New Iron(II) Spin Crossover Complexes with Unique Supramolecular Networks Assembled by Hydrogen Bonding and Intermetallic Bonding
1
Department of Creative Technology Engineering Course of Chemical Engineering, Anan College, 265 Aoki, Minobayashi, Anan, Tokushima 774-0017, Japan
2
Department of Chemistry, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
3
Department of Physics, Faculty of Science, Toho University, 2-2-1, Miyama 274-8510, Japan
*
Author to whom correspondence should be addressed.
Crystals 2018, 8(11), 415; https://doi.org/10.3390/cryst8110415
Submission received: 25 September 2018
/
Revised: 18 October 2018
/
Accepted: 20 October 2018
/
Published: 5 November 2018
(This article belongs to the Special Issue Synthesis and Applications of New Spin Crossover Compounds)
Abstract
:Two spin crossover (SCO) coordination polymers assembled by combining FeII octahedral ion, 4-cyanopyridine (4-CNpy) and [Au(CN)2]− liner unit are described. These compounds, Fe(4-CNpy)2[Au(CN)2]2·1/2(4-CNpy) (1a) and {Fe(4-CNpy)2[Au(CN)2]2}-{Fe(H2O)2[Au(CN)2]2} (1b), present quite different supramolecular networks that show different magnetic behaviors. Compound 1a crystallizes in the centrosymmetric space group Pbcn. The asymmetric unit contains two 4-CNpy, one type of Fe2+, and two types of crystallographically distinct [Au(CN)2]− units which form Hofmann-like two dimensional layer structures with guest spaces. The layers are combined with another layer by strong gold-gold intermetalic interactions. Compound 1b crystallizes in the centrosymmetric space group Pnma. The bent bismonodentate [AuI(CN)2] units and FeII ions form a complicated interpenetrated three dimensional structure. In addition, 1b exhibits ferromagnetic interaction.
1. Introduction
The designing of supramolecular networks is essential for practical spin crossover (SCO) materials [1,2,3,4]. The networks enhance the cooperativity in the entire crystal structure. Strong cooperativity leads to steep spin transition with a wide hysteresis loop [5,6]. From the viewpoint of constructing supramolecular networks, coordination polymers are useful material. However, systematic designing of networks is still hard because of the unexpected occurrence of supramolecular isomerism in the process of self-assembling. On the other hand, this structural diversity can result in unanticipated and interesting materials. Therefore, control of structural diversity represents fundamental research in crystal engineering. Since we reported the first Hofmann like two-dimensional (2-D) SCO coordination polymer {Fe(py)2[Ni(CN)4]}n (py = pyridine) [7], many 2-D layers of {FeII(L)2[MI(CN)2]2}n [8,9,10,11,12,13,14,15,16] (MI = Ag, or Au, L = monodentate pyridine derivatives) have been developed. These compounds show an almost similar bilayer structure because of their strongly determinate self-assembly process in which they link octahedral metal centers through the N atoms of the bidentate [Au(CN)2]− unit with strong aurophilic interaction between layers. This structural constancy enables us to precisely modify its crystal structure and properties. However, the applicable ligands for this system are still determinative. For instance, 3-cyano pyridine (3-CNpy) displays three different polymorphs [8]. A strong polarity of cyano substituent must cause variations of the supramolecular networks, which strongly affects SCO properties. Therefore, more applicable ligands for this structural system must be investigated. Vice versa, cyano substituent offers new interesting networks and properties in cyano-bridged coordination polymers. Here, we report new supramolecular isomers of the general formula Fe(4-CNpy)2[Au(CN)2]2 · 1/2(4-CNpy) (1a) and {Fe(4-CNpy)2[Au(CN)2]2}-{Fe(H2O)2[Au(CN)2]2} (1b).
2. Materials and Methods
2.1. Materials
All the chemicals were purchased from commercial sources and used without any further purification.
