N,N-Dimethyl Formamide

N,N-Dimethylformamide (DMF) is one of the simplest amides. The preferential aggregation of DMF molecules has not been well understood. Ratajczyk, Paulina et al. demonstrated that the enigmatic stability of the DMF crystal structure was due to the dense packing of molecules, which is found in both low-temperature and high-pressure phases. The existence of CH···O bonds also supports dense packing, but the crystal environment of different independent molecules are different to each other. The conformation of different independent molecules systematically varies. As a matter of course, the larger number of independent molecules Z′ prefers dense packing in the structure of DMF. Also, the triclinic symmetry of the DMF crystal cell does not allow any restriction on the shape of the unit cell.

Fig. 1 Intermolecular interactions in crystalline DMF under high-temperature/low-pressure conditions. (Ratajczyk; Paulina.; et al. 2019)

Titanium dioxide possesses photocatalytic optical properties that can selectively target different organic molecules present in drinking water. In order to improve the material's absorption capacity and photocatalytic performance in the visible range, the bandgap of titanium dioxide can be tuned through a self‑doping process (using either oxygen vacancies or Ti³⁺ ions) which darkens the material. In the current work, N,N-Dimethylformamide (DMF) was used for the first time as a reducing medium to prepare reduced TiO₂ with plentiful oxygen vacancies through laser ablation in liquid. Multidimensional characterization revealed that DMF can not only induce considerable optical bandgap changes in TiO₂ but also result in a larger amount of oxygen vacancies. These structural changes cause a decrease in specific surface area and a reconstruction of the surface morphology, which finally endow the material with superior photothermal conversion performance.

Fig. 2 Comparative study of Laser Ablation‑Induced reduction dynamics of TiO₂ in DMF versus aqueous medium. (Stterferson Emanoel da Silva.; et al. 2021)