Crystal structure of 2-oxo-1,2-diphenylethyl diisopropylcarbamate

The title compound, C21H25NO3, crystallized as a racemic twin in the Sohnke space group P21. In the molecular structure of the title compound, both enantiomers show a highly similar conformation with the urethane function and the benzoyl group showing an almost perpendicular arrangement [the dihedral angle is 72.46 (8)° in the S-enantiomer and 76.21 (8)° in the R-enantiomer]. In the crystal structure, molecules of both enantiomers show infinite helical arrangements parallel to the b axis formed by weak C—H...O hydrogen bonds between the phenyl ring of the benzoyl group and the carbamate carbonyl group. In case of the R-enantiomer, this helix is additionally stabilized by a bifurcated hydrogen bond between the carbonyl function of the benzoyl group towards both phenyl groups of the molecule.

N-(4-Ethoxy-2,5-dinitrophenyl)acetamide

In the title compound, C10H11N3O6, the torsion angles about the bonds to the benzene ring are less than 4°, except for the nitro groups, which are twisted out of the ring plane by 25.27 (3) and 43.63 (2)°. The N—H group forms a bifurcated hydrogen bond, with an intramolecular component to a nitro group O atom and an intermolecular component to the other nitro group, thereby forming chains propagating in the [010] direction. Several weak C—H...O interactions are also present.

Pyridine 1:1 adducts of urea (Z′ = 1) and thiourea (Z′ = 8)

During our studies of urea and thiourea adducts, we noticed that no adducts with unsubstituted pyridine had been structurally investigated. The 1:1 adduct of pyridine and urea, C5H5N·CH4N2O, crystallizes in the P21/c space group with Z = 4. The structure is of a standard type for urea adducts, whereby the urea molecules form a ribbon, parallel to the a axis, consisting of linked R 2 2(8) rings, and the pyridine molecules are attached to the periphery of the ribbon by bifurcated (N—H...)2N hydrogen bonds. The 1:1 adduct of pyridine and thiourea, C5H5N·CH4N2S, crystallizes in the P21/n space group, with Z = 32 (Z′ = 8). The structure displays similar ribbons to those of the urea adduct. There are two independent ribbons parallel to the b axis at z ≃ 0 and 1 \over 2, and three at z ≃ 1 \over 4 and 3 \over 4; the latter are crosslinked to form a layer structure by additional long N—H...S interactions, which each formally replace one branch of a bifurcated hydrogen-bond system.

(Acetamide-κO){2,2′,2′′-boranetriyltris[6-tert-butyl-4-methylpyridazine-3(2H)-thione]-κ4 B,S,S′,S′′}copper(I) trifluoromethanesulfonate chloroform disolvate

In the title solvated complex salt, [Cu(C27H39BN6S3)(C2H5NO)](CF3O3S)·2CHCl3, the CuI atom is coordinated by the three S atoms of the pyridazine-3-thione rings in the equatorial plane [Cu—S = 2.3072 (4)–2.3280 (4) Å] and the B atom of the scorpionate ligand and the O atom of an acetamide ligand as the apices of a trigonal bipyramid [Cu—B = 2.0456 (16) Å and Cu—O = 1.9957 (11) Å]. The amide group of the latter ligand is involved in a bifurcated hydrogen bond to the trifluoromethanesulfonate anion.

(Acetonitrile-κN)aqua[N,N′-bis(pyridin-2-ylmethyl)ethane-1,2-diamine-κ4N,N′,N′′,N′′′]zinc(II) perchlorate

The structure of the title compound, [Zn(C14H18N4)(C2H3N)(H2O)](ClO4)2, contains a six-coordinate cation consisting of the tetradentate bispicen ligand, coordinated water, and coordinated acetonitrile, with the latter two ligands adopting acisconfiguration. There are two formula units in the asymmetric unit. Both cations show almost identical structural features with the bispicen ligand adopting the more commoncis-β conformation. One of the four perchlorate anions is disordered over two positions, with occupancies of 0.9090 (15) and 0.0910 (15). There is extensive inter-ionic hydrogen bonding between the perchlorate anions and O—H and N—H groups in the cations, including a bifurcated hydrogen bond between an N—H group and two O atoms of one perchlorate anion. As a result of this extended hydrogen-bond network, the ions are linked into a complex three-dimensional array.

4-Ammonio-5-methoxy-2-methylbenzenesulfonate

The title compound, C8H11NO4S, crystallizes as a zwitterion, with the negatively charged benzenesulfonate group and the positively charged NH3+group in mutuallyparapositions. All the non-H atoms, except for one O atom of the sulfonate group, lie on a crystallographic mirror plane (Z′ = 1/2). In the crystal, the hydrogen-bonding structure is two-dimensional, propagating in thec-axis direction through a bifurcated hydrogen bond between the NH3+and the SO3−groups, and in theb-axis direction through anR22(16) ring motif involving the same functional groups. This latter hydrogen bonding is supported by offset π–π interactions [intercentroid distance = 3.8114 (4) Å].

Adducts of urea with pyrazines

The adducts urea:2,3-dimethylpyrazine (1:1) (1), urea:2-methylpyrazine (2:1) (2), urea:2,6-dimethylpyrazine (2:1) (3), urea:2,5-dimethylpyrazine (2:3) (4) and urea:2,5-dimethylpyrazine (2:1) (5), together with the related adduct methylthiourea:2-methylpyrazine (1:1) (6), were prepared and their structures determined. In all cases, the basic motif of the packing is a urea (or thiourea for 6) ribbon consisting of linked ${\rm{R}}_2^2$ (8) rings, to which the pyrazines are often attached by bifurcated hydrogen bond systems. Adducts 1–3 present standard packing patterns of 1:1 or 2:1 urea solvates. Adduct 4 consists of layers of standard 1:1 ribbons, between which are regions of interspersed pyrazines, connected to the main layers by C–H⋯N interactions. Adduct 5 contains the standard ribbons linked by pyrazines in one direction and (urea⋯pyrazine⋯urea) spacers in the other direction. The methylthiourea adduct 6 consists of the usual ribbons with pyrazines attached by two-centre hydrogen bonds (the methyl substituent blocks the formation of bifurcated systems).