Stabilization of hydrogen peroxide by hydrogen bonding in the crystal structure of 2-aminobenzimidazole perhydrate

2-Aminobenzimidazole peroxosolvate – the third H2O2 crystalline adduct stabilized with the maximum possible number of hydrogen bonds formed by one hydrogen peroxide molecule.

Crystal structure of the co-crystalline adduct 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD)–4-iodophenol (1/2): supramolecular assembly mediated by halogen and hydrogen bonding

The asymmetric unit of the title co-crystalline adduct, 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD)–4-iodophenol (1/2), C8H16N4·2C6H5IO, comprises a half molecule of the aminal cage polyamine plus a 4-iodophenol molecule. A twofold rotation axis generates the other half of the adduct. The components are linked by two intermolecular O—H...N hydrogen bonds. The adducts are further linked into a three-dimensional framework structure by a combination of N...I halogen bonds and weak non-conventional C—H...O and C—H...I hydrogen bonds.

Crystal structure of the co-crystalline adduct 4-((4,4-dimethyl-2,6-dioxocyclohexylidene)methylamino)-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide - acetic acid (1/1), C21H24N4O4S ⋅ C2H4O2

C23H28N4O6S, triclinic, P1̅ (no. 2), a = 7.3612(3) Å, b = 9.2370(4) Å, c = 19.2940(8) Å, α = 94.657(2)°, β = 96.902(2)°, γ = 113.010(2)°, V = 1186.92(9) Å3, Z = 2, Rgt(F) = 0.0617, wRref(F2) = 0.1575, T = 100 K.

Crystal structure of the 1,3,6,8-tetraazatricyclo[4.3.1.13,8]undecane (TATU)–4-nitrophenol (1/2) adduct: the role of anomeric effect in the formation of a second hydrogen-bond interaction

In the title ternary co-crystalline adduct, C7H14N4·2C6H5NO3, molecules are linked by two intermolecular O—H...N hydrogen bonds, forming a tricomponent aggregates in the asymmetric unit. The hydrogen-bond formation to one of the N atoms is enough to induce structural stereoelectronic effects in the normal donor→acceptor direction. In the title adduct, the two independent nitrophenol molecules are essentially planar, with maximum deviations of 0.0157 (13) and 0.0039 (13) Å. The dihedral angles between the planes of the nitro group and the attached benzene rings are 4.04 (17) and 5.79 (17)°. In the crystal, aggregates are connected by C—H...O hydrogen bonds, forming a supramolecular dimer enclosing anR66(32) ring motif. Additional C—H...O intermolecular hydrogen-bonding interactions form a second supramolecular inversion dimer with anR22(10) motif. These units are linkedviaC—H...O and C—H...N hydrogen bonds, forming a three-dimensional network.

Crystal structure of the co-crystalline adduct 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD)–4-chloro-3,5-dimethylphenol (1/1)

In the crystal of the title co-crystalline adduct, C8H16N4·C8H9ClO, (I), prepared by solid-state reaction, the molecules are linked by intermolecular O—H...N hydrogen bonds, forming aDmotif. The azaadamantane structure in (I) is slightly distorted, with N—CH2—CH2—N torsion angles of 10.4 (3) and −9.0 (3)°. These values differ slightly from the corresponding torsion angles in the free aminal cage (0.0°) and in related co-crystalline adducts, which are not far from a planar geometry and consistent with aD2dmolecular symmetry in the tetraazatricyclo structure. The structures also differ in that there is a slight elongation of the N—C bond lengths about the N atom that accepts the hydrogen bond in (I) compared with the other N—C bond lengths. In the crystal, the two molecules are not only linked by a classical O—H...N hydrogen bond but are further connected by weak C—H...π interactions, forming a two-dimensional supramolecular network parallel to thebcplane.

Crystal structure of the co-crystalline adduct 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD)–4-bromophenol (1/2)

The structure of the 1:2 co-crystalline adduct C8H16N4·2C6H5BrO, (I), from the solid-state reaction of 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD) and 4-bromophenol, has been determined. The asymmetric unit of the title co-crystalline adduct comprises a half molecule of aminal cage polyamine plus a 4-bromophenol molecule. A twofold rotation axis generates the other half of the adduct. The primary inter-species association in the title compound is through two intermolecular O—H...N hydrogen bonds. In the crystal, the adducts are linked by weak non-conventional C—H...O and C—H...Br hydrogen bonds, giving a two-dimensional supramolecular structure parallel to thebcplane.

