trans-Dichloro(dimethyl sulfide-κS)(pyridine-κN)platinum(II)

The structure of the title compound, [PtCl₂(C₅H₅N)(C₂H₆S)], consists of discrete mol­ecules in which the Pt-atom coordination is slightly distorted square planar. The Cl atoms are trans to each other, with a Cl—Pt—Cl angle of 176.60 (7)°. The pyridine ligand is rotated 64.5 (2)° from the Pt square plane and one of the Pt—Cl bonds essentially bisects the C—S—C angle of the di­methyl sulfide ligand. In the crystal structure, there are extensive weak C—H...Cl interactions, the shortest of which connects mol­ecules into centrosymmetric dimers. A comparison of the structural trans influence on Pt—S and Pt—­N distances for PtS(CH₃)₂ and Pt(pyridine) fragments, respectively, in square-planar Pt^II complexes is presented.

S1. Comment

The trans influence, i.e. the change in ground-state thermodynamic properties due to trans-ligand effects, has been widely studied, particularly for square-planar Pt^II complexes (Pidcock et al., 1966; Crabtree, 1988, Anderson & Orpen, 2001). Zumdahl & Drago (1968) have shown that the trans influence is due to the σ-donation ability of the trans ligand; stronger σ donors show a stronger trans influence, as noted by a weaker overlap of the ligand trans to the Pt atom. Some cis influence is also predicted. X-ray crystallographic studies have clearly shown the trans influence in Pt—Cl bond distances (Appleton et al., 1973; Kapoor et al., 1996, 1998; Norén et al., 1997; Otto & Johansson, 2002). In the title compound, trans-[PtCl₂(NC₅H₅)S(CH₃)₂], (I), the dimethyl sulfide ligand is trans to a pyridine ligand. Compound (I) is the first structurally characterized trans-[PtLSMe₂Cl₂] complex to be published. \sch

In (I), the Pt atom is in a slightly distorted squar-planar environment, with the coordination sphere consisting of trans Cl atoms, a dimethyl sulfide ligand and a pyridine ligand (Fig. 1). Selected geometric parameters for (I) are given in Table 1. The geometry about the Pt atom deviates little from an ideal square plane; the S—Pt—Cl1 angle [92.65 (8)°] is slightly larger than 90° in order to accommodate the methyl groups of the dimethyl sulfide ligand. The Pt atom is almost exactly coplanar with the plane defined by the four atoms bonded to it, with a deviation from the plane of 0.0029 (19) Å. The pyridine ring is tilted at an angle of 64.5 (2)° to the square plane. The angle between the PtCl₂NS and SC₂ planes is 87.0 (2)°.

In the crystal of (I), there are extensive weak C—H···Cl interactions (Table 2), the shortest of which connects molecules into centrosymmetric dimers (Fig. 2).

The dimethyl sulfide ligand is bonded via the S atom, which shows trigonal-pyramidal geometry. The S—C distances and C—S—C angles are close to the averages found for squar-planar Pt^II complexes in the Cambridge Structural Database (CSD, Version 5.24; Allen, 2002): the minimum and maximum C—S distances are 1.78 (2) and 1.796 (14) Å, respectively, and the mean OK? C—S—C angle is 99.3 (8)° for 21 observations. The Pt—Cl distance in (I) is comparable with those in tran-PtCl₂ moieties, which have an average of 2.300 (11) Å for 397 examples in the CSD, and the Pt—N distance is about the same as the average [2.05 (4) Å, 44 observations].

A total of seven complexes with the general formula [PtSMe₂L₃], and 15 complexes of the general formula [Pt(pyridine)L₃], where L is a simple monodentate ligand, have been structurally characterized and reported in the CSD. Table 3 lists the average Pt—S distances versus the trans-ligand for the first type. The structural trans-influence series from these observations is phenyl >> pyridine > SMe₂ > Cl⁻.

Table 4 lists the average Pt—N distances versus the trans-ligand for the second type of complex, [Pt(pyridine)L₃]. The Pt—N distances in trans-[Pt(pyridine)₂Cl₂], (CLPYPT; Colamarino & Oriolli, 1975) are unusually short [1.98 (1) Å] compared with the average calculated for trans pyridine ligands. As the authors state that the refinement showed problems, this value has been omitted. The structural trans-influence series follows the order: phenyl > AsPh₃ > –CH₂NC₅H₅ > –SCN⁻ > pyridine > Cl⁻ > –ONO₂⁻.

S2. Experimental

Compound (I) was crystallized from a solution of dichlorobis(dimethyl sulfide)platinum in dichloromethane with a small quantity of pyridine.

