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The title compound, C₁₈H₁₄O₂, is almost planar with a dihedral angle of 1.24 (2)° between the phenyl­ethynyl and styryl groups. The acet­oxy group is tilted by 82.46 (2) and 82.26 (3)° with respect to the benzene ring planes.

The mol­ecule of the title compound, C₂₄H₃₀O₈, has two chiral centers. As it occupies a special position on the twofold axis in a centrosymmetric group, the crystal represents a racemic mixture of RR and SS enantiomers.

The title compound, C₃₆H₄₅O₆Br₃, adopts the rigid `crown' conformation of the parent cyclo­triveratryl­ene (CTV) system and possesses molecular, but not crystallographic, C₃ symmetry. The cyclo­triveratryl­ene core is rigid.

The title compound, C₁₅H₁₁IO₄, was synthesized by the N,N'-dicyclo­hexyl­carbodiimide- and 4-dimethyl­amino­pyridine-catalyzed reaction of 3-hydr­oxy-4-methoxy­benzaldehyde and 2-iodo­benzoic acid. In the mol­ecule, the dihedral angle between the two benzene rings is 70.6 (1)°.

The title compound, [Mg(C₃H₁₀NO₆P₂)₂]_n, synthesized by a hydro­thermal method, adopts a one-dimensional polymeric chain structure and is isotypic with the previously reported Cd complex based on the ligand N,N-dimethyl­amino­methane-1,1-diphospho­nic acid (H₄L). The asymmetric unit contains one half Mg²⁺ ion and one H₃L^- anion. The unique Mg²⁺ ion lies on an inversion center and is octa­hedrally coordinated by O atoms from six phospho­nate groups of four different H₃L^- anions. Each H₃L^- anion, with one protonated N atom and two phospho­nate OH groups, serves as a tridentate ligand. Two of its six phospho­nate O atoms chelate to a Mg²⁺ cation in a bidentate fashion, while a third O atom bridges to a neighbouring Mg²⁺ ion. The inter­connection of Mg²⁺ ions by the H₃L^-anions leads to the formation of a polymer chain along the a axis in which the adjacent Mg²⁺ ions are doubly bridged by two equivalent H₃L^- anions. These discrete chains are further assembled into a three-dimensional supra­molecular network via O-HO and N-HO hydrogen bonds involving the non-coordin­ated phospho­nate O atoms and the protonated N atoms.

Two polymorphs of (2-carb­oxy­eth­yl)(phen­yl)­phosphinic acid, C₉H₁₁O₄P, crystallize in the chiral P2₁2₁2₁ space group with similar unit-cell parameters. They feature an essentially similar hydrogen-bonding motif but differ slightly in their detailed geometric parameters. For both polymorphs, the unequivocal location of the hydroxy H atoms together with the expected differences in the P-O bond lengths establish unequivocally that both forms contain the S isomer; the protonated phosphinic acid and carboxy O atoms serve as hydrogen-bond donors, while the second phosphinic acid O atom acts as a double hydrogen-bond acceptor and the remaining carboxy O atom is not involved in hydrogen bonding. Thus, an undulating two-dimensional supra­molecular layer aggregate is formed based on an R₄³(20) ring unit. Such polymorphism derives from the rotation of the C-C single bonds between the two hydrogen-bond-involved carboxy and phosphi­nic acid moieties.

In the title compound, (C₁₄H₂₄N₂O₈)[CdCl₄]·4H₂O, the Cd atom in the tetra­hedral [CdCl₄]^2- anion lies on a twofold rotation axis, and the diprotonated organic mol­ecule, trans-N,N,N',N'-tetra­kis(carb­oxy­meth­yl)cyclo­hexane-1,2-diammon­ium, has 2 symmetry with the twofold rotation axis running through the mid-point of two C-C bonds in the cyclo­hexane unit. In the crystal structure, classical intra­molecular O-HO and N-HO and inter­molecular O-HO, N-HO, O-HCl and C-HCl hydrogen bonds are observed.

The title compound, C₂₆H₃₁NO₅S, was synthesized by the palladium-catalyzed coupling reaction of 2-(3-bromo-4-methoxy­phenyl)-3,4-di­methyl-5-(3,4,5-tri­methoxy­phenyl)­thio­phene and morpholine. This mol­ecule is composed of four rings. Two benzene rings are linked by a thio­phene moiety which is planar. The morpholine group has a chair conform­ation.

In the molecule of the title cluster compound, ₄-selenido-bis[-(4-tolylselenido)-hexacarbonyldiiron], two identical (-4-CH₃C₆H₄Se)Fe₂(CO)₆ moieties are joined by a spiro-type four-coordinate Se atom, ₄-Se. The four Se-Fe bond lengths around the central Se atom are 2.353 (3), 2.353 (3), 2.347 (3) and 2.358 (3) Å. The average (2.353 Å) is shorter than that (2.392 Å) of Se-Fe bond lengths formed between Fe atoms and the 4-tolylselenido ligands. In each diiron subcluster core, the 4-tolylselenido ligand is bridged between two Fe atoms.

The title compound, C₆H₈N₄O₃·2H₂O, which crystallized as a dihydrate, has two almost planar segments viz. the pyrimidine ring and the C-N-C(=O)-C group [maxmum deviations of 0.020 (2) and 0.014 (2) Å, respectively], with a dihedral angle of 87.45°. In the crystal, the components are linked by O-HO and N-HO hydrogen bonds.

The title compound, C₁₃H₁₉N₃O₂, was obtained by the direct solvent-free reaction of 4-hy­droxy-3-meth­oxy­benzaldehyde with 1-amino-4-methyl­piperazine. The piperazine ring adopts a chair conformation. In the crystal, strong inter­molecular O-HN and weak inter­molecular C-HO and C-HN hydrogen bonds help to establish the packing.