[(1,2,5,6-η)-Cyclo­octa-1,5-diene]bis­­(thio­cyanato-κS)platinum(II)

In the title complex, [Pt(SCN)₂(C₈H₁₂)], the Pt^II ion lies in a square-planar coordination geometry defined by the mid-points of the two π-coordinated double bonds of cyclo­octa-1,5-diene and two S-bound SCN⁻ anions. The complex is disposed about a mirror plane passing through the Pt atom and the SCN⁻ ligands, and bis­ecting the cyclo­octa-1,5-diene mol­ecule. The room-temperature crystal structure of the title complex was previously reported in the ortho­rhom­bic space group Pna2₁ [Musitu & Garcia-Blanco (1984). Acta Cryst. A40, C101]. The low-temperature structure presented herein represents a different (higher symmetry) ortho­rhom­bic space group Pnma whereby the Pt^II atom lies on a mirror plane, lacking in the earlier study.

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Chemical scheme

Structure description

With reference to the title complex, [Pt(SCN)₂(cod)], the crystal structures of related cod–Pt^II complexes [PtX₂(cod)] (X = Cl, Br, I; cod = cyclo­octa-1,5-diene) have been determined previously. The chlorido complex [PtCl₂(cod)] (Goel et al., 1982; Syed et al., 1984; Musitu & Garcia-Blanco, 1984) and the bromido complex [PtBr₂(cod)] (Musitu & Garcia-Blanco, 1984) both crystallize in the ortho­rhom­bic space group P2₁2₁2₁. The iodido complex [PtI₂(cod)] crystallizes in the monoclinic space group P2₁/n (Musitu & Garcia-Blanco, 1984). The room-temperature crystal structure of the title complex was previously reported in the ortho­rhom­bic space group Pna2₁ (Musitu & Garcia-Blanco, 1984). The low-temperature structure presented herein represents a different (higher symmetry) ortho­rhom­bic space group Pnma whereby the Pt^II atom lies on a mirror plane, lacking in the earlier study (Musitu & Garcia-Blanco, 1984).

In the title complex, the central Pt^II ion has a square-planar coordination geometry defined by the mid-points of the two π-coordinated double bonds of cyclo­octa-1,5-diene and two S atoms derived from two SCN⁻ anions (Fig. 1). The complex is disposed about a mirror plane passing through the Pt atom and the SCN⁻ ligands, and bis­ecting cyclo­octa-1,5-diene. Therefore, the asymmetric unit contains one half of the complex mol­ecule. The cod ligand coordinates to the Pt atom in the boat conformation with the coordinated double-bond lengths of 1.386 (9) and 1.388 (9) Å, and with the cod ring angles lying in the range of 117.6 (4)–124.4 (3)°. The thio­cyanato ligands are linear displaying S—C—N bond angles of 179.0 (6) and 180.0 (5)°, and the S atoms are coordinated to the Pt atom with nearly tetra­hedral Pt—S—C bond angles of 106.0 (2) and 106.6 (2)°, characteristic of an S-bonded conformation (Ha, 2013).

Figure 1 The mol­ecular structure of the title complex showing the atom labelling and displacement ellipsoids drawn at the 40% probability level for non-H atoms [symmetry code: (i) x,  − y, z].

Synthesis and crystallization

To a solution of K₂PtCl₄ (2.0820 g, 5.016 mmol) and KSCN (2.3967 g, 24.662 mmol) in H₂O (40 ml) and EtOH (10 ml) was added cyclo­octa-1,5-diene (1.0235 g, 9.461 mmol) and refluxed for 2 h. The formed precipitate was separated by filtration, washed with H₂O and acetone, and dried at 323 K, to give a light-yellow powder (1.4009 g). Yellow crystals suitable for X-ray analysis were obtained by slow evaporation from an acetone solution at room temperature.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1.

