research communications
μ2-cyanido-1:2κ8N:C-bis(dimethyl sulfoxide-1κO)diargentate(I)iron(II)]
of poly[tetra-aDepartment of Chemistry, Taras Shevchenko National University of Kyiv, Volodymyrska St. 64, Kyiv 01601, Ukraine, bNational O.O. Bogomoletz Medical University, 13 T. Shevchenko Blvd., Kyiv, Ukraine, and cL. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, Prospekt Nauky 31, Kyiv 01601, Ukraine
*Correspondence e-mail: lesya.kucheriv@gmail.com
In the title polymeric complex, [Fe{OS(CH3)2}2{Ag(CN)2}2], the FeII cation is located at an inversion centre and is coordinated by four cyanide (CN−) anions and two dimethyl sulfoxide molecules in a slightly compressed N4O2 octahedral geometry, the AgI cation is C-coordinated by two CN− anions in a nearly linear geometry. The CN− anions bridge the FeII and AgI cations to form a two-dimensional polymeric structure extending parallel to (102). In the crystal, the nearest Ag⋯Ag distance between polymeric sheets is 3.8122 (12) Å. The crystal studied was a twin with a contribution of 0.2108 (12) for the minor component.
Keywords: crystal structure; FeII complex; Hofmann clathrate analogue; dicyanidoargentate; metal–organic framework.
CCDC reference: 1528660
1. Chemical context
Metal–organic frameworks (MOFs), also known as porous coordination polymers, form a group of compounds that consist of metal ions and organic ligand linkers (Zhou & Kitagawa, 2014). MOFs have attracted considerable attention over the past decades due to the ability to tune their porosity, structure and other properties by a rational choice of the metal and linkers. Despite the fact that the most investigated properties of MOFs are gas storage and separation, it has been shown that the incorporation of corresponding building blocks or guests into MOFs can provoke specific functional magnetic, chiral, catalytic, conductive, luminescence and other properties.
Hofmann clathrate analogues represent a huge group of MOFs. The first prototype clathrate of this family was [Ni(NH3)2{Ni(CN)4}] reported by Hofmann & Küspert (1897), however its structure was only obtained by Powell & Rayner (1949). The structure analysis showed that the coordination framework of this complex is supported by bridging square-planar tetracyanidonickelate ligands, and the octahedral coordination sphere of NiII is completed by two NH3 molecules. The layers in this clathrate are separated by ∼8 Å, which leads to the formation of guest-accessible cavities. This has allowed a series of to obtained with different aromatic guests such as benzene, phenol, aniline, pyridine, thiophene and pyrrole. Later, the group of Hofmann clathrate analogues was expanded to [M(L)2{M′(CN)4}] where M = Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Mn2+, M′ = Ni2+, Pd2+, Pt2+ and L is either a unidentate or bridging ligand to form two- or three-dimensional coordination frameworks, respectively.
More importantly, due to the rational choice of ligand, Kitazawa et al. (1996) succeeded in obtaining the first Hofmann-type complex [Fe(py)2{Ni(CN)4}] that exhibited spin-crossover behavior. This phenomenon is a spectacular ability of some 3d metals to exist in two different spin states. This discovery has led to multiple attempts to modify this compound in order to obtain other spin-crossover materials. The main synthetic approaches are: (a) the change of the pyridine ligand to other unidentate or bridging ligands; (b) the induction of various guest molecules that influence spin-crossover characteristics; (c) use of different square-planar {[M(CN)4]2−, M = Ni2+, Pt2+, Pd2+; Kucheriv et al., 2016}, dodecahedral {[Nb(CN)8]4−; Ohkoshi et al., 2013} or linear {[M(CN)2]−, M = Ag+, Au+; Gural'skiy et al., 2016b} linkers. Here we offer a new Hofmann-like coordination compound with general formula [Fe(dmso)2{Ag(CN)2}2] in which the FeII atoms are stabilized in a high-spin state.
