From the Design of Innovative Ti-Pt Heterometallic Complexes to the Development of Highly Anti-Proliferative Water-Soluble Cationic Titanocenes.

Two innovative early/late Ti-Pt-heterobimetallic complexes were synthesized, characterized, and screened in cell-based assays using several human (SW480 and MDA-MB-231) and murine cancer cell lines (CT26 and EMT6) as well as a non-cancerous cell line (HMEC). The combination of the two metals - titanium(IV) and platinum (IV) - in a single molecule led to a synergistic biological activity (higher anti-proliferative properties than a mixture of each of the corresponding monometallic complexes). This study also investigated the benefits of associating a metal-free terpyridine moiety (with intrinsic biological activity) with a water-soluble titanocene fragment. The present work reveals that these combinations results in water-soluble titanocene compounds displaying an anti-proliferative activity down to the submicromolar level. One of these complexes induced an antitumor effect in vivo in CT26 tumor bearing BALB/C mice. The terpyridine moiety was also used to track the complex in vitro by multiphoton microscopy imaging.

Functional Materials from Biomass-Derived Terpyridines: State of the Art and Few Possible Perspectives.

This review focuses on functional materials that contain terpyridine (terpy) units, which can be synthesized from biomass-derived platform chemicals. The latter are obtained by the chemical conversion of raw biopolymers such as cellulose (e.g., 2-furaldehyde) or lignin (e.g., syringaldehyde). These biomass-derived platform chemicals serve as starting reagents for the preparation of many different terpyridine derivatives using various synthetic strategies (e.g., Kröhnke reaction, cross-coupling reactions). Chemical transformations of these terpyridines provide a broad range of different ligands with various functionalities to be used for the modification or construction of various materials. Either inorganic materials (such as oxides) or organic ones (such as polymers) can be combined with terpyridines to provide functional materials. Different strategies are presented for grafting terpy to materials, such as covalent grafting through a carboxylic acid or silanization. Furthermore, terpy can be used directly for the elaboration of functional materials via complexation with metals. The so-obtained functional materials find various applications, such as photovoltaic devices, heterogeneous catalysts, metal-organic frameworks (MOF), and metallopolymers. Finally, some possible developments are presented.

Diethyl 2,2'-(1,4-phenyl-enedi-oxy)-diacetate.

In the title compound, C(14)H(18)O(6), a crystallographic center at the centroid of the aromatic ring generates the complete mol-ecule which is planar within 0.085 (1) Šfor the non-H atoms. In the crystal, weak C-H⋯O and C-H⋯π inter-actions link the molecules.

Syntheses and applications of furanyl-functionalised 2,2':6',2''-terpyridines.

Different synthetic routes leading to terpyridines functionalised with furan heterocycles are reviewed. The methodologies used to prepare such compounds include the ring closure of 1,5-diketones and cross-coupling reactions. These versatile terpyridines and their derived metal complexes find applications in various fields including coordination chemistry, medicinal chemistry and material sciences.

Combination of cobalt and iron polypyridine complexes for improving the charge separation and collection in Ru(terpyridine)(2)-sensitised solar cells.

Mixtures of polypyridine Fe(II) and Co(II) complexes are used as electron mediators in Ru-thienyltpy-sensitised solar cells (tpy=terpyridine). The use of the metalorganic redox couples allows for improved charge-collection efficiency with respect to the classical iodide/iodine couple which, when associated to Ru-tpy(2) dyes, usually produces poor performance. The improved charge collection is explained by a combination of effective dye regeneration and decreased recombination with the oxidised electrolyte on the basis of data obtained by transient spectroscopy and photoelectrochemical measurements. The efficiency of the regeneration cascade is also critically dependent upon the ability of the Co(II) complex to intercept Fe(III) centres, as clearly indicated by chronocoulometry experiments.

Efficent removal of nickel(II) salts from aqueous solution using carboxymethylchitosan-coated silica particles as adsorbent.

Three types of organo-mineral composites have been probed as adsorbents for the removal of Ni(II) ions from aqueous solution. Native Aerosil 200 silica particles have been encapsulated with carboxymethylchitosan (CM-CS) providing SiO2+CM-CS, surface-silanized silica particles SiO2NH2+CM-CS were obtained by treatment with APTES and subsequent encapsulation by CM-CS. Alternatively, surface-carboxylated Aerosil 200 was coated by CM-CS affording SiO2CO2H+CM-CS. The materials have been characterized by various techniques. The effects of counter ions (Cl-, Br-, CH3COO-, NO3- and SO42-), pH and initial Ni(II) concentration on the adsorption capacities have been systematically investigated. The maximum adsorption capacity qm of CM-CS-coated silica was determined using the Langmuir adsorption isotherm. For SiO2CO2H+CM-CS, SiO2+CM-CS and SiO2NH2+CM-CS, they decrease at pH 7 in the order 256mg/g>140mg/g>105mg/g. The adsorption kinetic fits well with a pseudo-second order model. These carbohydrate-derived biosorbents are excellent adsorbents with capacities superior to most other adsorbents reported in the literature.

Preparation of carboxylate derivatives of terpyridine via the furan pathway.

This protocol describes a practical procedure for the preparation of terpyridine carboxy derivatives, which have numerous applications, including being photoactive components of functional materials, and which can be used in medicinal chemistry or in catalysis. This protocol relies on the permanganate-mediated oxidation of a furan ring on the polypyridine system. The procedure involves three stages. First, a furan-functionalized terpyridine is synthesized from furfuraldehyde and a 2-acetylpyridine derivative. Second, the furan ring is oxidized thus providing a carboxylic acid. Finally, esters are prepared by reaction of the acids in refluxing alcohols. The procedure is simple, uses a reagent available from renewable resources (furfural) and avoids the use of noxious reagents or solvents, thus making it more environmentally friendly when compared with previously described methods. The whole protocol can be conducted in ∼10 d, including isolation and drying of intermediates and products.

Adsorption of Ni(II) ions on colloidal hybrid organic-inorganic silica composites.

Two new silica-based composites were prepared as adsorbents for the capture of Ni(II) ions. The first strategy consists in coating chitosan on colloidal fumed silica after acidic treatment yielding the composite SiO(2)+CS. The second route involves in a first step surface condensation of triethoxysilylbutyronitrile, followed by acidic hydrolysis of the surface-bound nitrile groups affording silica particles covered by carboxylic group. In a third step, chitosan has been grafted on the surface-bound C(=O)OH groups yielding the composite SiO(2)(CO(2)H)+CS. The novel hybrid materials were characterized by IR spectroscopy, scanning electron and AFM microscopy, and zeta potential measurements. Batch experiments were conducted to study the sorption performance of these composites for Ni(II) removal from aqueous NiCl(2) solution at different pH. Both Langmuir, Freundlich, and Temkin isotherm models provide good fits with the experimental data. It was shown that these low-cost materials present a promising capacity to adsorb Ni(II) ions. At pH 7, the maximum adsorption capacity q(max)of Ni(II) on the adsorbent, is found to be 182 mg g(-1) for SiO(2)+CS, and 210 mg g(-1) for SiO(2)(CO(2)H)+CS.