Table 1
Experimental details

Crystal data
Chemical formula	[Pt(SCN)2(C8H12)]
Mr	419.43
Crystal system, space group	Orthorhombic, Pnma
Temperature (K)	223
a, b, c (Å)	16.8696 (12), 7.5226 (6), 9.0540 (6)
V (Å^3)	1148.98 (14)
Z	4
Radiation type	Mo Kα
μ (mm^−1)	12.54
Crystal size (mm)	0.21 × 0.15 × 0.10
Data collection
Diffractometer	Bruker PHOTON 100 CMOS detector
Absorption correction	Multi-scan (SADABS; Bruker, 2016)
Tmin, Tmax	0.363, 0.745
No. of measured, independent and observed [I > 2σ(I)] reflections	27245, 1237, 1178
Rint	0.082
(sin θ/λ)max (Å^−1)	0.620
Refinement
R[F^2 > 2σ(F^2)], wR(F^2), S	0.019, 0.045, 1.11
No. of reflections	1237
No. of parameters	79
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å^−3)	0.55, −0.79
Computer programs: APEX2 and SAINT (Bruker, 2016), SHELXT2014 (Sheldrick, 2015a), SHELXL2014 (Sheldrick, 2015b) and ORTEP-3 for Windows (Farrugia, 2012).

Structural data

Computing details

Data collection: APEX2 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015b).

[(1,2,5,6-η)-Cycloocta-1,5-diene]bis(thiocyanato-κS)platinum(II)

Crystal data

[Pt(SCN)2(C8H12)]	Dx = 2.425 Mg m^−3
Mr = 419.43	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pnma	Cell parameters from 9838 reflections
a = 16.8696 (12) Å	θ = 2.4–26.1°
b = 7.5226 (6) Å	µ = 12.54 mm^−1
c = 9.0540 (6) Å	T = 223 K
V = 1148.98 (14) Å^3	Block, yellow
Z = 4	0.21 × 0.15 × 0.10 mm
F(000) = 784

Data collection

Bruker PHOTON 100 CMOS detector diffractometer	1178 reflections with I > 2σ(I)
Radiation source: sealed tube	Rint = 0.082
φ and ω scans	θmax = 26.1°, θmin = 3.3°
Absorption correction: multi-scan (SADABS; Bruker, 2016)	h = −20→20
Tmin = 0.363, Tmax = 0.745	k = −9→9
27245 measured reflections	l = −11→11
1237 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.019	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.045	H-atom parameters constrained
S = 1.11	w = 1/[σ^2(Fo^2) + (0.0127P)^2 + 2.853P] where P = (Fo^2 + 2Fc^2)/3
1237 reflections	(Δ/σ)max < 0.001
79 parameters	Δρmax = 0.55 e Å^−3
0 restraints	Δρmin = −0.79 e Å^−3

Special details

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. The hydrogen atoms were positioned geometrically and allowed to ride on their respective parent atoms: C—H = 0.99 Å (CH) or 0.98 Å (CH₂) and with U_iso(H) = 1.2U_eq(C).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Pt1	0.05447 (2)	0.2500	0.10287 (2)	0.01688 (8)
S1	−0.07951 (8)	0.2500	0.16871 (16)	0.0318 (3)
C1	−0.0816 (4)	0.2500	0.3536 (7)	0.0357 (14)
N1	−0.0841 (4)	0.2500	0.4801 (7)	0.0551 (17)
S2	−0.00113 (9)	0.2500	−0.13300 (15)	0.0321 (3)
C2	0.0746 (4)	0.2500	−0.2528 (6)	0.0311 (13)
N2	0.1258 (4)	0.2500	−0.3338 (5)	0.0472 (14)
C3	0.0990 (2)	0.1579 (6)	0.3169 (4)	0.0313 (9)
H3	0.0581	0.1037	0.3812	0.038*
C4	0.1716 (3)	0.0447 (9)	0.2949 (5)	0.0622 (18)
H4A	0.2115	0.0831	0.3669	0.075*
H4B	0.1574	−0.0781	0.3195	0.075*
C5	0.2080 (3)	0.0436 (9)	0.1537 (5)	0.0610 (17)
H5A	0.2086	−0.0793	0.1180	0.073*
H5B	0.2633	0.0805	0.1661	0.073*
C6	0.1717 (2)	0.1577 (6)	0.0354 (4)	0.0293 (8)
H6	0.1732	0.1041	−0.0644	0.035*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pt1	0.01299 (12)	0.02235 (12)	0.01529 (11)	0.000	−0.00064 (6)	0.000
S1	0.0154 (6)	0.0481 (9)	0.0317 (8)	0.000	0.0019 (5)	0.000
C1	0.026 (3)	0.039 (4)	0.042 (4)	0.000	0.008 (3)	0.000
N1	0.048 (3)	0.078 (5)	0.039 (3)	0.000	0.019 (3)	0.000
S2	0.0240 (7)	0.0505 (9)	0.0217 (6)	0.000	−0.0067 (5)	0.000
C2	0.037 (3)	0.042 (3)	0.015 (2)	0.000	−0.009 (2)	0.000
N2	0.055 (3)	0.067 (4)	0.020 (3)	0.000	−0.002 (3)	0.000
C3	0.0253 (18)	0.055 (2)	0.0132 (15)	0.0058 (18)	−0.0006 (14)	0.0082 (16)
C4	0.046 (3)	0.103 (5)	0.038 (2)	0.042 (3)	0.011 (2)	0.034 (3)
C5	0.056 (3)	0.090 (4)	0.037 (2)	0.048 (3)	0.011 (2)	0.017 (3)
C6	0.0202 (17)	0.049 (2)	0.0189 (16)	0.0121 (17)	0.0042 (14)	−0.0008 (17)

