Acta Cryst. (2007). E63, m2589 [ doi:10.1107/S1600536807045771 ]
The asymmetric unit in the title compound, [Pt(C6H6O4)(C6H7N)2], is composed of one-half of a molecule. The complex lies on a mirror plane which contains the Pt atom and three C atoms of the cyclobutane group, the fourth C atom being disordered with respect to the mirror plane. The PtII ion is tetracoordinated in a square-planar environment.
Potassium tetrachloroplatinate(II) (5 g, 12 mmol) was dissolved in water (50 ml) and KI (12 g, 72 mmol) was added. After standing in the dark for 30 min at room temperature, 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 1,1-cyclobutanedicarboxylate (1.07 g, 2.99 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 analysis.
All H atoms were initially located in a difference Fourier map but were positioned with idealized geometry and treated as riding on their parent atoms with C—H = 0.93 Å (aromatic), 0.96 Å (methyl) and 0.97 Å (methylene) and with Uiso(H) = 1.2Ueq(aromatic, methylene) and 1.5 for methyl H atoms) or Uiso(H) = 1.5Ueq(methyl).
The C10 atom is statistically distributed with respect to the crystallographic mirror plane. It was then refined using the PART −1 instruction within SHELXL97 (Sheldrick, 1997) and C—C restraints.
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: ORTEPIII (Burnett & Johnson, 1996) and ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
![[Figure 1]](./dn2231fig1thm.gif)
| Fig. 1. Molecular view of the complex, with the atomic labeling scheme. Displacement ellipsoids are drawn at the 30% probability level. Only one component of the disordered moiety is represented. H atoms have been omitted for clarity. [Symmetry code: (i) x, –Y+3/2, z]. |
| [Pt(C6H6O4)(C6H7N)2] | F000 = 1008 |
| Mr = 523.45 | Dx = 1.923 Mg m−3 |
| Orthorhombic, Pnma | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: -P2ac2n | Cell parameters from 2278 reflections |
| a = 12.7339 (7) Å | θ = 2.5–28.3º |
| b = 14.5313 (8) Å | µ = 7.79 mm−1 |
| c = 9.7716 (6) Å | T = 298 (2) K |
| V = 1808.14 (18) Å3 | Block, colourless |
| Z = 4 | 0.26 × 0.22 × 0.12 mm |
| Bruker APEXII CCD area-detector diffractometer | 2278 independent reflections |
| Radiation source: fine-focus sealed tube | 2031 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.028 |
| T = 298(2) K | θmax = 28.3º |
| φ and ω scans | θmin = 2.5º |
| Absorption correction: numerical (APEX2; Bruker, 2004) | h = −16→16 |
| Tmin = 0.237, Tmax = 0.455 | k = −19→19 |
| 14744 measured reflections | l = −12→12 |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.017 | H-atom parameters constrained |
