Recent advances on structural, thermal, vibrational, optical, phase transitions, and catalysis properties of alkylenediammonium halogenometallate materials (Metal: Bi, Sb, Halogen: Cl, Br, I)

This paper aims to review recent advances on synthesis, crystal structures, thermal, spectroscopic, phase transitions, optical, dielectric, and catalysis properties of hydrate and anhydrous alkylenediammonium halogenometallates materials (Metal: Bi, Sb, Halogen: Cl, Br, I). These hybrid materials present rich structural diversities based on octahedra forming infinite zero dimensional, 1-dimensional chains, 2-dimensional layers, discrete bioctahedra, and discrete tetramer units. The effect, contribution and importance of hydrogen bonding N–H … X (X: Cl, Br, I) are reviewed in terms of solid state relationship. Particularly, a comparative study is made on hydrate and anyhdrous aliphatic chlorobismuthates with alkylenediammonium +NH3(CH2) n NH3 + based on structural data and V/Z variation with (CH2) n chains (n = 2–8, 12), and variation of BiCl6 3− Raman frequencies modes versus (CH2) n chains (n = 3–8). Hydrate salts with (n = 3, 12) consist of isolated BiCl6 3− anions and two water molecules, against others ones with isolated anionic chains [BiCl5 2−] n or Bi2Cl10 4− dimers, formed by distorted octahedra BiCl6 3− sharing corners, vices or edges. The reviewed optical and electronic band gaps suggested interesting compounds with band gaps (1.85–2.4 eV), as suitable materials in optoelectronic properties, photoactive layer in solution-processed photovoltaics, and bio-imaging or photovoltaic applications. It was concluded that iodobismuthate salts have generally the lowest bands gap, compared to that of bromo and chlorobismuthate slats. Catalysis proprieties are reviewed n fast (RhB) degradation under dark conditions for (C4N2H7)4Bi2Cl10, (C5H9N2)BiI4, and {(H-BPA)4·[(BiI6)I13]·2I3} n , and in organic salts synthesis under solvent-free conditions. Herein NH3(CH2) n NH3BiCl5 (n = 5–7) salts were used as highly efficient catalysts, which is a novel tendency in chlorobismuthate researchs in the green chemistry field.

An Experimental and Theoretical Study of the Optical Properties of (C2H7N4O)2BiCl5 for an Optoelectronic Application

This study explores the electronic properties of (C2H7N4O)2BiCl5 using the density functional theory (DFT) method, which was compared with the experimental data. The band structure of the compound indicated that it is a direct semiconductor with a band gap energy of 3.54 eV, which was comparable with the value (3.20 eV) obtained experimentally from the UV–vis spectroscopy. The density of state study showed that the conduction band was formed mainly by Bi 6p, C 2p, and N 2p states, while the valence band was formed mainly by Cl 2p, O 2p, and N 2p states. Hirshfeld surface analysis and enrichment ratio (E) were further used to investigate and quantify the intermolecular interactions within the compound. These studies established that the most important role in the stability of the structure of this crystalline material was provided by hydrogen bonding and π–π stacking interactions. The crystalline morphology of the compound was determined using BFDH simulation, based on the single-crystal structure result. Furthermore, Fourier transform infrared spectroscopy (FTIR) was used to study the vibrational modes of carbamoyl-ganidinium cations. The charge transfer process within the anionic chains of [BiCl5]∝, studied using photoluminescence spectroscopy, resulted in a broad emission band with two positions of maxima centered at 336 and 358 nm. This work offers a good understanding of the optical, structural, as well as the electrical properties of (C2H7N4O)2BiCl5, which are necessary in its applications in areas such as multifunctional magnetic, optoelectronic, and photonic systems.