research papers\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296

Ammonium bis­­(salicyl­aldehyde thio­semi­car­ba­zonato)ferrate(III), a supra­molecular material containing low-spin FeIII

aSchool of Engineering and Applied Science, Chemical Engineering and Applied Chemistry, Aston University, Aston Triangle, Birmingham B4 7ET, West Midlands, UK, bAston Institute of Materials Research, Aston University, Birmingham B4 7ET, West Midlands, UK, cX-ray Center, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria, and dInstitute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-01-3, 1060 Vienna, Austria
*Correspondence e-mail: p.vankoningsbruggen@aston.ac.uk

Edited by A. R. Kennedy, University of Strathclyde, Scotland (Received 18 March 2020; accepted 13 May 2020; online 29 May 2020)

The synthesis and crystal structure (100 K) of the title com­pound, ammonium bis­[salicyl­aldehyde thio­semi­car­ba­zon­ato(2−)-κ3O,N1,S]iron(III), NH4[Fe(C8H7N3OS)2], is reported. The asymmetric unit consists of an octa­hedral [FeIII(thsa)2] fragment, where thsa2− is salicyl­aldehyde thio­semi­car­ba­zon­ate(2−), and an NH4+ cation. Each thsa2− ligand binds via the thiol­ate S, the imine N and the phenolate O donor atoms, resulting in an FeIIIS2N2O2 chromophore. The ligands are orientated in two perpendicular planes, with the O and S atoms in cis and the N atoms in trans positions. The FeIII ion is in the low-spin state at 100 K. The crystal structure belongs to a category I order–disorder (OD) family. It is a polytype of a maximum degree of order (MDO). Fragments of the second MDO polytype lead to systematic twinning by pseudomerohedry.

1. Introduction

The study of the coordination chemistry of thio­semi­car­ba­zones is an attractive research area. Thio­semicarbazones display a wide range of pharmacological uses based, for example, on their anti­neoplastic, anti­bacterial, anti­viral and anti­fungal activities (Beraldo & Gambino, 2004[Beraldo, H. & Gambino, D. (2004). Med. Chem. 4, 31-39.]; Yemeli Tido et al., 2010[Yemeli Tido, E. W. Y., Faulmann, R., Roswanda, A., Meetsma, A. & van Koningsbruggen, P. J. (2010). Dalton Trans. 39, 1643-1651.]). This pharmacological action is often related to coordination of the thio­semicarbazone to metal ions (Farrell, 2002[Farrell, N. (2002). Coord. Chem. Rev. 232, 1-4.]). On the other hand, the magnetic properties of iron(III) com­pounds of thio­carbazone derivatives have attracted attention, particularly as switching behaviour was displayed for iron(III) bound to particular salicyl­aldehyde thio­semicarbazone derivatives (van Koningsbruggen et al., 2004[Koningsbruggen, P. J. van, Maeda, Y. & Oshio, H. (2004). Top. Curr. Chem. 233, 259-324.]; Phonsri et al., 2017[Phonsri, W., Darveniza, L. C., Batten, S. R. & Murray, K. S. (2017). Inorganics, 5, 51.]; Powell et al., 2014[Powell, R. E., Schwalbe, C. H., Tizzard, G. J. & van Koningsbruggen, P. J. (2014). Acta Cryst. C70, 595-598.], 2015[Powell, R. E., Schwalbe, C. H., Tizzard, G. J. & van Koningsbruggen, P. J. (2015). Acta Cryst. C71, 169-174.]; Yemeli Tido, 2010[Yemeli Tido, E. W. (2010). PhD thesis, University of Groningen, The Netherlands.]; Zelentsov et al., 1973[Zelentsov, V. V., Bogdanova, L. G., Ablov, A. V., Gerbeleu, N. V. & Dyatlova, C. V. (1973). Russ. J. Inorg. Chem. 18, 2654-2657.], Ryabova et al., 1978[Ryabova, N. A., Ponomarev, V. I., Atovmyan, L. O., Zelentsov, V. V. & Shipilov, V. I. (1978). Koord. Khim. 4, 119-126.], 1981a[Ryabova, N. A., Ponomarev, V. I., Zelentsov, V. V. & Atovmyan, L. O. (1981a). Kristallografiya, 26, 101-108.],b[Ryabova, N. A., Ponomarev, V. I., Zelentsov, V. V., Shipilov, V. I. & Atovmyan, L. O. (1981b). J. Struct. Chem. 22, 234-238.], 1982[Ryabova, N. A., Ponomarev, V. I., Zelentsov, V. V. & Atovmyan, L. O. (1982). Kristallografiya, 27, 81-91.]; Floquet et al., 2003[Floquet, S., Boillot, M. L., Rivière, E., Varret, F., Boukheddaden, K., Morineau, D. & Négrier, P. (2003). New J. Chem. 27, 341-348.], 2006[Floquet, S., Guillou, N., Négrier, P., Rivière, E. & Boillot, M. L. (2006). New J. Chem. 30, 1621-1627.], 2009[Floquet, S., Muñoz, M. C., Guillot, R., Rivière, E., Blain, G., Réal, J. A. & Boillot, M. L. (2009). Inorg. Chim. Acta, 362, 56-64.]; Li et al., 2013[Li, Z. Y., Dai, J. W., Shiota, Y., Yoshizawa, K., Kanegawa, S. & Sato, O. (2013). Chem. Eur. J. 19, 12948-12952.]).