| wR(F2) = 0.044 | w = 1/[σ2(Fo2) + (0.027P)2 + 0.1067P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.04 | (Δ/σ)max = 0.003 |
| 2278 reflections | Δρmax = 0.78 e Å−3 |
| 125 parameters | Δρmin = −0.66 e Å−3 |
| 2 restraints | Extinction correction: none |
| Primary atom site location: structure-invariant direct methods |
| [Pt(C6H6O4)(C6H7N)2] | V = 1808.14 (18) Å3 |
| Mr = 523.45 | Z = 4 |
| Orthorhombic, Pnma | Mo Kα |
| a = 12.7339 (7) Å | µ = 7.79 mm−1 |
| b = 14.5313 (8) Å | T = 298 (2) K |
| c = 9.7716 (6) Å | 0.26 × 0.22 × 0.12 mm |
| Bruker APEXII CCD area-detector diffractometer | 2278 independent reflections |
| Absorption correction: numerical (APEX2; Bruker, 2004) | 2031 reflections with I > 2σ(I) |
| Tmin = 0.237, Tmax = 0.455 | Rint = 0.028 |
| 14744 measured reflections |
| R[F2 > 2σ(F2)] = 0.017 | 2 restraints |
| wR(F2) = 0.044 | H-atom parameters constrained |
| S = 1.04 | Δρmax = 0.78 e Å−3 |
| 2278 reflections | Δρmin = −0.66 e Å−3 |
| 125 parameters |
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 > 2sigma(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. |
| x | y | z | Uiso*/Ueq | Occ. (<1) | |
| Pt1 | 0.615174 (10) | 0.7500 | 0.091373 (11) | 0.02943 (6) | |
| N1 | 0.66661 (15) | 0.64874 (13) | −0.03283 (19) | 0.0326 (4) | |
| O1 | 0.56091 (14) | 0.65080 (11) | 0.21436 (17) | 0.0401 (4) | |
| O2 | 0.50259 (19) | 0.60774 (15) | 0.41509 (18) | 0.0605 (6) | |
| C1 | 0.76953 (19) | 0.62816 (18) | −0.0318 (3) | 0.0401 (6) | |
| H1 | 0.8138 | 0.6634 | 0.0227 | 0.048* | |
| C2 | 0.8127 (3) | 0.5579 (2) | −0.1070 (3) | 0.0484 (7) | |
| H2 | 0.8839 | 0.5442 | −0.1011 | 0.058* | |
| C3 | 0.7478 (2) | 0.50885 (18) | −0.1906 (3) | 0.0547 (8) | |
| H3 | 0.7752 | 0.4629 | −0.2464 | 0.066* | |
| C4 | 0.6415 (2) | 0.5272 (2) | −0.1925 (3) | 0.0524 (7) | |
| H4 | 0.5971 | 0.4929 | −0.2483 | 0.063* | |
| C5 | 0.6010 (2) | 0.5970 (2) | −0.1110 (3) | 0.0401 (6) | |
| C6 | 0.4857 (2) | 0.6157 (2) | −0.1055 (3) | 0.0571 (8) | |
| H6A | 0.4658 | 0.6300 | −0.0132 | 0.086* | |
| H6B | 0.4480 | 0.5624 | −0.1360 | 0.086* | |
| H6C | 0.4694 | 0.6669 | −0.1639 | 0.086* | |
| C7 | 0.54870 (18) | 0.66383 (16) | 0.3446 (3) | 0.0377 (5) | |
| C8 | 0.5967 (3) | 0.7500 | 0.4092 (3) | 0.0397 (9) | |
| C9 | 0.5995 (4) | 0.7500 | 0.5655 (4) | 0.0626 (14) | |
| H9A | 0.5886 | 0.8102 | 0.6059 | 0.075* | 0.50 |
| H9B | 0.5538 | 0.7045 | 0.6070 | 0.075* | 0.50 |
| C11 | 0.7208 (4) | 0.7500 | 0.4086 (4) | 0.0517 (11) | |
| H11A | 0.7519 | 0.7040 | 0.3492 | 0.062* | 0.50 |
| H11B | 0.7520 | 0.8101 | 0.3941 | 0.062* | 0.50 |
| C10 | 0.7137 (6) | 0.7211 (7) | 0.5593 (7) | 0.097 (5) | 0.50 |
| H10A | 0.7242 | 0.6557 | 0.5735 | 0.117* | 0.50 |
