Methyl β-lactoside [methyl β-D-galactopyranosyl-(1→4)-β-D-glucopyranoside] monohydrate: a solvomorphism study

Methyl β-lactoside [methyl β-D-galactopyranosyl-(1→4)-β-D-glucopyranoside] monohydrate, C13H24O11·H2O, (I), was obtained via spontaneous transformation of methyl β-lactoside methanol solvate, (II), during air-drying. Cremer–Pople puckering parameters indicate that the β-D-Galp (β-D-galactopyranosyl) and β-D-Glcp (β-D-glucopyranosyl) rings in (I) adopt slightly distorted 4 C 1 chair conformations, with the former distorted towards a boat form (B C1,C4) and the latter towards a twist-boat form (O5 S C2). Puckering parameters for (I) and (II) indicate that the conformation of the βGalp ring is slightly more affected than the βGlcp ring by the solvomorphism. Conformations of the terminal O-glycosidic linkages in (I) and (II) are virtually identical, whereas those of the internal O-glycosidic linkage show torsion-angle changes of 6° in both C—O bonds. The exocyclic hydroxymethyl group in the βGalp residue adopts a gt conformation (C4′ anti to O6′) in both (I) and (II), whereas that in the βGlcp residue adopts a gg (gauche–gauche) conformation (H5 anti to O6) in (II) and a gt (gauche–trans) conformation (C4 anti to O6) in (I). The latter conformational change is critical to the solvomorphism in that it allows water to participate in three hydrogen bonds in (I) as opposed to only two hydrogen bonds in (II), potentially producing a more energetically stable structure for (I) than for (II). Visual inspection of the crystalline lattice of (II) reveals channels in which methanol solvent resides and through which solvent might exchange during solvomorphism. These channels are less apparent in the crystalline lattice of (I).

Crystal structure and Hirshfeld surface analysis of ethyl (4R,4aS)-2-methyl-5,8-dioxo-6-phenyl-4a,5,6,7,7a,8-hexahydro-4H-furo[2,3-f]isoindole-4-carboxylate

In the title compound, C20H19NO5, the central six-membered ring has a slightly distorted half-chair conformation, with puckering parameters of Q T = 0.3387 (11) Å, θ = 49.11 (19)° and φ = 167.3 (2)°. The conformation of the fused pyrrolidine ring is that of an envelope. Molecules are connected by intermolecular C—H...O hydrogen bonds, C—H...π interactions and π–π stacking interactions [centroid-to-centroid distance = 3.9536 (11) Å, with a slippage of 2.047 Å], forming a three-dimensional network. The most important contributions to the surface contacts are from H...H (46.3%), O...H/H...O (31.5%) and C...H/H...C (17.3%) interactions, as concluded from a Hirshfeld surface analysis.

Crystal and molecular structure of bis(N-(diethylcarbamothioyl)cyclohexane carboxamido)copper(II) complex

Herein, we describe the synthesis and characterization of bis(N-(diethylcarbamothioyl)cyclohexane carboxamido)copper(II) complex, cis-[Cu(L-κ2S,O)2], has been prepared by the reaction of N-(diethyl carbamothioyl)cyclohexanecarboxamide ligand with copper(II) acetate. The green colored crystals of the complex were obtained by slow evaporation of their dichloromethane:ethanol solution (2:1, v:v). The crystal structure of cis-[Cu(L-κ2S,O)2] was obtained by single-crystal X-ray diffraction. The crystal structure reveals an monoclinic C2 (no. 5) space group with cell parameters a = 14.848(3) Å, b = 10.543(2) Å, c = 10.511(2) Å, β = 123.84(3)°, V = 1366.7(7) Å3, Z = 2, T = 153(2) K, μ(MoKα) = 0.979 mm-1, Dcalc = 1.327 g/cm3, 4979 reflections measured (6.6° ≤ 2Θ ≤ 50.68°), 2243 unique (Rint = 0.0223, Rsigma = 0.0444) which were used in all calculations. The final R1 was 0.0225 (>2sigma(I)) and wR2 was 0.0490 (all data). The angular structural index parameter, τ4, is equal to 0.40, which confirms the distorted square planar geometry for the title compound. The puckering parameters (q2 = 0.015(3) Å, q3 = 0.576(3) Å, QT = 0.577(3) Å, θ = 1.6(3)° and φ = 20(11)°) of the title complex show that the cyclohexane ring adopts a chair conformation. The two ethyl groups of the diethyl amine group have anti-orientation with respect to one another. The crystal packing shows the molecules stacked in parallel sheets along [010], accompanied by C3-H3A···O1ⁱ (i -x, +y, 1-z) intermolecular contact.

Crystal structure and Hirshfeld surface analysis of (E)-3-[(4-methylbenzylidene)amino]-5-phenylthiazolidin-2-iminium bromide N,N-dimethylformamide monosolvate

In the cation of the title salt, C17H18N3S+·Br−·C3H7NO, the central thiazolidine ring adopts an envelope conformation with puckering parameters Q(2) = 0.310 (3) Å and φ(2) = 42.2 (6)°. In the crystal, each cation is connected to two anions by N—H... Br hydrogen bonds, forming an R 4 2(8) motif parallel to the (10\overline{1}) plane. van der Waals interactions between the cations, anions and N,N-dimethylformamide molecules further stabilize the crystal structure in three dimensions. The most important contributions to the surface contacts are from H...H (55.6%), C...H/H...C (17.9%) and Br...H/H...Br (7.0%) interactions, as concluded from a Hirshfeld analysis.

