The anti-tumor effects of imidazolium salts on oral squamous cell carcinoma.

BACKGROUND: Imidazolium salts (IS), ionic derivatives of neutral imidazoles, have properties that can be adjusted by structural modifications to their cations and anions, which makes this particular class of compounds a promising option for developing biologically active compounds. The anti-tumor effects of the IS 1-n-butyl-3-methylimidazolium chloride (C4 MImCl), 1-n-decyl-3-methylimidazolium chloride (C10 MImCl), 1-n-hexadecyl-3-methylimidazolium chloride (C16 MImCl), 1-n-hexadecyl-2,3-dimethylimidazolium chloride (C16 M2 ImCl), 1-n-octadecyl-3-methylimidazolium chloride (C18 MImCl), 1-n-hexadecyl-3-methylimidazolium methanesulfonate (C16 MImMeS), and 1-n-hexadecyl-2,3- dimethylimidazolium methanesulfonate (C16 M2 ImMeS) on oral squamous cell carcinoma (OSCC) have been studied here. METHODS: Oral squamous cell carcinoma cells (CAL27) were incubated with increasing IS doses and then submitted to proliferation (2D), cell death (2D) and spheroid assay (3D). RESULTS: The IS anti-tumor effect was dependent on both its N-alkyl chain length and anion, whereby C16 MImCl proved to be more effective in combination for inhibiting cell proliferation and cell-cell adhesion, outperforming the methylated C16 M2 ImCl derivative and, most importantly, the gold standard-cisplatin. In addition, C16 MImCl had little effect on keratinocytes and more pronounced effects on more aggressive tumor cells. It also exhibited similar effects on inducing cell death when compared to Cisplatin. This compound spread to a greater area of the tumor sphere and produced an enhanced number of apoptotic and necrotic cells in the tumor cell line, demonstrating only a small rise in the healthy cells. CONCLUSION: These data indicate that the effect of C16 MlmCl on OSCC is promising, as it is selective for cancer cells.

Ring opening polymerization of d,l-lactide and ε-caprolactone catalysed by (pyrazol-1-yl)copper(ii) carboxylate complexes.

1,2-Bis{(3,5-dimethylpyrazol-1-yl)methyl}benzene (L) reacts with [Cu(OAc)2] and C6H5COOH, 4-OH-C6H4COOH, 2-Cl-C6H4COOH and (3,5-NO2)2-C6H3COOH to afford the copper complexes [Cu2(C6H5COO)4(L)2] (1), [Cu2(4-OH-C6H4COO)4(L)2] (2), [Cu2(2-Cl-C6H4COO)4(L)2] n (3) and [Cu{(3,5-NO2)2-C6H3COO}2L] n (4) which are characterised by IR, mass spectrometry, elemental analyses, and X-ray crystallography. The structural data revealed two geometries that are adopted by the complexes: (i) paddle wheel in 1, 2·7H2O, 3 and (ii) regular chains in 3 and 4. Magnetic studies show strong antiferromagnetic couplings in the paddle wheel complexes and a weak antiferromagnetic coupling in the monometallic chain one. Catalysis studies performed with these complexes (1-4) showed that they initiate ring opening polymerization (ROP) of ε-caprolactone (ε-CL) under solvent-free conditions and d,l-lactide in toluene at elevated temperatures. Polycaprolactone (PCL) and poly(d,l-lactide) (PLA) obtained from the polymerization reactions are of low molecular weights (858 for PCL and 602 Da for PLA for initiator 1) and polydispersity indices (typically 2.16 for PCL and 1.64 for PLA with 1 as the initiator). End group analysis of the polymers, determined by MALDI-ToF MS, indicates that the polymers have benzoate, hydroxyl, methoxy and cyclic end groups.

Fischer Carbene Complexes of Iridium(I) for Application in Catalytic Transfer Hydrogenation.

New examples of the very rare class of iridium(I) Fischer carbene complexes (FCCs) are reported from the facile transmetalation from group 6 FCCs. Postcomplexation modification of either the carbene ligand or the ancillary coligands results in a tunable IrI metal center, for unprecedented application as a (pre)catalyst in a benchmark transfer hydrogenation reaction. The introduction of an aminocarbene ligand with a pendant N-donor moiety capable of hemilabile coordination yielded the best catalytic results with turnover frequencies reaching 445 h-1 and requiring 0.1 mol % catalyst and 0.5 mol % base loading, respectively.

Elucidating the effect of precursor decomposition time on the structural and optical properties of copper(i) nitride nanocubes.

To study the effect of time on the colloidal synthesis of Cu3N nanoparticles, copper(ii) nitrate was thermally decomposed at 260 °C for up to 60 min in octadecylamine as a stabilizing ligand. Thermolysis of the nitrate followed four steps which included; nucleation, growth, ripening and decomposition. At 5 min, partially developed nanocubes were found in a dense population of Cu3N nuclei. Well-defined Cu3N nanocubes were obtained at 15 min with no presence of the nuclei. TEM images showed disintegration of the cubes at 20 min and as time progressed, all the Cu3N decomposed to Cu by 60 min. The formation of the Cu3N nanocubes was confirmed by XRD and XPS. FTIR suggested the formation of a nitrile (RCN) as a result of the thermal decomposition in octadecylamine (ODA) and this was confirmed using NMR and hence, a reaction mechanism was then proposed. The optical properties of the as-synthesized Cu3N were studied using UV-vis and photoluminescence spectroscopies. The absorption spectra for particles synthesized from 5 min to 15 min showed a singular exciton peak while from 20 min to 60 min two peaks were observed. The two peaks may both be associated with the two direct transitions observed in Cu3N or the more red-shifted peak could be a result of localized surface plasmon resonance due to the Cu nanoparticles. Nevertheless, similar to other studies, it is clear that the optical properties of Cu3N are complex.

Tetra-µ-acetato-κO:O'-bis-[(3,5-di-methyl-1H-pyrazole-κN)-copper(II)].

The dinuclear centrosymmetric title compound, [Cu(2)(CH(3)CO(2))(4)(C(5)H(8)N(2))(2)], has a distorted square-pyramidal coordination geometry around each Cu(II) atom in which four O atoms from the bridging acetate ligands form the basal plane while two N atoms from the pyrazole ligands occupy the apical positions. The crystal has two half mol-ecules in the asymmetric unit with a Cu⋯Cu distance of 2.6762 (4) Å. Disorder was found for two O atoms and two C atoms of one acetate ligand and refined with occupancies of 0.265 (7) and 0.735 (7). The crystal also features mol-ecules linked through two N-H⋯O hydrogen bonds resulting in one-dimensional chains extending along the crystallographic b axis.