| H10B | 0.7589 | 0.7567 | 0.6191 | 0.117* | 0.50 |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Pt1 | 0.02763 (8) | 0.03190 (8) | 0.02875 (8) | 0.000 | 0.00074 (4) | 0.000 |
| N1 | 0.0328 (11) | 0.0361 (10) | 0.0290 (10) | −0.0017 (8) | 0.0011 (8) | −0.0006 (8) |
| O1 | 0.0460 (10) | 0.0357 (9) | 0.0385 (9) | −0.0090 (7) | 0.0058 (7) | 0.0003 (7) |
| O2 | 0.0720 (16) | 0.0569 (13) | 0.0527 (13) | −0.0192 (11) | 0.0175 (10) | 0.0103 (9) |
| C1 | 0.0373 (14) | 0.0443 (14) | 0.0389 (14) | 0.0011 (10) | −0.0007 (10) | −0.0031 (11) |
| C2 | 0.0447 (16) | 0.0495 (16) | 0.0510 (16) | 0.0106 (13) | 0.0063 (12) | −0.0044 (12) |
| C3 | 0.067 (2) | 0.0439 (16) | 0.0532 (17) | 0.0066 (14) | 0.0063 (14) | −0.0108 (12) |
| C4 | 0.0647 (19) | 0.0453 (16) | 0.0472 (16) | −0.0095 (13) | −0.0023 (13) | −0.0129 (13) |
| C5 | 0.0444 (16) | 0.0387 (15) | 0.0372 (14) | −0.0077 (11) | −0.0014 (10) | −0.0014 (11) |
| C6 | 0.0415 (17) | 0.068 (2) | 0.062 (2) | −0.0114 (15) | −0.0108 (13) | −0.0126 (14) |
| C7 | 0.0335 (13) | 0.0376 (13) | 0.0420 (14) | 0.0011 (10) | 0.0043 (10) | 0.0044 (11) |
| C8 | 0.036 (2) | 0.046 (2) | 0.036 (2) | 0.000 | 0.0050 (13) | 0.000 |
| C9 | 0.083 (4) | 0.069 (3) | 0.035 (2) | 0.000 | −0.003 (2) | 0.000 |
| C11 | 0.037 (2) | 0.052 (2) | 0.066 (3) | 0.000 | −0.0118 (17) | 0.000 |
| C10 | 0.089 (6) | 0.140 (14) | 0.062 (4) | 0.003 (5) | −0.032 (4) | 0.023 (5) |
| Pt1—O1i | 1.9999 (15) | C6—H6A | 0.9600 |
| Pt1—O1 | 1.9999 (15) | C6—H6B | 0.9600 |
| Pt1—N1 | 2.0167 (19) | C6—H6C | 0.9600 |
| Pt1—N1i | 2.0167 (19) | C7—C8 | 1.530 (3) |
| N1—C1 | 1.344 (3) | C8—C9 | 1.528 (5) |
| N1—C5 | 1.359 (3) | C8—C7i | 1.530 (3) |
| O1—C7 | 1.296 (3) | C8—C11 | 1.580 (6) |
| O2—C7 | 1.218 (3) | C9—C10i | 1.514 (8) |
| C1—C2 | 1.373 (4) | C9—C10 | 1.514 (8) |
| C1—H1 | 0.9300 | C9—H9A | 0.9700 |
| C2—C3 | 1.363 (4) | C9—H9B | 0.9700 |
| C2—H2 | 0.9300 | C11—C10i | 1.533 (7) |
| C3—C4 | 1.380 (4) | C11—C10 | 1.533 (7) |
| C3—H3 | 0.9300 | C11—H11A | 0.9700 |
| C4—C5 | 1.389 (4) | C11—H11B | 0.9700 |
| C4—H4 | 0.9300 | C10—H10A | 0.9700 |
| C5—C6 | 1.493 (4) | C10—H10B | 0.9700 |
| O1i—Pt1—O1 | 92.24 (9) | O1—C7—C8 | 118.5 (2) |
| O1i—Pt1—N1 | 178.71 (7) | C9—C8—C7 | 114.97 (19) |
| O1—Pt1—N1 | 87.02 (8) | C9—C8—C7i | 114.97 (19) |
| O1i—Pt1—N1i | 87.02 (8) | C7—C8—C7i | 109.8 (3) |
| O1—Pt1—N1i | 178.71 (7) | C9—C8—C11 | 88.9 (3) |
| N1—Pt1—N1i | 93.71 (11) | C7—C8—C11 | 113.47 (19) |
| C1—N1—C5 | 118.7 (2) | C7i—C8—C11 | 113.47 (19) |
| C1—N1—Pt1 | 118.33 (16) | C10i—C9—C10 | 32.2 (8) |
| C5—N1—Pt1 | 122.83 (17) | C10i—C9—C8 | 89.0 (4) |
| C7—O1—Pt1 | 121.76 (15) | C10—C9—C8 | 89.0 (4) |
| N1—C1—C2 | 123.5 (3) | C10i—C9—H9A | 84.5 |