2.2. Synthesis
2.2.1. Preparation of Compound 1a
FeSO4·(NH4)2SO4·6H2O (0.0397 g, 1.01 × 10−4 mol) ascorbic acid (0.0208 g, 1.18 × 10−4 mol) and K[Au(CN)2] (0.0582 g, 2.02 × 10−4 mol) were dissolved in 2 mL of water. The other solution contained 4-CNpy (0.0204 g, 1.96 × 10−4 mol) in 5 mL water. The two solutions were mixed together. Yellow single crystals suitable for single crystal X-ray diffraction were formed over a day. The powder sample for superconducting quantum interference device (SQUID), X-ray powder diffraction (XRPD), thermos gravimetry/differential thermal analysis (TG/DTA) and elemental analysis was also prepared. One of these contained a mixture of FeSO4·(NH4)2SO4·6H2O (0.0400 g, 1.02 × 10−4 mol), ascorbic acid (0.0204 g, 1.36 × 10−4 mol) and K[AuI(CN)2] (0.0570 g, 1.98 × 10−4 mol) in 1 mL water. The other contained a 1 mL ethanol–water (1:1) solution of 4-CNpy (0.0206 g, 1.98 × 10−4 mol). Yellow powder sample of 1a was formed immediately. The powder sample was checked by XRPD data (see Figure S1). Impurity and isomers were observed as almost absent. Elem. Anal. Calcd for C19H8Au2FeN9: C, 28.03; H, 1.24; N, 15.48. Found: C, 27.92; H, 1.38; N, 15.35. IR(cm−1): 2237 (νCN (4-CNpy)), 2157, 2169 (νCN).
2.2.2. Preparation of Compound 1b
Complex 1b was prepared by the same procedure as 1a. The reaction mixture was allowed to stand undisturbed for 2 days. After forming yellow single crystals (1a), orange crystals (1b) slowly grew. The crystalline sample for SQUID measurement was picked up using a binocular lens. The samples were checked by XRPD data (Figure S1). Impurity of the samples was observed as almost absent. Due to the small amount of sample picked, the background of the diffraction data were very high. Elem. Anal. Calcd for C20H11Au4Fe2N12O2: C, 17.77; H, 0.89; N, 12.43. Found: C, 17.75; H, 1.13; N, 12.15. IR (cm−1): 2250 (νCN (4-CNpy)), 2169 (νCN)
2.3. X-ray Crystallography
Data collection was performed on a BRUKER APEX SMART CCD area-detector diffractometer for 1a and 1b with Monochrometed Mo–Kα radiation (λ = 0.71073 Å) (Bruker, Billerica, MA, USA). A selected single crystal was carefully mounted on a thin glass capillary and immediately placed under liquid N2 cooled N2 stream in each case. The diffraction data were treated using SMART and SAINT, and absorption correction was performed using SADABS [17]. The structures were solved by using direct methods with SHELXTL [18]. All non-hydrogen atoms were refined anisotropically, and the hydrogen atoms were generated geometrically. Pertinent crystallographic parameters and selected metric parameters for 1a and 1b are displayed in Table 1, Table 2 and Table 3. Diffraction data of 1a in high spin (HS) state was measured at 150 K in order to suppress the thermal motion of the guest molecules. When the sample was sufficiently cooled, both compounds showed a drastic and reversible change of color from yellow (1a) or orange (1b) to purple. The crystal structure of 1a in low spin (LS) state could not be determined. The low-quality data at 90 K was likely due to the occurrence of a sharp phase transition that provoked a notable increase of the mosaicity of the whole crystal structure. We described here the only HS state at 150 K. Crystallographic data have been deposited with Cambridge Crystallographic Data Centre: Deposition numbers CCDC-1869343 for compound 1a (150 K), CCDC-1869342 for 1b (298 K), and CCDC-1869341 for 1b (90 K). These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html.
2.4. Magnetic Measurements
Measurements of the temperature dependence of the magnetic susceptibility of the complexes 1a and 1b of the powdered samples in the temperature range 2–300 K with a cooling and heating rate of 2 K·min−1 in a 1 kOe field were measured on a MPMS-XL Quantum Design SQUID magnetometer. The diamagnetism of the samples and sample holders were taken into account.
