Coordination complexes can have a metal center with at least one unsubstituted catecholate ligand and at least one monosulfonated catecholate ligand or a salt thereof bound thereto. Some coordination complexes can have a formula of D.sub.gTi(L.sub.1).sub.x(L.sub.2).sub.y, in which D is a counterion selected from NH.sub.4.sup.+, Li.sup.+, Na.sup.+, K.sup.+, or any combination thereof; g ranges between 2 and 6; L.sub.1 is an unsubstituted catecholate ligand; L.sub.2 is a monosulfonated catecholate ligand; and x and y are non-zero numbers such that x+y=3. Methods for synthesizing such coordination complexes can include providing a neat mixture of catechol and a sub-stoichiometric amount of sulfuric acid, heating the neat mixture to form a reaction product containing catechol and a monosulfonated catechol or a salt thereof, and forming a coordination complex from the reaction product without separating the catechol and the monosulfonated catechol or the salt thereof from one another.

A method of making an organic salt comprising: reacting a polyphenol with a base and optionally a dihaloaromatic compound. The polyphenol is resveratrol; dihydroresveratrol; 4,4-(but-2-ene-1,4-diyl)bis-2-methoxyphenol; 4,4-(1,4-butane-diyl)bis-2-methoxyphenol; 1-ethyl-2-methyl-3-(4-hydroxyphenyl)-5-hydroxyindane; 4,4-(ethane-1,1-diyl)diphenol; 5,5-methylenebis(2-methoxy-4-methylphenol); 4,4-methylenebis(5-isopropyl-2-methylphenol); 4,4-(1-ethyl-2-methyl-1,3-propanediyl)bisphenol; or 5,5-(ethane-1,1-diyl)bis(2-methoxy-4-methylphenol. The dihaloaromatic compound if present comprises a carbonyl group, a sulfonyl group, a sulfinyl group, or a phosphoryl group. There is a molar excess of the hydroxy groups of the polyphenol relative to halo groups of the dihaloaromatic compound if present. The corresponding phthalonitrile monomers and thermosets made from the organic salts are disclosed.

A method of making an organic salt comprising: reacting a polyphenol with a base and optionally a dihaloaromatic compound. The polyphenol is resveratrol; dihydroresveratrol; 4,4-(but-2-ene-1,4-diyl)bis-2-methoxyphenol; 4,4-(1,4-butane-diyl)bis-2-methoxyphenol; 1-ethyl-2-methyl-3-(4-hydroxyphenyl)-5-hydroxyindane; 4,4-(ethane-1,1-diyl)diphenol; 5,5-methylenebis(2-methoxy-4-methylphenol); 4,4-methylenebis(5-isopropyl-2-methylphenol); 4,4-(1-ethyl-2-methyl-1,3-propanediyl)bisphenol; or 5,5-(ethane-1,1-diyl)bis(2-methoxy-4-methylphenol. The dihaloaromatic compound if present comprises a carbonyl group, a sulfonyl group, a sulfinyl group, or a phosphoryl group. There is a molar excess of the hydroxy groups of the polyphenol relative to halo groups of the dihaloaromatic compound if present. The corresponding phthalonitrile monomers and thermosets made from the organic salts are disclosed.

A method of making an organic salt comprising: reacting a polyphenol with a base and optionally a dihaloaromatic compound. The polyphenol is resveratrol; dihydroresveratrol; 4,4-(but-2-ene-1,4-diyl)bis-2-methoxyphenol; 4,4-(1,4-butane-diyl)bis-2-methoxyphenol; 1-ethyl-2-methyl-3-(4-hydroxyphenyl)-5-hydroxyindane; 4,4-(ethane-1,1-diyl)diphenol; 5,5-methylenebis(2-methoxy-4-methylphenol); 4,4-methylenebis(5-isopropyl-2-methylphenol); 4,4-(1-ethyl-2-methyl-1,3-propanediyl)bisphenol; or 5,5-(ethane-1,1-diyl)bis(2-methoxy-4-methylphenol. The dihaloaromatic compound if present comprises a carbonyl group, a sulfonyl group, a sulfinyl group, or a phosphoryl group. There is a molar excess of the hydroxy groups of the polyphenol relative to halo groups of the dihaloaromatic compound if present. The corresponding phthalonitrile monomers and thermosets made from the organic salts are disclosed.

