Synthesis and solution structures of some platinum(II) complexes containing chelating safrole and amine

Synthesis and crystal structures of three organoplatinum(II) complexes bearing natural aryl-olefin and quinoline derivatives

Three organoplatinum(II) complexes bearing natural aryl-olefin and quinoline derivatives, namely, [4-meth-oxy-5-(2-meth-oxy-2-oxoeth-oxy)-2-(prop-2-en-1-yl)phen-yl](quinolin-8-olato)platinum(II), [Pt(C13H15O4)(C9H6NO)], (I), [4-meth-oxy-5-(2-oxo-2-propoxyeth-oxy)-2-(prop-2-en-1-yl)phen-yl](quinoline-2-carboxy-l-ato)platinum(II), [Pt(C15H19O4)(C10H6NO2)], (II), and chlorido-[4-meth-oxy-5-(2-oxo-2-propoxyeth-oxy)-2-(prop-2-en-1-yl)phen-yl](quinoline)-plat-inum(II), [Pt(C15H19O4)Cl(C9H7N)], (III), were synthesized and structurally characterized by IR and 1H NMR spectroscopy, and by single-crystal X-ray diffraction. The results showed that the cyclo-platinated aryl-olefin coordinates with PtII via the carbon atom of the phenyl ring and the C=Colefinic group. The deprotonated 8-hy-droxy-quinoline (C9H6NO) and quinoline-2-carb-oxy-lic acid (C10H6NO2) coordinate with the PtII atom via the N and O atoms in complexes (I) and (II) while the quinoline (C9H7N) coordinates via the N atom in (III). Moreover, the coordinating N atom in complexes (I)-(III) is in the cis position compared to the C=Colefinic group. The crystal packing is characterized by C-H⋯π, C-H⋯O [for (II) and (III)], C-H⋯Cl [for (III) and π-π [for (I)] inter-actions.

Crystal structures of three platinacyclic complexes bearing isopropyl eugenoxyacetate and pyridine derivatives

Three new platinum(II) complexes bearing a eugenol and a pyridine derivative, namely (η2-2-allyl-4-meth-oxy-5-{[(propan-2-yl-oxy)carbon-yl]meth-oxy}phenyl-κC 1)chlorido-(pyridine-κN)platinum(II), [Pt(C15H19O4)Cl(C5H5N)], (I), (η2-2-allyl-4-meth-oxy-5-{[(propan-2-yl-oxy)carbon-yl]meth-oxy}phenyl-κC 1)chlorido-(4-methyl-pyridine-κN)platinum(II), [Pt(C15H19O4)Cl(C6H7N)], (II), and (η2-2-allyl-4-meth-oxy-5-{[(propan-2-yl-oxy)carbon-yl]meth-oxy}phenyl-κC 1)chlorido(pyridine-4-carb-oxy-lic acid-κN)platinum(II), [Pt(C15H19O4)Cl(C6H5NO2)], (III), have been synthesized and further characterized by single-crystal X-ray diffraction. The PtII atoms exhibit the usual distorted square-planar coordination and are surrounded by one Cl atom, one N atom, and a C atom and C=C double bond of the eugenol ligand. The donor N atom of the pyridine ligand occupies a cis position with respect to the double bond. Complexes (I) and (II) crystallize isomorphously in space group P and display a similar crystal packing characterized by C-H⋯O hydrogen bonding, C-H⋯π and π-π inter-actions. However, the presence of the additional methyl group in the 4-methyl-pyridine ligand in (II) disturbs the π-π inter-actions. The crystal packing of (III) is characterized by O-H⋯O hydrogen bonding, resulting in the formation of chains of mol-ecules connected in a head-to-tail fashion and running in the [101] direction. The IC50 values for the HepG2 and KB cell lines are 150.9, 122.3 µM for (I) and 138.9, 93.2 µM for (II), respectively.

Synthesis, structure and in vitro cytotoxicity of platinum(II) complexes containing eugenol and a quinolin-8-ol-derived chelator

The synthesis of potassium (η2-4-allyl-2-methoxyphenol)trichloridoplatinate(II), K[PtCl3(C10H12O2)], (1), starting from Zeise's salt and Ocimum sanctum L. oil has been optimized. Starting from (1), three new platinum(II) complexes, namely (η2-4-allyl-2-methoxyphenol)chlorido(2-methylquinolin-8-olato-κ2 N,O)platinum(II), (2), (η2-4-allyl-2-methoxyphenol)chlorido(5-nitroquinolin-8-olato-κ2 N,O)platinum(II), (3), and (η2-4-allyl-2-methoxyphenol)chlorido(5,7-dichloroquinolin-8-olato-κ2 N,O)platinum(II), [Pt(C9H4Cl2NO)Cl(C10H12O2)], (4), containing eugenol and a quinolin-8-ol derivative (R-OQ), have been synthesized and characterized by elemental analyses, MS, IR, 1H NMR and NOESY spectra. For (1) and (4), single-crystal X-ray diffraction studies were also carried out. Complexes (2)–(4) show good inhibiting abilities on three human cancer cell lines, i.e. KB, Hep-G2 and LU, with IC50 values of 1.42–17.8 µM. Complex (3) gives an impressively high activity against KB, Hep-G2, LU and MCF-7, with IC50 values of 1.42–4.91 µM, which are much lower than those of cisplatin and some other platinum(II) complexes.

