Hirshfeld and DFT analysis of the N-heterocyclic carbene proligand methyl­enebis(N-butyl­imid­azolium) as the aceto­nitrile-solvated diiodide salt

The NHC proligand methyl­enebis(N-butyl­imidazolium) displays an inter­esting cation–anion connection pattern, in which three iodide anions inter­act simultaneously with the cisoid-oriented cation. A Hirshfeld surface analysis reveals the predominance of hydrogen bonding over anion–π inter­actions. Density functional theory calculations with aceto­nitrile as solvent reproduce the geometry of the cation.

Two tautomeric forms of 2-amino-5,6-di­methyl­pyrimidin-4-one

Two tautomeric forms of 2-amino-5,6-di­methyl­pyrimidin-4-one were obtained under aqueous crystallization conditions. One form consists of only the 1H-keto tautomer, while the other form has a 1:1 ratio of the 1H-keto and 3H-keto tautomers.

Purine 3′:5′-cyclic nucleotides with the nucleobase in a syn orientation: cAMP, cGMP and cIMP

Five crystals of purine 3′:5′-cyclic nucleotides, viz. cAMP·2H₂O, cAMP·0.3H₂O, cGMP·5H₂O, Na(cGMP)·4H₂O and Na(cIMP)·4H₂O, have been characterized in terms of the nucleobase syn–anti conformation, ribose and O/P/O/C/C/C ring puckering, inter-nucleotide inter­actions and nucleotide–Na inter­actions. The syn–anti preference of various purine nucleotides is analysed statistically based on data from the Cambridge Structural Database.

A new one-dimensional Cd^II coordination polymer with a two-dimensional layered structure incorporating 2-[(1H-imidazol-1-yl)meth­yl]-1H-benzimidazole and benzene-1,2-di­carboxyl­ate ligands

In a new cadmium (II) coordination polymer based on multidentate N-donor 2-[(1H-imidazol-1-yl)meth­yl]-1H-benzimidazole (imb) and bridging O-donor benzene-1,2-di­carboxyl­ate (1,2-bdic²⁻) ligands, binuclear [Cd₂(1,2-bdic)₂] units are connected by pairs of bridging imb ligands yielding an infinite one-dimensional chain.

Synthesis, crystal structure and anti­fungal activity of a divalent cobalt(II) complex with uniconazole

A Co^II complex displays coordination in a distorted octa­hedral fashion by N atoms from four uniconazole [1-(4-chloro­phen­yl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)pent-1-en-3-ol] ligands in the equatorial plane and two chloride ligands in axial positions. The anti­fungal activity of this complex is enhanced for Botryosphaeria ribis, Wheat gibberellic and Grape anthracnose compared with the fungicide uniconazole.

Structural and spectroscopic characterization of two new blue luminescent pyridyl­benzimidazole zinc(II) complexes

The structures of two zinc(II) complexes of 5,6-dimethyl-2-(pyridin-2-yl)-1-[(pyridin-2-yl)meth­yl]-1H-benzimidazole were determined. The absorption and emission data of the complexes and the free ligand are reported. The spectra are examined in the context of a frontier orbital analysis based on DFT calculations of the benzimidazole ligand and the zinc(II) complexes.

Synthesis and crystal structures of C24-epimeric 20(R)-ocotillol-type saponins

Two C24-epimeric ocotillol-type saponins were synthesized, and their structures were confirmed by spectral studies and single-crystal X-ray analysis. The epimerization of C24 resulted in remarkable differences in both the mol­ecular conformation and the crystal-packing arrangements.

Highly functionalized alkenes produced from base-free organocatalytic Wittig reactions: (E)-3-benzyl­idenepyrrolidine-2,5-dione, (E)-3-benzyl­idene-1-methyl­pyrrolidine-2,5-dione and (E)-3-benzyl­idene-1-tert-but­ylpyrrolidine-2,5-dione

Three 3-benzylidenepyrrolidine-2,5-dione derivatives have been synthesized by the base-free catalytic Wittig reaction and have been analyzed by X-ray crystallography. A mechanism, backed up by ¹H NMR analysis, is proposed for the formation of the products.