metal-organic compounds
Potassium tetracyanidoaurate(III) monohydrate: a redetermination
aDepartment of Chemistry & Research Center for Smart Molecules, Rikkyo University, Nishi-Ikebukuro 3-34-1, Toshima-ku, 171-8501 Tokyo, Japan, and bDepartment of Chemistry, Rikkyo University, Nishi-Ikebukuro 3-34-1, Toshima-ku, 171-8501 Tokyo, Japan
*Correspondence e-mail: cnmatsu@rikkyo.ac.jp
The structure of the title metal complex salt, K[Au(CN)4]·H2O, has been redetermined using X-ray diffraction data at 173 K in order to improve the precision. The previous determination was based on neutron diffraction data [Bertinotti & Bertinotti (1970). Acta Cryst. B26, 422–428]. The title compound crystallizes in the P212121 with one potassium cation, one [Au(CN)4]− anion and one water molecule in the The AuIII atom lies on a general position and has an almost square-planar coordination sphere defined by four cyanide ligands. Interactions between the potassium cation and N atoms of the complex anion, as well as O—H⋯N hydrogen bonds, lead to the formation of a three-dimensional framework structure.
CCDC reference: 1536909
Structure description
Potassium tetracyanidoaurate(III) monohydrate, K[Au(CN)4]·H2O, is one of the typical starting compounds for preparation of various tetracyanidoaurate(III) salts. The of K[Au(CN)4]·H2O has already been determined by neutron diffraction (Bertinotti & Bertinotti, 1970). However, because of the need for more precise structural data, we have redetermined the using X-ray diffraction data at 173 K. The redetermination of the title salt confirms the previous model but shows an improvement with respect to the precision on bond lengths and angles, with respective standard uncertainties decreased to about one half to one third of those of the previous determination by neutron diffraction. In addition, in the current study all atoms were refined with anisotropic displacement parameters and the was determined.
The components of the title salt are displayed in Fig. 1. The comprises one potassium cation, one [Au(CN)4]− anion and one water molecule. The AuIII atom of the [Au(CN)4]− anion is coordinated by four C atoms of four cyanido ligands in an almost square-planar configuration. The r.m.s. deviation of the least-squares plane formed by atoms Au, C1, C2, C3, C4, N1, N2, N3 and N4 is 0.0265 Å. The Au—C [1.998 (4)–2.007 (4) Å] and C≡N [1.138 (5)–1.146 (5) Å] bond lengths, C—Au—Ctrans [178.63 (18), 179.39 (17)°], C—Au—Ccis [89.22 (16)–90.75 (17)°] and Au—C—N [177.3 (4)–179.7 (4)°] bond angles are consistent with values reported by Geisheimer et al. (2011) for the [Au(CN)4]− anion in related compounds: [N(C4H9)4][Au(CN)4] [Au—C = 1.992 (3)–2.002 (3) Å, C≡N = 1.139 (5)–1.148 (5) Å, C—Au—Ctrans = 178.03 (12), 179.25 (13)°, C—Au—Ccis = 89.44 (13)–90.49 (14)°, Au—C—N = 177.0 (3)–178.4 (3)°]; [As(C6H5)4][Au(CN)4] [Au—C = 1.985 (2)–1.996 (2) Å, C≡N = 1.140 (3)–1.150 (3) Å, C—Au—Ctrans = 179.35 (9), 179.74 (9)°, C—Au—Ccis = 89.41 (10)–90.75 (9)°, Au—C—N = 177.8 (2)–179.7 (3)°]; [N(P(C6H5)3)2][Au(CN)4] [Au—C = 1.987 (6)–1.997 (5) Å, C≡N = 1.118 (5)–1.132 (6) Å, C—Au—Ctrans = 179.10 (19), 179.47 (18)°, C—Au—Ccis = 88.85 (18)–91.00 (19)°, Au—C—N = 177.7 (6)–179.4 (6)°].