This type of magnetic inter­conversion between the low-spin (S = [1 \over 2]) and high-spin (S = [5 \over 2]) state in FeIII (3d5) systems has now been found to be triggered by a change in temperature or pressure, or by light irradiation (Hayami et al., 2000[Hayami, S., Gu, Z., Shiro, M., Einaga, Y., Fujishima, A. & Sato, O. (2000). J. Am. Chem. Soc. 122, 7126-7127.], 2009[Hayami, S., Hiki, K., Kawahara, T., Maeda, Y., Urakami, D., Inoue, K., Ohama, M., Kawata, S. & Sato, O. (2009). Chem. Eur. J. 15, 3497-3508.]; van Koningsbruggen et al., 2004[Koningsbruggen, P. J. van, Maeda, Y. & Oshio, H. (2004). Top. Curr. Chem. 233, 259-324.]) and may be used in a functional way in research and technology (Létard et al., 2004[Létard, J. F., Guionneau, P. & Goux-Capes, L. (2004). Top. Curr. Chem. 235, 221-249.]; Gütlich et al., 2004[Gütlich, P., van Koningsbruggen, P. J. & Renz, F. (2004). Struct. Bond. 107, 27-75.]; Gütlich & Goodwin 2004[Gütlich, P. & Goodwin, H. A. (2004). Top. Curr. Chem. 233, 1-47.]; van Koningsbruggen et al., 2004[Koningsbruggen, P. J. van, Maeda, Y. & Oshio, H. (2004). Top. Curr. Chem. 233, 259-324.]; Nihei et al., 2007[Nihei, M., Shiga, T., Maeda, Y. & Oshio, H. (2007). Coord. Chem. Rev. 251, 2606-2621.]; Halcrow, 2013[Halcrow, M. A. (2013). In Spin-Crossover Materials: Properties and Applications, 1st ed. Chichester: John Wiley & Sons Ltd.]; Harding et al., 2016[Harding, D. J., Harding, P. & Phonsri, W. (2016). Coord. Chem. Rev. 313, 38-61.]).

In recent years, particular inter­est has focused on FeIII com­plexes of substituted derivatives of R-salicyl­aldehyde 4R′-thio­semicarbazone (Powell et al., 2014[Powell, R. E., Schwalbe, C. H., Tizzard, G. J. & van Koningsbruggen, P. J. (2014). Acta Cryst. C70, 595-598.], 2015[Powell, R. E., Schwalbe, C. H., Tizzard, G. J. & van Koningsbruggen, P. J. (2015). Acta Cryst. C71, 169-174.]; Yemeli Tido, 2010[Yemeli Tido, E. W. (2010). PhD thesis, University of Groningen, The Netherlands.]; Floquet et al., 2003[Floquet, S., Boillot, M. L., Rivière, E., Varret, F., Boukheddaden, K., Morineau, D. & Négrier, P. (2003). New J. Chem. 27, 341-348.], 2006[Floquet, S., Guillou, N., Négrier, P., Rivière, E. & Boillot, M. L. (2006). New J. Chem. 30, 1621-1627.], 2009[Floquet, S., Muñoz, M. C., Guillot, R., Rivière, E., Blain, G., Réal, J. A. & Boillot, M. L. (2009). Inorg. Chim. Acta, 362, 56-64.]; Li et al., 2013[Li, Z. Y., Dai, J. W., Shiota, Y., Yoshizawa, K., Kanegawa, S. & Sato, O. (2013). Chem. Eur. J. 19, 12948-12952.]) for generating FeIII spin crossover. In solution, free R-salicyl­aldehyde 4R′-thio­semicarbazone (H2L) exists in two tautomeric forms, i.e. the thione and thiol forms, as illustrated in Scheme 1. The chemistry of the FeIII com­pounds is rather com­plicated as it is possible for the tridentate R-salicyl­alde­hyde 4R′-thio­semicarbazone ligand (H2L) to exist in tautomeric forms; moreover, the ligand may also be present in its neutral, anionic or dianionic form. However, the formation of a particular type of FeIII com­plex unit, i.e. neutral, monocationic or monoanionic, can be achieved by tuning the degree of deprotonation of the ligand through pH variation of the reaction solution during the synthesis (Powell et al., 2014[Powell, R. E., Schwalbe, C. H., Tizzard, G. J. & van Koningsbruggen, P. J. (2014). Acta Cryst. C70, 595-598.], 2015[Powell, R. E., Schwalbe, C. H., Tizzard, G. J. & van Koningsbruggen, P. J. (2015). Acta Cryst. C71, 169-174.]; Powell, 2016[Powell, R. E. (2016). PhD thesis, Aston University, Birmingham, UK.]; Yemeli Tido, 2010[Yemeli Tido, E. W. (2010). PhD thesis, University of Groningen, The Netherlands.]; Floquet et al., 2009[Floquet, S., Muñoz, M. C., Guillot, R., Rivière, E., Blain, G., Réal, J. A. & Boillot, M. L. (2009). Inorg. Chim. Acta, 362, 56-64.]). We have been particularly skilled in preparing anionic FeIII com­plexes of the general formula (cation+)[Fe(L2−)2x(solvent), for which it became evident that the electronic state of the FeIII ion is dependent on the nature of the counter-ion, the nature and degree of solvation and the nature of the R,R′-substituted ligands (Powell et al., 2014[Powell, R. E., Schwalbe, C. H., Tizzard, G. J. & van Koningsbruggen, P. J. (2014). Acta Cryst. C70, 595-598.], 2015[Powell, R. E., Schwalbe, C. H., Tizzard, G. J. & van Koningsbruggen, P. J. (2015). Acta Cryst. C71, 169-174.]; Powell, 2016[Powell, R. E. (2016). PhD thesis, Aston University, Birmingham, UK.]; Yemeli Tido, 2010[Yemeli Tido, E. W. (2010). PhD thesis, University of Groningen, The Netherlands.]).

[Scheme 1]

We report here a novel FeIII com­pound, ammonium bis­[salicyl­aldehyde thio­semi­car­ba­zon­ato(2−)-κ3O,N1,S]iron(III), (I)[link] (see Scheme 2), containing two dianionic tridentate ligands, i.e. salicyl­aldehyde thio­semi­car­ba­zon­ate(2−), abbreviated as thsa2−, whose structure was determined at 100 K. Ryabova et al. (1981a[Ryabova, N. A., Ponomarev, V. I., Zelentsov, V. V. & Atovmyan, L. O. (1981a). Kristallografiya, 26, 101-108.]) reported the crystallographic data of the related com­pound Cs[Fe(thsa)2] at 103 and 298 K, which contains FeIII in the high-spin electronic state (S = [5 \over 2]). The main difference between NH4[Fe(thsa)2] and Cs[Fe(thsa)2] is the associated outer-sphere cation. This article describes that the variation in the cation leads to a modification of the structure of the FeIII com­pound, also changing the crystal packing, and being responsible for the FeIII in the present NH4[Fe(thsa)2] com­pound exhibiting the low-spin electronic state (S = [1 \over 2]).

