Crystal structure of benzyl 3-oxo-2-oxa-5-aza-bicyclo-[2.2.1]heptane-5-carboxyl-ate.

The title compound, C13H13NO4 (also known as N-benzyl-oxycarbonyl-4-hy-droxy-l-proline lactone), crystallizes with two mol-ecules in the asymmetric unit. They have slightly different conformations: the fused ring systems almost overlap, but different C-O-C-C torsion angles for the central chains of -155.5 (2) and -178.6 (2)° lead to different twists for the terminal benzene ring. In the crystal, the mol-ecules are linked by C-H⋯O inter-actions, generating a three-dimensional network. The absolute structure was established based on an unchanging chiral centre in the synthesis.

Crystal structure of (1R,4R)-tert-butyl 3-oxo-2-oxa-5-aza-bicyclo-[2.2.2]octane-5-carboxyl-ate.

In the title compound, C11H17NO4, commonly known as N-tert-but-oxy-carbonyl-5-hy-droxy-d-pipecolic acid lactone, the absolute configuration is (1R,4R) due to the enantiomeric purity of the starting material which remains unchanged during the course of the reaction. In the crystal there no inter-molecular hydrogen bonds.

Crystal structure of (tert-butyl-carbamo-yl)(4-chloro-2-oxo-2H-chromen-3-yl)methyl acetate.

In the title compound, C17H18ClNO5, which was synthesized by reacting 4-chloro-3-formyl-coumarin, acetic acid and tert-butyl isocyanide, the acetamido side chain is convoluted with ring-to-side chain C-C-C-C, C-C-C-N and C-C-N-C torsion angles of -123.30 (14), -135.73 (12) and 176.10 (12)°, respectively. In the crystal, N-H⋯O and weak C-H⋯O hydrogen bonds are present, which together with π-π coumarin-ring inter-actions [ring centroid separations = 3.4582 (8) and 3.6421 (9) Å], give rise to a layered structure lying parallel to (001).

Crystal structure of 3,4-dimethyl 2-(tert-butyl-amino)-5-[2-oxo-4-(thio-morpholin-4-yl)-2H-chromen-3-yl]furan-3,4-di-carboxyl-ate ethyl acetate hemisolvate.

In the title hemisolvate, C25H28N2O7S·0.5C4H8O2, the thio-morpholine ring adopts a chair conformation, with the exocyclic N-C bond in an equatorial orientation. The dihedral angle between the coumarin ring system (r.m.s. deviation = 0.044 Å) and the furan ring is 64.84 (6)°. An intra-molecular N-H⋯O hydrogen bond closes an S(6) ring. The ethyl acetate solvent mol-ecule is disordered about a crystallographic inversion centre. In the crystal, the components are linked by C-H⋯O and C-H⋯S hydrogen bonds, generating a three-dimensional network.

Crystal structure of ethyl 2-(2-{1-[N-(4-bromo-phen-yl)-2-oxo-2-phenyl-acetamido]-2-tert-butyl-amino-2-oxo-ethyl}-1H-pyrrol-1-yl)acetate.

In the title compound, C28H30BrN3O5, there is an intra-molecular N-H⋯O hydrogen bond and an intra-molecular C-H⋯O hydrogen bond, both forming S(9) ring motifs. The planes of the 4-bromo-phenyl ring and the phenyl ring are inclined to that of the pyrrole ring by 48.05 (12) and 77.45 (14)°, respectively, and to one another by 56.25 (12)°. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds and C-H⋯π inter-actions, forming slabs parallel to (10-1).

Long-term air-stable n-channel organic thin-film transistors using 2,5-difluoro-1,4-phenylene-bis{2-[4-(trifluoromethyl)phenyl]acrylonitrile}.

A long-term air-stable n-type organic semiconductor, 2,5-difluoro-1,4-phenylene-bis{2-[4-(trifluoromethyl)phenyl]acrylonitrile}, was synthesized by a high-yield simple procedure of Knoevenagel condensation with aldehyde and acetonitrile derivatives. A fabricated organic thin-film transistor (OTFT) using this compound exhibited good n-channel OTFT properties with a high electron mobility of 0.17 cm(2) V(-1) s(-1) and an on/off current ratio of 10(6) under both vacuum and ambient air operation. After storage in ambient air for 1 year, a stored n-channel OTFT still shows good n-channel OTFT performance with little degradation in ambient air operation.