Arrays of Stereogenic Centers: The Carbery Synthesis of Mycestericin G

Chi-Ming Che of the University of Hong Kong devised (Chem. Commun. 2011, 47, 11204) a manganese catalyst for the enantioselective cis-dihydroxylation of electron-deficient alkenes such as 1. Christine Greck of Université de Versailles-St-Quentin effected (Tetrahedron Lett. 2012, 53, 1085) enantioselective alkoxylation of 3, remarkably without β-elimination. Keiji Maruoka of Kyoto University developed (J. Am. Chem. Soc. 2012, 134, 7516) an organocatalyst for the enantioselective anti addition of 5 to 6 to give 7. Barry M. Trost of Stanford University developed (J. Am. Chem. Soc. 2012, 134, 2075) a Mg catalyst for the enantioselective addition of ethyl diazoacetate to an aldehyde 8, and carried the adduct onto 9. Professor Maruoka designed (Angew. Chem. Int. Ed. 2012, 51, 1187) for the enantioselective addition of a ketone 10 to the alkynyl ketone 11 to give 12. Naoya Kumagai and Masakatsu Shibasaki of the Institute of Microbial Chemistry found (Org. Lett. 2012, 14, 3108) that 14 could be added under very soft conditions to 13 to give the anti adduct 15. René Peters of the Universität Stuttgart added (Adv. Synth. Catal. 2012, 354, 1443) the azlactone formed in situ to 17 in a conjugate sense to give 18. Kaïss Aouadi and Jean-Pierre Praly of the Université de Lyon prepared (Tetrahedron Lett. 2012, 53, 2817) the nitrone 19 from the inexpensive (–)-menthone. Dipolar cycloaddition to a range of alkenes proceeded with substantial diastereocontrol, as illustrated for 20, which gave the crystalline adduct 21. Jeffrey S. Johnson of the University of North Carolina reduced (J. Am. Chem. Soc. 2012, 134, 7329) the α-keto ester 22 under equilibrating conditions to give the lactone 23. Claudio Palomo of the Universidad del País Vasco alkylated (J. Org. Chem. 2012, 77, 747) the aldehyde 24 with 25 to give the diester 26. Damien Bonne and Jean Rodriguez of Aix-Marseille Université added (Adv. Synth. Catal. 2012, 354, 563) the α-keto ester 27 to 28 in a conjugate sense to give 29. Glenn C. Micalizio of Scripps/Florida developed (Angew. Chem. Int. Ed. 2012, 51, 5152) a general strategy for the stereocontrolled construction of skipped-conjugate dienes such as 30.

Crystal structures of the co-crystalline adduct 5-(4-bromophenyl)-1,3,4-thiadiazol-2-amine–4-nitrobenzoic acid (1/1) and the salt 2-amino-5-(4-bromophenyl)-1,3,4-thiadiazol-3-ium 2-carboxy-4,6-dinitrophenolate

The structures of the 1:1 co-crystalline adduct C8H6BrN3S·C7H5NO4, (I), and the salt C8H7BrN3S+·C7H3N2O7−, (II), obtained from the interaction of 5-(4-bromophenyl)-1,3,4-thiadiazol-2-amine with 4-nitrobenzoic acid and 3,5-dinitrosalicylic acid, respectively, have been determined. The primary inter-species association in both (I) and (II) is through duplexR22(8) (N—H...O/O—H...O) or (N—H...O/N—H...O) hydrogen bonds, respectively, giving heterodimers. In (II), these are close to planar [the dihedral angles between the thiadiazole ring and the two phenyl rings are 2.1 (3) (intra) and 9.8 (2)° (inter)], while in (I) these angles are 22.11 (15) and 26.08 (18)°, respectively. In the crystal of (I), the heterodimers are extended into a chain alongbthrough an amine N—H...Nthiadiazolehydrogen bond but in (II), a centrosymmetric cyclic heterotetramer structure is generated through N—H...O hydrogen bonds to phenol and nitro O-atom acceptors and features, together with the primaryR22(8) interaction, conjoinedR46(12),R21(6) andS(6) ring motifs. Also present in (I) are π–π interactions between thiadiazole rings [minimum ring-centroid separation = 3.4624 (16) Å], as well as short Br...Onitrointeractions in both (I) and (II) [3.296 (3) and 3.104 (3) Å, respectively].