3. Results and Discussion
3.1. Crystal Structures
3.1.1. Crystal Structure of Compound 1a (T = 298 K)
The crystal structure of 1a at 298 K crystallized in the orthorhombic centrosymmetric space group Pbcn. The asymmetric unit of the complex consisted of the Fe(ligand)2[Au(CN)2]2 formula with a guest molecule (Figure 1a). This complex had one type of independent FeII ion octahedrally coordinated by six N atoms. The axial Fe(1)–Npy bond lengths (Fe(1)–N(1) = 2.234(9) Å, Fe(1)–N(3) = 2.227(8) Å) and Fe(1)–NCN bond lengths (Fe(1)–N(5) = 2.161(8) Å, Fe(1)–N(6) = 2.129(8) Å, Fe(1)–N(7) = 2.121(8) Å, Fe(1)–N(8) = 2.146(8) Å) were almost identical to that of 1b. The equatorial positions were occupied by two quasilinear [AuI(CN)2]−, which comprised a 2-D layer structure defined by square-shaped [FeIIAuI(CN)2]4 windows (Figure 1b). The layers interacted via pairs of defining bilayers (Figure 1c,d), in which strong aurophilic interactions held them together. The Au···Au intermetallic distance was 3.1134(6) Å which was much shorter than that of 1b. Although the former reported bilayer structures had no guest spaces, the interlayer space of 1a formed one dimensional (1-D) channels parallel to the c axis, which were occupied by uncoordinated 4-CNpy. The guest molecules were disordered at two positions. The reason for enough space to include guest molecules was the steric effect from the 4-position substituent bulk. As shown in Figure 1c, the four position substituent was almost vertical to the layer. Thus, it would cause the pressure on the layer resulting in expanded interlayer space.
The closely related Hofmann-like 2-D clathrate compound, {Fe[4-(3-pentyl)pyridine]2[AuI(CN)2]2·(guest)}n (guest = 4-(3-pentyl)pyridine), had been reported [19]. This compound formed a flat monolayer structure. 4-(3-pentyl) substituent was apparently of lager bulk than that of the 4-CN substituent. This much larger bulk caused bilayer interaction to break.
3.1.2. Crystal Structure of Compound 1b (T = 298 K)
Compound 1b at 298 K crystallized in the orthorhombic centrosymmetric space group Pnma. The asymmetric unit also consisted of the cyano bridged hetero-metal coordination (Figure 2a). There were two crystallographically different octahedral FeII ions. Fe(1) was coordinated by six N atoms of two 4-CNpy ligands and four CN substituents from [AuI(CN)2]− units, which was similar to that of 1a. The axial Fe(1)–Npy bond lengths (Fe(1)–N(1) = 2.226(7) Å) were apparently longer than the Fe(1)–NCN bond lengths (Fe(1)–N(3) = 2.157(7) Å, Fe(1)–N(4) = 2.144(7) Å). On the other hand, the axial Fe(2)–O bond lengths (Fe(2)–O(1) = 2.078(13) Å, Fe(2)–O(2) = 2.158(9) Å) were close to the Fe(2)–NCN bond lengths (Fe(2)–N(5) = 2.130(8) Å, Fe(2)–N(6) = 2.187(8) Å). It is important to note that hydrogen bonds existed between N(2) of cyano group in 4-CNpy and O(1) (N(2)···O(1) = 2.905(15) Å). Due to the different coordination environment, the apical axis of Fe(1) was not parallel to the apical axis of Fe(2). Furthermore, the coordination geometry of the Fe(1) site was almost octahedron; the bond angle of the apical axis was 180(4)°. On the other hand, the Fe(2) site showed a quite distorted octahedron (O(1)–Fe(2)–O(2) = 169.5(6)° and N(5)–Fe(2)–N(6) = 172.3(3)°). Consequently, the bent bismonodentate [AuI(CN)2] units and FeII ions formed bent rectangular [FeIIAuI(CN)2]4 mesh network topology (Figure 2b). The rectangular moieties were penetrated by the other frameworks, which gave rise to a triply interpenetrated structure (Figure 2c). In addition, the closest approach between Au···Au suggested the presence of aurophilic interactions (Au(1)···Au(2) = 3.3705(5) Å and 3.3876(5) Å) which linked the other frameworks (Figure 2c,d). In previous works, isostructural compound {Mn(4-CNpy)2[Ag(CN)2]2}-{Mn(H2O)2[Ag(CN)2]2} (1b’) had been reported [20]. This compound also showed similar hydrogen bonding and intermetallic Ag···Ag interactions.
