The present invention relates to a method to synthesize with high yield a
colored metal complex of β-diketones and / or polyphenols by
mechanochemistry without using aqueous or organic solvents and covers new complexes obtained therefrom. In an embodiment, only the reactants, a
metal alkoxide and a β-
diketone and / or a
polyphenol, are present and react at different
molar ratios to form a
metal complex in the form of a homogeneous
colored material (i.e.
powder) with high yield. If
curcumin is used, the color of the final metal complex dye depends on several factors such as the curcuminoids, the metal, the type of
alkoxide used, the stoichiometric
molar ratio of both reactants and the additives used. If
titanium alkoxide and any additive is used, a red or violet
colored titanium curcumin complex in
powder form is produced. The production process of the metal complex in
powder form is characterized by facility of scale up. The entire product is ready to be used in several applications. If polyphenols such as
ferulic acid,
quercetin,
ellagic acid or
lignin are used instead of
curcumin, other colored complexes are obtained using
mechanochemistry. In addition, the product comprising metal complexes of β-diketones and / or polyphenols is characterized by
green chemistry manufacture. Besides, these metal complexes of β-diketones and / or polyphenols in several formulations are characterized by improved stability under storage conditions and improved
sun protection against UV rays for
human skin and human hair. The product is ready to be used alone or in combination with other additives or active ingredients in different formulations. The invention also covers the use of these metal β-diketones /
polyphenol complexes in food,
cosmetics, the pharmaceutical field and in the creativity field, as sunscreen,
skin and hair
concealer or foundation in powder form or cream, keratinous dye,
textile dye, food dye, dye emulsions, miniemulsions,
polymer colloids and catalysts.The production process of these novel metal-complex dyes is also characterized by rapid production of colored compounds without using solvents and, thus, ecofriendliness. The process of the production of metal β-
diketone and / or
polyphenol complexes is characterized by the non-formation of toxic by-products and high yield.In addition, the present invention comprises a hair
dyeing molecule or formulation and procedure combining excellent
dyeing properties with
reduced risk of development
cancer or allergies, while being ecological and of the natural origin.