The co-crystals of squaric acid with dipyridyl-type ligands, 1 and 2, are isomorphous and form in the triclinic crystal system. The co-crystals contain linear and flat hydrogen-bonded molecular tape structures along the [120] direction (Figure 1). The squarate monoanions form a rare ten-membered dimer linked by two intermolecular O–H···O hydrogen bonds [2.511(3) Å for 1 and 2.503(2) Å for 2]. E...

The title compound, 5-[4-[(2-pyridylideneamino)sulfonyl]phenyldiazenyl]salicylic acid, C(18)H(14)N(4)O(5)S, crystallizes as the imide tautomer in the monoclinic space group P2(1)/c. In addition to an intramolecular O-H.O hydrogen bond, intermolecular O-H.O interactions link adjacent molecules into helices, which are connected by pairwise N-H.N interactions into two-dimensional hydrogen-bonded l...

CRYSTALS OF THE TITLE COMPOUND [SYSTEMATIC NAME: (3R,6R,7S,8aR,9R,12aR)-7-hydr-oxy-3,6,9-trimethyl-octa-hydro-3,12-ep-oxy[1,2]dioxepino[4,3-i]isochromen-10(3H)-one], C(15)H(22)O(6), were obtained from microbial transformation of artemisinin by a culture of Cunninghamella elegans. The stereochemistry of the compound is consistent with the spectroscopic findings in previously published works. A w...

Vibrational spectroscopy with inelastic neutron scattering can provide spectra that are more detailed and easier to interpret than optical spectra. The spectral intensity depends on energy transfer and kinetic momentum transfer, allowing determination of the potential function. Experiments reveal that the proton involved in intermolecular hydrogen bonding in N-methylacetamide and polyglycine I ...

The title compound, [Cu2(C6)H12N4O2)(ClO4)2(C11H6N2O)2].-2C11H6N2O, contains a dinuclear copper(II) complex which lies about a twofold axis at the mid-point of the C-C bond of the oxamide ligand that bridges the two Cu(II) atoms. The Cu...Cu distance is 5.215 (2) A and the Cu atoms have distorted octahedral coordination geometry. Intramolecular N-H...O and N-H...N hydrogen bonds and intermolecu...

Treatment of bis(diphenylphosphino)amine (dppa) with (dimethylsulfide)gold(I) chloride in the molar ratio 1:2 leads to the dinuclear complex (dppa)Au2Cl2 in 95% yield. The compound was crystallized from diethyl ether/dimethylformamide as the 1:1 solvate with dmf, the crystal struc­ ture of which has been determined. The complex features an intramolecular Au—Au contact [3.121(1) A] and an interm...

First principle calculations of periodic crystal structure were successfully combined with powder X-ray diffraction measures to determine the structure of orotaldehyde monohydrate. This approach was particularly helpful to overcome the inadequacy of powder X-ray diffraction to reliably locate the hydrogen atoms of the intermolecular bond network of the crystal molecules. Density functional calc...

THE TITLE COMPOUND (SYSTEMATIC NAME 1,2-dimethyl-6-meth-oxy-1,2,3,4-tetra-hydro-isoquinolin-7-ol), C(12)H(17)NO(2), is a major alkaloid isolated from Hammada scoparia leaves. It belongs to the isoquinoline family and it was characterized by NMR spectroscopy and X-ray crystallographic techniques. The absolute configuration could not be reliably determined. An intermolecular O-H⋯N hydrogen bond i...

The absolute structure has been determined by X-ray analysis for the title compound, C(11)H(8)Cl(2)O(2). The five-membered ring of the mol-ecule is best described as a flattened envelope conformation with the methyl-ene C atom located 0.208 (2) Å below the plane formed by the other four atoms. A weak intermolecular C-H⋯O hydrogen bond is present in the crystal structure.