Anna Michta

Thioacetanilide at 120 K.

The title compound, C(8)H(9)NS, has four symmetry-independent molecules in the asymmetric unit. These molecules link into two independent infinite N-H...S hydrogen-bonded chains in the a-axis direction with graph-set notation C(2)(2)(8). The NH-CS group adopts a trans conformation and forms a dihedral angle of about 50 degrees with the phenyl ring. The intermolecular hydrogen-bond energy calculated by the density functional theory (DFT) method is -14.95 kJ mol(-1). The correlation between the IR spectrum of this compound and the hydrogen-bond energy is also discussed. This molecular system is of interest because of its biological function.

X-ray, Hirshfeld surface analysis, spectroscopic and DFT studies of PAHs: fluoranthene and acenaphthene

The X-ray structure, theoretical calculation, Hirshfeld surfaces analysis, IR and Raman spectra of fluoranthene and acenaphthene were reported. The acenaphthene crystallizes in the orthorhombic crystal system and space group P 2 1 ma , with crystal parameters a = 7.2053 (9) A, b = 13.9800 (15) A, c = 8.2638 (8) A, Z = 4 and V = 2135.5 (4) A 3 . In turn, the grown crystals of fluoranthene are in monoclinic system with space group P2 1 /n. The unit cell parameters are a = 18.349 (2) A, b = 6.2273 (5) A, c = 19.861 (2) A, β = 109.787 (13) °, Z = 8 and unit cell volume is 832.41 (16) A 3 . The structure was solved by direct methods and refined by full-matrix least squares based on F2 with weight w=1/[σ 2 (F 0 2 )+(0.0702P) 2 +0.5131P] where P=(F 0 2 +2F c 2 )/3 and w=1/[σ 2 (F 0 2 )+(0.0589P) 2 ] where P = (F 0 2 +2F c 2 )/3 for fluoranthene and acenaphthene respectively . Theoretical calculations of the title compounds isolated molecule have been carried out using DFT at the B3LYP level. The intermolecular interactions in the crystal structure, for both the title PAHs, were analyzed using Hirshfeld surfaces computational method.

Quinolin-6-ol at 100 K.

The title compound, C(9)H(7)NO, has two symmetry-independent molecules in the asymmetric unit, which have different conformations of the hydroxy group with respect to the quinoline ring. One of the molecules adopts a cis conformation, while the other shows a trans conformation. Each type of independent molecule links into a separate infinite O-H...N hydrogen-bonded chain with the graph-set notation C(7). These chains are perpendicular in the unit cell, one extended in the a-axis direction and the other in the b-axis direction. There is also a weak C-H...O hydrogen bond with graph-set notation D(2), which runs in the c-axis direction and joins the two separate O-H...N chains. The significance of this study lies in the comparison drawn between the experimental and calculated data of the crystal structure of the title compound and the data of several other derivatives possessing the hydroxy group or the quinoline ring. The correlation between the IR spectrum of this compound and the hydrogen-bond energy is also discussed.