2. Structural commentary
The II cation is located at an inversion centre and coordinated by four CN− anions and two dimethylsulfoxide molecules in a slightly compressed N4O2 octahedral environment (Fig. 1). The AgI cation is C-coordinated by two CN− anions in a nearly linear mode [C1—Ag—C2 = 173.0 (3)°]. The CN− anions bridge the FeII and AgI cations to form a two-dimensional polymeric structure. In the structure, the equatorial Fe—N bonds [2.166 (4) and 2.176 (4) Å] have the typical value for FeII in a high-spin state. The axial positions of the FeII cation are occupied by two dimethylsulfoxide molecules with an Fe—O bond length of 2.096 (4) Å. The S=O bond length of 1.532 (4) Å is increased by 0.03 Å with respect to non-coordinating dmso; the average S—C bond of 1.774 (6) Å is shorter than in those in non-coordinating dimethylsulfoxide. This is a typical value for O-bonded dimethylsulfoxide complexes (Calligaris, 2004). The torsion angles around the Fe—O bond are Fe1—O1—S1—C3 = 96.3 (3)° and Fe1—O1—S1—C4 = −159.2 (3)°. The polyhedral distortion which is described by the deviation from an octahedral geometry is ΣFe|90 − Θ| = 9.86 (16)° where Θ is the N—Fe—N or O—Fe—N angle in the coordination environment of the metal; however, this value is slightly lower than expected for a high-spin FeII complex.
of the title compound was determined from 243 K data. The Fe3. Supramolecular features
The coordination framework is connected by bridging dicyanidoargentate moieties into a two-dimensional grid that propagates along the (102) plane (Fig. 2a). The short interlayer Ag⋯Ag distance of 3.8122 (12) Å indicates argentophilic interactions that propagate along the c-axis direction. A similar type of intermolecular bonding between seemingly closed-shell metal atoms has previously been reported for many Ag- and Au-containing Hofmann-type structures, e.g. Au⋯Au distances of 3.3792 (3) Å were found between the [Fe{Au(CN)2}−] planes (Gural'skiy et al., 2016a). In addition, in the title compound the Fe—N—C and Ag—C—N linkages show a slight deviation from linearity (9.5 and 6° on average, respectively) that leads to a slight corrugation of [Fe{Ag(CN)2}−] layers (Fig. 2b).
4. Database survey
The title compound has never been obtained before. A database survey reveals numerous Fe–Ag CN-bridged frameworks supported by various co-ligands axially bound to the iron atoms.
5. Synthesis and crystallization
Crystals of the title compound were obtained by the slow-diffusion method within three layers in 10 ml tubes: the first layer was a solution of Fe(ClO4)2 (0.1 mmol, 26 mg) in dimethylsulfoxide (2 ml); second one was a dimethylsulfoxide–ethanol mixture (1:1, 5 ml); the third was a solution of K[Ag(CN)2] (0.1 mmol, 20 mg) in an ethanol–water mixture (9:1 ratio v/v, 2 ml). After two weeks, orange crystals grew in the second layer; they were collected and kept under the mother solution prior to the measurements.
6. Refinement
Crystal data, data collection and structure . All H atoms of methyl groups were placed geometrically at their expected calculated positions with C—H = 0.97 Å and Uiso(H) = 1.5Ueq(C). The idealized CH3 group was fixed using an AFIX 137 command that allowed the H atoms to ride on C atom and rotate around S—C bond. Twining of two components was considered with the transformation matrix ( 0 0 0 0 0 1) and a twin contribution of BASF = 0.2108 (12).
