Investigations of new potential photo-acid generators: crystal structures of 2-[(E)-2-phenylethenyl]phenol (orthorhombic polymorph) and (2E)-3-(2-bromophenyl)-2-phenylprop-2-enoic acid

Abstract

The title compounds, C14H12O, (I), and C15H11BrO2, (II), were prepared and characterized as part of our studies of potential new photo-acid generators. In (I), which crystallizes in the orthorhombic space groupPca21, compared toP21/nfor the previously known monoclinic polymorph [Cornella & Martin (2013).Org. Lett.15, 6298–6301], the dihedral angle between the aromatic rings is 4.35 (6)° and the OH group is disordered over two sites in a 0.795 (3):0.205 (3) ratio. In the crystal of (I), molecules are linked by O—H...π interactions involving both the major and minor –OH disorder components, generating [001] chains as part of the herringbone packing motif. The asymmetric unit of (II) contains two molecules with similar conformations (weighted r.m.s. overlay fit = 0.183 Å). In the crystal of (II), both molecules form carboxylate inversion dimers linked by pairs of O—H...O hydrogen bonds, generatingR22(8) loops in each case. The dimers are linked by pairs of C—H...O hydrogen bonds to form [010] chains.