3.1.3. Structure of Compound 1b (T = 90 K)
The crystal structure of 1b at 90 K was almost identical to that observed at 298 K. The Fe(1)–Npy bond lengths (Fe(1)–N(1) = 1.998(7) Å) and Fe(1)–NCN bond lengths (Fe(1)–N(3) = 1.937(7) Å, Fe(1)–N(4) = 1.941(7) Å) corresponded quite well to those expected for LS state. On the other hand Fe(2)–O bond lengths (Fe(2)–O(1) = 2.095(9) Å, Fe(2)–O(2) = 2.112(9) Å) and Fe(2)–NCN bond lengths (Fe(2)–N(5) = 2.132(7) Å, Fe(2)–N(6) = 2.190(8) Å) were almost identical to that of 298 K. Hydrogen bonding and intermetallic interactions were slightly shorter than that of the HS state (Au(1)···Au(2) = 3.3462(4) Å, 3.3745(4) Å and N(2)···O(1) = 2.862(11) Å). The shortest Fe···Fe separation was 5.811(2) Å between Fe(2) centers which was bridged by the aurophilic interactions (see Figure S3). This was much shorter than that of the other Fe···Fe separation (Fe(1)···Fe(1) = 13.280(1) Å, Fe(1)···Fe(2) = 9.746(1) Å).
3.2. Thermal Analysis
The thermal analysis of 1a showed the three step weight loss between 380 K and 580 K corresponded to the loss of the two coordinated molecules of 4-CNpy and 0.5 solvent molecules (observed loss: 18.0% (first step) = ca. 1.5 molecules, 6.4% (second step) = ca. 0.5 molecule, 6.7% (third step) = ca. 0.5 molecule) (Figure S2). This result was consistent with the elemental analysis.
3.3. Magnetic Properties
3.3.1. Thermal Dependence Magnetic Behavior of Compound 1a
Figure 3a shows the thermal dependence of χMT for 1a with χM being the molar magnetic susceptibility and T the temperature. At room temperature, χMT was 4.21 m3·K·mol−1. Upon cooling, χMT remained almost constant down to 120 K; below this temperature, χMT underwent a sharp decrease to around 50% conversion with approximately 1 K hysteresis loop (Tc down = 111 K, Tc up = 112 K). The decrease in the value of χMT at lower temperature was due to the typical behavior of zero-field splitting (ZFS).
3.3.2. Thermal Dependence Magnetic Behavior of Compound 1b
χMT versus T plotted for 1b are shown in Figure 3b. At room temperature, the χMT value was 7.25 which indicated the characteristic of two Fe(II) ions in HS state. The value was slightly higher than that of a pure spin only system, whereas the value was similar to the values of other Hofmann-like SCO Fe(II) compounds. The χMT value was constant in the range 215–300 K. Below this temperature range, it displayed almost 50% abrupt spin transition (Tc = 211 K). This half spin transition behavior agreed quite well with the different Fe-N bond lengths between Fe(1) and Fe(2) species at 90 K. Thus only Fe(1) species change the spin state. On the other hand, [Fe(2)N4O2] coordination environment must maintain the HS state at the full temperature range. After the transition, it then increased to a maximum of 4.77 cm3·K·mol−1 at around 20 K, indicative of a ferromagnetic interaction between the Fe(II) centers. On the other hand, the isostructural former reported that compound 1b’ showed weak antiferromagnetic interaction between two MnII (HS state, S = 5/2). Although in a similar coordination environment, 1b showed ferromagnetic interaction. In terms of the spin state, the X-ray structural analysis of 1b at 90 K gave evidence of the arrangement of a···Fe(HS)–Fe(LS)···pair. On the other hand, 1b showed the different arrangement of···Mn(HS)–Mn(HS)···. Thus, 1b apparently much further distorted structure. Consequently, the magnetic structure of the residual HS site of Fe(2) could cause the different magnetic coupling. In fact Fe(2) ions of HS site were close to each other in the supramolecular networks. At even lower temperature, the decrease in the value of χMT was similar to 1a due to ZFS effects.