details are summarized in Table 1Supporting information
CCDC reference: 1528660
https://doi.org/10.1107/S2056989017001049/xu5899sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989017001049/xu5899Isup2.hkl
Data collection: SMART (Bruker, 2013); cell
SAINT (Bruker, 2013); data reduction: SAINT (Bruker, 2013); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg et al., 1999); software used to prepare material for publication: publCIF (Westrip, 2010).[Ag2Fe(CN)4(C2H6OS)2] | F(000) = 512 |
Mr = 531.93 | Dx = 2.160 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 8.4125 (16) Å | Cell parameters from 4840 reflections |
b = 14.492 (3) Å | θ = 2.7–26.2° |
c = 7.4679 (14) Å | µ = 3.50 mm−1 |
β = 116.053 (4)° | T = 243 K |
V = 817.9 (3) Å3 | Plate, orange |
Z = 2 | 0.15 × 0.1 × 0.05 mm |
Bruker SMART diffractometer | 1726 reflections with I > 2σ(I) |
φ and ω scans | Rint = 0.045 |
Absorption correction: multi-scan (SADABS; Bruker, 2013) | θmax = 28.0°, θmin = 1.4° |
Tmin = 0.625, Tmax = 0.746 | h = −11→11 |
16468 measured reflections | k = −19→19 |
1970 independent reflections | l = −8→9 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.031 | H-atom parameters constrained |
wR(F2) = 0.071 | w = 1/[σ2(Fo2) + (0.0068P)2 + 2.779P] where P = (Fo2 + 2Fc2)/3 |
S = 1.16 | (Δ/σ)max = 0.001 |
1970 reflections | Δρmax = 0.42 e Å−3 |
91 parameters | Δρmin = −1.05 e Å−3 |
0 restraints |
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. |
x | y | z | Uiso*/Ueq | ||
Ag1 | 0.45426 (6) | 0.72349 (3) | 0.33300 (9) | 0.05178 (15) | |
Fe1 | 1.0000 | 0.5000 | 0.5000 | 0.0255 (2) | |
S1 | 1.17380 (18) | 0.39095 (9) | 0.9253 (2) | 0.0377 (3) | |
C3 | 1.3090 (7) | 0.4721 (4) | 1.1049 (9) | 0.0494 (16) | |
H3A | 1.3567 | 0.5158 | 1.0427 | 0.074* | |
H3B | 1.4054 | 0.4402 | 1.2119 | 0.074* | |
H3C | 1.2389 | 0.5049 | 1.1586 | 0.074* | |
C4 | 1.0778 (8) | 0.3340 (4) | 1.0651 (9) | 0.0478 (15) | |
H4A | 1.0194 | 0.3789 | 1.1121 | 0.072* | |
H4B | 1.1697 | 0.3029 | 1.1782 | 0.072* | |
H4C | 0.9920 | 0.2890 | 0.9811 | 0.072* | |
O1 | 1.0225 (5) | 0.4471 (3) | 0.7713 (5) | 0.0376 (8) | |
N1 | 0.7675 (5) | 0.5774 (3) | 0.4638 (7) | 0.0349 (10) | |
C1 | 0.6498 (6) | 0.6262 (4) | 0.4204 (9) | 0.0404 (12) | |
N2 | 0.1741 (5) | 0.8859 (3) | 0.1555 (7) | 0.0391 (11) | |
C2 | 0.2720 (7) | 0.8283 (4) | 0.2252 (10) | 0.0419 (13) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ag1 | 0.03045 (19) | 0.0337 (2) | 0.0765 (3) | 0.01486 (16) | 0.0099 (2) | 0.0063 (2) |
