- Molecular interaction fields vs. quantum-mechanical-based descriptors in the modelling of lipophilicity of platinum(iv) complexes
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We report QSAR calculations using VolSurf descriptors to model the lipophilicity of 53 Pt(iv) complexes with a diverse range of axial and equatorial ligands. Lipophilicity is measured using an efficient HPLC method. Previous models based on a subset of these data are shown to be inadequate, due to incompatibility of whole molecule descriptors between carboxylato and hydroxido ligands. Instead, the interaction surfaces of complexes with various probes are used as independent descriptors. Partial least squares modelling using three latent variables results in an accurate (R2 = 0.92) and robust model (Q2 = 0.87) of lipophilicity, that moreover highlights the importance of size and hydrophobicity terms and the modest relevance of hydrogen bonding.
- Ermondi, Giuseppe,Caron, Giulia,Ravera, Mauro,Gabano, Elisabetta,Bianco, Sabrina,Platts, James A.,Osella, Domenico
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supporting information
p. 3482 - 3489
(2013/03/28)
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- Synthesis, multinuclear magnetic resonance and crystal structures of Pt(II) complexes containing amines and bidentate carboxylate ligands
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A novel synthetic method for the synthesis of the complexes cis-Pt(amine)2R(COO)2 is compared to two other methods involving the use of either barium dicarboxylate or sodium carboxylate. Pt(II) compounds with monodentate and bidentate amines were studied. The reaction involves the use of a silver dicarboxylato complex, which is the intermediate in the new synthetic procedure. The crystal structure of the silver intermediate with the ligand 1,1-cyclobutanedicarboxylate (1,1-CBDCA) was determined by X-ray diffraction. The crystal Ag2(1,1-CBDCA) has a very interesting 3-D extended structure. The complexes cis-Pt(amine)2R(COO)2 were studied in solution by multinuclear (1H, 13C and 195Pt) magnetic resonance spectroscopy, but the solubilities are very low. D2O was found to be the best solvent. In 195Pt NMR, the complexes containing bidentate amines forming five-membered chelates were observed at higher fields than those containing monodentate amines. The resonances of the NH3 compounds were also found at lower fields than the primary amine complexes. All the dicarboxylato ligands form six-membered chelates except 1,2-CBDCA, whose Pt(II) compounds were observed at lower fields than the others. The crystal structures of Pt(en)(1,1-CBDCA), Pt(Meen)(1,1-CBDCA) and Pt(en)(benzylmalonato) were confirmed by X-ray diffraction methods. Several compounds are disordered. The crystals are stabilized by intermolecular hydrogen bonds between the -NH2 groups and the carboxylato O atoms.
- Rochon, Fernande D.,Massarweh, Gassan
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p. 4095 - 4104
(2008/10/09)
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