In the crystal, the potassium cation exhibits a ). Two O—H⋯N hydrogen bonds between the water molecule of crystallization and the [Au(CN)4]− anion further stabilize the crystal packing of the title salt (Fig. 3, Table 1).
of eight and is surrounded by six N atoms of the cyanido ligands [K⋯N = 2.891 (4)–3.431 (4) Å] and two O atoms of water molecules [K⋯O = 2.804 (3), 2.886 (3) Å] (Fig. 2Synthesis and crystallization
To an aqueous solution of H[AuCl4]·4H2O (2.007 g) neutralized by an aqueous solution of KOH was added an aqueous solution of KCN (1.286 g) at room temperature under stirring. The colour of the solution also changed immediately from yellow to colourless just after the addition. Slow evaporation of the solution gave colourless platelet single crystals.
Refinement
Crystal data, data collection and structure . In the final refinements, five reflections, (0 1 23), (0 3 23), (1 0 24), ( 6 20) and (1 6 20), were omitted due to poor agreements between observed and calculated intensities. The maximum and minimum electron density peaks are located 0.75 and 0.75 Å, respectively, from the Au atom.
details are summarized in Table 2Structural data
CCDC reference: 1536909
https://doi.org/10.1107/S2414314617003820/wm4042sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314617003820/wm4042Isup2.hkl
Data collection: RAPID-AUTO (Rigaku, 2006); cell
RAPID-AUTO (Rigaku, 2006); data reduction: RAPID-AUTO (Rigaku, 2006); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg, 2017); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015b) and publCIF (Westrip, 2010).K[Au(CN)4]·H2O | Dx = 2.902 Mg m−3 |
Mr = 358.16 | Mo Kα radiation, λ = 0.71075 Å |
Orthorhombic, P212121 | Cell parameters from 8740 reflections |
a = 6.6460 (7) Å | θ = 3.1–31.9° |
b = 7.0733 (8) Å | µ = 18.40 mm−1 |
c = 17.4356 (19) Å | T = 173 K |
V = 819.63 (15) Å3 | Platelet, colorless |
Z = 4 | 0.30 × 0.30 × 0.20 mm |
F(000) = 640 |
Rigaku R-AXIS RAPID imaging-plate diffractometer | 2828 independent reflections |
Radiation source: X-ray sealed tube | 2666 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.045 |
Detector resolution: 10.00 pixels mm-1 | θmax = 32.0°, θmin = 3.1° |
ω scans | h = −9→9 |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | k = −10→10 |
Tmin = 0.437, Tmax = 1.000 | l = −25→23 |
17391 measured reflections |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.015 | w = 1/[σ2(Fo2) + (0.0069P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.034 | (Δ/σ)max = 0.001 |
S = 1.03 | Δρmax = 1.44 e Å−3 |
2828 reflections | Δρmin = −1.09 e Å−3 |
101 parameters | Extinction correction: SHELXL2014 (Sheldrick, 2015b), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0093 (3) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack x determined using 1076 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013) |
