Water-Soluble Curcumin Derivatives Including Aza-Crown Ether Macrocycles as Enhancers of their Cytotoxic Activity.

The synthesis of three novel curcumin derivative compounds, featuring aza-crown ether macrocycles of various sizes (aza-12-crown-4, aza-15-crown-5, and aza-18-crown-6), is described. The incorporation of these aza-crown macrocycles significantly enhances their water solubility, positioning them as groundbreaking instances of curcumin derivatives that are fully soluble in aqueous environments. These curcumin ligands (L1, L2, and L3) were then reacted with zinc acetate to afford the coordination metal complexes (L1-Zn, L2-Zn, and L3-Zn).

Synthesis of Para-Acetylated Functionalized Ni(II)-POCOP Pincer Complexes and Their Cytotoxicity Evaluation Against Human Cancer Cell Lines.

A series of three Ni(II)-POCOP complexes para-functionalized with an acetoxyl fragment were synthesized. All complexes (2 a-c) were fully characterized through standard analytical techniques. The molecular structure of complex 2 b was unambiguously determined by single-crystal X-ray diffraction, revealing that the metal center is situated in a slightly distorted square-planar environment.

NHC-based pincer ligands: carbenes with a bite.

In this frontier article we overview the emergence and scope of NHC-based CCC and CNC pincer systems, i.e. complexes containing mer-tridentate ligands bearing two NHC donor groups, comment on their effectiveness in applications, and highlight areas for future development and exploitation.

Reduction of CO2 and SO2 with low valent nickel compounds under mild conditions.

The reaction of [(dippe)Ni(μ-H)](2) (A) (dippe = 1,2-bis(diisopropyl-phosphinoethane) with CO(2) in toluene afforded the carbonyl nickel(0) compounds of the type {(dippe)Ni(CO)](2)(μ-dippe)}(1) and (dippe)Ni(CO)(dippe==O)] (2), which were characterized by standard spectroscopic methods; complex (1) was also characterized by single crystal X-ray diffraction. Reaction of (A) with SO(2) yields the thiosulfate nickel(II) compound [Ni(dippe)(S(2)O(3))] (5), which was fully characterized by standard spectroscopic methods and X-ray crystallography. In both cases, a reduction reaction of CO(2) to CO and SO(2) to S(2)O(3)(2-) with (A) took place under mild conditions.

Solvent and pH effects on the redox behavior and catecholase activity of a dicopper complex with distant metal centers.

A dicopper complex is described for which significant catecholase activity was found, particularly for a compound in which the two metal ions are more than 7A apart. Variations on the catecholase activity of this complex were explored in a range of pH values from 5.5 to 9.