Synthesis, crystal structure and determination of the pK_a value of 2,6-di­meth­oxy­cyclo­hexa-2,5-diene-1,4-dione 1-[2-(quinolin-8-yl)hydrazone]

The bond lengths of 8-[1-(2,6-di­meth­oxy­phenyl-4-hy­droxy)diazen­yl]quinoline are typical for the structure of a quinoid hydrazone. The changes in the absorption spectra when the pH of the buffer was varied suggested the production of an azo form by deprotonation. We report the synthesis, X-ray crystal structure and acidity.

Two-dimensional rare-earth-metal coordination polymers based on bi­phenyl-3,3′,5,5′-tetra­carb­oxy­lic acid displaying luminescence

Two coordination polymers were rationally designed and successfully constructed using the rigid multi­carb­oxy­lic ligand biphenyl-3,3′,5,5′-tetra­carb­oxy­lic acid (H₄BPTC) and rare-earth-metal ions (Eu³⁺ and Ho³⁺) under solvothermal conditions. The polymers both possess a two-dimensional structure and display good thermal stability and photoluminescence with an orange–red light emission.

The 2′-de­oxy­ribo­furan­oside of 3-phenyl­tetra­hydropyrimido[4,5-c]pyridazin-7-one: a bicyclic nucleoside with sugar residues in N and S con­formations, and its mol­ecular recognition

3-Phenyl­tetra­hydro­pyrimido[4,5-c]pyridazine 2′-de­oxy­ribonucleoside shows two con­formations in the crystalline state with distinct differences observed for the sugar moiety (N versus S sugar pucker). The nucleoside mimics the recognition face of dT and forms stable base pairs with dA.

Synthesis, X-ray structure, anti­microbial activity, DFT and mol­ecular docking studies of N-(thio­phen-2-ylmeth­yl)thio­phene-2-carboxamide

Thio­phene-based mol­ecules are of great importance in terms of their biological activity. N-(Thio­phen-2-ylmeth­yl)thio­phene-2-carboxamide is found to have an effective anti­bacterial activity due to the presence of S atoms and an amide functional group in the structure.

A new two-dimensional cadmium(II) coordination polymer based on Cd₆(CHADC)₆ clusters (H₂CHADC is cyclo­hexane-1,2-di­carb­oxy­lic acid): synthesis, structure and properties

A cadmium(II) coordination polymer prepared by the reaction of Cd(NO₃)₂·6H₂O with cis-cyclo­hexane-1,2-di­carb­oxy­lic acid and 4,4′-bis­(2-methyl-1H-imidazol-1-yl)biphenyl in a mixture of H₂O and di­methyl­formamide, possesses a 6-connected hxl two-dimensional layer based on Cd₆(CHADC)₆ clusters with the point symbol (3⁶·4⁶·5³). The coordination polymer displays a highly selective and sensitive sensing for Fe³⁺ cations and Cr₂O₇²⁻/CrO₄²⁻ anions through luminescence quenching effects in aqueous solutions.

A new mixed-valence Cu^I/Cu^II three-dimensional coordination polymer constructed with an N,O-donor ligand generated via solvothermal synthesis: structural features and magnetic properties

A new mixed-valence Cu^I/Cu^II three-dimensional coordination polymer incorporating 2-(pyra­zin-2-yl)quinoline-4-carb­oxy­lic acid was synthesized and characterized. The ligand was also isolated as its hydrated hydro­chloride salt. The compounds show luminescence and the ligand structure was rationalized by means of quantum-chemical calculations.

Structure determination and Hirshfeld surface analysis of new cocrystal and salt forms of 5-amino­tetra­zole with hy­droxy- and nitro-substituted carb­oxy­lic acids

In two crystalline solids (a cocrystal and a salt) of 5-amino­tetra­zole, the crystal packing arrangements are governed by N—H⋯O and O—H⋯O hydrogen-bonding inter­actions. The Hirshfeld surface analysis and fingerprint plots reveal that O⋯H/H⋯O inter­actions contribute 34.4% of the total inter­actions in the crystal packing of the cocrystal and 36.7% in the salt.

Co-operative halogen bonds and nonconventional sp-C—H⋯O hydrogen bonds in 1:1 cocrystals formed between diethynyl­pyridines and N-halosuccinimides

The X-ray structures of three 1:1 cocrystals formed between reactive diethynyl­pyridine and N-halosuccinimide partners are reported. Each cocrystal features a short halogen bond and two short com­plementary nonconventional C—H⋯O hydrogen bonds.