Secondary atom site location: difference Fourier map | Absolute structure parameter: −0.006 (6) |
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. Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) - 2.5906 (0.0057) x + 6.3743 (0.0030) y + 3.3049 (0.0146) z = 2.5384 (0.0067) * 0.0043 (0.0013) Au * -0.0216 (0.0038) C1 * 0.0054 (0.0039) C2 * -0.0097 (0.0037) C3 * 0.0245 (0.0037) C4 * -0.0325 (0.0030) N1 * 0.0402 (0.0031) N2 * -0.0400 (0.0030) N3 * 0.0293 (0.0030) N4 Rms deviation of fitted atoms = 0.0265 |
x | y | z | Uiso*/Ueq | ||
Au | 0.75839 (2) | 0.57191 (2) | 0.26080 (2) | 0.01211 (5) | |
C1 | 0.6473 (6) | 0.4715 (7) | 0.3595 (2) | 0.0172 (9) | |
C2 | 1.0114 (6) | 0.6470 (7) | 0.3147 (2) | 0.0177 (8) | |
C3 | 0.8687 (6) | 0.6664 (6) | 0.1607 (2) | 0.0163 (8) | |
C4 | 0.5035 (6) | 0.4994 (6) | 0.2069 (2) | 0.0165 (8) | |
N1 | 0.5844 (5) | 0.4150 (6) | 0.4160 (2) | 0.0214 (8) | |
N2 | 1.1526 (6) | 0.6928 (7) | 0.3475 (2) | 0.0255 (9) | |
N3 | 0.9262 (6) | 0.7151 (6) | 0.1027 (2) | 0.0220 (8) | |
N4 | 0.3604 (5) | 0.4584 (6) | 0.1752 (2) | 0.0228 (8) | |
K | 0.23731 (16) | 0.46003 (12) | 0.51708 (4) | 0.02024 (17) | |
O | 0.6252 (5) | 0.3372 (5) | 0.01812 (17) | 0.0252 (7) | |
H1 | 0.6663 | 0.3529 | 0.0632 | 0.038* | |
H2 | 0.7007 | 0.4050 | −0.0090 | 0.038* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Au | 0.01349 (7) | 0.01157 (7) | 0.01126 (8) | −0.00070 (7) | 0.00035 (6) | −0.00005 (4) |
C1 | 0.0172 (18) | 0.018 (2) | 0.017 (2) | 0.0028 (16) | −0.0013 (15) | −0.0003 (16) |
C2 | 0.0190 (19) | 0.015 (2) | 0.0191 (19) | 0.0003 (17) | 0.0032 (16) | 0.0007 (17) |
C3 | 0.0159 (18) | 0.016 (2) | 0.0173 (19) | 0.0017 (16) | 0.0008 (15) | −0.0012 (16) |
C4 | 0.0193 (19) | 0.015 (2) | 0.0151 (19) | 0.0006 (16) | 0.0010 (15) | 0.0038 (16) |
N1 | 0.0222 (17) | 0.025 (2) | 0.0169 (18) | 0.0003 (18) | 0.0017 (13) | 0.0020 (16) |
N2 | 0.0248 (19) | 0.026 (2) | 0.0257 (19) | −0.0061 (17) | −0.0049 (16) | −0.0004 (18) |
N3 | 0.0233 (18) | 0.024 (2) | 0.0189 (18) | −0.0015 (17) | 0.0023 (14) | 0.0012 (17) |
N4 | 0.0215 (17) | 0.024 (2) | 0.0228 (19) | −0.0051 (16) | −0.0039 (14) | 0.0029 (16) |
K | 0.0197 (4) | 0.0224 (4) | 0.0186 (4) | 0.0006 (5) | 0.0028 (4) | −0.0012 (3) |
O | 0.0252 (15) | 0.031 (2) | 0.0194 (15) | 0.0023 (13) | 0.0014 (12) | 0.0035 (14) |
Au—C2 | 1.998 (4) | K—Ovi | 2.804 (3) |
Au—C1 | 2.002 (4) | K—Oiii | 2.886 (4) |
Au—C4 | 2.003 (4) | K—N4vi | 2.891 (4) |
Au—C3 | 2.007 (4) | K—N3vii | 2.923 (4) |
C1—N1 | 1.143 (5) | K—N3viii | 2.961 (4) |
C2—N2 | 1.146 (5) | K—N1ix | 3.071 (4) |
C3—N3 | 1.135 (5) | K—N2x | 3.431 (4) |
C4—N4 | 1.138 (5) | K—Ki | 4.4972 (12) |
