Henk Schalekamp

Pyridine-2,3-diamine

The molecule of the title pyridine derivative, C5H7N3, shows approximately non-crystallographic C s symmetry. Intracyclic angles cover the range 117.50 (14)–123.03 (15)°. In the crystal, N—H⋯N hydrogen bonds connect molecules into a three-dimensional network. The closest intercentroid distance between two π-systems occurs with the c-axis repeat at 3.9064 (12) Å.

1,3-Diethyl-1,3-diphenyl­urea

The molecule of the title compound, C17H20N2O, a symmetrical derivative of urea, shows non-crystallographic C 2 symmetry. Interaction with the aromatic system of the phenyl substituents as well as amide-type resonance is responsible for the marked planarization of the coordination environments of the N atoms. C—H⋯O contacts give rise to the formation of centrosymmetric dimers in the crystal structure. The closest distance between the centroids of two adjacent rings is 3.8938 (11) Å.

Bis(2-hy­droxy­phen­yl)methanone

In the title compound, C13H10O3, a benzophenone derivative, the least-squares planes defined by the C atoms of the 2-hydroxyphenyl rings intersect at an angle of 45.49 (3)°. The substituents on the aromatic systems are both orientated towards the central O atom. Intra- as well as intermolecular O—H⋯O hydrogen bonds are observed, the latter giving rise to the formation of centrosymmetric dimers. The closest centroid–centroid distance between two π-systems is 3.7934 (7) Å.

1,6-Bis(chloro-meth-yl)pyridine.

In the title compound, C7H7Cl2N, a halogenated derivative of 2,6-lutidine, the C—Cl vectors of the chloromethyl groups point at opposite sides of the aromatic plane to each other. A weak dispersive Cl⋯Cl contact [3.4342 (3) Å] connects the molecules into a chain along the [101] direction. A π–π interaction with a centroid–centroid distance of 3.7481 (5) Å is also observed.

Bis(piperidin-1-yl)methanone

The title compound, C11H20N2O, is a urea derivative bearing two piperidine moieties in place of the amino groups. The molecule shows approximate non-crystallographic C 2 symmetry. The six-membered rings adopt 1 C 4 and 4 C 1 conformations and their mean planes make a dihedral angle of 35.87 (5)°. In the crystal, intermolecular C—H⋯O contacts connect the molecules into infinite strands along the a axis.

2-[(4-Methyl­phen­yl)sulfan­yl]aniline

The least-squares planes defined by the aromatic moieties in the title aniline derivative, C13H13NS, are nearly perpendicular to each other, forming a dihedral angle of 87.80 (7)°. Apart from a weak intramolecular N—H⋯S hydrogen bond, a co-operative set of N—H⋯N hydrogen bonds present in the crystal structure leads to the formation of tetrameric units.

2-Hy-droxy-N-(2-hy-droxy-eth-yl)benzamide.

In the title compound, C9H11NO3, a derivative of salicylamide, the intracyclic C—C—C angles span the range 117.96 (13)–121.56 (14)°. An intramolecular O—H⋯O hydrogen bond occurs. In the crystal, intermolecular O—H⋯O and N—H⋯O hydrogen bonds occur and C—H⋯O contacts connect the molecules into a three-dimensional network. The closest intercentroid distance between two π-systems is 3.8809 (10) Å.

Redetermination of the crystal structure of endo-2-carboxy-bicyclo[2.2.1]- heptane, C8H12O2

Abstract C8H12O2, triclinic, P1̅ (no. 2), a = 5.8945(4) Å, b = 6.0522(3) Å, c = 10.7643(7) Å, α = 101.219(2)°, β = 90.581(2)°, γ = 95.445(2)°, V = 374.8 Å3, Z = 2, Rgt(F) = 0.0417, wRref(F2) = 0.1105, T = 200 K.

Refinement of the crystal structure of L-valinemethylester hydrochloride, C6H13NO2 ) HCl, at 200 K

C6H14ClNO2, orthorhombic, P212121 (no. 19), a = 5.9023(2) Å, b = 7.2617(2) Å, c = 21.5387(7) Å, V = 923.2 Å, Z = 4, Rgt(F) = 0.026, wRref(F ) = 0.070, T = 200 K.

5-Amino­pentan-1-ol

The title compound, C5H13NO, is an aliphatic aminoalcohol with both functional groups residing on terminal C atoms. Apart from the hydroxy group, all non-H atoms are nearly co-planar, the maximum deviation of an atom taking part in the least-squares plane defined by the mentioned non-H atoms being 0.029 (1) Å. In the crystal, O—H⋯N and N—H⋯O hydrogen bonds connect the molecules, forming a three-dimensional network.