S3. Refinement

The H atoms of the dimethyl sulfide ligand were refined as riding atoms, with an ideal tetrahedral geometry allowed to rotate to fit the electron density; C—H = 0.98 Å and U_iso(H) = 1.5U_eq(C). The H atoms on the pyridine ring were constrained to positions bisecting the C—C—C angles; C—H = 0.95 Å and U_iso(H) = 1.2U_eq(C). The largest residual peak in the difference Fourier map is 2.04 Å from atom H4 and the largest hole is 0.94 Å from the Pt atom.

Computing details

Data collection: KappaCCD Server Software (Nonius, 1997); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. A view of the molecule of (I) with the atomic labelling scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. A diagram showing the molecules of (I) connected into centrosymmetric dimers by weak C—H···Cl interactions (shown as dashed lines). The atom Cl1a is related by the symmetry operator (-x, 1 − y, −z).

trans-Dichloro(dimethyl sulfide-κS)(pyridine-κN)platinum(II)

Crystal data

[PtCl2(C5H5N)(C2H6S)]	F(000) = 752
Mr = 407.22	Dx = 2.504 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 36336 reflections
a = 8.5159 (17) Å	θ = 4.1–27.5°
b = 5.9128 (12) Å	µ = 13.62 mm^−1
c = 21.586 (4) Å	T = 100 K
β = 96.32 (3)°	Block, orange
V = 1080.3 (4) Å^3	0.22 × 0.22 × 0.19 mm
Z = 4

Data collection

Nonius KappaCCD area-detector diffractometer	2459 independent reflections
Radiation source: fine-focus sealed tube	1756 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.096
ϕ scans and ω scans with κ offsets	θmax = 27.5°, θmin = 4.2°
Absorption correction: multi-scan DENZO-SMN (Otwinowski & Minor, 1997)	h = −11→11
Tmin = 0.060, Tmax = 0.075	k = −7→7
11912 measured reflections	l = −27→27

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)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.082	H-atom parameters constrained
S = 0.97	w = 1/[σ^2(Fo^2) + (0.0353P)^2] where P = (Fo^2 + 2Fc^2)/3
2459 reflections	(Δ/σ)max = 0.001
111 parameters	Δρmax = 2.14 e Å^−3
0 restraints	Δρmin = −1.94 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
Pt	0.30654 (3)	0.93969 (5)	0.137114 (13)	0.02717 (12)
Cl1	0.0402 (2)	0.9030 (4)	0.14632 (9)	0.0354 (5)
Cl2	0.5687 (2)	0.9856 (4)	0.12215 (9)	0.0323 (5)
S	0.3490 (2)	1.1506 (4)	0.22550 (9)	0.0310 (5)
N	0.2765 (7)	0.7342 (11)	0.0607 (3)	0.0290 (15)
C1	0.3484 (10)	0.5317 (16)	0.0614 (4)	0.035 (2)
H1	0.4193	0.4924	0.0969	0.042*
C2	0.3243 (9)	0.3783 (14)	0.0132 (4)	0.033 (2)
H2	0.3770	0.2365	0.0158	0.040*
C3	0.2223 (9)	0.4336 (15)	−0.0389 (4)	0.0350 (19)
H3	0.2011	0.3298	−0.0724	0.042*
C4	0.1509 (9)	0.6477 (16)	−0.0409 (4)	0.036 (2)
H4	0.0832	0.6930	−0.0766	0.043*
C5	0.1793 (9)	0.7918 (15)	0.0091 (4)	0.0336 (19)
H5	0.1294	0.9357	0.0075	0.040*
C6	0.2692 (10)	0.9923 (14)	0.2856 (4)	0.033 (2)
H6A	0.2773	1.0818	0.3241	0.050*
H6B	0.3287	0.8512	0.2931	0.050*
H6C	0.1580	0.9573	0.2726	0.050*
C7	0.2098 (11)	1.3837 (14)	0.2192 (4)	0.039 (2)
H7A	0.2143	1.4624	0.2593	0.059*
H7B	0.1028	1.3253	0.2078	0.059*
H7C	0.2371	1.4893	0.1871	0.059*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pt	0.02837 (17)	0.02433 (18)	0.02783 (17)	0.00028 (15)	−0.00126 (11)	−0.00113 (15)
Cl1	0.0290 (10)	0.0400 (14)	0.0361 (10)	−0.0019 (9)	−0.0013 (8)	−0.0016 (9)
Cl2	0.0296 (10)	0.0349 (12)	0.0316 (10)	−0.0001 (8)	−0.0006 (8)	−0.0040 (8)
S	0.0325 (11)	0.0275 (11)	0.0323 (10)	0.0000 (9)	0.0009 (9)	−0.0050 (9)
N	0.025 (3)	0.027 (4)	0.035 (4)	−0.005 (3)	−0.001 (3)	0.003 (3)
C1	0.032 (4)	0.042 (6)	0.032 (4)	0.005 (4)	0.005 (4)	−0.002 (4)
C2	0.026 (4)	0.032 (5)	0.042 (5)	0.000 (3)	0.004 (4)	0.002 (4)
C3	0.040 (5)	0.036 (5)	0.029 (4)	−0.006 (4)	0.004 (4)	−0.002 (4)
C4	0.034 (5)	0.038 (5)	0.032 (4)	−0.001 (4)	−0.007 (4)	0.000 (4)
C5	0.034 (5)	0.025 (5)	0.041 (5)	0.000 (4)	−0.003 (4)	0.001 (4)
C6	0.043 (5)	0.028 (5)	0.028 (4)	−0.002 (4)	−0.001 (4)	0.000 (3)
C7	0.055 (6)	0.032 (5)	0.031 (4)	0.009 (4)	0.007 (4)	0.000 (4)