Compound (I)[link] systematically crystallizes as twins. The twinning will be inter­preted in the light of order–disorder (OD) theory (Dornberger-Schiff & Grell-Niemann, 1961[Dornberger-Schiff, K. & Grell-Niemann, H. (1961). Acta Cryst. 14, 167-177.]). The OD theory was created in the 1950s to explain the common occurrence of polytypism and stacking faults. It has since been developed into a com­prehensive theory of local/partial symmetry. According to OD theory, if a structure is com­posed of layers and the layers are related by partial symmetry that is not valid for the whole structure, then the stacking becomes ambiguous. This means that the layers can be arranged in different ways, which are nevertheless all locally equivalent. Owing to the short range of inter­atomic inter­actions, these different stacking arrangements are also energetically equivalent. Consequently, OD structures often feature stacking faults. In OD twins, such as the title com­pound, the stacking faults lead to domains with different spacial orientations and are sporadic, i.e. the resulting domains are macroscopic and do not diffract coherently.

[Scheme 2]

2. Experimental

2.1. Spectroscopic measurements

Room-temperature IR spectra within the range 4000–400 cm−1 were recorded on a PerkinElmer FT–IR spectrometer Spectrum RXI using KBr pellets. Variable-temperature FT–IR spectra were measured with the attenuated total reflectance (ATR) technique using a PerkinElmer spectrum 400 with a Harrick diamond ATR equipped with a thermostatable temperature-control device. 1H and 13C{1H} NMR spectra were recorded on a Bruker 200 spectrometer with a broadband probe head. All NMR chemical shifts are reported in ppm; 1H and 13C shifts are established on the basis of the residual solvent resonance.

2.2. Synthesis and crystallization

The synthesis of H2thsa was carried out according to the general procedure described by Yemeli Tido (2010[Yemeli Tido, E. W. (2010). PhD thesis, University of Groningen, The Netherlands.]). Salicyl­aldehyde (49 mmol, 5.98 g) was dissolved in ethanol (80 ml) with constant stirring, and was added to a solution of thio­semicarbazide (49 mmol, 3.68 g) in ethanol (40 ml). The corresponding mixture was refluxed for 120 min. The resulting solution was cooled to room temperature and the solid isolated by filtration, washed with ether and dried in a vacuum for 2 d (yield: 7.75 g, 39.7 mmol, 81.0%; m.p. 491 K). H2thsa is soluble in methanol, acetone and dimethyl sulfoxide (DMSO). 1H NMR (200 MHz, DMSO-d6): δ (ppm) 11.39 (s, 1H, NH), 9.84 (s, 1H, OH), 8.40 (s, 1H, CH), 8.10 (s, 1H, o-ArCH), 7.87 (d, J = 8.8 Hz, 2H, NH2), 7.19 (t, J = 7.7 Hz, 1H, p-ArCH), 6.92–6.71 (m, 2H, m-ArCH). 13C NMR (50 MHz, DMSO-d6): δ (ppm) 177.76 (C=S), 156.52 (C—OH), 140.16 (C=N), 131.31 (ArCH), 126.99 (ArCH), 120.33 (ArCH), 119.48 (ArCH), 116.22 (ArCH). IR (cm−1, KBr): 3445 (νOH), 3175 (νNH), 3319 (νNH2), 1616 (νC=N), 1540–1603 (νC=C), 1266 (νC—N), 1111 (νC=S).

For the synthesis of NH4[Fe(thsa)2], (I)[link], Fe(p-CH3C6H4SO3)3·6H2O (1.0 mmol, 0.68 g) was dissolved in methanol (5 ml). H2thsa (1.0 mmol, 0.20 g) was dissolved in methanol (25 ml) with the addition of NH4OH (20 ml, 35 wt% in water). To this mixture, the methano­lic solution of the FeIII salt was added dropwise with constant stirring. The resulting dark-green solution was stirred and heated to 353 K for approximately 10 min. The solution was then allowed to stand at room temperature until crystals had formed. The dark-green microcrystals were isolated by filtration and dried (yield: 0.10 g, 0.22 mmol, 21.7%). Elemental analysis found/calculated (%) for C16H18FeN7O2S2: C, 41.47/41.47, H 3.90/3.94, N 20.99/21.30, O 8.05/6.95, S 13.87/13.93. IR (cm−1, KBr): 3472, 3240 (νNH), 3016 (νNH2), 1595 (νC=N), 1546–1509 (νC=C ring), 1278 (νC—O), 1203 (νN—N), 1027 (νC—N), 756 (νC—S).

2.3. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1[link]. The crystal was modelled as twinned by reflection at (100). The positions of the H atoms on the amine N atoms were located in difference Fourier maps and were refined with restrained N—H distances of 0.87 (2) Å. The NH4+ cation is disordered around a pseudo-twofold axis. The ammonium N atom was refined as disordered about two positions (N7 and N7′). The sum of the occupancy parameters was constrained to 1. The atomic displacement parameters (ADPs) were constrained to the same value, resulting in a significant decrease of the estimated standard uncertainty on the occupancy parameters. Even though residual electron density in the difference Fourier maps could be attributed to the H atoms of the disordered ammonium positions, a reliable refinement was not possible. The ammonium H atoms were therefore ultimately omitted from the refinement. Other H atoms were included in the refinement in calculated positions and allowed to ride on their parent atoms.

Table 1
Experimental details

Crystal data
Chemical formula (NH4)[Fe(C8H7N3OS)2]
Mr 460.34
Crystal system, space group Monoclinic, P21/n
Temperature (K) 100
a, b, c (Å) 8.4393 (8), 18.2444 (17), 11.7635 (11)
β (°) 90.052 (4)
V3) 1811.2 (3)
Z 4
Radiation type Mo Kα
μ (mm−1) 1.09
Crystal size (mm) 0.60 × 0.36 × 0.18
 
Data collection
Diffractometer Bruker Kappa APEXII CCD
Absorption correction Multi-scan (SADABS; Bruker, 2012[Bruker (2012). APEX2 and SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.601, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections 62618, 5355, 4839
Rint 0.041
(sin θ/λ)max−1) 0.708
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.042, 0.110, 1.10
No. of reflections 5355
No. of parameters 274
No. of restraints 4
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.93, −0.74
Computer programs: APEX2 (Bruker, 2012[Bruker (2012). APEX2 and SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA.]), SAINT-Plus (Bruker, 2012[Bruker (2012). APEX2 and SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA.]), SUPERFLIP (Palatinus & Chapuis, 2007[Palatinus, L. & Chapuis, G. (2007). J. Appl. Cryst. 40, 786-790.]), SHELXL2018 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]) and ORTEP-3 (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]).

