Multifunctional Urea Cocrystal with Combined Ureolysis and Nitrification Inhibiting Capabilities for Enhanced Nitrogen Management

Abstract

The novel ternary Zn­(II)-thiourea–urea ionic cocrystal [Zn­(thiourea)­(urea)­Cl2], (ZnTU) has been prepared by both solution and mechanochemical processes and structurally characterized by solid-state methods. ZnTU exhibited improved response properties to water as relative humidity as inherited from thiourea. The results of enzymatic activity measurements provide evidence that ZnTU is effective in modulating urea hydrolysis both in vitro (negatively impacting on the activity of isolated urease) and in vivo (decreasing the ureolytic activity of Sporosarcina pasteurii, a widespread soil bacterium), and that Zn­(II) is the component of the cocrystal acting as the actual urease inhibitor. Concomitantly, the analysis of the ammonia monooxygenase (AMO) enzymatic activity in Nitrosomonas europaea, taken as a representative of soil ammonia-oxidizing bacteria, in the presence of ZnTU reveals that thiourea is the only component of ZnTU able to inhibit ammonia conversion to nitrite. It has also been shown that ZnTU maintains these capabilities when applied to bacterial cultures containing both S. pasteurii and N. europaea working in tandem. The compound can thus act both as a fertilizer via urea and via the Zn­(II) and thiourea components, as a dual action inhibitor of the activities of the enzymes urease and AMO, which are responsible for the negative environmental and economic impact of the agricultural use of urea as soil fertilizer. These results indicate that ZnTU should be considered a novel material to improve N fertilization efficiency, toward a more environment-friendly agricultural practice.

Urea as a Cocrystal Former—Study of 3 Urea Based Pharmaceutical Cocrystals

“…Urea shows a single melting point with onset at 134 °C immediately followed by a degradation as illustrated by the TGA analysis, similar to previous report [ 31 ]. The UC cocrystal shows a melting temperature of 176 °C with a corresponding heat of fusion of 162.78 J/g ( Figure 4 ), which is followed by a degradation endotherm.…”

Mechanochemistry as an emerging tool for the preparation of sustained release urea cocrystals as a nitrogen source

“…Using the same precursor ZnCl 2 , Mazzei et al prepared 62 a novel ternary Zn( ii )–thiourea–urea ionic cocrystal [Zn(thiourea)(urea)Cl 2 ] (ZnTU) using mechanochemistry that exhibits improved stability towards atmospheric moisture, reduced solubility compared to pure urea and binary ionic cocrystal of Zn, [Zn(urea) 2 Cl 2 ] (ZnU). DVS analysis showed better stability of the ternary ionic cocrystal compared to urea (Fig.…”

Antimicrobial activity of supramolecular salts of gallium(III) and proflavine and the intriguing case of a trioxalate complex

“…Our objective towards contributing to the quest for novel antimicrobials relies on an approach used successfully in previous occasions to prepare compounds possessing enzymatic inhibition capacity against enzymes such as amino-mono oxygenase and urease 12 , 13 . Essentially, this approach utilizes crystal engineering methods, such as the direct reaction between preformed molecular salts, to combine organic biocides with metal atom complexes that also possess antimicrobial properties.…”