19244-98-5Relevant articles and documents
Role of Hydrogen Bonding in Phase Change Materials
Matuszek, Karolina,Vijayaraghavan,Kar, Mega,Macfarlane, Douglas R.
, p. 1285 - 1291 (2020)
Phase change materials (PCMs), which melt in the temperature range of 100-230 °C, are a promising alternative for the storage of thermal energy. In this range, large amounts of energy available from solar-thermal, or other forms of renewable heat, can be stored and applied to domestic or industrial processes, or to an organic Rankine cycle (ORC) engine to generate electricity. The amount of energy absorbed is related to the latent heat of fusion ( "Hf) and is often connected to the extent of hydrogen bonding in the PCM. Herein, we report fundamental studies, including crystal structure and Hirshfeld surface analysis, of a family of guanidinium organic salts that exhibit high values of "Hf ?, demonstrating that the presence and strength of H-bonds between ions play a key role in this property.
Finding Short-Wavelength Birefringent Crystals with Large Optical Anisotropy Activated by π-Conjugated [C(NH2)3] Units
Xia, Ming,Mutailipu, Miriding,Li, Fuming,Yang, Zhihua,Pan, Shilie
, p. 1869 - 1877 (2021)
Looking for ultraviolet (UV) crystals with large birefringence that are easy to grow, and nontoxic, has always been a hotspot in the field of optical materials. Thus, finding novel chromophores and discovering new candidates that are constructed by them enable us to obtain high performance short-wavelength birefringent crystals. Here, we synthesized five guanidine-based crystals with large birefringence (calcd. 0.072-0.371@532 nm) and short UV cutoff edges (201-254 nm). Among them, [C(NH2)3]HC2O4·H2O possesses a giant birefringence of Δn = 0.371@532 nm, which is even larger than that of most of the commercialized UV birefringent crystals. Moreover, these crystals can be obtained by a simple aqueous solution volatilization method, and they have unique advantages including low cost, easy to grow, and free of toxic reactants. Further analysis confirmed that the large birefringence in them originates from the π-conjugated [C(NH2)3] units, which implies that the guanidine-based compound is a promising system for exploring UV and even deep-UV materials with large birefringence.
Syntheses, Crystal Structures, and Optical Properties of the Hexagonal Perovskites Variants ABX3 (B = Ni, A = Gu, FA, MA, X = Cl, Br; B = Mn, A = MA, X = Br)
Daub, Michael,Ketterer, Ines,Hillebrecht, Harald
, p. 280 - 287 (2018/02/09)
Herein we report on our systematic investigations on the solution processed synthesis and characterization of transition metal halides (guanidinium, formamidinium, and methylammonium nickel bromides and chlorides as well as methylammonium manganese bromide) with the composition ABX3 (A = organic cation; B = Mn, Ni; X = Cl, Br). The investigations were carried out with respect to possible applications of 3d transition metal compounds for the perovskite solar cell. All the compounds represent different variants of the hexagonal perovskite structure (2H). Crystal structures and symmetry relations are discussed. Additionally, (CH3NH3)2MnI4, which consists of tetrahedral coordinated Mn2+, and the water containing compounds (CH3NH3)MnBr3·2H2O, which forms chains of edge sharing octahedra, as well as (CH3NH3)NiCl3·2H2O, which consists of dimers of octahedra, are presented. Investigations on the crystal structures are supported by vibrational and optical spectroscopy.