Fe1 | 0.0182 (4) | 0.0186 (4) | 0.0328 (5) | 0.0011 (3) | 0.0048 (4) | 0.0001 (4) |
S1 | 0.0387 (7) | 0.0344 (6) | 0.0375 (7) | 0.0129 (5) | 0.0146 (6) | 0.0053 (5) |
C3 | 0.029 (3) | 0.057 (4) | 0.053 (4) | −0.006 (2) | 0.010 (3) | 0.008 (3) |
C4 | 0.057 (4) | 0.035 (3) | 0.045 (3) | −0.007 (3) | 0.017 (3) | 0.002 (3) |
O1 | 0.0322 (18) | 0.041 (2) | 0.034 (2) | 0.0086 (16) | 0.0097 (16) | 0.0076 (17) |
N1 | 0.0260 (19) | 0.033 (2) | 0.039 (3) | 0.0043 (16) | 0.0084 (18) | −0.0005 (19) |
C1 | 0.028 (2) | 0.035 (3) | 0.051 (3) | 0.006 (2) | 0.011 (2) | 0.001 (3) |
N2 | 0.025 (2) | 0.027 (2) | 0.054 (3) | 0.0036 (17) | 0.007 (2) | 0.001 (2) |
C2 | 0.028 (2) | 0.031 (3) | 0.057 (4) | 0.003 (2) | 0.009 (3) | 0.000 (3) |
Ag1—C1 | 2.044 (5) | S1—O1 | 1.523 (4) |
Ag1—C2 | 2.054 (5) | C3—H3A | 0.9700 |
Fe1—O1i | 2.096 (4) | C3—H3B | 0.9700 |
Fe1—O1 | 2.096 (4) | C3—H3C | 0.9700 |
Fe1—N1 | 2.166 (4) | C4—H4A | 0.9700 |
Fe1—N1i | 2.166 (4) | C4—H4B | 0.9700 |
Fe1—N2ii | 2.176 (4) | C4—H4C | 0.9700 |
Fe1—N2iii | 2.176 (4) | N1—C1 | 1.142 (6) |
S1—C3 | 1.771 (6) | N2—Fe1iv | 2.176 (4) |
S1—C4 | 1.778 (6) | N2—C2 | 1.127 (6) |
C1—Ag1—C2 | 173.0 (3) | O1—S1—C4 | 104.3 (3) |
O1i—Fe1—O1 | 180.0 | S1—C3—H3A | 109.5 |
O1—Fe1—N1i | 89.82 (16) | S1—C3—H3B | 109.5 |
O1—Fe1—N1 | 90.18 (16) | S1—C3—H3C | 109.5 |
O1i—Fe1—N1 | 89.82 (16) | H3A—C3—H3B | 109.5 |
O1i—Fe1—N1i | 90.18 (16) | H3A—C3—H3C | 109.5 |
O1i—Fe1—N2ii | 89.54 (17) | H3B—C3—H3C | 109.5 |
O1—Fe1—N2iii | 89.54 (17) | S1—C4—H4A | 109.5 |
O1i—Fe1—N2iii | 90.46 (17) | S1—C4—H4B | 109.5 |
O1—Fe1—N2ii | 90.46 (17) | S1—C4—H4C | 109.5 |
N1—Fe1—N1i | 180.0 | H4A—C4—H4B | 109.5 |
N1i—Fe1—N2iii | 91.82 (16) | H4A—C4—H4C | 109.5 |
N1i—Fe1—N2ii | 88.18 (16) | H4B—C4—H4C | 109.5 |
N1—Fe1—N2ii | 91.83 (16) | S1—O1—Fe1 | 128.0 (2) |
N1—Fe1—N2iii | 88.17 (16) | C1—N1—Fe1 | 168.3 (5) |
N2ii—Fe1—N2iii | 180.0 | N1—C1—Ag1 | 173.7 (5) |
C3—S1—C4 | 99.8 (3) | C2—N2—Fe1iv | 173.6 (5) |
O1—S1—C3 | 105.2 (3) | N2—C2—Ag1 | 175.5 (6) |
C3—S1—O1—Fe1 | 96.3 (3) | C4—S1—O1—Fe1 | −159.2 (3) |
Symmetry codes: (i) −x+2, −y+1, −z+1; (ii) x+1, −y+3/2, z+1/2; (iii) −x+1, y−1/2, −z+1/2; (iv) −x+1, y+1/2, −z+1/2. |
Funding information
Funding for this research was provided by: Ministry of Education and Science of Ukrainehttps://doi.org/10.13039/501100007684 (award No. 16BF037-01M).
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