Geometric parameters (Å, º)

Pt—N	2.042 (6)	C3—C4	1.402 (12)
Pt—S	2.275 (2)	C3—H3	0.95
Pt—Cl1	2.309 (2)	C4—C5	1.376 (11)
Pt—Cl2	2.307 (2)	C4—H4	0.95
S—C6	1.794 (8)	C5—H5	0.95
S—C7	1.813 (8)	C6—H6A	0.98
N—C1	1.344 (11)	C6—H6B	0.98
N—C5	1.355 (9)	C6—H6C	0.98
C1—C2	1.379 (12)	C7—H7A	0.98
C1—H1	0.95	C7—H7B	0.98
C2—C3	1.383 (10)	C7—H7C	0.98
C2—H2	0.95
N—Pt—S	176.36 (18)	C4—C3—H3	121.0
N—Pt—Cl1	88.66 (18)	C5—C4—C3	119.8 (7)
S—Pt—Cl1	92.65 (8)	C5—C4—H4	120.1
N—Pt—Cl2	89.66 (18)	C3—C4—H4	120.1
S—Pt—Cl2	89.20 (7)	N—C5—C4	121.8 (8)
Cl2—Pt—Cl1	176.60 (7)	N—C5—H5	119.1
C6—S—C7	98.9 (4)	C4—C5—H5	119.1
C6—S—Pt	106.4 (3)	S—C6—H6A	109.5
C7—S—Pt	108.2 (3)	S—C6—H6B	109.5
C1—N—C5	118.0 (7)	H6A—C6—H6B	109.5
C1—N—Pt	120.3 (5)	S—C6—H6C	109.5
C5—N—Pt	121.6 (6)	H6A—C6—H6C	109.5
N—C1—C2	123.2 (7)	H6B—C6—H6C	109.5
N—C1—H1	118.4	S—C7—H7A	109.5
C2—C1—H1	118.4	S—C7—H7B	109.5
C1—C2—C3	119.1 (8)	H7A—C7—H7B	109.5
C1—C2—H2	120.4	S—C7—H7C	109.5
C3—C2—H2	120.4	H7A—C7—H7C	109.5
C2—C3—C4	118.0 (8)	H7B—C7—H7C	109.5
C2—C3—H3	121.0
Cl1—Pt—S—C6	52.9 (3)	C5—N—C1—C2	−2.0 (12)
Cl2—Pt—S—C6	−130.0 (3)	Pt—N—C1—C2	175.2 (6)
Cl1—Pt—S—C7	−52.6 (3)	N—C1—C2—C3	0.4 (13)
Cl2—Pt—S—C7	124.6 (3)	C1—C2—C3—C4	1.7 (12)
Cl1—Pt—N—C1	−115.9 (6)	C2—C3—C4—C5	−2.2 (12)
Cl2—Pt—N—C1	67.0 (6)	C1—N—C5—C4	1.4 (12)
Cl1—Pt—N—C5	61.2 (6)	Pt—N—C5—C4	−175.8 (6)
Cl2—Pt—N—C5	−115.9 (6)	C3—C4—C5—N	0.7 (13)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7B···Cl1	0.98	2.85	3.484 (9)	123
C4—H4···Cl1^i	0.95	2.95	3.752 (9)	142
C3—H3···Cl1^ii	0.95	2.82	3.632 (8)	144
C6—H6B···Cl2^iii	0.98	2.90	3.773 (8)	148
C6—H6A···Cl2^iv	0.98	2.90	3.711 (8)	140
C7—H7A···Cl2^iv	0.98	2.99	3.772 (9)	138
C3—H3···Cl2^v	0.95	2.99	3.640 (9)	127

Symmetry codes: (i) −x, −y+2, −z; (ii) −x, −y+1, −z; (iii) −x+1, y−1/2, −z+1/2; (iv) −x+1, y+1/2, −z+1/2; (v) −x+1, −y+1, −z.