3-(4-Methoxy­phen­yl)-1-(2-pyrrol­yl)prop-2-en-1-one

The title mol­ecule, C14H13NO2, is almost flat with a dihedral angle of 8.0 (1)° between the pyrrole and benzene rings. The central C3O ketone unit has an s-cis conformation and is also coplanar with a torsion angle of −0.6 (3) °. An intra­molecular C—H⋯O hydrogen bond generates an S(5) ring motif. In addition, the meth­oxy group is coplanar with the attached benzene ring. In the crystal structure, neighboring mol­ecules are paired through N—H⋯O hydrogen bonds into centrosymmetric dimers with an R 2 2(10) motif

(E)-3-(4-Chloro­phen­yl)-1-(5-hy­droxy-2,2-dimethyl-2H-chromen-6-yl)prop-2-en-1-one

There are two independent mol­ecules in the asymmetric unit of the title compound, C20H17ClO3, each having an E configuration about the –C=C– bond. The dihedral angles between the two benzene rings in the two mol­ecules are 7.17 (11) and 9.82 (11)°. In both mol­ecules, the hy­droxy group is involved in an intra­molecular O—H⋯O hydrogen bond

A monoclinic polymorph of 1-(4-chloro­phen­yl)-3-(4-methoxy­phen­yl)prop-2-en-1-one

The crystal structure of the title compound, C16H13ClO2 (II), (space group P21/c,) is a polymorph of the structure, (I), reported by Harrison, Yathirajan, Sarojini, Narayana & Indira [Acta Cryst. (2006), E62, o1647–o1649] in the ortho­rhom­bic space group Pna21. The dihedral angle between the mean planes of the 4-chloro- and 4-meth­oxy-substituted benzene rings is 52.9 (1)° in (II) compared to 21.82 (6)° for polymorph (I). The dihedral angles between the mean planes of the prop-2-en-1-one group and those of the 4-chloro­phenyl and 4-methoxy­phenyl rings are 23.3 (3) and 33.7 (1)°, respectively. in (II). The corresponding values are 17.7 (1) and 6.0 (3)°, respectively, in polymorph (I). In the crystal, weak C—H⋯π inter­actions are observed

(2E)-3-(2-Chloro-6-methyl-3-quinol­yl)-1-(1-naphth­yl)prop-2-en-1-one

In the title mol­ecule, C23H16ClNO, the quinoline and naphthalene ring systems are individually planar, with maximum deviations of 0.020 (2) and 0.033 (2) Å, respectively, and are inclined at a dihedral angle of 30.01 (4)°. Intra­molecular C—H⋯O and C—H⋯Cl inter­actions occur. The crystal structure is devoid of any classical hydrogen bonds, but symmetry-related mol­ecules are linked via weak C—H⋯Cl inter­actions, forming chains propagating in [001]

3-Phenyl-1-(pyrrol-2-yl)prop-2-en-1-one

The title mol­ecule, C13H11NO, is almost flat, the angle between the pyrrole and the phenyl rings being 10.9 (1)°. The atoms of the central C3O unit are coplanar, with a mean deviation from the plane of 0.001 (1) Å. The angles between this plane and the pyrrole and phenyl rings are 3.3 (1) and 8.0 (1)°, respectively. The mol­ecules form centrosymmetric dimers through a pair of N—H⋯O hydrogen bonds with an R 2 2(10) motif

(E)-3-(3-Chloro­phen­yl)-1-(4-methoxy­phen­yl)prop-2-en-1-one

The title mol­ecule, C16H13ClO2, is trans with respect to the C=C double bond. The dihedral angles between the mean plane of the prop-2-en-1-one unit and those of the 3-chloro- and 4-meth­oxy-substituted benzene rings are 20.93 (9) and 20.42 (10)°, respectively, and the dihedral angle between the mean planes of the two benzene rings is 40.96 (5)°. The crystal structure is stabilized by weak inter­molecular C—H⋯O hydrogen bonds, forming chains along the b axis

A second polymorph of (2E)-1-(4-fluoro­phen­yl)-3-(3,4,5-trimethoxy­phen­yl)prop-2-en-1-one

The crystal structure of the title compound, C18H17FO4, reported here is a polymorph of the structure first reported by Patil et al. [Mol. Cryst. Liq. Cryst. Sci. Technol. Sect. A (2007), 461, 123–130]. It is a chalcone analog and consists of substituted phenyl rings bonded at the opposite ends of a propenone group, the biologically active region. The dihedral angle between the mean planes of the aromatic rings within the 4-fluoro­phenyl and trimethoxy­phenyl groups is 28.7 (1)° compared to 20.8 (6)° in the published structure. The angles between the mean plane of the prop-2-ene-1-one group and the mean plane of aromatic rings within the 4-fluoro­phenyl and trimethoxy­phenyl groups are 30.3 (4) and 7.4 (7)°, respectively, in contast to 10.7 (3) and 12.36° for the polymorph. While the two 3-meth­oxy groups are in the plane of the trimeth­oxy-substituted ring, the 4-meth­oxy group is in a synclinical [−sc = −78.1 (2)°] or anti­clinical [+ac = 104.0 (4)°] position, compared to a +sc [53.0 (4)°] or −ac [−132.4 (7)°] position. While no classical hydrogen bonds are present, weak inter­molecular C—H⋯π-ring inter­actions are observed which contribute to the stability of the crystal packing. The two polymorphs crystallize in the same space group, P21/c, but have different cell parameters for the a, b and c axes and the β angle. A comparison of the mol­ecular geometries of both polymorphs to a geometry optimized density functional theory (DFT) calculation at the B3-LYP/6–311+G(d,p) level for each structure provides additional support to these observations