Dibromidodimethyl­dipyridine­platinum(IV)

In the title complex, [PtBr₂(CH₃)₂(C₅H₅N)₂], the Pt^IV metal centre lies on a twofold rotation axis and adopts a slightly distorted octa­hedral coordination geometry. The structure displays weak intra­molecular C—H...Br hydrogen-bonding inter­actions.

Key indicators

• Single-crystal X-ray study
• T = 220 K
• Mean [sigma](C-C) = 0.010 Å
• R factor = 0.037
• wR factor = 0.091
• Data-to-parameter ratio = 18.2

checkCIF/PLATON results

No syntax errors found



Alert level C
            Value of measurement temperature given =   220.000
            Value of melting point given =     0.000
RINTA01_ALERT_3_C  The value of Rint is greater than 0.10
            Rint given   0.144
PLAT020_ALERT_3_C The value of Rint is greater than 0.10 .........       0.14
PLAT342_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...         10

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The structure of the title compound is one of a relatively small number of structures with the PtBr₂Me₂ moiety (Contreras et al., 2001; Kaluderović et al., 2007; Kelly, Gómez-Ruiz, Kluge et al., 2008; Kelly, Gómez-Ruiz, Schmidt et al., 2008; Kelly, Dietrich et al., 2008). The compound crystallizes in the orthorhombic space group Pbcn and half the molecule is generated by a twofold crystallographic axis bisecting the C—Pt—N axis as illustrated in Fig. 1. The ligating atoms have an approximate octahedral arrangement around the platinum atom. The Pt—N bond length (2.226 (5) Å) is slightly longer than expected for a platinum(IV)—N bond trans-configured to a ligating carbon atom (median: 2.156 Å; lower/upper quartile: 2.135/2.194 Å for 402 entries in the Cambridge Structural Database; CSD, Version 5.28, August 2007; Allen, 2002). The Pt—Br bond length (2.461 (1) Å) and the Pt—C bond length (2.053 (7) Å) are typical for bonds of these types (Clark et al., 1983; Klingler et al., 1982; Burton et al., 1983; Hughes et al., 2001; Canty et al., 1990; Hindmarch et al., 1997; Kelly, Gómez-Ruiz, Kluge et al., 2008; Kelly, Gómez-Ruiz, Schmidt et al., 2008; Kelly, Dietrich et al., 2008). A short intramolecular distance between the C6 carbon atom of the pyridine ligand and a bromo ligand of the same molecule is found, indicating the presence of weak C—H···Br interactions (Brammer et al., 2001).

Related literature

For the crystal structures of related compounds, see: Brammer et al. (2001); Burton et al. (1983); Canty et al. (1990); Clark et al. (1983); Contreras et al. (2001); Hall & Swile (1971); Hindmarch et al. (1997); Hughes et al. (2001); Kaluderović et al. (2007); Kelly, Gómez-Ruiz, Kluge et al. (2008); Kelly, Gómez-Ruiz, Schmidt et al. (2008); Kelly, Dietrich et al. (2008); Klingler et al. (1982). For bond-length data, see: Allen (2002).

S2. Experimental

The title compound was prepared by dissolving [(PtBr₂Me₂)_n] in an excess of pyridine (Hall & Swile, 1971). Single crystals suitable for X-ray analysis were obtained by slow evaporation of a chloroform solution.

S3. Refinement

H atoms were positioned geometrically and treated as riding, with C—H bonding lengths constrained to 0.93–0.96 Å and with U_iso(H) = 1.2U_eq(C). The poor quality of the crystal may account for the rather high R_int value.

Computing details

Data collection: IPDS (Stoe & Cie, 1999); cell refinement: IPDS (Stoe & Cie, 1999); data reduction: IPDS (Stoe & Cie, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

Fig. 1. A view of the title complex with displacement ellipsoids drawn at the 30% probability level. H atoms are shown as small spheres of arbitrary radii. [Symmetry code: (i) -x, y, -z + 3/2z].

Dibromidodimethyldipyridineplatinum(IV)

Crystal data

[PtBr2(CH3)2(C5H5N)2]	F(000) = 1000
Mr = 543.18	Dx = 2.421 Mg m^−3
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 8000 reflections
a = 13.297 (2) Å	θ = 2.2–25.9°
b = 8.2906 (15) Å	µ = 14.76 mm^−1
c = 13.516 (3) Å	T = 220 K
V = 1490.1 (5) Å^3	Block, orange
Z = 4	0.40 × 0.34 × 0.30 mm

Data collection

Stoe IPDS diffractometer	1453 independent reflections
Radiation source: fine-focus sealed tube	1166 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.144
area detector scans	θmax = 26.0°, θmin = 2.9°
Absorption correction: numerical (IPDS; Stoe & Cie, 1999)	h = −16→16
Tmin = 0.024, Tmax = 0.069	k = −10→10
10568 measured reflections	l = −16→16

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.037	H-atom parameters constrained
wR(F^2) = 0.091	w = 1/[σ^2(Fo^2) + (0.0472P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.01	(Δ/σ)max = 0.002
1453 reflections	Δρmax = 1.71 e Å^−3
80 parameters	Δρmin = −1.68 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0012 (2)