Crystal structures of two platinum(II) complexes containing ethyl eugenoxyacetate and 2-amino-pyridine

In the title complexes, trans-(2-amino-pyridine-κN)di-chlorido-{4-eth-oxy-carbonyl-meth-oxy-3-meth-oxy-1-[(2,3-η)-prop-2-en-1-yl]benzene}-platinum(II), [PtCl2(C5H6N2)(C14H18O4)], (I), and (2-amino-pyridine-κN)chlorido{5-eth-oxy-car-bon-yl-meth-oxy-4-meth-oxy-1-[(2,3-η)-prop-2-en-1-yl]phenyl-κC1}-platinum(II), [Pt(C14H17O4)Cl(C5H6N2)], (II), the central PtII metal atom displays a distorted square-planar coordination, with the PtII atom coordinated by the pyridine N atom, the C=C double bond of the eugenol ligand and two Cl atoms for (I) or one Cl atom and a C atom of the phenyl ring for (II). The allyl fragment in (I) is disordered, with population parameters 0.614 (14) and 0.386 (14) for the two positions of the central C atom. The least-squares planes through the two aromatic ring systems make a dihedral angle of 51.10 (13)° for (I) and 78.5 (2)° for (II). Intra-molecular N-H⋯O and N-H⋯π inter-actions occur in (I). In (I), inversion dimers formed by C-H⋯Cl inter-actions are further linked into chains parallel to the b axis by C-H⋯O hydrogen bonds. Both aromatic rings are involved in π-π inter-actions, with centroid-to-centroid distances of 3.508 (3) and 3.791 (3) Å. In (II), inversion dimers form chains parallel to the b axis by C-H⋯O inter-actions.

Crystallization experiments with the dinuclear chelate ring complex di-μ-chlorido-bis[(η2-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC1)platinum(II)]

Crystallization experiments with the dinuclear chelate ring complex di-μ-chlorido-bis[(η²-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC¹)platinum(II)], [Pt₂(C₁₅H₁₉O₄)₂Cl₂], containing a derivative of the natural compound eugenol as ligand, have been performed. Using five different sets of crystallization conditions resulted in four different complexes which can be further used as starting compounds for the synthesis of Pt complexes with promising anticancer activities. In the case of vapour diffusion with the binary chloroform-diethyl ether or methylene chloride-diethyl ether systems, no change of the molecular structure was observed. Using evaporation from acetonitrile (at room temperature), dimethylformamide (DMF, at 313 K) or dimethyl sulfoxide (DMSO, at 313 K), however, resulted in the displacement of a chloride ligand by the solvent, giving, respectively, the mononuclear complexes (acetonitrile-κN)(η²-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC¹)chloridoplatinum(II) monohydrate, [Pt(C₁₅H₁₉O₄)Cl(CH₃CN)]·H₂O, (η²-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC¹)chlorido(dimethylformamide-κO)platinum(II), [Pt(C₁₅H₁₉O₄)Cl(C₂H₇NO)], and (η²-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC¹)chlorido(dimethyl sulfoxide-κS)platinum(II), determined as the analogue {η²-2-allyl-4-methoxy-5-[(ethoxycarbonyl)methoxy]phenyl-κC¹}chlorido(dimethyl sulfoxide-κS)platinum(II), [Pt(C₁₄H₁₇O₄)Cl(C₂H₆OS)]. The crystal structures confirm that acetonitrile interacts with the Pt^II atom via its N atom, while for DMSO, the S atom is the coordinating atom. For the replacement, the longest of the two Pt-Cl bonds is cleaved, leading to a cis position of the solvent ligand with respect to the allyl group. The crystal packing of the complexes is characterized by dimer formation via C-H...O and C-H...π interactions, but no π-π interactions are observed despite the presence of the aromatic ring.

Crystal structures of organoplatinum complexes containing alkyl-eugenoxyacetate and p-chloro-aniline

In the title complexes, trans-di-chlorido-(4-chloro-aniline-κN){3-meth-oxy-4-meth-oxy-carbonyl-meth-oxy-1-[(2,3-η)-prop-2-en-1-yl]benzene}-platinum(II) 0.1-hydrate, [PtCl2(C6H6ClN)(C13H16O4)]·0.1H2O, (I), and trans-di-chlorido-(4-chloro-aniline-κN){4-eth-oxy-carbonyl-meth-oxy-3-meth-oxy-1-[(2,3-η)-prop-2-en-1-yl]benzene}-platinum(II), [PtCl2(C6H6ClN)(C14H18O4)], (II), the Pt(II) metal atom displays a slightly distorted square-planar coordination geometry defined by the aniline N atom, two chloride anions (trans-positioned) and one ethyl-enic double bond. The least-squares planes through the two aromatic ring systems make an angle of 47.3 (3)° for (I) and 38.6 (2)° for (II). Both structures show disorder for the PtCl2 fragment, in the case of (I) even further extended towards the CH2-CH=CH2 ligand. An intra-molecular C-H⋯Cl hydrogen bond occurs in (I). In the crystal packing of (I), which is dominated by N-H⋯O and C-H⋯Cl inter-actions, a partially occupied water mol-ecule is observed on a twofold rotation axis with a refined site occupancy of 0.10 (1). A C-H⋯π inter-action is also present. In (II), inversion dimers form chains along the b-axis direction by N-H⋯O hydrogen bonds.