Synthesis and spectroscopic and structural characterization of spiro­[indoline-3,3′-indolizine]s formed by 1,3-dipolar cyclo­additions between isatins, pipecolic acid and an electron-deficient alkene

New spiro­[indoline-3,3′-indolizine]s have been synthesized with high regio- and stereo­specificity from simple starting materials in a one-step process. Different combinations of hydrogen bonds link the mol­ecules to form either sheets or chains of rings.

Anthelmintic flavonoids and other com­pounds from Combretum glutinosum Perr. ex DC (Combretaceae) leaves

Nine known com­pounds have been isolated from Combretum glutinosum leaves, including flavonoids and triterpenes. The crystal structures of umuhengerin and (20S,24R)-ocotillone are reported for the first time; the latter structure confirms the absolute configuration. The crude extracts and the isolated com­pounds were tested for their anthelmintic activity on the larvae and adult worms of Haemonchus contortus. The best activity on both stages of the parasite was obtained with the flavonoids.

Structural trends in a series of bulky di­alkyl­biaryl­phosphane com­plexes of Cu^I

Six Cu^I com­plexes containing 2-di-tert-butyl­phosphanyl-2′,4′,6′-triiso­propyl­biphenyl (^tBuXPhos) and an ancillary ligand were prepared and characterized. A weaker inter­action between the metal and ancillary ligand was observed to result in a stronger copper–arene inter­action.

Polyoxometalate-like structure of new potassium tri­phenyl­sil­oxides: [K₆(OSiPh₃)₆(C₃H₇OH)(H₂O)]·2C₆H₅CH₃ and [K₆(OSiPh₃)₆(H₂O)₂]

The synthesis and structural characterization of new potassium tri­phenyl­sil­oxides manifesting a polyoxometalate-like structure are reported.

Synthesis and structures of three new pyridine-containing oxazoline ligands of com­plexes for asymmetric catalysis

The synthesis and crystal structures of three new chiral pyridine-containing derivatives as chiral ligands in metal-catalysed asymmetric reactions are reported. The possibility and mechanism of metal com­plex formation based on structural, conformational and energetic data is discussed.

Two crystallographic forms and the absolute structure of 5α,14α-androstane

5α,14α-Androstane crystallizes in two different crystallographic forms, which have been calculated to be isoergic in terms of their free energy. The presence of the ketone impurity 5α,14α-androstan-17-one was detected in Form II crystals grown from diethyl ether, while the absolute stereochemistry has been determined in pure Form II crystals.

Iron(II)–alkoxide and –aryl­oxide com­plexes of a tris­(thio­ether)borate ligand: synthesis, mol­ecular structures, and implications on the origin of instability of their iron(II)–catecholate counterpart

Tris(thio­ether) ligand-supported Fe^II–alkoxide/aryl­oxides were obtained in either monomeric or dimeric form, depending on the identity of the alkoxide/aryl­oxide ligand.

Synthesis of luminescent cocrystals based on fluor­anthene and the analysis of weak inter­actions and photophysical properties

A series of luminescent cocrystals with fluor­an­thene as fluoro­phore and 1,2,4,5-tetra­cyano­benzene (TCNB), tetra­fluoro­terephthalo­nitrile (TFP) and octa­fluoro­naphthalene (OFN) as coformer was designed and synthesized. Structure analysis revealed that the layered structures were due to charge transfer, π–π inter­actions and hydrogen bonding.

Square network based upon the mol­ecular salt of the tetra­protonated photo­product rtct-tetra­kis­(pyri­din-4-yl)cyclo­butane and the sulfate anion

The single-crystal X-ray structure of a hydrated mol­ecular salt based upon the tetra­protonated photo­product rtct-tetra­kis­(pyri­din-4-yl)cyclo­butane along with the sulfate anion is reported. The resulting square network is sustained by an array of N⁺—H⋯O hydrogen bonds where the photo­product acts as a four-connecting node.

Mechanochemical synthesis insights and solid-state characterization of quininium aspirinate, a glass-forming drug–drug salt

The mechanochemical synthesis, crystal structure analysis, and Hirshfeld surface analysis of quininium aspirinate are reported. This salt was synthesized by liquid-assisted grinding and characterized by X-ray diffraction (single crystal and powder), FT–IR spectroscopy, thermogravimetry, differential scanning calorimetry, and aqueous solubility measurements. The amorphous powders obtained by neat grinding or neat ball milling crystallize upon storage into the salt reported.

Synthesis and characterization of a range of anti­mony(I/III) N,N′-bis­(2,6-diiso­propyl­phen­yl)form­amidinate com­plexes

This is the first contribution for form­ami­din­ate-based mono- and trivalent anti­mony chemistry. Metathesis reactions produced monomeric structures with the generic formula [Sb(DippForm)_3–nX_n] [n = 1 and X = Cl, Br and I; n = 2 and X = Br and I; DippForm is N,N′-bis­(2,6-diiso­propyl­phen­yl)form­ami­din­ate], synthesized by the addition of M(DippForm) (M = Li or Na) to the appropriate SbX₃ (X = Cl, Br or I) com­pound. The sterically bulky form­ami­din­ate ligand highlights the ability to stabilize low-oxidation-state p-block com­pounds with unusual coordination modes.