Bis(2,2′-bipyridine-κ²N,N′)platinum(II) bis­(perchlorate)

The title complex, [Pt(C₁₀H₈N₂)₂](ClO₄)₂, adopts a square-planar geometry in which all four N-atom donors are strictly coplanar as the Pt ion lies on an inversion centre. However, the 2,2′-bipyridine ligand deviates significantly from planarity, as demonstrated by the angle of 20.52 (11)° between the mean planes of the two pyridine rings.

Key indicators

• Single-crystal X-ray study
• T = 85 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.014
• wR factor = 0.036
• Data-to-parameter ratio = 18.8

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR) is > 1.10
            Tmin and Tmax reported:      0.361     0.572
            Tmin and Tmax expected:      0.275     0.572
            RR =      1.315
            Please check that your absorption correction is appropriate.
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT060_ALERT_3_C Ratio Tmax/Tmin (Exp-to-Rep) (too) Large .......       1.33

Alert level G
REFLT03_ALERT_1_G ALERT: Expected hkl max differ from CIF values
           From the CIF: _diffrn_reflns_theta_max           33.20
           From the CIF: _reflns_number_total               3010
           From the CIF: _diffrn_reflns_limit_ max hkl   10.   12.   13.
           From the CIF: _diffrn_reflns_limit_ min hkl   -7.  -11.  -13.
           TEST1: Expected hkl limits for theta max
           Calculated maximum hkl   12.   13.   13.
           Calculated minimum hkl  -12.  -13.  -13.

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

   2 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
   2 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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S1. Comment

The title complex, (I) (Fig. 1), was obtained during a study of the reactivity of [Pt(C₁₀H₈N₂)₂]²⁺ in aqueous alkaline solution (McInnes et al., 2003). Complex (I) crystallizes in the triclinic space group P1 with the Pt ion lying on an inversion centre, thus requiring it to be strictly coplanar with the four attached N atoms. The Pt—N distances [2.0227 (18) and 2.0292 (17) Å] are similar to those found in [Pt(C₁₀H₈N₂)₂](NO₃)₂·H₂O (Hazell et al., 1986) and [Pt(C₁₀H₈N₂)₂](CF₃SO₃)₂ (Fedotova et al., 2003), and are typical of those found in Pt complexes containing pyridine ligands (mean = 2.064 Å, SD = 0.074 Å for 997 structurally characterized complexes and 2214 individual Pt—N distances; Cambridge Structural Database, Version 5.26 of November 2004 (Allen, 2002)]. The 2,2'-bipyridine ligands display a bow distortion (Fig. 2) with a remarkably large angle of 20.52 (11)° between the mean planes of the two rings (Hazell, 2004). A similar distortion is seen in the trifluoromethanesulfonate salt of the complex (Fedotova et al., 2003) and presumably prevents the close inter-ligand approach of atoms H1 and H10. It is tempting to speculate that the strain inherent in such a distortion is responsible for the unusual behaviour of [Pt(C₁₀H₈N₂)₂]²⁺ in aqueous alkaline solution, allowing facile coordination of hydroxide ion to give a pseudo-five-coordinate complex (McInnes et al., 2003).

There are weak π-stacking interactions throughout the three-dimensional structure (Fig. 3), with centroid-to-centroid distances between the pyridine rings of 3.703 (3) (−1 − x, −y, −z) and 3.924 (3) Å (−x, −y, 1 − z). The perchlorate ions are also involved in anion–π interactions, with O1–centroid (at 1 + x, y, 1 + z) and O4–centroid (at −x, 1 − y, 1 − z) distances of 3.064 (3) and 3.356 (3) Å, respectively.

S2. Experimental

Complex (I) precipitated on addition of one drop of 6 M NaClO₄(aq) to a solution of [Pt(C₁₀H₈N₂)₂](NO₃)₂·H₂O (53 mg), prepared according to McInnes et al. (2003) in water (1 ml) to which one equivalent of 1 M NaOH(aq) (84 ml) had been added. Dilution to approximately 20 ml with hot water and subsequent slow cooling gave (I) as small pale-yellow crystals.

S3. Refinement

All H atoms were included in the riding-model approximation, with C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C). The highest residual peak in the difference map is 0.79 Å from atom Pt1.

