ChemInform Abstract: Synthesis and Characterization of the Quaternary Thioaluminogermanates A(AlS₂)(GeS₂) (A: Na, K).

Abstract

The title compounds are prepared from stoichiometric mixtures of M2S (M: Na, K) and elemental Al, Ge, and S (fused silica ampules, 850 °C, 4 d).

Thioaluminogermanate M(AlS2)(GeS2)4 (M = Na, Ag, Cu): Synthesis, Crystal Structures, Characterization, Ion-Exchange and Solid-State 27Al and 23Na NMR Spectroscopy

“…The spectra show similar characteristic features related to the GeS 4 tetrahedra in T d point group symmetry. The sharp peak at 340 cm −1 corresponds to the Ge−S−Ge stretching mode, which falls in the same range as the ones found in AAlGeS 4 (A = Na, K) 14 and some alkali-metal thiogermanate glasses. 44 The weak peak at 171 cm −1 can be assigned to the G−S bending mode referring to the Raman spectrum of CsGe 4 S 10 •3H 2 O.…”

“…38,39 The weak peaks at 14 ppm can be assigned to the octahedral resonance of aluminum Al (octa) , 40 which is associated with the oxidation product α-Al 2 O 3 formed during sample preparation. 14,41 As expected, there is a slight shifting of the Al peak positions due to the replacement of Na with Ag in 2 and Cu in 3 (changing of the physical interaction of Na, Ag, and Cu with S). This observation confirms that the coordination around Al atoms did not change; otherwise the shift would be more significant.…”

“…13 The A/Al/Ge/S (A = alkali metal, transition metal) family remains largely unexplored, and only two structures are reported to date, Rb 3 (AlQ 2 ) 3 (GeQ 2 ) 7 (Q = S, Se) 12 and A(AlS 2 )(GeS 2 ) (A = Na, K). 14 The thiogermanates were mainly synthesized by conventional solid-state and hydro(solvo)thermal synthetic routes. 15−18 One of the most powerful methods is the reactive molten alkali-metal polysulfide flux, which has been employed in the exploratory synthesis of a large set of ternary and quaternary thiogermanates.…”

Synthesis, Crystal Structures, Optical Properties and Theoretical Calculations of Two Metal Chalcogenides Ba2AlSbS5 and Ba2GaBiSe5

“…Note that there were no obvious absorption bands above 400 cm −1 in Ba 2 AlSbS 5 or 300 cm −1 in Ba 2 GaBiSe 5 , which shows that they may have wide IR transmission ranges. As for Ba 2 AlSbS 5 , the absorption bands above 200 cm −1 , such as 242, 304, and 352 cm −1 , can be can be assigned to the characteristic absorptions of the Al-S and Sb-S modes, which are similar to those of other related compounds, such as Al-S (375 cm −1 ) in K(AlS 2 )(GeS 2 ) [35], Sb-S (360, 300, 340, and 270 cm -1 ) in A 2 Sb 2 Sn 3 S 10 (A = K, Rb, Cs) [36]. Additionally, owing to the heavier Se atoms, the Bi-Se and Ga-Se vibrations occur at lower bands of 193 and 230 cm −1 in Ba 2 GaBiSe 5 , which are also similar to those in Ba 4 CuGa 5 Se 12 (Ga-Se, 185-262 cm −1 ) [37] and (Bi 4 Se 4 )[AlCl 4 ] 4 (Bi-Se, 189 and 183 cm −1 ) [38].…”

Using NMR spectroscopy to investigate the role played by copper in prion diseases

“…Thus, NMR spectroscopy is extensively used in a wide range of applications, including organic chemistry [108], biochemistry, polymer chemistry [122], inorganic chemistry [122], structural biology [52], physics [61,[123][124][125][126][127], biology, and drug discovery [52,128,129]. Through NMR experiments, researchers can study samples in the solid state [130][131][132], gel phase [133][134][135][136], tissue state [137][138][139], gas phase, and solution state [140][141][142][143]; these approaches have been used to investigate molecular structures, concentration levels, and molecular dynamics [144][145][146]. Moreover, the continuous development of NMR experimental methods and NMR machinery, such as dynamic nuclear polarization (DNP) and high-field NMR spectrometers, has continuously enhanced research on the physical and chemical properties of samples [216][217][218].…”