4. Conclusions
The new supramolecular networks designed by the components of Hofmann-like frameworks with 4-CNpyridine were reported. These compounds showed unique multi-dimensional supramolecular networks involving hydrogen interactions and strong metallophilic interactions. Specifically, 1b exhibited the two magnetic functions of a SCO and a ferromagnetic transition. The diversity of the self-assembly process offered both unexpectedly interesting structure and properties.
Supplementary Materials
The following are available online at https://www.mdpi.com/2073-4352/8/11/415/s1, Figure S1. X-ray powder diffraction data of 1a and 1b (red line: calculation, black line: experiment); Figure S2. Thermogravimetric analysis for complex 1a was carried under nitrogen atmosphere at a heating rate of 10 K/min; Figure S3. Showing the closet approach between Fe(2) centers for 1b at 90 K.
Author Contributions
Data curation, I.T.; Formal analysis, D.A. and T.S.; Investigation, T.K. and I.T.; Project administration, T.K.; Supervision, T.K.
Funding
This work was financially supported by KAKENHI (JSPS/15K05485 and 18K04964) and the Yashima Environment Technology Foundation. Part of this work was supported by the Ministry of Education, Culture, Sports, Science, and Technology, Japan (MEXT)-Supported program for the Strategic Research Foundation at Private Universities 2012–2016.
Conflicts of Interest
The authors declare no conflict of interest.
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Figure 1.
(a) Coordination structure of 1a containing its asymmetric unit at 150 K; (b) view of the bilayer structure; (c,d) stacking of bilayers of 1a along c (c) and b (d) axis involved in Au···Au intermetallic interactions as indicated by red and white lines. In these pictures, hydrogen atoms are omitted for clarity.
Figure 1.
(a) Coordination structure of 1a containing its asymmetric unit at 150 K; (b) view of the bilayer structure; (c,d) stacking of bilayers of 1a along c (c) and b (d) axis involved in Au···Au intermetallic interactions as indicated by red and white lines. In these pictures, hydrogen atoms are omitted for clarity.
Figure 2.
(a) Coordination structure of 1b containing its asymmetric unit at 298 K involved in hydrogen bonding interactions as indicated by blue and white lines; (b) bent rectangular [FeIIAuI(CN)2]4 mesh structure; (c) cylinder drawing of triply interpenetrated 3D-networks of 1b involved in hydrogen bonding interactions as indicated by red and white lines; (d) perspective view of the crystal structure along a axis. In these pictures, hydrogen atoms are omitted for clarity.
Figure 2.
(a) Coordination structure of 1b containing its asymmetric unit at 298 K involved in hydrogen bonding interactions as indicated by blue and white lines; (b) bent rectangular [FeIIAuI(CN)2]4 mesh structure; (c) cylinder drawing of triply interpenetrated 3D-networks of 1b involved in hydrogen bonding interactions as indicated by red and white lines; (d) perspective view of the crystal structure along a axis. In these pictures, hydrogen atoms are omitted for clarity.
Figure 3.
(a) Thermal dependence of χMT plot for 1a; (b) thermal dependence of χMT plot for 1b.
Table 1.
Crystal data and structure refinement for compounds 1a and 1b.
