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8426213 
Journal Article 
Structure and dynamics of chlorocyclohexane/thiourea inclusion compound C6H11Cl/SC(NH2)2 studied by X-ray diffraction and1H-NMR 
Ishibashi, T; Machida, M; Kobayashi, T; Koyano, N 
2004 
1 
Physical Society of Japan. Journal
ISSN: 0031-9015 
73 
9 
2458-2463 
English 
Structure and dynamics of chlorocyclohexane/thiourea inclusion compound C6H11Cl/SC(NH2)2 have been studied by single crystal X-ray structure analysis and 1H-NMR. The structure analysis at room temperature disclosed hydrogen bonds in host subunit and molecular arrangement of chlorocyclohexane guest molecule. In the host subunit, thiourea molecule has fairly good planarity and its N and S atoms are bounded by two and four hydrogen bonds grouped into two types, respectively. Inside the thiourea channel, the guest molecules are disordered among six orientations around the special positions with site symmetry D3d. Proton second moments of C6H11Cl/SC(NH2)2 and C6H11Cl/SC(ND2)2 gave the following results about the dynamics of the host subunit in the high-temperature phase stable above 197 K. In C6H11Cl/SC(NH2) 2, amino group undergoes a uniaxial rotation about its C-N bond, and this rotation begins to freeze at 240K. For C6H11Cl/ SC(ND2)2, the freezing temperature of this rotation is found to elevate by 30 K. This phenomenon can be understood by the isotope effect on the NH2 rotation, hindered by the hydrogen bonds. The both moments exhibit slightly discontinuous changes in the phase transition and increase with decreasing temperature even in the low-temperature phase. ©2004 The Physical Society of Japan. 
1H-NMR; Crystal structure; Isotope effect; Thiourea inclusion compound; X-ray diffraction