| N1—C1—H1 | 118.2 | C10—C9—H9A | 113.8 |
| C2—C1—H1 | 118.2 | C8—C9—H9A | 113.8 |
| C3—C2—C1 | 117.8 (3) | C10i—C9—H9B | 141.4 |
| C3—C2—H2 | 121.1 | C10—C9—H9B | 113.8 |
| C1—C2—H2 | 121.1 | C8—C9—H9B | 113.8 |
| C2—C3—C4 | 120.2 (3) | H9A—C9—H9B | 111.0 |
| C2—C3—H3 | 119.9 | C10i—C11—C10 | 31.8 (8) |
| C4—C3—H3 | 119.9 | C10i—C11—C8 | 86.4 (4) |
| C3—C4—C5 | 119.8 (3) | C10—C11—C8 | 86.4 (4) |
| C3—C4—H4 | 120.1 | C10i—C11—H11A | 142.0 |
| C5—C4—H4 | 120.1 | C10—C11—H11A | 114.2 |
| N1—C5—C4 | 119.9 (3) | C8—C11—H11A | 114.2 |
| N1—C5—C6 | 118.9 (2) | C10i—C11—H11B | 85.3 |
| C4—C5—C6 | 121.3 (3) | C10—C11—H11B | 114.2 |
| C5—C6—H6A | 109.5 | C8—C11—H11B | 114.2 |
| C5—C6—H6B | 109.5 | H11A—C11—H11B | 111.4 |
| H6A—C6—H6B | 109.5 | C9—C10—C11 | 91.1 (4) |
| C5—C6—H6C | 109.5 | C9—C10—H10A | 113.4 |
| H6A—C6—H6C | 109.5 | C11—C10—H10A | 113.4 |
| H6B—C6—H6C | 109.5 | C9—C10—H10B | 113.4 |
| O2—C7—O1 | 121.0 (2) | C11—C10—H10B | 113.4 |
| O2—C7—C8 | 120.4 (2) | H10A—C10—H10B | 110.7 |
| Symmetry codes: (i) x, −y+3/2, z. |
This work was financially supported by Yunnan Natural Science Foundation (grant Nos. 20032 C06 and 2006 C0070M) and the National Science Foundation of Yunnan University (grant No. 2005Q002A).
Ali, M. S., Thurston, J. H., Whitmire, K. H. & Khokhar, A. R. (2002). Polyhedron, 21, 2659–2662.
Bruker (2004). APEX2 (Version ??) and SAINT (Version 7.23A) Bruker AXS Inc., Madison, Wisconsin, USA. [These programs do not have concurrent version numbers. Please give the correct values]
Burnett, M. N. & Johnson, C. K. (1996). ORTEPIII. Report ORNL-6895. Oak Ridge National Laboratory, Tennessee, USA.
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565–?.
Jakuper, M. A., Galanski, M. & Keppler, B. K. (2003). Rev. Physiol. Biochem. Pharmacol. 146, 1–53.
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.
Tu, C., Wu, X. F., Liu, Q., Wang, X. Y., Xu, Q. & Guo, Z. J. (2004). Inorg. Chim. Acta, 357, 95–102.
Zhang, J. Y., Liu, Q., Duan, C., Shao, Y., Ding, J., Miao, Z., You, X.-Z. & Guo, Z. (2002). J. Chem. Soc. Dalton Trans. pp. 591–594.
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 asymmetric unit in the title compound, C18H20N2O4Pt,is composed of half a molecule (Fig. 1). Indeed the complex is distributed around a mirror plane which contains the Platinum and the C8, C9 and C11 atoms of the cyclobutane group, the fourth one, C10, is disordered with respect to the mirror plane. The Pt atom is coordinated in a square-pyramidal enironment (Fig. 1). The 1,1-cyclobutanedicarboxylate 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 symetry related 2-methylpyridine liagnds are oriented perpendicular to each other.