N1—K | 2.920 (4) | K—Kix | 4.4972 (12) |
N1—Ki | 3.071 (4) | O—Kv | 2.804 (3) |
N2—Kii | 3.431 (4) | O—Kvii | 2.886 (3) |
N3—Kiii | 2.923 (4) | O—H1 | 0.8400 |
N3—Kiv | 2.961 (4) | O—H2 | 0.8400 |
N4—Kv | 2.891 (4) | ||
C2—Au—C1 | 90.01 (16) | N4vi—K—N1ix | 74.67 (11) |
C2—Au—C4 | 179.39 (17) | N1—K—N1ix | 113.35 (8) |
C1—Au—C4 | 90.03 (17) | N3vii—K—N1ix | 68.68 (11) |
C2—Au—C3 | 90.75 (17) | N3viii—K—N1ix | 72.36 (10) |
C1—Au—C3 | 178.63 (18) | Ovi—K—N2x | 67.62 (9) |
C4—Au—C3 | 89.22 (16) | Oiii—K—N2x | 54.90 (9) |
N1—C1—Au | 179.7 (4) | N4vi—K—N2x | 133.59 (12) |
N2—C2—Au | 177.7 (4) | N1—K—N2x | 70.24 (10) |
N3—C3—Au | 177.3 (4) | N3vii—K—N2x | 66.90 (11) |
N4—C4—Au | 178.9 (4) | N3viii—K—N2x | 139.40 (10) |
C1—N1—K | 140.5 (3) | N1ix—K—N2x | 133.45 (10) |
C1—N1—Ki | 120.6 (3) | Ovi—K—Ki | 166.83 (8) |
K—N1—Ki | 97.27 (11) | Oiii—K—Ki | 110.40 (7) |
C2—N2—Kii | 115.4 (3) | N4vi—K—Ki | 115.09 (9) |
C3—N3—Kiii | 133.8 (3) | N1—K—Ki | 42.63 (8) |
C3—N3—Kiv | 125.2 (3) | N3vii—K—Ki | 77.79 (8) |
Kiii—N3—Kiv | 99.69 (11) | N3viii—K—Ki | 39.84 (7) |
C4—N4—Kv | 126.9 (3) | N1ix—K—Ki | 73.99 (8) |
Ovi—K—Oiii | 78.50 (5) | N2x—K—Ki | 108.91 (7) |
Ovi—K—N4vi | 72.47 (10) | Ovi—K—Kix | 72.78 (7) |
Oiii—K—N4vi | 95.14 (11) | Oiii—K—Kix | 144.74 (7) |
Ovi—K—N1 | 137.61 (11) | N4vi—K—Kix | 95.29 (8) |
Oiii—K—N1 | 73.89 (11) | N1—K—Kix | 115.57 (9) |
N4vi—K—N1 | 140.78 (11) | N3vii—K—Kix | 40.46 (8) |
Ovi—K—N3vii | 89.34 (10) | N3viii—K—Kix | 110.40 (9) |
Oiii—K—N3vii | 120.90 (10) | N1ix—K—Kix | 40.10 (7) |
N4vi—K—N3vii | 135.75 (11) | N2x—K—Kix | 94.69 (7) |
N1—K—N3vii | 78.33 (10) | Ki—K—Kix | 95.28 (3) |
Ovi—K—N3viii | 149.29 (10) | Kv—O—Kvii | 138.03 (13) |
Oiii—K—N3viii | 104.76 (11) | Kv—O—H1 | 102.6 |
N4vi—K—N3viii | 76.83 (10) | Kvii—O—H1 | 102.6 |
N1—K—N3viii | 70.24 (11) | Kv—O—H2 | 102.6 |
N3vii—K—N3viii | 113.15 (8) | Kvii—O—H2 | 102.6 |
Ovi—K—N1ix | 98.92 (11) | H1—O—H2 | 105.0 |
Oiii—K—N1ix | 169.76 (10) |
Symmetry codes: (i) x+1/2, −y+1/2, −z+1; (ii) x+1, y, z; (iii) −x+1, y+1/2, −z+1/2; (iv) −x+3/2, −y+1, z−1/2; (v) −x+1/2, −y+1, z−1/2; (vi) −x+1/2, −y+1, z+1/2; (vii) −x+1, y−1/2, −z+1/2; (viii) −x+3/2, −y+1, z+1/2; (ix) x−1/2, −y+1/2, −z+1; (x) x−1, y, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O—H2···N1iv | 0.84 | 2.32 | 3.157 (5) | 178 |
O—H1···N2xi | 0.84 | 2.27 | 2.952 (5) | 139 |
Symmetry codes: (iv) −x+3/2, −y+1, z−1/2; (xi) −x+2, y−1/2, −z+1/2. |
Funding information
Funding for this research was provided by: Ministry of Education, Culture, Sports, Science and Technology, MEXT-Supported Program for the Strategic Research Foundation at Private Universitieshttps://doi.org/10.13039/501100001700 (award No. S1311027).
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