| 1a (150 K) | 1b (298 K) | 1b (90 K) | |
|---|---|---|---|
| Empirical formula | C19H8Au2FeN9 | C20H11Au4Fe2N12O2 | C20H11Au4Fe2N12O2 |
| Formula weight | 812.13 | 1350.97 | 1350.97 |
| Crystal size/mm3 | 0.55 × 0.28 × 0.22 | 0.15 × 0.13 × 0.05 | 0.38 × 0.15 × 0.05 |
| Crystal system | Orthorhombic | Orthorhombic | Orthorhombic |
| a/Å | 21.658(2) | 7.6273(7) | 7.6243(4) |
| b/Å | 13.7647(15) | 30.007(3) | 29.1960(16) |
| c/Å | 15.5895(17) | 13.7694(13) | 13.5000(7) |
| V/Å3 | 4647.4(9) | 3151.5(5) | 3005.1(3) |
| Space group | Pbcn | Pnma | Pnma |
| Z value | 8 | 4 | 4 |
| Dcalc | 2.321 | 2.847 | 2.986 |
| F(000) | 2952 | 2396 | 2396 |
| No. of reflections | 28,466 | 19,996 | 20,977 |
| No. of observations | 5443 | 3976 | 3808 |
| Parameters | 284 | 196 | 186 |
| Temperature/K | 150(2) | 298 | 90 |
| Final R1, Rw (I > 2s) | 0.0411, 0.1043 | 0.0474, 0.1168 | 0.0396, 0.1048 |
| Final R1, Rw (all data) | 0.0715, 0.1197 | 0.0730, 0.1346 | 0.0439, 0.1212 |
| Goodness-of-fit | 1.050 | 0.965 | 1.413 |
Table 2.
Selected bond lengths and angles for 1a.
| Bond Lengths (Å) for 1a (150 K) | Bond Angles (°) for 1a (150 K) | |
|---|---|---|
| Fe(1)–N(1): 2.234(9) | N(1)–Fe(1)–N(3): 175.9(3) | N(5)–Fe(1)–N(8): 90.0(3) |
| Fe(1)–N(3): 2.227(8) | N(1)–Fe(1)–N(5): 93.0(3) | N(6)–Fe(1)–N(7): 88.2(3) |
| Fe(1)–N(5): 2.161(8) | N(1)–Fe(1)–N(6): 94.5(3) | N(6)–Fe(1)–N(8): 176.4(3) |
| Fe(1)–N(6): 2.129(8) | N(1)–Fe(1)–N(7): 89.4(3) | N(7)–Fe(1)–N(8): 95.1(3) |
| Fe(1)–N(7): 2.121(8) | N(1)–Fe(1)–N(8): 84.0(3) | C(13)–N(5)–Fe(1): 167.4(8) |
| Fe(1)–N(8): 2.146(8) | N(3)–Fe(1)–N(5): 86.9(3) | C(14)–N(6)–Fe(1): 162.4(8) |
| Au(1)–C(13): 1.999(9) | N(3)–Fe(1)–N(6): 89.6(3) | C(15)–N(7)–Fe(1): 163.2(8) |
| Au(1)–C(16): 1.990(9) | N(3)–Fe(1)–N(7): 91.1(3) | C(16)–N(8)–Fe(1): 161.3(9) |
| Au(2)–C(14): 1.986(9) | N(3)–Fe(1)–N(8): 91.9(3) | C(13)–Au(1)–C(16): 178.0(4) |
| Au(2)–C(15): 1.981(10) | N(5)–Fe(1)–N(6): 86.8(3) | C(14)–Au(2)–C(15): 176.8(4) |
| N(5)–Fe(1)–N(7): 174.6(3) | ||
Table 3.
Selected bond lengths and angles for 1b.
