Felix Katzsch

A comparison of X-ray crystal structures including methyl 3,5-bis(hydroxymethyl)benzoate, its phenylethynyl extended derivative in polymorphous forms and the corresponding carboxylic acids

Considering the specific supramolecular synthon design of carboxylic acid and alcoholic hydroxyl groups in the field of crystal engineering, we compared the solid state structures of particular benzoates and corresponding acids 1–4 both in the non-spacered (1, 2) and spacered (3, 4) forms. Based on the single crystal X-ray study, there is only a slight influence of the phenylacetylene spacer with regard to the layer lattice arrangement of the benzoates while referring to the benzoic acid analogues the addition of the spacer gives rise to a modification of the lattice from a layer to a tape structure. Dependent on the crystallization conditions, two crystalline polymorphs of compound 3 (3a, 3b) were obtained and discussed regarding their structural differences.

X-ray crystal structures and conformational analysis of cyclic acetals derived from tartaric acid and rigid spacer units

Three tartaric ester and tartaric acid derivatives (1–3) with the hydroxy groups being linked via cyclic acetal (1,3-dioxolane) formation to a rigid core, containing phenyl and ethynyl units, have been synthesized. Their crystal structures are reported, emphasizing the molecular geometry, intermolecular interactions, and the resulting packing motifs. All dioxolane rings present in the crystal structures of 1–3 are analyzed and compared with regard to their conformational behavior. In spite of similar substitution patterns, the dioxolane units adopt different conformations including twist and varying envelope isomers. The crystal structures are dominated by C–H···O (esters 1 and 2) and O–H···O (acid 3) hydrogen bonds, leading to different types of packing motifs being characteristic of strand and layer formation.

Crystalline inclusion properties of new pyridine and thiophene modified wheel-and-axle diol hosts

Structural extension of the ‘wheel-and-axle’ host concept has given rise to the design of a new type of host derivative (1–3) featuring two di(pyrid-2-yl)hydroxymethyl or di(thien-2-yl)hydroxymethyl moieties attached to a central phenylene unit, i.e. having the phenyl groups of a well-known model compound (Ph) substituted by heteroaromatics. Syntheses of the new derivative compounds are described, and the capability to form crystalline inclusions obtained from solvent solution compared to the prototype molecule is studied, including X-ray diffraction analysis of relevant crystal structures. Sorption measurements of the compounds as solid receptor films coated on a quartz crystal microbalance considering a variety of solvent vapors have been performed, showing potential application as mass sensitive sensor materials.

Redetermination of tetra­methyl tetra­thia­fulvalene-2,3,6,7-tetra­carboxyl­ate

An improved crystal structure of the title compound, C14H12O8S4, is reported. The structure, previously solved using the heavy-atom method (R = 7.1%), has now been solved using direct methods. Due to the improved quality of the data set an R value of 2.06% could be achieved. In the crystal, C—H⋯S and C—H⋯O contacts link the molecules.

5,5'-(Ethyne-1,2-di-yl)diisophthalic acid dimethyl sulfoxide tetra-solvate.

In the title compound, C18H10O8·4C2H6OS, the mid-point of the triple bond of the main molecule is located on a special position, i.e. about an inversion center. The carboxyl groups are twisted slightly out of the planes of the aromatic rings to which they are attached, making dihedral angles of 24.89 (1) and 7.40 (2)°. The cystal packing features strong O—H⋯O hydrogen bonds, weaker C—H⋯O interactions and O⋯S contacts [3.0981 (11) Å] and displays channel-like voids extending along the a-axis direction which contain the dimethyl sulfoxide solvent molecules.

S,S′-(Pyridazine-3,6-di­yl)dithio­uronium dichloride methanol monosolvate

In the title compound, C6H10N6S2 2+·2Cl−·CH3OH, the pyridazine ring is almost planar, the greatest deviation from the mean plane being 0.025 (2) Å for one of the ring N atoms. The two thiouronium substituents are tilted out of this plane by 60.87 (6) and 57.94 (7)°. The thiouronium cations and the chloride anions are linked by strong N—H⋯Cl hydrogen bonds. The methanol solvent molecule interacts with both the chloride ion (through an O—H⋯Cl hydrogen bond) and the cation (through an N—H⋯O hydrogen bond), resulting in a three-dimensional supramolecular arrangement.