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Acta Cryst. (2007). E63, m2627    [ doi:10.1107/S1600536807047034 ]

cis-(Malonato-[kappa]2O,O')bis(2-methylpyridine-[kappa]N)platinum(II)

M.-J. Xie, Y. Yu, W.-P. Liu, S.-Q. Hou and X.-Z. Chen

Abstract top

In the crystal structure of the title compound, [Pt(C3H2O4)(C6H7N)2], the PtII ion is tetracoordinated in a square-planar coordination geometry. There are intermolecular C-H...O hydrogen bonds.

Comment top

cis-diammine(1,1-cyclobutanedicarboxylato) platinum(II) (Carboplatin) is commonly used for the treatment of testicular and overian cancer as well as cervical, bladder and head and neck tumors. It has proven to be the only second-generation platinum complex commercially available worldwide at present (Jakuper et al., 2003). But the application of carboplatin in therapy is limited by the dose-dependent nephrotoxicity and other side effects. Therefore, the search for the new potent platinum complexes possessing high antitumor activity and lack of cross-resistance is needed. The title compound is a new soluble carboplatin analogue containing an asymmetric chelating malonate anion as its carrier and anticancer tests are presently being carried out.

The title complex consists of discrete monomeric complexes, in which the Pt(II) is coordinated by two crystallographically independent 2-methylpyridine ligands and one malonate anions within an square planar geometry. The coordination behaviour of the tetradentate ligand displays similar features to those described in the literature (Tu et al., 2004; Zhang et al., 2002; Ali et al., 2002). The six-membered chelate ring built up of the Pt(II) atom and the malonate anion adopts a boat conformation and the two 2-methylpyridine liagnds are oriented perpendicular to each other.

Related literature top

For related literature, see: Ali et al. (2002); Jakuper et al. (2003); Tu et al. (2004); Zhang et al. (2002).

Experimental top

Potassium tetrachloroplatinate(II) (5 g, 12 mmol) was dissolved in water (50 ml) and KI (12 g, 72 mmol) was added. The mixture were stored in the dark for 30 min at room temperature and afterwards a solution of 2-methylpyridine (1.08 g, 12 mmol in 50 ml water) was added dropwise. The mixture was stirred for 4 h and the yellow precipitate of di(2-methylpyridine)PtI2 was filtered off. Afterwards 2.5 g (0.044 mmol) of di(2-methylpyridine)PtI2, 75 ml of water and disilver malonate (1.36 g, 3.65 mmol) were stirred at 50°C for 72 h. The precipitate of AgI was filtered off and the filtrate was concentrated at 40°C under reduced pressure to about 5 ml until a white crystalline solid of the title compound precipitate. The compound was recrystallized from water to obtain crystals suitable for X-ray crystallography.

Refinement top

All H atoms were initially located in a difference Fourier map but were positioned with idealized geometry and refined isotropic with Uiso(H) = 1.2Ueq(C) (1.5 for methyl H atoms) using a riding model with C—H = 0.93 (aromatic), 0.97 (methylen) and 0.96 Å) (methyl).

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 2000); software used to prepare material for publication: SHELXTL (Sheldrick, 2000).

Figures top
[Figure 1] Fig. 1. Molecular view of the complex, with the atomic labeling scheme. Displacement ellipsoids are drawn at the 30% probability level.
cis-(Malonato-κ2O,O')bis(2-methylpyridine-κN)platinum(II) top
Crystal data top
[Pt(C3H2O4)(C6H7N)2]F000 = 920
Mr = 483.39Dx = 2.150 Mg m−3
Monoclinic, P21/nMo Kα radiation
λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 3532 reflections
a = 8.5790 (6) Åθ = 2.3–28.3º
b = 15.8079 (11) ŵ = 9.42 mm−1
c = 11.5595 (8) ÅT = 298 (2) K
β = 107.7480 (10)ºBlock, colourless
V = 1493.04 (18) Å30.24 × 0.19 × 0.16 mm
Z = 4
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		3532 independent reflections
Radiation source: fine-focus sealed tube3007 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.029
T = 298(2) Kθmax = 28.3º
φ and ω scansθmin = 2.3º
Absorption correction: numerical
(APEX2; Bruker, 2004)		h = −11→11
Tmin = 0.141, Tmax = 0.235k = −20→20
12687 measured reflectionsl = −15→15
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.021H-atom parameters constrained
wR(F2) = 0.046  w = 1/[σ2(Fo2) + (0.0222P)2 + 0.6402P]
where P = (Fo2 + 2Fc2)/3
S = 0.95(Δ/σ)max = 0.002
3532 reflectionsΔρmax = 0.53 e Å−3
201 parametersΔρmin = −0.76 e Å−3
Primary atom site location: structure-invariant direct methodsExtinction correction: none
Crystal data top
[Pt(C3H2O4)(C6H7N)2]V = 1493.04 (18) Å3
Mr = 483.39Z = 4
Monoclinic, P21/nMo Kα
a = 8.5790 (6) ŵ = 9.42 mm−1
b = 15.8079 (11) ÅT = 298 (2) K
c = 11.5595 (8) Å0.24 × 0.19 × 0.16 mm
β = 107.7480 (10)º
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer		3532 independent reflections
Absorption correction: numerical
(APEX2; Bruker, 2004)		3007 reflections with I > 2σ(I)
Tmin = 0.141, Tmax = 0.235Rint = 0.029
12687 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.021Δρmax = 0.53 e Å−3
wR(F2) = 0.046Δρmin = −0.76 e Å−3
S = 0.95Absolute structure: ?
3532 reflectionsFlack parameter: ?
201 parametersRogers parameter: ?
H-atom parameters constrained
Special details top