Titanium complexes containing at least one catecholate ligand can be desirable active materials for flow batteries and other electrochemical energy storage systems. Such complexes can be formed through reacting a catechol compound with a titanium reagent in an organic solvent, removing a byproduct species, and then obtaining an aqueous phase containing a salt form of the titanium catechol complex, particularly an alkali metal salt form. More specifically, the methods can include: forming a catechol solution containing a catechol compound and an organic solvent, contacting a titanium reagent with the catechol solution to form a reaction mixture, reacting the titanium reagent with the catechol compound to form an intermediate titanium catechol complex and a byproduct species, separating the byproduct species, and combining an alkaline aqueous solution containing a base with the intermediate titanium catechol complex to produce a salt form titanium catechol complex at least partially dissolved in an aqueous phase.

Titanium complexes containing at least one catecholate ligand can be desirable active materials for flow batteries and other electrochemical energy storage systems. Such complexes can be formed through reacting a catechol compound with a titanium reagent in an organic solvent, removing a byproduct species, and then obtaining an aqueous phase containing a salt form of the titanium catechol complex, particularly an alkali metal salt form. More specifically, the methods can include: forming a catechol solution containing a catechol compound and an organic solvent, contacting a titanium reagent with the catechol solution to form a reaction mixture, reacting the titanium reagent with the catechol compound to form an intermediate titanium catechol complex and a byproduct species, separating the byproduct species, and combining an alkaline aqueous solution containing a base with the intermediate titanium catechol complex to produce a salt form titanium catechol complex at least partially dissolved in an aqueous phase.

Titanium complexes containing catecholate ligands can be desirable active materials for flow batteries and other electrochemical energy storage systems. Such complexes can be formed, potentially on very large scales, through reacting a catechol compound in an organic solvent with titanium tetrachloride, and then obtaining an aqueous phase containing an alkali metal salt form of the titanium catechol complex. More specifically, the methods can include: forming a catechol solution and heating, adding titanium tetrachloride to the catechol solution, reacting the titanium tetrachloride with a catechol compound to evolve HCl gas and to form an intermediate titanium catechol complex, and adding an alkaline aqueous solution to the intermediate titanium catechol complex to form an alkali metal salt form titanium catechol complex that is at least partially dissolved in an aqueous phase. The aqueous phase can be separated from an organic phase. The resulting complexes can be substantially free of alkali metal halide salts.

Titanium complexes containing catecholate ligands can be desirable active materials for flow batteries and other electrochemical energy storage systems. Such complexes can be formed, potentially on very large scales, through reacting a catechol compound in an organic solvent with titanium tetrachloride, and then obtaining an aqueous phase containing an alkali metal salt form of the titanium catechol complex. More specifically, the methods can include: forming a catechol solution and heating, adding titanium tetrachloride to the catechol solution, reacting the titanium tetrachloride with a catechol compound to evolve HCl gas and to form an intermediate titanium catechol complex, and adding an alkaline aqueous solution to the intermediate titanium catechol complex to form an alkali metal salt form titanium catechol complex that is at least partially dissolved in an aqueous phase. The aqueous phase can be separated from an organic phase. The resulting complexes can be substantially free of alkali metal halide salts.

Titanium complexes containing catecholate ligands can be desirable active materials for flow batteries and other electrochemical energy storage systems. Such complexes can be formed, potentially on very large scales, through reacting a catechol compound in an organic solvent with titanium tetrachloride, and then obtaining an aqueous phase containing an alkali metal salt form of the titanium catechol complex. More specifically, the methods can include: forming a catechol solution and heating, adding titanium tetrachloride to the catechol solution, reacting the titanium tetrachloride with a catechol compound to evolve HCl gas and to form an intermediate titanium catechol complex, and adding an alkaline aqueous solution to the intermediate titanium catechol complex to form an alkali metal salt form titanium catechol complex that is at least partially dissolved in an aqueous phase. The aqueous phase can be separated from an organic phase. The resulting complexes can be substantially free of alkali metal halide salts.

A method for the manufacture of a metal salt of a hydroxy-substituted aromatic compound comprises: contacting a hydroxy-substituted aromatic compound with a base comprising a metal cation in molten diphenyl sulfone or sulfolane to provide a mixture comprising water, diphenyl sulfone or sulfolane, and a metal salt of the hydroxy-substituted aromatic compound; and removing water from the mixture in the absence of an azeotrope solvent to provide the metal salt of the hydroxy-substituted aromatic compound that contains less than 3,000 ppm of water.