Geometric parameters (Å, º)

Pt1—C6^i	2.183 (3)	C3—C4	1.505 (6)
Pt1—C6	2.183 (3)	C3—H3	0.9900
Pt1—C3^i	2.191 (3)	C4—C5	1.418 (6)
Pt1—C3	2.191 (3)	C4—H4A	0.9800
Pt1—S2	2.3324 (13)	C4—H4B	0.9800
Pt1—S1	2.3375 (13)	C5—C6	1.503 (6)
S1—C1	1.674 (7)	C5—H5A	0.9800
C1—N1	1.146 (9)	C5—H5B	0.9800
S2—C2	1.676 (6)	C6—C6^i	1.388 (9)
C2—N2	1.133 (8)	C6—H6	0.9900
C3—C3^i	1.386 (9)
C6^i—Pt1—C6	37.1 (2)	C3^i—C3—H3	114.3
C6^i—Pt1—C3^i	80.59 (14)	C4—C3—H3	114.3
C6—Pt1—C3^i	92.15 (14)	Pt1—C3—H3	114.3
C6^i—Pt1—C3	92.15 (14)	C5—C4—C3	118.3 (4)
C6—Pt1—C3	80.58 (14)	C5—C4—H4A	107.7
C3^i—Pt1—C3	36.9 (2)	C3—C4—H4A	107.7
C6^i—Pt1—S2	96.21 (10)	C5—C4—H4B	107.7
C6—Pt1—S2	96.21 (10)	C3—C4—H4B	107.7
C3^i—Pt1—S2	161.39 (12)	H4A—C4—H4B	107.1
C3—Pt1—S2	161.39 (12)	C4—C5—C6	117.6 (4)
C6^i—Pt1—S1	161.32 (11)	C4—C5—H5A	107.9
C6—Pt1—S1	161.32 (11)	C6—C5—H5A	107.9
C3^i—Pt1—S1	96.07 (10)	C4—C5—H5B	107.9
C3—Pt1—S1	96.07 (10)	C6—C5—H5B	107.9
S2—Pt1—S1	81.06 (5)	H5A—C5—H5B	107.2
C1—S1—Pt1	106.0 (2)	C6^i—C6—C5	124.8 (3)
N1—C1—S1	179.0 (6)	C6^i—C6—Pt1	71.47 (11)
C2—S2—Pt1	106.63 (19)	C5—C6—Pt1	110.6 (3)
N2—C2—S2	180.0 (5)	C6^i—C6—H6	114.1
C3^i—C3—C4	124.4 (3)	C5—C6—H6	114.1
C3^i—C3—Pt1	71.56 (12)	Pt1—C6—H6	114.1
C4—C3—Pt1	109.9 (3)
C3^i—C3—C4—C5	−68.8 (7)	C4—C5—C6—C6^i	68.2 (7)
Pt1—C3—C4—C5	12.0 (7)	C4—C5—C6—Pt1	−13.0 (7)
C3—C4—C5—C6	0.6 (9)

Symmetry code: (i) x, −y+1/2, z.