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
C1	0.0667 (6)	−0.0872 (9)	0.6693 (6)	0.0487 (17)
H3	0.1207	−0.1336	0.7069	0.058*
H1	0.0928	−0.0434	0.6087	0.058*
H2	0.0179	−0.1690	0.6544	0.058*
C2	−0.1238 (5)	0.4045 (8)	0.7975 (5)	0.0412 (15)
H4	−0.1268	0.4089	0.7288	0.049*
C3	−0.1703 (5)	0.5237 (9)	0.8514 (6)	0.0479 (17)
H5	−0.2038	0.6070	0.8191	0.057*
C4	−0.1673 (5)	0.5196 (10)	0.9542 (6)	0.0526 (19)
H6	−0.1976	0.6001	0.9918	0.063*
C5	−0.1182 (5)	0.3930 (10)	0.9987 (6)	0.057 (2)
H7	−0.1161	0.3847	1.0673	0.068*
C6	−0.0716 (4)	0.2771 (9)	0.9396 (4)	0.0423 (15)
H8	−0.0373	0.1928	0.9699	0.051*
N	−0.0747 (3)	0.2833 (7)	0.8400 (3)	0.0355 (11)
Br	−0.14288 (5)	0.08616 (9)	0.63441 (5)	0.0465 (2)
Pt	0.0000	0.09312 (4)	0.7500	0.03167 (18)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.055 (4)	0.047 (4)	0.044 (4)	−0.004 (3)	0.007 (3)	−0.012 (3)
C2	0.039 (3)	0.045 (4)	0.039 (4)	0.002 (3)	−0.001 (3)	0.003 (3)
C3	0.036 (3)	0.044 (4)	0.064 (5)	0.000 (3)	0.004 (3)	0.003 (4)
C4	0.035 (3)	0.062 (5)	0.061 (5)	−0.001 (3)	0.010 (3)	−0.023 (4)
C5	0.045 (4)	0.087 (7)	0.038 (4)	0.002 (3)	0.006 (3)	−0.010 (4)
C6	0.034 (3)	0.063 (4)	0.030 (3)	0.007 (3)	−0.002 (2)	−0.004 (3)
N	0.029 (2)	0.047 (3)	0.030 (3)	0.000 (2)	0.0029 (19)	0.003 (2)
Br	0.0385 (3)	0.0661 (5)	0.0347 (4)	−0.0103 (3)	−0.0087 (3)	0.0010 (3)
Pt	0.0312 (2)	0.0397 (2)	0.0242 (3)	0.000	−0.00189 (11)	0.000

Geometric parameters (Å, º)

C1—Pt	2.053 (7)	C4—H6	0.9300
C1—H3	0.9600	C5—C6	1.394 (10)
C1—H1	0.9600	C5—H7	0.9300
C1—H2	0.9600	C6—N	1.347 (7)
C2—N	1.329 (8)	C6—H8	0.9300
C2—C3	1.375 (10)	N—Pt	2.226 (5)
C2—H4	0.9300	Br—Pt	2.4605 (7)
C3—C4	1.391 (10)	Pt—C1^i	2.053 (7)
C3—H5	0.9300	Pt—N^i	2.226 (5)
C4—C5	1.375 (11)	Pt—Br^i	2.4605 (7)
Pt—C1—H3	109.5	C5—C6—H8	118.9
Pt—C1—H1	109.5	C2—N—C6	118.4 (6)
H3—C1—H1	109.5	C2—N—Pt	121.2 (4)
Pt—C1—H2	109.5	C6—N—Pt	120.4 (5)
H3—C1—H2	109.5	C1—Pt—C1^i	86.5 (4)
H1—C1—H2	109.5	C1—Pt—N	178.4 (2)
N—C2—C3	122.4 (7)	C1^i—Pt—N	91.9 (3)
N—C2—H4	118.8	C1—Pt—N^i	91.9 (3)
C3—C2—H4	118.8	C1^i—Pt—N^i	178.4 (2)
C2—C3—C4	119.9 (7)	N—Pt—N^i	89.8 (3)
C2—C3—H5	120.0	C1—Pt—Br^i	89.2 (2)
C4—C3—H5	120.0	C1^i—Pt—Br^i	88.8 (2)
C5—C4—C3	117.9 (7)	N—Pt—Br^i	90.80 (12)
C5—C4—H6	121.0	N^i—Pt—Br^i	91.11 (12)
C3—C4—H6	121.0	C1—Pt—Br	88.8 (2)
C4—C5—C6	119.1 (7)	C1^i—Pt—Br	89.2 (2)
C4—C5—H7	120.4	N—Pt—Br	91.11 (12)
C6—C5—H7	120.4	N^i—Pt—Br	90.80 (12)
N—C6—C5	122.2 (7)	Br^i—Pt—Br	177.31 (4)
N—C6—H8	118.9
N—C2—C3—C4	−0.3 (10)	C5—C6—N—Pt	−179.4 (5)
C2—C3—C4—C5	−0.9 (11)	C2—N—Pt—N^i	49.9 (4)
C3—C4—C5—C6	1.6 (11)	C6—N—Pt—N^i	−130.6 (6)
C4—C5—C6—N	−1.3 (11)	C2—N—Pt—Br^i	141.0 (4)
C3—C2—N—C6	0.7 (9)	C6—N—Pt—Br^i	−39.5 (5)
C3—C2—N—Pt	−179.8 (5)	C2—N—Pt—Br	−40.9 (4)
C5—C6—N—C2	0.1 (10)	C6—N—Pt—Br	138.6 (5)

Symmetry code: (i) −x, y, −z+3/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H8···Br^i	0.93	2.92	3.412 (6)	115

Symmetry code: (i) −x, y, −z+3/2.