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 (Å2) top
xyzUiso*/Ueq
Pt10.636843 (15)0.055740 (8)0.171724 (11)0.02722 (5)
N10.8270 (3)−0.00984 (17)0.1478 (2)0.0287 (6)
N20.6310 (3)−0.01854 (18)0.3124 (3)0.0306 (6)
O10.6260 (3)0.12457 (15)0.0230 (2)0.0361 (6)
O20.4457 (3)0.11978 (15)0.1953 (2)0.0384 (6)
O30.3179 (4)0.24193 (18)0.1819 (3)0.0663 (9)
O40.5635 (5)0.24575 (19)−0.0733 (3)0.0718 (10)
C10.8018 (4)−0.0905 (2)0.1111 (3)0.0374 (8)
H10.6975−0.11320.09560.045*
C20.9251 (5)−0.1411 (2)0.0956 (4)0.0436 (9)
H20.9039−0.19690.07000.052*
C31.0802 (5)−0.1078 (3)0.1186 (3)0.0443 (9)
H31.1662−0.14110.11170.053*
C41.1050 (4)−0.0241 (3)0.1521 (3)0.0410 (9)
H41.2080−0.00010.16560.049*
C50.9767 (4)0.0250 (2)0.1660 (3)0.0318 (7)
C61.0016 (5)0.1165 (2)0.2008 (4)0.0428 (9)
H6A0.92580.15040.14020.064*
H6B1.11150.13280.20660.064*
H6C0.98320.12500.27790.064*
C70.5863 (4)0.2049 (2)0.0186 (3)0.0400 (9)
C80.5686 (5)0.2435 (2)0.1339 (3)0.0401 (9)
H8A0.54440.30330.12080.048*
H8B0.67140.23800.19840.048*
C90.4338 (4)0.2013 (2)0.1732 (3)0.0392 (9)
C100.5415 (4)−0.0904 (2)0.2854 (4)0.0395 (8)
H100.4901−0.10350.20420.047*
C110.5237 (5)−0.1446 (2)0.3729 (4)0.0520 (11)
H110.4602−0.19310.35120.062*
C120.6005 (6)−0.1267 (3)0.4929 (4)0.0576 (12)
H120.5932−0.16350.55380.069*
C130.6891 (6)−0.0524 (3)0.5207 (4)0.0547 (11)
H130.7399−0.03840.60170.066*
C140.7036 (5)0.0014 (3)0.4304 (3)0.0415 (9)
C150.7993 (6)0.0816 (3)0.4616 (4)0.0636 (13)
H15A0.90390.07440.44870.095*
H15B0.81480.09540.54520.095*
H15C0.74070.12650.41080.095*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pt10.02567 (7)0.02699 (8)0.02939 (8)0.00007 (5)0.00899 (5)−0.00007 (5)
N10.0244 (14)0.0320 (15)0.0288 (14)0.0016 (12)0.0070 (11)0.0013 (12)
N20.0252 (14)0.0321 (15)0.0342 (15)0.0014 (12)0.0084 (12)0.0009 (13)
O10.0420 (14)0.0362 (14)0.0310 (13)0.0048 (11)0.0125 (11)0.0050 (11)
O20.0345 (14)0.0330 (14)0.0530 (16)0.0052 (11)0.0212 (12)0.0032 (12)
O30.0483 (18)0.0439 (17)0.115 (3)0.0094 (14)0.0381 (19)−0.0085 (18)
O40.120 (3)0.0455 (18)0.0496 (19)0.0080 (18)0.0254 (19)0.0192 (15)
C10.0315 (19)0.039 (2)0.042 (2)0.0010 (16)0.0105 (16)−0.0006 (17)
C20.052 (2)0.033 (2)0.047 (2)0.0064 (18)0.0173 (19)−0.0038 (17)
C30.043 (2)0.053 (3)0.040 (2)0.0174 (19)0.0182 (18)0.0073 (19)
C40.0287 (19)0.057 (2)0.038 (2)0.0051 (17)0.0111 (16)0.0029 (18)
C50.0314 (18)0.0384 (19)0.0242 (17)0.0017 (15)0.0062 (14)0.0038 (15)
C60.035 (2)0.047 (2)0.047 (2)−0.0091 (17)0.0132 (17)−0.0061 (18)
C70.037 (2)0.039 (2)0.041 (2)−0.0022 (16)0.0071 (17)0.0033 (17)
C80.042 (2)0.0283 (19)0.049 (2)0.0016 (16)0.0124 (18)−0.0034 (17)
C90.0321 (19)0.040 (2)0.045 (2)0.0001 (16)0.0101 (17)−0.0067 (17)
C100.037 (2)0.035 (2)0.047 (2)−0.0030 (16)0.0134 (17)−0.0001 (17)
C110.053 (3)0.034 (2)0.074 (3)−0.0059 (19)0.027 (2)0.010 (2)
