Approximate symmetry in the third reported structure of a metal complex of L-DOPA

Although L-DOPA is a major drug that has been used for more than 50 years to treat the motor symptoms of Parkinson's disease, the Cambridge Structural Database contains only two structures in which it is coordinated to a metal. Why are there not more? The new structure is also notable for an approximate 4₂ axis.

Ψ-Polyhedral symbols for coordination geometries of lead(II) with a stereochemically active lone pair

Because an IUCr/IUPAC-designated set of letters/numbers identifies the configuration of the atoms linked to the Pb^II atom in its coordination com­pounds, a Ψ prefix before such as a polyhedral symbol provides useful information when its lone pair is stereochemically active. The polyhedral symbols for the crystal structures in some 50 articles published after 2000 are reported here as the original studies did not expressly identify coordination geometries.

Induction of Λ-helicity in a zinc com­plex with an alanine-appended amino­pyridine ligand

The structure of [Zn(L)₃](NO₃)₂·3CH₃CN, with a Λ-helical [ZnL₃]²⁺ mononuclear com­plex cation, has been determined by single-crystal X-ray diffraction (L is an O,N-bidentate ligand). The Λ-helicity is induced by pendant L-alanine residues, through intra­molecular inter­actions, namely, hydrogen bonding and aromatic stacking, between two coordinated chiral ligands.

Ionic cocrystals of di­thio­bis­pyridines: the role of I⋯I halogen bonds in the building of iodine frameworks and the stabilization of crystal structures

2-Mercapto- and 4-mercapto­pyridine in iodine solution condense into di­thio­pyridines. In the crystalline state, these com­pounds exist as protonated mol­ecules embedded in a network of iodine mol­ecules and iodide anions. All the mol­ecular com­ponents are stabilized by various inter­molecular inter­actions, viz. hydrogen, halogen and chalcogen bonds.

Crystallographic studies of piperazine derivatives of 3-methyl-5-spiro­fluorenehydantoin in search of structural features of P-gp inhibitors

Crystal structure analyses showed the conformational properties of 3-methyl-5-spirofluorenehydantoin derivatives associated with different linker lengths and different substituents on the piperazine ring. Docking calculations indicated the same region of the glycoprotein P inter­nal cavity as the most probable binding site for all the docked com­pounds, wherein the docking scores of the five-carbon alkyl chain derivatives were in a higher range in com­parison to those of the three-carbon alkyl chain analogues.

A rare case of a 2:2:1 ternary cocrystal of pyri­dine sulfides and tri­thio­cyanuric acid

A rare case of a 2:2:1 ternary cocrystal consisting of tri­thio­cyanuric acid and two pyri­dine sulfides is reported, of which 1,4-bis­(pyri­din-4-yl)tetra­sulfane is characterized by X-ray diffraction for the first time.

Conformational control through co-operative nonconventional C—H⋯N hydrogen bonds

Co-operative nonconventional sp²-C—H⋯N hydro­gen bonds control the conformation of a dipyridyl mol­ecule to a rhombus shape.

Iso­propyl 3-de­oxy-α-D-ribo-hexo­pyran­oside (iso­propyl 3-de­oxy-α-D-gluco­pyran­oside): evaluating trends in structural parameters

The X-ray crystal structure of isopropyl 3-de­oxy-α-D-ribo-hexo­pyran­oside (isopropyl 3-de­oxy-α-D-gluco­pyran­oside) was determined and com­pared to the structures obtained previously for three related com­pounds. Density functional theory (DFT) calculations were used to validate the trends observed in bond lengths, angles and torsion angles in these structures.