Creatine is recognized as a dietary staple among athletes, with two supplement formulations currently available on the United States market: creatine monohydrate and creatine hydrochloride. Creatine monohydrate has relatively low aqueous solubility, which hampers its ease of preparation by consumers. Creatine hydrochloride has excellent aqueous solubility; however, it exhibits a strong acidic taste with potentially harmful effects on dental health. Herein, we report a mechanochemical synthesis of a 1:1 coamorphous formulation of creatine and citric acid, a-CCA. Milling of anhydrous creatine and anhydrous citric acid yielded a-CCA, which was found to be structurally stable under dry conditions. Upon exposure to humid air, a-CCA rapidly converted into a 1:1 cocrystalline formulation, c-CCA. Correspondingly, milling of creatine and citric acid, with at least one source present as a monohydrate, resulted in direct mechanosynthesis of the cocrystal. The crystal structure was solved and refined from powder X-ray diffraction data, and the obtained structure solution was evaluated by energy minimization calculations. Close inspection of the hydrogen-bonding network revealed the presence of creatine in zwitterionic form and of citric acid as a neutral molecule. Additionally, the coamorphous solid and the cocrystal were studied by infrared spectroscopy, differential scanning calorimetry, and thermogravimetry. The aqueous solubility of the cocrystal (32.0(8) g/L) was determined to be ∼2.5× higher compared to that of commercial creatine monohydrate (13.3(6) g/L). The cocrystal formulation was determined to be ∼10× less acidic compared to commercial creatine hydrochloride. The simple, efficient, and scalable method of preparation, the phase-purity and high degree of crystallinity under ambient conditions, and the increased solubility (compared to the creatine monohydrate) and decreased acidity (compared to creatine hydrochloride) render the 1:1 creatine:citric acid cocrystal an improved and potentially marketable creatine supplement formulation.

Ethylene bis­(dithiocarbamates) (EBDTCs) have been used as staple fungicides for over 75 years. The first industrially manufactured EBDTC was zineb, zinc ethylene bis­(dithiocarbamate), marketed under the trade name Dithane. Even though zineb has been used as a fungicide since the 1940s, its crystal structure has remained unknown. Herein, we describe the crystal structure of zineb (triclinic crystal system, space group P1̅, a = 7.5094(9) Å, b = 9.4356(9) Å, c = 7.4120(7) Å, α = 107.945(8)°, β = 100.989(7)°, γ = 105.365(8)°, V = 460.07(10) Å3). The inorganic fragment of the structure consists of two Zn2+ cations, coordinated by the thiocarbamate groups. There are four Zn–S bonds with lengths in the range of 2.325–2.426 Å, and one rather long Zn–S contact of 2.925(8) Å. Inorganic fragments are linked by organic EBDTC ligands to form extended, polymeric layers. The layers are packed in an ABAB manner, related by the inversion symmetry and held together by a hydrogen bonding network. In this article, in addition to describing the crystal structure, we correlate the structural features with the vibrational spectroscopic and thermal characteristics of zineb, and we provide a short summary of the major developments of fungicides in the 20th century.

The controlled introduction of defects into MOFs is a powerful strategy to induce new physiochemical properties and improve their performance for target applications. Herein, we present a new strategy for...

We report the phase diagram for the binary creatine–citric acid mixture which features a stable and broad eutectic region.

Laboratory X-ray powder diffraction was used to solve and refine the crystal structures of appended guest molecules within the pores of metal–organic frameworks (MOFs). Herein, we report the crystal structure of 1-propanethiol adsorbed in the pores of Co2(dobdc) (dobdc4– = 2,5-dioxido-1,4-benzenedicarboxylate, MOF-74). Soaking the activated MOF in neat 1-propanethiol resulted in the formation of 1-propanethiol–Co2(dobdc). The thiol appendant MOF maintained the crystal symmetry, with a rhombohedral space group R-3 and unit-cell parameters a = 25.9597(9) Å, c = 6.8623(5) Å, and V = 4005.0(4) Å3. As expected, the thiol sulfur formed a bond with the open cobalt metal site. The alkane chain was directed toward the center of the pore, participating in numerous van der Waals weak interactions with neighboring molecules. For the final Rietveld refinement, soft restrains were applied using bond distances obtained by periodic density functional theory (DFT) geometry optimization.