3. Results and discussion

3.1. Crystal structure

The structure of NH4[Fe(thsa)2], (I)[link] (Fig. 1[link]), was determined at 100 K and was found to crystallize in the monoclinic space group P21/n. The asymmetric unit consists of one for­mula unit, i.e. NH4[Fe(thsa)2], with no atom on a special position. The FeIII cation is coordinated by two dianionic O,N,S-tridentate chelating thsa2− ligands, displaying a dis­torted octa­hedral FeIIIO2N2S2 geometry. Selected geometric parameters are listed in Table 2[link]. The twofold deprotonated ligands are coordinated to the FeIII atom via the phenolate O, thiol­ate S and imine N atoms. These donor–FeIII bonds are located in two perpendicular planes, with the O and S atoms in cis positions, whereby the S1—Fe—S2 and O1—Fe—O2 angles are 92.07 (3) and 88.53 (12)°, respectively. In addition, the N atoms are situated in trans positions, which is evidenced by the N1—Fe—N4 bond angle of 176.71 (11)°. The FeO2N2S2 coordination core is distorted; the Fe–donor atom distances fall within the range expected for FeIII in the low-spin state (van Koningsbruggen et al., 2004[Koningsbruggen, P. J. van, Maeda, Y. & Oshio, H. (2004). Top. Curr. Chem. 233, 259-324.]).

Table 2
Selected geometric parameters (Å, °)

Fe1—N1 1.937 (3) S1—C8 1.745 (3)
Fe1—O1 1.941 (3) S2—C16 1.747 (3)
Fe1—N4 1.944 (3) N1—C7 1.295 (4)
Fe1—O2 1.952 (3) N1—N2 1.398 (4)
Fe1—S1 2.2369 (10) N4—C15 1.293 (4)
Fe1—S2 2.2377 (10) N4—N5 1.406 (4)
       
N1—Fe1—O1 93.08 (11) C16—S2—Fe1 95.57 (12)
N1—Fe1—N4 176.71 (11) C2—O1—Fe1 126.5 (2)
O1—Fe1—N4 88.73 (11) C10—O2—Fe1 126.4 (2)
N1—Fe1—O2 88.97 (11) C7—N1—Fe1 125.7 (2)
O1—Fe1—O2 88.53 (12) C8—N2—N1 113.4 (3)
N4—Fe1—O2 93.83 (11) C15—N4—Fe1 125.0 (2)
N1—Fe1—S1 86.44 (9) C16—N5—N4 113.7 (3)
O1—Fe1—S1 177.74 (10) C2—C1—C7 122.4 (3)
N4—Fe1—S1 91.85 (9) O1—C2—C1 124.5 (3)
O2—Fe1—S1 89.26 (10) N1—C7—C1 126.9 (3)
N1—Fe1—S2 91.60 (9) N2—C8—S1 124.7 (2)
O1—Fe1—S2 90.15 (9) C10—C9—C15 124.2 (3)
N4—Fe1—S2 85.65 (9) O2—C10—C9 123.6 (3)
O2—Fe1—S2 178.59 (10) N4—C15—C9 126.4 (3)
S1—Fe1—S2 92.07 (3) N5—C16—S2 124.0 (3)
C8—S1—Fe1 94.63 (11)    
[Figure 1]
Figure 1
The mol­ecular structure and atom-numbering scheme for NH4[Fe(thsa)2], (I)[link]. The N atom of the NH4+ cation has been omitted for clarity. Displacement ellipsoids are drawn at the 50% probability level.

The incorporation of a monovalent NH4+ cation could be corroborated by variable-temperature FT–IR spectroscopy, which revealed the sharpening of the N—H stretching vibrational mode of the NH4+ cation at 3240 cm−1 upon cooling from ambient temperature to 173 K, which is in line with the freezing of the rotation of the NH4+ cation in the cavity.

The presence of the trivalent iron cation is supported by the coordination of two doubly deprotonated ligands to the FeIII ion. In addition, the presence of both dianionic ligands is confirmed by the C—S, C—N and N—N bond lengths (Table 2[link]) obtained for NH4[Fe(thsa)2], which show characteristics of a bond order between single and double bonds. Ryabova et al. (1981a[Ryabova, N. A., Ponomarev, V. I., Zelentsov, V. V. & Atovmyan, L. O. (1981a). Kristallografiya, 26, 101-108.]) reported the structure of the related high-spin com­pound Cs[Fe(thsa)2] at 103 and 298 K, which crystallizes in the space group Pna21 with an asymmetric unit consisting of a Cs+ cation and an [Fe(thsa)2] anionic unit. The C—S, C—N and N—N bond lengths [at 103 K: C—S = 1.749 (9) and 1.761 (9) Å; C—N = 1.314 (10) and 1.303 (11) Å; N—N = 1.371 (11) and 1.380 (11) Å; at 298 K: C—S = 1.743 (14) and 1.775 (17) Å; C—N = 1.281 (19) and 1.281 (19) Å; N—N = 1.393 (18) and 1.412 (18) Å] reported by Ryabova et al. (1981a[Ryabova, N. A., Ponomarev, V. I., Zelentsov, V. V. & Atovmyan, L. O. (1981a). Kristallografiya, 26, 101-108.]) for Cs[Fe(thsa)2], correspond to the bond lengths for NH4[Fe(thsa)2], (I)[link], at 100 K.

The hydrogen-bonding inter­actions of NH4[Fe(thsa)2] are listed in Table 3[link] and are displayed in Fig. 2[link]. The terminal N atoms of the tridentate ligands (N3 and N6), form N6—HN62⋯O2i and N3—HN32⋯O1ii contacts with the phe­nol­ate donor atoms O1 and O2, respectively. In this manner, successive FeIII entities are linked in the c direction. The NH4+ cations are distributed in between the layers of the FeIII entities, with alternate separations of the N atoms of the NH4+ cation of 3.915 (7) [at (x + 1, y, z), denoted iii] and 4.547 (7) Å [at (x + [{1\over 2}], −y + [{1\over 2}], z + [{1\over 2}]), denoted iv] in the a direction. The FeIII⋯FeIII separations in the present com­pound are 8.4393 (8) Å for FeIII⋯FeIIIiii and 9.7134 (13) Å for FeIII⋯FeIIIv [symmetry code: (v) −x, −y + 1, −z + 1]. The FeIII units in NH4[Fe(thsa)2] are linked by hydrogen-bonding inter­actions between the corresponding phenolate O and amino N atoms of the FeIII units.

