1—C2 | 108.08 (18) | N4—N3—B1 | 118.6 (2) |
| N1—C1—H1 | 126.0 | C4—N4—N3 | 106.6 (2) |
| C2—C1—H1 | 126.0 | C4—N4—Fe1 | 134.45 (17) |
| C1—C2—C3 | 105.17 (18) | N3—N4—Fe1 | 118.91 (18) |
| C1—C2—H2 | 127.4 | ||
| N1—C1—C2—C3 | 0.4 (2) | N4iii—Fe1—N2—N1 | −136.67 (14) |
| C1—C2—C3—N2 | −0.2 (2) | N4—Fe1—N2—N1 | 43.33 (14) |
| N4—C4—C5—C6 | 0.0 | C5—C6—N3—N4 | 0.0 |
| C4—C5—C6—N3 | 0.0 | C5—C6—N3—B1 | 180.0 |
| C2—C1—N1—N2 | −0.6 (2) | N1ii—B1—N3—C6 | 122.08 (15) |
| C2—C1—N1—B1 | 179.4 (2) | N1—B1—N3—C6 | −122.08 (15) |
| N1ii—B1—N1—C1 | −124.0 (2) | N1ii—B1—N3—N4 | −57.92 (15) |
| N3—B1—N1—C1 | 121.1 (2) | N1—B1—N3—N4 | 57.92 (15) |
| N1ii—B1—N1—N2 | 55.9 (3) | C5—C4—N4—N3 | 0.0 |
| N3—B1—N1—N2 | −58.9 (2) | C5—C4—N4—Fe1 | −180.0 |
| C2—C3—N2—N1 | −0.2 (2) | C6—N3—N4—C4 | 0.0 |
| C2—C3—N2—Fe1 | 178.11 (14) | B1—N3—N4—C4 | 180.0 |
| C1—N1—N2—C3 | 0.4 (2) | C6—N3—N4—Fe1 | 180.0 |
| B1—N1—N2—C3 | −179.50 (18) | B1—N3—N4—Fe1 | 0.0 |
| C1—N1—N2—Fe1 | −178.13 (13) | N2i—Fe1—N4—C4 | 44.17 (5) |
| B1—N1—N2—Fe1 | 1.9 (2) | N2ii—Fe1—N4—C4 | −135.83 (5) |
| N2i—Fe1—N2—C3 | −43.85 (17) | N2—Fe1—N4—C4 | 135.83 (5) |
| N2ii—Fe1—N2—C3 | 136.15 (17) | N2iii—Fe1—N4—C4 | −44.17 (5) |
| N2iii—Fe1—N2—C3 | 39 (32) | N4iii—Fe1—N4—C4 | 0 (100) |
| N4iii—Fe1—N2—C3 | 45.2 (2) | N2i—Fe1—N4—N3 | −135.83 (5) |
| N4—Fe1—N2—C3 | −134.8 (2) | N2ii—Fe1—N4—N3 | 44.17 (5) |
| N2i—Fe1—N2—N1 | 134.26 (16) | N2—Fe1—N4—N3 | −44.17 (5) |
| N2ii—Fe1—N2—N1 | −45.74 (16) | N2iii—Fe1—N4—N3 | 135.83 (5) |
| N2iii—Fe1—N2—N1 | −143 (32) | N4iii—Fe1—N4—N3 | 180.00 (3) |
| Symmetry codes: (i) −y, −x, −z; (ii) y, x, z; (iii) −x, −y, −z. |
Experimental details
| Crystal data | |
| Chemical formula | [Fe(C9H10BN6)2] |
| Mr | 481.93 |
| Crystal system, space group | Tetragonal, P42/ncm |
| Temperature (K) | 123 |
| a, c (Å) | 17.017 (3), 7.4099 (15) |
| V (Å3) | 2145.7 (7) |
| Z | 4 |
| Radiation type | Mo Kα |
| µ (mm−1) | 0.74 |
| Crystal size (mm) | 0.2 × 0.15 × 0.12 |
| Data collection | |
| Diffractometer | Bruker APEXII CCD area-detector diffractometer |
| Absorption correction | Multi-scan (SADABS; Sheldrick, 2003) |
| Tmin, Tmax | 0.867, 0.916 |
| No. of measured, independent and observed [I > 2σ(I)] reflections | 14091, 1099, 1095 |
| Rint | 0.034 |
| (sin θ/λ)max (Å−1) | 0.617 |
| Refinement | |
| R[F2 > 2σ(F2)], wR(F2), S | 0.037, 0.123, 0.95 |
| No. of reflections | 1099 |
| No. of parameters | 87 |
| H-atom treatment | H-atom parameters not refined |
| Δρmax, Δρmin (e Å−3) | 0.43, −0.39 |
Computer programs: APEX2 (Bruker, 2004), SAINT-Plus (Bruker, 2001), SAINT-Plus (Bruker, 2001, SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XP (Sheldrick, 1998).
Acknowledgements
This work was supported by the Fundamental Research Funds for the Central Universities (China University of Mining and Technology). The authors thank Professors Hui-Zhong Kou and Seik Weng Ng for helpful comments and assistance in the preparation of this paper.
References
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Oliver, J. D., Mullica, D. F., Hutchinson, B. B. & Milligan, W. O. (1980). Inorg. Chem. 19, 165–168. CSD CrossRef CAS Web of Science Google Scholar
Reger, D. L., Gardinier, J. R., Smith, M. D., Shahin, A. M., Long, G. J., Rebbouh, L. & Grandjean, F. (2005). Inorg. Chem. 44, 1852–1856. Web of Science CSD CrossRef PubMed CAS Google Scholar
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| CRYSTALLOGRAPHIC COMMUNICATIONS |
Recently, hydro-tris(1-pyrazolyl)-borate (Tp-)and its derivatives have been employed as tridentate ligands to assembly molecular functional materials such as cyanide-bridged magnetic complexes, spin cross-over compounds and optic materials. In these cases, some mononuclear iron(II) complexes with two such tridendate ligands have been synthesized and crystal structures characterized (Janiak et al., 2000; Reger et al., 2005). The crystal structure of the title compound has been reported previously (Oliver et al., 1980) which was measured at room temperature and crystallized in monoclinic space group of P21/c (Z = 4). Recently, we synthesized this compound and measured its crystal structure at temperature 123 K. The result indicated that the crystal structure of the compound is significantly from the previous report. Herein, we report the crystal structure of the title compound [FeII(C9H10N6B)2] (I).
The title compound in this paper crystallizes in a tetragonal space group P42/ncm, suggesting there is a fourfold rotation symmetry axis in the unit cell. In the molecular structure of the title compound, there is a pseudo C3 rotation axis. The geometry and labeling scheme for the crystal structure of the title complex are depicted in Figure 1. The molecular structure of title compound in this work comprises of two Tp- ligands and one central iron(II) ion. In the molecular structure, the cental metal iron(II) ion is coordinated by six pyrazole nitrogen atoms from the same two Tp- ligands, yielding a distorted bipyramidal FeN6 geometry.
The Fe—N bond length is 1.975 (2)Å for Fe1—N2 and 1.983 (2)Å for Fe1—N4, respectively. which are simiar to those in the polymorph of the title compound reported previously at room temperature (Oliver et al., 1980). The N—Fe—N bond angle is 89.05 (18)° for N2—Fe1—N4 and 88.33 (18)° for N2—Fe1—N2[+y, +x, +z.], respectively. These Fe—N bond lengthes suggest that the iron(II) center of the title compound is low spin state whether at low temperature or at room temperature (Oliver et al., 1980).