Computing details

Data collection: APEX-II (Bruker, 2004); cell refinement: APEX-II and SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997 and SHELXTL (Bruker, 2001); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The structure of the cation of (I), with displacement ellipsoids drawn at the 50% probability level.
	Fig. 2. View of the cation of (I), emphasizing the bow distortion of the 2,2'-bipyridine ligands.
	Fig. 3. Packing, viewed down the a axis. Close interactions are indicated as dashed lines.

bis(2,2'-bipyridine-κ²N,N')platinum(II) bis(perchlorate)

Crystal data

[Pt(C10H8N2)2](ClO4)2	Z = 1
Mr = 706.35	F(000) = 340
Triclinic, P1	Dx = 2.227 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71069 Å
a = 7.811 (5) Å	Cell parameters from 5644 reflections
b = 8.621 (5) Å	θ = 2.4–33.0°
c = 9.054 (5) Å	µ = 6.97 mm^−1
α = 72.972 (5)°	T = 85 K
β = 86.553 (5)°	Plate, pale-yellow
γ = 64.960 (5)°	0.32 × 0.16 × 0.08 mm
V = 526.7 (5) Å^3

Data collection

Bruker Kappa-APEX-II area-detector diffractometer	3010 independent reflections
Radiation source: fine-focus sealed tube	3010 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.028
ϕ and ω scans	θmax = 33.2°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −7→10
Tmin = 0.361, Tmax = 0.572	k = −11→12
11349 measured reflections	l = −13→13

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)] = 0.014	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.036	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0182P)^2 + 0.2101P] where P = (Fo^2 + 2Fc^2)/3
3010 reflections	(Δ/σ)max < 0.001
160 parameters	Δρmax = 1.19 e Å^−3
0 restraints	Δρmin = −1.34 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
Pt1	0.0000	0.0000	0.0000	0.00959 (3)
Cl1	0.72870 (7)	0.55282 (6)	0.74243 (5)	0.01562 (9)
O3	0.6723 (2)	0.74430 (19)	0.68472 (17)	0.0190 (3)
O4	0.5894 (3)	0.5191 (3)	0.8406 (2)	0.0298 (4)
O1	0.9085 (2)	0.4714 (2)	0.8310 (2)	0.0302 (4)
N1	−0.1963 (2)	−0.0954 (2)	0.07318 (17)	0.0107 (3)
O2	0.7429 (4)	0.4830 (3)	0.6145 (2)	0.0413 (5)
C2	−0.3843 (3)	−0.2526 (3)	0.0693 (2)	0.0148 (3)
H2	−0.4358	−0.3007	0.0147	0.018*
C4	−0.3484 (3)	−0.1824 (3)	0.2993 (2)	0.0142 (3)
H4	−0.3730	−0.1858	0.4017	0.017*
N2	−0.1036 (2)	0.1103 (2)	0.17412 (17)	0.0113 (3)
C8	−0.2114 (3)	0.1948 (3)	0.4482 (2)	0.0152 (4)
H8	−0.2407	0.2189	0.5425	0.018*
C9	−0.1373 (3)	0.2933 (3)	0.3368 (2)	0.0145 (3)
H9	−0.1217	0.3881	0.3534	0.017*
C1	−0.2730 (3)	−0.1673 (2)	−0.0017 (2)	0.0128 (3)
H1	−0.2502	−0.1592	−0.1051	0.015*
C10	−0.0865 (3)	0.2491 (2)	0.2004 (2)	0.0135 (3)
H10	−0.0392	0.3171	0.1249	0.016*
C3	−0.4180 (3)	−0.2651 (3)	0.2239 (2)	0.0154 (4)
H3	−0.4861	−0.3281	0.2761	0.018*
C7	−0.2414 (3)	0.0596 (3)	0.4169 (2)	0.0137 (3)
H7	−0.2956	−0.0050	0.4884	0.016*
C6	−0.1895 (3)	0.0221 (2)	0.2780 (2)	0.0115 (3)
C5	−0.2424 (3)	−0.0950 (2)	0.2205 (2)	0.0119 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pt1	0.01102 (5)	0.00998 (5)	0.00989 (5)	−0.00593 (4)	0.00202 (3)	−0.00391 (3)
Cl1	0.0217 (2)	0.0170 (2)	0.01378 (18)	−0.01234 (18)	0.00363 (16)	−0.00656 (15)
O3	0.0224 (7)	0.0149 (6)	0.0192 (6)	−0.0078 (6)	−0.0016 (6)	−0.0038 (5)
O4	0.0348 (10)	0.0429 (10)	0.0297 (8)	−0.0320 (8)	0.0123 (7)	−0.0143 (7)
O1	0.0205 (8)	0.0213 (8)	0.0394 (9)	−0.0071 (7)	−0.0057 (7)	0.0029 (7)
N1	0.0113 (7)	0.0108 (6)	0.0121 (6)	−0.0065 (6)	0.0020 (5)	−0.0036 (5)
O2	0.0820 (16)	0.0377 (10)	0.0229 (8)	−0.0363 (11)	0.0158 (9)	−0.0208 (8)
C2	0.0136 (8)	0.0154 (8)	0.0181 (8)	−0.0070 (7)	0.0011 (7)	−0.0076 (7)
C4	0.0150 (8)	0.0151 (8)	0.0143 (8)	−0.0079 (7)	0.0033 (7)	−0.0049 (6)
N2	0.0116 (7)	0.0121 (7)	0.0125 (6)	−0.0066 (6)	0.0017 (5)	−0.0045 (5)
C8	0.0139 (8)	0.0185 (9)	0.0156 (8)	−0.0064 (7)	0.0026 (7)	−0.0094 (7)
C9	0.0138 (9)	0.0133 (8)	0.0191 (8)	−0.0058 (7)	0.0015 (7)	−0.0087 (6)
C1	0.0120 (8)	0.0135 (8)	0.0139 (7)	−0.0048 (7)	0.0008 (6)	−0.0064 (6)
C10	0.0127 (8)	0.0123 (8)	0.0168 (8)	−0.0062 (7)	0.0019 (7)	−0.0051 (6)
C3	0.0151 (9)	0.0154 (8)	0.0195 (9)	−0.0094 (7)	0.0042 (7)	−0.0067 (7)
C7	0.0128 (8)	0.0161 (8)	0.0134 (8)	−0.0067 (7)	0.0024 (6)	−0.0055 (6)
C6	0.0101 (8)	0.0116 (7)	0.0132 (7)	−0.0048 (6)	0.0011 (6)	−0.0041 (6)
C5	0.0109 (8)	0.0125 (8)	0.0123 (7)	−0.0047 (7)	0.0010 (6)	−0.0042 (6)