Table 3
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N3—HN31⋯O1i 0.87 (2) 2.03 (3) 2.879 (4) 164 (6)
N6—HN62⋯O2ii 0.88 (2) 1.96 (2) 2.834 (4) 178 (5)
Symmetry codes: (i) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]; (ii) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}].
[Figure 2]
Figure 2
A projection showing the unit cell of NH4[Fe(thsa)2], (I)[link]. The N atom of the NH4+ cation has been omitted for clarity. Displacement ellipsoids are drawn at the 50% probability level. Dashed lines indicate hydrogen bonds. [Symmetry codes: (i) x − [{1\over 2}], −y + [{1\over 2}], z − [{1\over 2}]; (ii) x − [{1\over 2}], −y + [{1\over 2}], z + [{1\over 2}].]

The embedding of the NH4+ cation is, therefore, essentially different from that of the Cs+ cation in Cs[Fe(thsa)2] at 103 and 298 K, where the nearest-neighbour coordination sphere of the Cs+ cation is constituted by O, N and C atoms, which form a seven-pointed polyhedron with Cs–(ligand donor atom) separations between 3.06 and 3.82 Å (Ryabova et al., 1981a[Ryabova, N. A., Ponomarev, V. I., Zelentsov, V. V. & Atovmyan, L. O. (1981a). Kristallografiya, 26, 101-108.]). This feature shows some similarity with the Cs+ cation in Cs[Fe(5-Br-thsa)2] (Powell et al., 2015[Powell, R. E., Schwalbe, C. H., Tizzard, G. J. & van Koningsbruggen, P. J. (2015). Acta Cryst. C71, 169-174.]) that is at the centre of an irregular seven-donor-atom polyhedron, the donor atoms of which originate from symmetry-related equivalents of both symmetry-independent 5-bromo­salicyl­aldehyde thio­semi­car­ba­zon­ate(2−) (5-Br-thsa) ligands. Several donor atoms coordinated to the FeIII atom of Cs[Fe(5-Br-thsa)2] form inter­actions with the Cs+ cation in the second coordination sphere; this is likely to modulate the electron density of the Fe–(donor atom) bonds and hence influence the electronic state of the FeIII cation. The latter is also prone to be affected by the assembly of FeIII units in the unit cell. The presence of the Br substituent on the salicyl­aldehyde group of the ligand in Cs[Fe(5-Br-thsa)2] is a factor in determining the crystal packing, as the Br substituent of one Cs[Fe(5-Br-thsa)2] unit provides a hydrogen-bonding inter­action with an amino group of a neighbouring FeIII unit, creating ring systems.

Clearly, the variation in cation, ligand substituents and crystal packing is related to the spin state of FeIII being high-spin in Cs[Fe(thsa)2] at 103 and 298 K (Ryabova et al., 1981a[Ryabova, N. A., Ponomarev, V. I., Zelentsov, V. V. & Atovmyan, L. O. (1981a). Kristallografiya, 26, 101-108.]), low-spin in Cs[Fe(5-Br-thsa)2] at 293 K (Powell et al., 2015[Powell, R. E., Schwalbe, C. H., Tizzard, G. J. & van Koningsbruggen, P. J. (2015). Acta Cryst. C71, 169-174.]) and low-spin in the present NH4[Fe(thsa)2] at 100 K. Variable-temperature magnetic susceptibility measurements (10–300 K) confirm that the FeIII ion in NH4[Fe(thsa)2] remains in the low-spin state over this temperature range (Powell, 2016[Powell, R. E. (2016). PhD thesis, Aston University, Birmingham, UK.]). In addition, within this family of cation(+) bis­[R-salicyl­aldehyde 4R′-thio­semi­car­ba­zon­ato(2−)]ferrate(III) salts, the presence of particular solvent mol­ecules may further affect the crystal packing, with the associated inter­molecular effects influencing the electronic structure of FeIII, e.g. leading to a low-spin state of FeIII in Cs[Fe(L)2]·CH3OH [L = 3-eth­oxy­salicyl­aldehyde 4-methyl­thio­semi­car­ba­zon­ate(2−)] at 100 K (Powell et al., 2014[Powell, R. E., Schwalbe, C. H., Tizzard, G. J. & van Koningsbruggen, P. J. (2014). Acta Cryst. C70, 595-598.]). Our further studies of members of this FeIII family may shed more light on how the spin state of FeIII may be tuned in these systems.

3.2. Systematic twinning and OD theory

Even though NH4[Fe(thsa)2] crystallizes in the monoclinic space group P21/n, the lattice is metrically virtually ortho­rhom­bic primitive [oP, β = 90.052 (4)°]. The crystals are systematically twinned by the additional symmetry of the lattice with respect to the 2/m point symmetry of the crystal. Thus, the twin law com­prises the operations {2[100], m[100], 2[001], m[001]} and the twin point group (Nespolo, 2004[Nespolo, M. (2004). Z. Kristallogr. 219, 57-71.]) is 2′/m′2/m2′/m′. Since the reflections of both domains overlap nearly perfectly (twin index 1, twin obliquity ∼0), the twinning can be classified as being by metric pseudomerohedry (Nespolo & Ferraris, 2000[Nespolo, M. & Ferraris, G. (2000). Z. Kristallogr. 215, 77-81.]).

A higher point symmetry of the lattice com­pared to the point symmetry of the crystal is often associated with twinning. However, it is not a sufficient precondition for its existence. In fact, many polar structures do not form twins by inversion despite inversion being an intrinsic symmetry of any lattice. One common and often overlooked cause of twinning is partial symmetry, which may lead to a twin inter­face that is locally equivalent to the twin individuals. The order–disorder (OD) theory (Dornberger-Schiff & Grell-Niemann, 1961[Dornberger-Schiff, K. & Grell-Niemann, H. (1961). Acta Cryst. 14, 167-177.]) was introduced in the 1950s to deal precisely with these kinds of structures.