C120.064 (3)0.058 (3)0.057 (3)0.003 (2)0.027 (2)0.024 (2)
C130.056 (3)0.070 (3)0.036 (2)0.000 (2)0.010 (2)0.011 (2)
C140.036 (2)0.050 (2)0.037 (2)−0.0046 (18)0.0102 (16)−0.0012 (18)
C150.071 (3)0.068 (3)0.048 (3)−0.028 (3)0.013 (2)−0.015 (2)
Geometric parameters (Å, °) top
Pt1—O12.013 (2)C5—C61.499 (5)
Pt1—O22.015 (2)C6—H6A0.9600
Pt1—N22.019 (3)C6—H6B0.9600
Pt1—N12.022 (3)C6—H6C0.9600
N1—C11.340 (5)C7—C81.515 (5)
N1—C51.354 (4)C8—C91.519 (5)
N2—C141.353 (4)C8—H8A0.9700
N2—C101.353 (5)C8—H8B0.9700
O1—C71.312 (4)C10—C111.369 (5)
O2—C91.311 (4)C10—H100.9300
O3—C91.213 (4)C11—C121.371 (6)
O4—C71.207 (4)C11—H110.9300
C1—C21.381 (5)C12—C131.383 (6)
C1—H10.9300C12—H120.9300
C2—C31.380 (5)C13—C141.382 (5)
C2—H20.9300C13—H130.9300
C3—C41.376 (6)C14—C151.493 (6)
C3—H30.9300C15—H15A0.9600
C4—C51.395 (5)C15—H15B0.9600
C4—H40.9300C15—H15C0.9600
O1—Pt1—O290.94 (10)H6B—C6—H6C109.5
O1—Pt1—N2175.20 (10)O4—C7—O1121.4 (4)
O2—Pt1—N287.82 (10)O4—C7—C8121.8 (3)
O1—Pt1—N189.39 (10)O1—C7—C8116.7 (3)
O2—Pt1—N1179.30 (10)C7—C8—C9112.1 (3)
N2—Pt1—N191.80 (11)C7—C8—H8A109.2
C1—N1—C5119.3 (3)C9—C8—H8A109.2
C1—N1—Pt1118.2 (2)C7—C8—H8B109.2
C5—N1—Pt1122.5 (2)C9—C8—H8B109.2
C14—N2—C10118.9 (3)H8A—C8—H8B107.9
C14—N2—Pt1124.0 (2)O3—C9—O2121.4 (3)
C10—N2—Pt1117.0 (2)O3—C9—C8120.7 (3)
C7—O1—Pt1120.0 (2)O2—C9—C8117.9 (3)
C9—O2—Pt1119.0 (2)N2—C10—C11122.5 (4)
N1—C1—C2122.4 (3)N2—C10—H10118.7
N1—C1—H1118.8C11—C10—H10118.7
C2—C1—H1118.8C10—C11—C12119.4 (4)
C3—C2—C1119.0 (4)C10—C11—H11120.3
C3—C2—H2120.5C12—C11—H11120.3
C1—C2—H2120.5C11—C12—C13118.1 (4)
C4—C3—C2118.6 (3)C11—C12—H12120.9
C4—C3—H3120.7C13—C12—H12120.9
C2—C3—H3120.7C14—C13—C12121.1 (4)
C3—C4—C5120.5 (3)C14—C13—H13119.4
C3—C4—H4119.8C12—C13—H13119.4
C5—C4—H4119.8N2—C14—C13119.9 (4)
N1—C5—C4120.0 (3)N2—C14—C15119.5 (3)
N1—C5—C6119.0 (3)C13—C14—C15120.7 (4)
C4—C5—C6121.0 (3)C14—C15—H15A109.5
C5—C6—H6A109.5C14—C15—H15B109.5
C5—C6—H6B109.5H15A—C15—H15B109.5
H6A—C6—H6B109.5C14—C15—H15C109.5
C5—C6—H6C109.5H15A—C15—H15C109.5
H6A—C6—H6C109.5H15B—C15—H15C109.5
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C10—H10···O1i0.932.533.455 (5)173
C6—H6B···O3ii0.962.553.422 (5)151
C6—H6A···O10.962.553.254 (5)130
Symmetry codes: (i) −x+1, −y, −z; (ii) x+1, y, z.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C10—H10···O1i0.932.533.455 (5)173
C6—H6B···O3ii0.962.553.422 (5)151
C6—H6A···O10.962.553.254 (5)130
Symmetry codes: (i) −x+1, −y, −z; (ii) x+1, y, z.
Acknowledgements top

This work was financially supported by Yunnan Natural Science Foundation (grant Nos. 20032 C06 and 20052 C0067M) and the National Science Foundation of Yunnan University (grant No. 2005Q002A).

references
References top

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