CRYSTAL STRUCTURES OF TWO 4-PHENYLBENZOPHENONES (330,00 руб.)

There are four crystallographically independent molecules with different conformations in the crystal structure of [1,1™-biphenyl]-4-yl(2-chlorophenyl)methanone (I). <...> Torsion angles between the biphenyl rings are between 28.5 and 30.8. <...> Several C—H…O and C—H…Cl hydrogen bonds and weak ƒ—ƒ stacking contacts consolidate the crystal. <...> The torsion angle between the biphenyl rings is 28.1 and C—H…O hydrogen bonds are observed in compound (II). <...> INTRODUCTION Biphenyl is a challenging molecule from the structural point of view because its conformations in crystals, gas and other condensed phases can differ substantially. <...> In the crystalline state at room temperature, biphenyl owns a coplanar conformation [ 1 ]. <...> In the gas phase, Almenningen et al. found by electron diffraction that the equilibrium torsion angle between the two phenyl planes was 44.41.2 [ 2 ]. <...> However, in solution, twisted conformations depend largely on the nature of the solvent and the temperature [ 3 ], and for a biphenyl melt the dihedral angle was 324 [ 4 ]. <...> These torsion angles of biphenyl are driven by the ƒ-conjugation of phenyl rings, electron exchange, and steric repulsion between the adjacent hydrogen atoms in ortho positions [ 5 ]. <...> Furthermore, the debate for nonplanarity is still ongoing with the viewpoint that an unfavorable lengthening of the central C—C bond might cause a hydrogen-hydrogen interaction once the planes become more coplanar [ 6 ]. <...> Moreover, in search for one subtype multidrug resistance-associated protein (ABCC2/MRP2) inhibitor, it was concluded that in various biphenylsubstituted heterocycles, the degrees of twisting between the two phenyl rings are crucial to the inhibition of ABCC2/MRP2 [ 9 ]. <...> The para-substituents X and Y were limited to H, halogens, CH3, OH, COOH, NH2, NO2, and CN moieties. <...> Herein, we synthesized two 4-phenylbenzophenones (I) and (II) via Friedel—Crafts reactions, as shown in Scheme 1, and discussed their crystallographic properties. <...> Scheme 1 EXPERIMENTAL Melting points were taken on an X-4 apparatus and are uncorrected. <...> Ultraviolet spectra (UV) were obtained on a Jasco V-550 UV/VIS spectrophotometer. 1H NMR spectra were recorded on a Brucker AVANCE III spectrometer operating at 500 MHz. [1,1™-Biphenyl]-4-yl(2-chlorophenyl)methanone (I) was obtained as follows [ 14 <...>