In the light of OD theory, the crystal structure of NH4[Fe(thsa)2] can be decom­posed into OD layers An (n being a sequential number) parallel to (010), which, in this case, also correspond to layers in the crystallochemical sense (Fig. 3[link]). The crucial point of an OD structure is that partial symmetry operations relate individual layers, yet need not be valid for the whole structure. In the case of NH4[Fe(thsa)2], the An layers possess (idealized) P2(n)a symmetry (Fig. 4[link]). In this layer-group notation, which is commonly used in the OD literature, the parentheses indicate the direction missing translational symmetry. The [Fe(thsa)2] ions are located on the twofold axes of the An layers, whereas the ammonium ions are disordered about these axes.

[Figure 3]
Figure 3
The crystal structure of NH4[Fe(thsa)2], viewed down [100]. The names of the OD layers are indicated to the right and a dotted line indicates the inter­face between the OD layers, which in this case is not planar.
[Figure 4]
Figure 4
A layer in the crystal structure of NH4[Fe(thsa)2] projected on the layer plane (010). Symmetry elements are represented by the usual graphical symbols. The indicated unit cell corresponds to the standard origin choice of the P2(n)a layer group (on 2[100]), not of the overall crystal structure.

The set of partial symmetry operations of any possible stacking of NH4[Fe(thsa)2] is described by the OD groupoid family symbol (Dornberger-Schiff & Grell-Niemann, 1961[Dornberger-Schiff, K. & Grell-Niemann, H. (1961). Acta Cryst. 14, 167-177.]).

P 2 (n) a

n2,r 22 2r–1

OD groupoid families are the analogue of space group types in classical crystallography. They abstract from metric parameters and additionally of the particular stacking. The first line of the symbol indicates the layer symmetry, the second line one set of operations relating adjacent layers. Since the intrinsic translations are not limited to those found in space groups, a generalization of the Hermann-Mauguin notation is used. For example, n2,r represents a glide reflection with the intrinsic translation b/2 + rc/2, whereby r is one of the metric parameters the OD groupoid family abstracts from.

Owing to the partial symmetry, layers can be arranged in different ways while keeping pairs of adjacent layers geometrically equivalent. These stacking possibilities can be enumerated using the NFZ relationship (Ďurovič, 1997[Ďurovič, S. (1997). EMU Notes in Mineralogy, Vol. 1, edited by S. Merlino, pp. 3-28. Jena, Germany: European Mineralogical Union.]), which reads as Z = N/F = [Gn:GnGn+1]. Gn = P1(1)a is the group of operations of the An layer that do not invert An with respect to the stacking direction. Since the a-glide planes of adjacent layers do not overlap, GnGn+1 = P1(1)1. The possible layer arrangements are determined by coset decom­position of the latter in the former. In other words, given the An layer, the adjacent An+1 layer can be placed in Z = [P1(1)a:P1(1)1] = 2 ways, which are related by the a-glide reflection of the An layer.

Of the infinity of the thus obtained locally equivalent polytypes, a finite number is especially simple in the sense that they cannot be decom­posed into fragments of even simpler polytypes. In these polytypes, which are said to be of a maximum degree of order (MDO), not only pairs but also triples, quadruples and generally n-tuples of adjacent layers are equivalent (for a more rigorous definition, see Dornberger-Schiff, 1982[Dornberger-Schiff, K. (1982). Acta Cryst. A38, 483-491.]). Polytypes of the MDO type play a special role in OD theory, because all other polytypes can be decom­posed into fragments of MDO polytypes. Moreover, experience shows that ordered bulk polytypes are in most cases of the MDO type. The OD family of NH4[Fe(thsa)2] contains two MDO polytypes:

MDO1: P2/b11, b = 2b0 + rc

MDO2: P21/n, b = 2b0

where b0 is the vector perpendicular to the layer lattices with the length of one layer width. Both MDO polytypes are shown schematically in Fig. 5[link]. The twin individuals of NH4[Fe(thsa)2] correspond to the MDO2 polytype. A fragment of the MDO1 polytype is located at the twin inter­face.

[Figure 5]
Figure 5
Schematic representation of the (top) MDO1 and (bottom) MDO2 polytypes of NH4[Fe(thsa)2]. [Fe(thsa)2] ions are represented by pairs of triangles which are blue on one side and red on the other side. Darker colours indicate a translation by a/2. The geometrical elements of partial sym­metry operations of layers and those relating adjacent layers are represented by the usual graphical symbols for symmetry elements. Screw axes and glide planes with nonstandard intrinsic translations are represented using the symbols for the 21 and n symmetry elements. Symbols of operations that are valid for the whole polytype are shown in red.

Thus, the OD theory plausibly explains the formation of the observed twins, as the twin inter­face is geometrically and, if inter­actions over one layer width are ignored, also energetically equivalent to the twin individuals. Moreover, it explains the pseudo-oP metrics of the lattice. Such a metric pseudo-symmetry has often been considered as `accidental'. However, here it is clearly very much intrinsic to the structure family.

Finally, it should be noted that an OD description is usually based on a certain degree of idealization. Ordered polytypes are desymmetrized with respect to the ideal description (Ďurovič, 1979[Ďurovič, S. (1979). Krist. Tech. 14, 1047-1053.]). Indeed, in the actual MDO2 polytypes of NH4[Fe(thsa)2], the symmetry of the An layers is reduced by an index of 2 from P2(n)a to P1(n)1. Accordingly, the site symmetry of the [Fe(thsa)2] ion is reduced from 2 to 1. Moreover, the unit-cell parameters deviate slightly from ortho­rhom­bic metrics [β = 90.052 (4)°, according to single-crystal diffraction]. Finally, the desymmetrization is also observed by a splitting of the single disordered ammonium position into two independent positions, which are now not forcibly disordered in a 1:1 manner. Indeed, the ratio of the occupancies of both positions refines to 52.7 (9):47.3 (9). However, collectively the deviations from the idealized partial symmetry are minute and the OD description can be considered as correct.

Supporting information


Computing details top

Data collection: APEX2 (Bruker, 2012); cell refinement: APEX2 (Bruker, 2012); data reduction: SAINT-Plus (Bruker, 2012); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015); molecular graphics: ORTEP-3 (Farrugia, 2010); software used to prepare material for publication: SHELXL2018 (Sheldrick, 2015).