Geometric parameters (Å, º)

Pt1—N1^i	2.0227 (18)	C4—H4	0.9300
Pt1—N1	2.0227 (18)	N2—C10	1.346 (2)
Pt1—N2	2.0292 (17)	N2—C6	1.360 (2)
Pt1—N2^i	2.0292 (17)	C8—C9	1.385 (3)
Cl1—O2	1.4328 (18)	C8—C7	1.387 (3)
Cl1—O4	1.4350 (18)	C8—H8	0.9300
Cl1—O1	1.4420 (19)	C9—C10	1.384 (3)
Cl1—O3	1.4488 (17)	C9—H9	0.9300
N1—C1	1.346 (2)	C1—H1	0.9300
N1—C5	1.362 (2)	C10—H10	0.9300
C2—C1	1.381 (3)	C3—H3	0.9300
C2—C3	1.389 (3)	C7—C6	1.385 (3)
C2—H2	0.9300	C7—H7	0.9300
C4—C5	1.380 (3)	C6—C5	1.465 (3)
C4—C3	1.388 (3)
N1^i—Pt1—N1	180.00 (8)	C9—C8—C7	118.97 (17)
N1^i—Pt1—N2	101.17 (7)	C9—C8—H8	120.5
N1—Pt1—N2	78.83 (7)	C7—C8—H8	120.5
N1^i—Pt1—N2^i	78.83 (7)	C10—C9—C8	119.34 (18)
N1—Pt1—N2^i	101.17 (7)	C10—C9—H9	120.3
N2—Pt1—N2^i	180.00 (10)	C8—C9—H9	120.3
O2—Cl1—O4	109.56 (12)	N1—C1—C2	122.41 (17)
O2—Cl1—O1	110.92 (13)	N1—C1—H1	118.8
O4—Cl1—O1	109.44 (12)	C2—C1—H1	118.8
O2—Cl1—O3	109.35 (11)	N2—C10—C9	121.75 (18)
O4—Cl1—O3	109.29 (11)	N2—C10—H10	119.1
O1—Cl1—O3	108.25 (10)	C9—C10—H10	119.1
C1—N1—C5	118.46 (16)	C4—C3—C2	119.06 (18)
C1—N1—Pt1	127.86 (13)	C4—C3—H3	120.5
C5—N1—Pt1	113.52 (12)	C2—C3—H3	120.5
C1—C2—C3	118.82 (18)	C6—C7—C8	119.21 (18)
C1—C2—H2	120.6	C6—C7—H7	120.4
C3—C2—H2	120.6	C8—C7—H7	120.4
C5—C4—C3	119.23 (17)	N2—C6—C7	121.46 (17)
C5—C4—H4	120.4	N2—C6—C5	114.00 (16)
C3—C4—H4	120.4	C7—C6—C5	124.07 (17)
C10—N2—C6	118.88 (16)	N1—C5—C4	121.63 (17)
C10—N2—Pt1	127.63 (13)	N1—C5—C6	114.01 (16)
C6—N2—Pt1	113.36 (12)	C4—C5—C6	123.97 (16)

Symmetry code: (i) −x, −y, −z.