| Bond Lengths (Å) for 1b (298 K) | Bond Angles (°) for 1b (298 K) | |
| Fe(1)–N(1): 2.226(7) | N(1)–Fe(1)–N(1): 180.0(3) | O(1)–Fe(2)–O(2): 169.5(6) |
| Fe(1)–N(3): 2.157(7) | N(1)–Fe(1)–N(3): 90.0(3) | O(1)–Fe(2)–N(5): 96.6(4) |
| Fe(1)–N(4): 2.144(7) | N(1)–Fe(1)–N(4): 89.5(3) | O(1)–Fe(2)–N(6): 89.9(3) |
| Fe(2)–O(1): 2.078(13) | N(3)–Fe(1)–N(3): 180.0(3) | O(2)–Fe(2)–N(5): 90.8(4) |
| Fe(2)–O(2): 2.158(9) | N(3)–Fe(1)–N(4): 91.3(3) | O(2)–Fe(2)–N(6): 83.3(3) |
| Fe(2)–N(5): 2.130(8) | N(4)–Fe(1)–N(4): 180.0(4) | N(5)–Fe(2)–N(5):89.5(5) |
| Fe(2)–N(6): 2.187(8) | C(7)–N(3)–Fe(1): 167.1(8) | N(5)–Fe(2)–N(6): 85.6(3) |
| Au(1)–C(8): 1.985(9) | C(8)–N(4)–Fe(1): 166.6(8) | N(6)–Fe(2)–N(6): 98.7(4) |
| Au(1)–C(9): 1.978(9) | C(8)–Au(1)–C(9): 175.9(4) | N(5)–Fe(2)–N(6): 172.3(3) |
| Au(2)–C(7): 1.992(9) | C(7)–Au(2)–C(10): 176.6(3) | C(9)–N(5)–Fe(2): 169.6(8) |
| Au(2)–C(10): 1.992(9) | C(10)–N(6)–Fe(2): 162.0(8) | |
| Bond Lengths (Å) for 1b (90 K) | Bond Angles (°) for 1b (90 K) | |
| Fe(1)–N(1): 1.998(7) | N(1)–Fe(1)–N(1): 180.0(4) | O(1)–Fe(2)–O(2): 169.1(4) |
| Fe(1)–N(3): 1.937(7) | N(1)–Fe(1)–N(3): 90.5(3) | O(1)–Fe(2)–N(5): 96.2(3) |
| Fe(1)–N(4): 1.941(7) | N(1)–Fe(1)–N(4): 90.4(3) | O(1)–Fe(2)–N(6): 89.3(3) |
| Fe(2)–O(1): 2.095(9) | N(3)–Fe(1)–N(3): 180.0(2) | O(2)–Fe(2)–N(5): 91.5(3) |
| Fe(2)–O(2): 2.112(9) | N(3)–Fe(1)–N(4): 90.3(3) | O(2)–Fe(2)–N(6): 83.6(3) |
| Fe(2)–N(5): 2.132(7) | N(4)–Fe(1)–N(4): 180.0(4) | N(5)–Fe(2)–N(5): 90.6(4) |
| Fe(2)–N(6): 2.190(8) | C(7)–N(3)–Fe(1): 170.7(7) | N(5)–Fe(2)–N(6): 85.0(3) |
| Au(1)–C(8): 1.985(9) | C(8)–N(4)–Fe(1): 172.3(7) | N(6)–Fe(2)–N(6): 98.9(4) |
| Au(1)–C(9): 1.977(9) | C(8)–Au(1)–C(9): 174.8(3) | N(5)–Fe(2)–N(6): 173.4(3) |
| Au(2)–C(7): 1.983(9) | C(7)–Au(2)–C(10): 174.2(3) | C(9)–N(5)–Fe(2): 168.6(7) |
| Au(2)–C(10): 1.989(8) | C(10)–N(6)–Fe(2): 161.7(7) | |
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Kosone, T.; Tomori, I.; Akahoshi, D.; Saito, T.; Kitazawa, T. New Iron(II) Spin Crossover Complexes with Unique Supramolecular Networks Assembled by Hydrogen Bonding and Intermetallic Bonding. Crystals 2018, 8, 415. https://doi.org/10.3390/cryst8110415
AMA Style
Kosone T, Tomori I, Akahoshi D, Saito T, Kitazawa T. New Iron(II) Spin Crossover Complexes with Unique Supramolecular Networks Assembled by Hydrogen Bonding and Intermetallic Bonding. Crystals. 2018; 8(11):415. https://doi.org/10.3390/cryst8110415
Chicago/Turabian StyleKosone, Takashi, Itaru Tomori, Daisuke Akahoshi, Toshiaki Saito, and Takafumi Kitazawa. 2018. "New Iron(II) Spin Crossover Complexes with Unique Supramolecular Networks Assembled by Hydrogen Bonding and Intermetallic Bonding" Crystals 8, no. 11: 415. https://doi.org/10.3390/cryst8110415
APA StyleKosone, T., Tomori, I., Akahoshi, D., Saito, T., & Kitazawa, T. (2018). New Iron(II) Spin Crossover Complexes with Unique Supramolecular Networks Assembled by Hydrogen Bonding and Intermetallic Bonding. Crystals, 8(11), 415. https://doi.org/10.3390/cryst8110415
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