(I) top
Crystal data top
C16H18FeN7O2S2F(000) = 948
Mr = 460.34Dx = 1.688 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 8.4393 (8) ÅCell parameters from 9753 reflections
b = 18.2444 (17) Åθ = 2.8–30.2°
c = 11.7635 (11) ŵ = 1.09 mm1
β = 90.052 (4)°T = 100 K
V = 1811.2 (3) Å3Rhombic prism, green
Z = 40.60 × 0.36 × 0.18 mm
Data collection top
Bruker Kappa APEXII CCD
diffractometer
4839 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.041
ω– and φ–scansθmax = 30.2°, θmin = 1.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2012)
h = 1111
Tmin = 0.601, Tmax = 0.746k = 2525
62618 measured reflectionsl = 1616
5355 independent reflections
Refinement top
Refinement on F24 restraints
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.042H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.110 w = 1/[σ2(Fo2) + (0.0283P)2 + 5.6668P]
where P = (Fo2 + 2Fc2)/3
S = 1.10(Δ/σ)max < 0.001
5355 reflectionsΔρmax = 0.93 e Å3
274 parametersΔρmin = 0.74 e Å3
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. Refined as a 2-component twin.

Crystal data collection for NH4[Fe(thsa)2] was carried out after attaching a single crystal to a Kapton micro mount by using perfluorinated oil and mounted on a Bruker KAPPA APEX II diffractometer equipped with a CCD detector. Data were collected at 100 K in a dry stream of nitrogen with MoKα radiation (λ = 0.71073 Å). Data were reduced to intensity values using SAINT-Plus (Bruker, 2012) and absorption correction was applied using the multi-scan method implemented by SADABS (Bruker, 2012). The structure was solved using charge-flipping implemented by SUPERFLIP (Palatinus & Chapuis, 2007) and refined against F2 with SHELX (Sheldrick, 2014).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Fe10.18454 (6)0.24824 (3)0.47816 (5)0.01283 (9)
S10.36955 (12)0.16316 (4)0.51161 (7)0.02015 (17)
S20.36760 (11)0.33417 (4)0.44372 (7)0.01932 (17)
O10.0177 (3)0.31944 (16)0.4514 (2)0.0256 (6)
O20.0210 (3)0.17473 (16)0.5062 (2)0.0269 (6)
N10.1906 (3)0.26809 (14)0.6398 (2)0.0151 (5)
N20.2879 (3)0.22705 (15)0.7119 (2)0.0155 (5)
N30.4684 (4)0.13350 (17)0.7206 (3)0.0202 (6)
N40.1913 (3)0.22967 (15)0.3155 (2)0.0135 (5)
N50.2879 (3)0.27192 (16)0.2434 (2)0.0164 (5)
N60.4642 (4)0.36688 (17)0.2347 (3)0.0201 (6)
N70.2779 (9)0.2599 (4)0.4588 (7)0.0181 (8)0.473 (9)
N7'0.2763 (8)0.2370 (4)0.4976 (6)0.0181 (8)0.527 (9)
C10.0056 (4)0.37125 (18)0.6414 (3)0.0168 (6)
C20.0357 (4)0.3690 (2)0.5250 (3)0.0197 (6)
C30.1472 (4)0.4205 (2)0.4859 (3)0.0260 (8)
H30.1784720.4195640.4083180.031*
C40.2126 (4)0.47272 (19)0.5580 (3)0.0255 (8)
H40.2860560.5072600.5284610.031*
C50.1725 (5)0.47535 (18)0.6724 (3)0.0227 (7)
H5A0.2179160.5108690.7217080.027*
C60.0642 (4)0.42452 (19)0.7123 (3)0.0202 (7)
H60.0358850.4255760.7904120.024*
C70.1138 (4)0.31973 (19)0.6915 (3)0.0178 (6)
H70.1307240.3240310.7710630.021*
C80.3732 (4)0.17776 (17)0.6582 (3)0.0142 (6)
C90.0054 (4)0.12707 (18)0.3156 (3)0.0168 (6)
C100.0329 (4)0.12625 (19)0.4325 (3)0.0190 (6)
C110.1425 (4)0.0731 (2)0.4712 (3)0.0255 (7)
H110.1682530.0713160.5498250.031*
C120.2123 (4)0.02419 (19)0.3988 (3)0.0244 (8)
H120.2856680.0107840.4272760.029*
C130.1755 (5)0.02567 (18)0.2828 (3)0.0234 (7)
H130.2245360.0080080.2322640.028*
C140.0679 (4)0.07619 (19)0.2421 (3)0.0210 (7)
H140.0427480.0767660.1633690.025*
C150.1132 (4)0.17866 (18)0.2639 (3)0.0164 (6)
H150.1281690.1747340.1840330.020*
C160.3709 (4)0.32150 (17)0.2965 (3)0.0162 (6)
HN310.496 (8)0.154 (3)0.785 (3)0.06 (2)*
HN320.534 (5)0.104 (2)0.684 (4)0.040 (15)*
HN610.523 (5)0.400 (2)0.264 (4)0.028 (12)*
HN620.484 (6)0.355 (2)0.164 (2)0.027 (12)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Fe10.01120 (16)0.01814 (17)0.00915 (15)0.00055 (17)0.00122 (18)0.00086 (13)
S10.0290 (4)0.0192 (3)0.0123 (4)0.0058 (3)0.0039 (3)0.0012 (3)
S20.0272 (4)0.0188 (3)0.0120 (4)0.0058 (3)0.0018 (3)0.0016 (3)
O10.0215 (13)0.0417 (15)0.0136 (12)0.0145 (11)0.0028 (10)0.0018 (10)
O20.0283 (14)0.0434 (15)0.0091 (11)0.0183 (12)0.0018 (10)0.0033 (10)
N10.0121 (12)0.0176 (11)0.0156 (13)0.0010 (10)0.0009 (10)0.0042 (9)