Spiro[cyclopentane-1,11′-hexacyclo[7.6.0.01,6.06,13.08,12.010,14]pentadecane]-7′,15′-dione

An unusual rearrangement of spiro cage dione to a trishomocubane derivatives is reported by acid-catalysed rearrangement with the aid of BF3·OEt2 in benzene (solvent) reflux conditions. Here, the molecular structure of cage molecule C19H22O2 (major product) consists of five-membered rings, which adopt an envelope conformation and six-membered rings adopt a chair or boat conformation. The Cremer & Pople puckering parameters of all four six-membered rings are calculated.

Crystal structure and Hirshfeld surface analysis of (E)-5-phenyl-3-[(pyridin-4-ylmethylidene)amino]thiazolidin-2-iminium bromide monohydrate

In the cation of the title salt, C15H15N4S+·Br−·H2O, the central thiazolidine ring adopts an envelope conformation with puckering parameters Q(2) = 0.279 (4) Å and φ(2) = 222.5 (9)°. The mean plane of the thiazolidine ring makes dihedral angles of 12.4 (2) and 66.8 (3)° with the pyridine and phenyl rings, respectively. The pyridine ring in the title molecule is essentially planar (r.m.s deviation = 0.005 Å). In the crystal, the cations, anions and water molecules are linked into a three-dimensional network, which forms cross layers parallel to the (120) and (\overline{1}20) planes via O—H...Br, N—H...Br and N—H...N hydrogen bonds. C—H...π interactions also help in the stabilization of the molecular packing. Hirshfeld surface analysis and 2D (two-dimensional) fingerprint plots indicate that the most important contributions to the crystal packing are from H...H (35.5%), C...H/H...C (23.9%), Br...H/H...Br (16.4%), N...H/H...N (10.6%) and S...H/H...S (7.9%) interactions.

Crystal structure of bis[(5-amino-1H-1,2,4-triazol-3-yl-κN4)acetato-κO]diaquanickel(II) dihydrate

The title compound, [Ni(C4H5N4O2)2(H2O)2]·2H2O, represents the first transition metal complex of the novel chelating triazole ligand, 2-(5-amino-1H-1,2,4-triazol-3-yl)acetic acid (ATAA), to be structurally characterized. In the molecule of the title complex, the nickel(II) cation is located on an inversion centre and is coordinated by two water molecules in axial positions and two O and two N atoms from twotrans-oriented chelating anions of the deprotonatedATAAligand, forming a slightly distorted octahedron. Thetransangles of the octahedron are all 180° due to the inversion symmetry of the molecule. Thecis-angles are in the range 87.25 (8)–92.75 (8)°. The six-membered chelate ring adopts a slightly twisted boat conformation with puckering parametersQ= 0.542 (2) Å, Θ = 88.5 (2) and ϕ = 15.4 (3)°. The molecular conformation is stabilized by intramolecular N—H...O hydrogen bonds between the amino group and the chelating carboxylate O atom of twotrans-oriented ligands. In the crystal, the complex molecules and lattice water molecules are linked into a three-dimensional framework by an extensive network of N—H...O, O—H...O and O—H...N hydrogen bonds.

Crystal structure of (N1-benzyl-N1,N2,N2-trimethylethane-1,2-diamine-κ2N,N′)dichloridomercury(II)

In the structure of the title compound, [HgCl2(C12H20N2)], the HgIIatom has a distorted tetrahedral coordination sphere defined by two tertiary amine N-atom donors, as well as two Cl−anions [the dihedral angle between the N—Hg—N and Cl—Hg—Cl planes is 82.80 (9)°]. The five-membered chelate ring adopts an envelope conformation, with puckering parameters ofQ(2) = 0.446 (6) Å and ϕ(2) = 88.8 (6)°, with the two amine CH3substituents on opposite sides of the ring. In the crystal, the molecules are linked by C—H...Cl interactions into a zigzag chain parallel to [101].

(3aR,8bR)-3a,8b-Dihydroxy-1-(4-methoxyphenyl)-2-methylsulfanyl-3-nitro-1,8b-dihydroindeno[1,2-b]pyrrol-4(3aH)-one

In the title compound, C19H16N2O6S, the pyrrolidine ring adopts a twisted conformation with puckering parametersq2= 0.088 (3) Å and Φ2= 61.5 (14)°. The cyclopentane ring adopts a twisted conformation with puckering parametersq2= 0.099 (2) Å and Φ2= 242.8 (14)°. A weak intramolecular O—H...O interaction occurs. In the crystal, pairs of C—H...O interactions generate dimers with graph-set motifR22(24) and they are interconnected by pairs of O—H...O hydrogen bonds, which link the molecules into inversion dimers with graph-set motifR22(10).