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91.
A density functional theory (DFT) study aimed at understanding structure–reactivity relationships in the oxidized metabolites of cyclopenta‐fused polycyclic aromatic hydrocarbons (CP‐PAHs) is reported. Epoxidation at various positions was examined in order to identify the most stable epoxide in each class of CP‐PAHs. Relative energies of the carbocations resulting from O‐protonation and epoxide ring opening were analyzed and compared, taking into account the available biological activity data on these compounds. Geometrical, electronic, and conformational issues were considered. Charge delocalization modes in the resulting carbocations were deduced via the natural population analysis (NPA)‐derived changes in charges. Computational results pointed to the importance of the unsaturated cyclopenta ring on the reactivity of these compounds. The reported bioactivity of this highly mutagenic/carcinogenic family of PAHs was observed to parallel their relative carbocation stabilities. A different behavior was observed in crowded non‐planar structures possessing a distorted aromatic system. A covalent adduct formed between a CP‐PAH epoxide and a purine base was computed inside a DNA fragment employing the ONIOM method. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
92.
The EPR g factors gi (i = x, y, z) for the interstitial Ti3+ in rutile are theoretically studied from the perturbation formulas of these parameters for a 3d1 ion in rhombically compressed octahedra. The ligand octahedron in the impurity center is found to be less compressed than that on the host interstitial site due to the Jahn-Teller effect. The local compression parameter (≈0.026) and the rhombic distortion angle δϕ′ (≈0.7°) around the impurity Ti3+ are smaller than the host values (≈0.091 and 3.5°). The theoretical g factors based on the above local structural parameters are in good agreement with the experimental data. In addition, the g factors for a tetragonal interstitial Ti3+ center are also reasonably interpreted.   相似文献   
93.
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94.
95.
The two independent and coordination sites of a newly synthesized bis[2-(hydroxyphenyl)-1,2,4-triazole] platform have been exploited to prepare four monometallic neutral ()PtII complexes carrying DMSO, pyridine, triphenylphosphine, or N-heterocyclic carbene as the fourth ligand. Then, the second coordination site was used to introduce an IR-active rhenium tricarbonyl entity, affording the four corresponding heterobimetallic neutral PtII/ReI complexes, as well as a cationic PtII/ReI derivative. X-ray crystallographic studies showed that distortion of the organic platform occurred to accommodate the coordination geometry of both metal centers. No ligand exchange or transchelation occurred upon incubation of the PtII complexes in aqueous environment or in the presence of FeIII, respectively. The antiproliferative activity of the ligand and complexes was first screened on the triple-negative breast cancer cell line MDA-MB-231. Then, the IC50 values of the most active candidates were determined on a wider panel of human cancer cells (MDA-MB-231, MCF-7, and A2780), as well as on a nontumorigenic cell line (MCF-10A). Low micromolar activities were reached for the complexes carrying a DMSO ligand, making them the first examples of highly active, but hydrolytically stable, PtII complexes. Finally, the characteristic mid-IR signature of the {Re(CO)3} fragment in the Pt/Re heterobimetallic complexes was used to quantify their uptake in breast cancer cells.  相似文献   
96.
The molecular structures of S-phenyl-thiabenzene 1, S-phenyl-1-thianaphthalene 2, S-phenyl-2-thianaphthalene 3, and S-phenyl-9-thiaanthracene 4 are studied by ab initio calculations using HF as well as DFT methods at the 6–311+G? level of theory. The non-planar boat conformers of 1–4 with 6π electrons in the heterocyclic ring appear to be more stable than the corresponding planar conformers with 8π electrons in the ring. The activation energy for the inversion at the sulfur atom is compared for 1–4. Conformational flexibility of 1–4 is studied.  相似文献   
97.
Abstract

Novel, aromatic bisphosphonates have been synthesised as non-systematic analogues of 1,3-bisphosphoglyceric acid (1,3-BPG). These incorporate non-scissile α-halo and α-methylene phosphonates and have submicromolar K i values for 3 -PGK.  相似文献   
98.
Dialkyldithiophosphate derivatives of macrocyclic complexes of Pb(II), having N2S2 potential donors, of the general formula, [Pb(L)S2P(OR)2] (where L = macrocyclic ligands L1, L2, L3, L4 & L5 and R = CH3-, C3H7 n- & C3H7 i-) have been Synthesized from the reactions of [Pb(L)X2] (where X = Cl, NO3, or CH3COO) with sodium dialkyl dithiophosphates in 1:2 molar ratios in THF. Fifteen new derivatives have been synthesized by the combination of five macrocyclic complexes of 14–20 member rings with three different types of dialkyldithiophosphate. These compounds have been characterized by elemental analysis, molar conductance, molecular weight determination, IR, 1H NMR, 13C, and 31P NMR. Molecular weight determinations of these complexes indicate their monomeric nature. An octahedral structure is proposed.  相似文献   
99.
Abstract

The symmetric 'end-off' compartmental proligand 2,6-[N,N′-bis(2-hydroxy-phenylmethyl)-N,N′-bis(2-pyridylmethyl)aminomethyl]-4-methylphenol (H3L) has been used to generate homodinuclear nickel(II) and zinc(II) complexes. The crystal structures of the complexes reveal that the di-nickel(II) complex is donor asymmetric and the di-zinc(II) complex is coordination number asymmetric. In both complexes non-coordinated acetic acid molecules are tightly hydrogen-bonded to the pendant phenols of the ligand generating a double acid salt of the type[CH3COO…H…L…H…OOCCH3]3? in the dinickel complex and a single acid salt of the type [CH3COO…H…L]3? in the dizinc complex. In both cases the ligand periphery has been extended to provide a supraligand in which the donor potential of the original ligand has been enhanced.  相似文献   
100.
Three novel coordination polymers, [Co(NH2-Aip)(H2Bibim)] n (1), [Co(NH2-Aip)(HBibimop)] n  √ nH2O (2) and [Mn(NH2-Aip) √ H2O] n  √ 2nH2O (3) with NH2-Aip and similar benzimidazole derivative ligands (NH2-Aip = 5-aminoisophthalic acid, H2Bibim = 2,2′-bibenzimidazole and HBibimop = 1,3-bis(benzimidazol-2-yl)-2-oxapropane), have been synthesised under hydrothermal conditions and structurally characterised by single-crystal X-ray diffraction analysis, elemental analysis and IR spectroscopy. 5-Aminoisophthalic acid ligand adopts μ2-, μ3- and μ4-bridge coordination fashion and benzimidazole derivatives exist as terminal- and bridge-mode in complexes 13. The intricate hydrogen bonds and π–π stacking interactions in supramolecular framework are discussed. Using the combination of ultraviolet–visible absorption titration and fluorescence spectra, the experimental results show that complexes 1 and 2 bind to DNA in an intercalative mode and their DNA-binding constants (K b ) are also found.  相似文献   
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