N20.0137 (14)0.0211 (12)0.0117 (11)0.0005 (10)0.0040 (9)0.0005 (9)
N30.0254 (16)0.0178 (13)0.0175 (14)0.0029 (11)0.0060 (12)0.0008 (11)
N40.0120 (11)0.0231 (12)0.0055 (11)0.0001 (10)0.0000 (9)0.0003 (9)
N50.0149 (14)0.0206 (12)0.0137 (12)0.0020 (10)0.0006 (10)0.0021 (10)
N60.0257 (16)0.0197 (14)0.0148 (14)0.0038 (11)0.0040 (12)0.0010 (11)
N70.0184 (15)0.020 (2)0.016 (2)0.003 (2)0.003 (2)0.0010 (14)
N7'0.0184 (15)0.020 (2)0.016 (2)0.003 (2)0.003 (2)0.0010 (14)
C10.0156 (15)0.0206 (14)0.0142 (15)0.0007 (12)0.0013 (12)0.0008 (11)
C20.0149 (14)0.0279 (16)0.0162 (15)0.0055 (12)0.0008 (12)0.0034 (13)
C30.0241 (18)0.0355 (19)0.0186 (16)0.0105 (14)0.0018 (13)0.0035 (14)
C40.0233 (19)0.0233 (15)0.0299 (19)0.0041 (13)0.0013 (14)0.0059 (14)
C50.0225 (17)0.0168 (14)0.0289 (19)0.0001 (13)0.0001 (15)0.0041 (12)
C60.0182 (15)0.0187 (15)0.0236 (17)0.0001 (12)0.0004 (13)0.0015 (13)
C70.0133 (14)0.0260 (15)0.0141 (14)0.0000 (12)0.0015 (12)0.0013 (12)
C80.0167 (13)0.0155 (13)0.0104 (14)0.0006 (11)0.0046 (12)0.0016 (10)
C90.0122 (14)0.0203 (14)0.0180 (15)0.0011 (11)0.0027 (11)0.0006 (12)
C100.0176 (15)0.0261 (16)0.0132 (15)0.0037 (12)0.0033 (12)0.0004 (12)
C110.0219 (17)0.0359 (19)0.0188 (17)0.0124 (14)0.0024 (13)0.0041 (14)
C120.0210 (19)0.0223 (15)0.030 (2)0.0049 (13)0.0035 (14)0.0038 (13)
C130.0222 (17)0.0184 (14)0.0296 (19)0.0007 (14)0.0026 (16)0.0051 (12)
C140.0213 (16)0.0204 (16)0.0214 (17)0.0011 (13)0.0019 (13)0.0048 (13)
C150.0162 (14)0.0225 (15)0.0106 (13)0.0007 (12)0.0027 (12)0.0011 (11)
C160.0159 (13)0.0158 (13)0.0168 (16)0.0024 (11)0.0022 (13)0.0010 (11)
Geometric parameters (Å, º) top
Fe1—N11.937 (3)N5—C161.304 (4)
Fe1—O11.941 (3)N6—C161.354 (4)
Fe1—N41.944 (3)C1—C61.410 (5)
Fe1—O21.952 (3)C1—C21.413 (5)
Fe1—S12.2369 (10)C1—C71.438 (5)
Fe1—S22.2377 (10)C2—C31.408 (5)
S1—C81.745 (3)C3—C41.389 (5)
S2—C161.747 (3)C4—C51.389 (5)
O1—C21.330 (4)C5—C61.384 (5)
O2—C101.320 (4)C9—C141.412 (5)
N1—C71.295 (4)C9—C101.413 (5)
N1—N21.398 (4)C9—C151.443 (5)
N2—C81.313 (4)C10—C111.415 (5)
N3—C81.355 (4)C11—C121.367 (5)
N4—C151.293 (4)C12—C131.400 (5)
N4—N51.406 (4)C13—C141.380 (5)
N1—Fe1—O193.08 (11)C6—C1—C7118.2 (3)
N1—Fe1—N4176.71 (11)C2—C1—C7122.4 (3)
O1—Fe1—N488.73 (11)O1—C2—C3117.9 (3)
N1—Fe1—O288.97 (11)O1—C2—C1124.5 (3)
O1—Fe1—O288.53 (12)C3—C2—C1117.6 (3)
N4—Fe1—O293.83 (11)C4—C3—C2121.6 (3)
N1—Fe1—S186.44 (9)C3—C4—C5121.2 (3)
O1—Fe1—S1177.74 (10)C6—C5—C4117.8 (3)
N4—Fe1—S191.85 (9)C5—C6—C1122.5 (3)
O2—Fe1—S189.26 (10)N1—C7—C1126.9 (3)
N1—Fe1—S291.60 (9)N2—C8—N3118.2 (3)
O1—Fe1—S290.15 (9)N2—C8—S1124.7 (2)
N4—Fe1—S285.65 (9)N3—C8—S1117.0 (2)
O2—Fe1—S2178.59 (10)C14—C9—C10119.3 (3)
S1—Fe1—S292.07 (3)C14—C9—C15116.5 (3)
C8—S1—Fe194.63 (11)C10—C9—C15124.2 (3)
C16—S2—Fe195.57 (12)O2—C10—C9123.6 (3)
C2—O1—Fe1126.5 (2)O2—C10—C11118.3 (3)
C10—O2—Fe1126.4 (2)C9—C10—C11118.0 (3)
C7—N1—N2113.5 (3)C12—C11—C10121.9 (3)
C7—N1—Fe1125.7 (2)C11—C12—C13120.0 (3)
N2—N1—Fe1120.8 (2)C14—C13—C12119.8 (3)
C8—N2—N1113.4 (3)C13—C14—C9121.0 (3)
C15—N4—N5114.0 (3)N4—C15—C9126.4 (3)
C15—N4—Fe1125.0 (2)N5—C16—N6118.6 (3)
N5—N4—Fe1121.0 (2)N5—C16—S2124.0 (3)
C16—N5—N4113.7 (3)N6—C16—S2117.4 (3)
C6—C1—C2119.4 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11—H11···N6i0.952.693.409 (5)133
N3—HN31···O1ii0.87 (2)2.03 (3)2.879 (4)164 (6)
N6—HN62···O2iii0.88 (2)1.96 (2)2.834 (4)178 (5)
Symmetry codes: (i) x+1/2, y+1/2, z+1/2; (ii) x1/2, y+1/2, z+1/2; (iii) x1/2, y+1/2, z1/2.
 

Acknowledgements

Elemental analysis was performed at the Microanalytical Laboratory, Vienna University. PW thanks the Distinguished Visitor Fund of Aston University enabling his research visits to Aston University. The Austrian Science Fund (FWF) is kindly acknowledged for financial support for PW. PvK thanks the TU Wien Inter­national Office for financial support for her research visits to the TU Wien.

Funding information

Funding for this research was provided by: Austrian Science Fund (project No. P 31076).

References

First citationBeraldo, H. & Gambino, D. (2004). Med. Chem. 4, 31–39.  Google Scholar
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