Terahertz Absorption Spectroscopy of Benzamide, Acrylamide, Caprolactam, Salicylamide, and Sulfanilamide in the Solid State

Terahertz (THz) absorption spectra of the similarly structured molecules with amide groups including benzamide, acrylamide, caprolactam, salicylamide, and sulfanilamide in the solid phase at room temperature and 7.8 K for salicylamide are reported and compared to infrared vibrational spectral calculations using density functional theory. The results of THz absorption spectra show that the molecules have characteristic bands in the region of 0.2–2.6 THz (~7–87 cm−1). THz technique can be used to distinguish different molecules with amide groups. In the THz region benzamide has three bands at 0.83, 1.63, and 1.73 THz; the bands are located at 1.44 and 2.00 THz for acrylamide; the bands at 1.24, 1.66 and 2.12 THz are observed for caprolactam. The absorption bands are located at 1.44, 1.63, and 2.39 THz at room temperature, and at 1.22, 1.46, 1.66, and 2.41 THz at low temperature for salicylamide. The bands at 1.63, 1.78, 2.00, and 2.20 THz appear for sulfanilamide. These bands in the THz region may be related to torsion, rocking, wagging, and other modes of different groups in the molecules

Sugar–Metal Ion Interactions: The Complicated Coordination Structures of Cesium Ion with d‑Ribose and <i>myo</i>-Inositol

The novel cesium chloride–d-ribose complex (CsCl·C₅H₁₀O₅; Cs-R) and cesium chloride–<i>myo</i>-inositol complex (CsCl·C₆H₁₂O₆; Cs-I) have been synthesized and characterized using X-ray diffraction and FTIR, FIR, THz, and Raman spectroscopy. Cs⁺ is eight-coordinated to three chloride ions, O1 and O2 from one d-ribose molecule, O1 from another d-ribose molecule, and O4 and O5 from the third d-ribose molecule in Cs-R. For one d-ribose molecule, the oxygen atom O1 in the ring is coordinated to two cesium ions as an oxygen bridge, O2 is cocoordinated with O1 to one of the two cesium ions, and O4 and O5 are coordinated to the third cesium ion, respectively. O3 does not coordinate to metal ions and only takes part in forming hydrogen bonds. One chloride ion is connected to three cesium ions. Thus, a complicated structure of Cs–d-ribose forms. For Cs-I, Cs⁺ is 10-coordinated to three chloride ions, O1 and O2 from one <i>myo</i>-inositol molecule, O3 and O4 from another <i>myo</i>-inositol molecule, O5 and O6 from the third <i>myo</i>-inositol molecule, and O6 from the fourth <i>myo</i>-inositol molecule. One metal ion is connected to four ligands, and one <i>myo</i>-inositol is coordinated to four Cs⁺ ions, which is also a complicated coordination structure. Crystal structure results, FTIR, FIR, THz, and Raman spectra provide detailed information on the structure and coordination of hydroxyl groups to metal ions in the cesium chloride–d-ribose and cesium chloride–<i>myo</i>-inositol complexes

Sugar–Metal Ion Interactions: The Complicated Coordination Structures of Cesium Ion with d‑Ribose and <i>myo</i>-Inositol

The novel cesium chloride–d-ribose complex (CsCl·C₅H₁₀O₅; Cs-R) and cesium chloride–<i>myo</i>-inositol complex (CsCl·C₆H₁₂O₆; Cs-I) have been synthesized and characterized using X-ray diffraction and FTIR, FIR, THz, and Raman spectroscopy. Cs⁺ is eight-coordinated to three chloride ions, O1 and O2 from one d-ribose molecule, O1 from another d-ribose molecule, and O4 and O5 from the third d-ribose molecule in Cs-R. For one d-ribose molecule, the oxygen atom O1 in the ring is coordinated to two cesium ions as an oxygen bridge, O2 is cocoordinated with O1 to one of the two cesium ions, and O4 and O5 are coordinated to the third cesium ion, respectively. O3 does not coordinate to metal ions and only takes part in forming hydrogen bonds. One chloride ion is connected to three cesium ions. Thus, a complicated structure of Cs–d-ribose forms. For Cs-I, Cs⁺ is 10-coordinated to three chloride ions, O1 and O2 from one <i>myo</i>-inositol molecule, O3 and O4 from another <i>myo</i>-inositol molecule, O5 and O6 from the third <i>myo</i>-inositol molecule, and O6 from the fourth <i>myo</i>-inositol molecule. One metal ion is connected to four ligands, and one <i>myo</i>-inositol is coordinated to four Cs⁺ ions, which is also a complicated coordination structure. Crystal structure results, FTIR, FIR, THz, and Raman spectra provide detailed information on the structure and coordination of hydroxyl groups to metal ions in the cesium chloride–d-ribose and cesium chloride–<i>myo</i>-inositol complexes