Crystal structure and electrostatic properties of prednisolone acetate studied using a transferred multipolar atom model

The crystal structure of the opthalmic drug prednisolone acetate has been refined using the classical independent atom model (IAM), as well as by using the transferred electron-density parameters from an electron-density database. The results of the two refinements have been compared. Structure–property relationships have been described based on the calculation of electron-density-derived properties.

Synthesis and characterization of a photochromic magnesium(II) coordination polymer based on a naphthalene di­imide ligand

A photochromic one-dimensional magnesium(II) linear coordination polymer has been prepared using the N,N′-bis­(3-carb­oxy­phen­yl)naphthalene-1,8:4,5-tetra­carboximide ligand and exhibits prominent photochromic behaviour upon light irradiation.

The first-row transition-metal series of tris­(ethyl­enedi­amine) di­acetate complexes [M(en)₃](OAc)₂ (M is Mn, Fe, Co, Ni, Cu, and Zn)

The crystal structures of the first-row transition-metal (Mn to Zn) complexes of the form [M(en)₃](OAc)₂ (en is ethyl­enedi­amine and OAc is acetate) are presented. The structures are isomorphous, with the [M(en)₃]²⁺ complex cations connected through a series of hydrogen bonds to the acetate ions, generating three-dimensional networks.

Di­phenyl­alanine in tetra­hydro­furan: a highly potent candidate for the development of novel nanomaterials

The crystal structures of di-L-phenyl­alanine obtained by slow evaporation of tetra­hydro­furan are presented at two temperatures (100 and 299 K). The hydrogen-bond patterns are different compared to that of crystals grown from water and methanol.

A di­hydro-β-agaro­furan sesquiterpene from Maytenus boaria

The mol­ecular structure of a natural di­hydro-β-agaro­furan sesquiterpene, isolated from Maytenus boaria, is reported and its hydrogen-bonded three-dimensional crystal structure discussed.

Optical properties of (Z)-2-(2-phenyl­hydrazinyl­idene)acenaphthen-1(2H)-one: a potential electron donor in organic solar cells

Mol­ecules of (Z)-2-(2-phenyl­hydrazinyl­idene)acenaphthen-1(2H)-one (PDAK) are linked together forming face-to-face assemblies held together by inter­molecular C—H⋯O, π–π and C—H⋯π inter­actions. PDAK exhibits a broadband UV–Vis absorption (200–648 nm) and a low HOMO–LUMO energy gap (1.91 eV), while fluorescence quenching experiments provide evidence for electron transfer from the excited state of PDAK to C₆₀.

Synthesis and crystal structures of a 3-acetyl­ated (20S,24S)-ocotillol-type saponin and its C-24 epimer

Two C-24 epimeric 20(S)-ocotillol-type saponins were synthesized and their structures characterized. One of the epimers was obtained in two different solvate forms which display identical conformations but different crystal packings.

A twofold inter­penetrating three-dimensional heterometallic metal–organic framework with pcu topology based on 2-methyl­biphenyl-4,4′-di­carb­oxy­lic acid

The hydro­thermal synthesis of a twofold three-dimensional heterometallic metal–organic framework (MOF) involving the 2-methyl­biphenyl-4,4′-di­carboxyl­ate ligand leads to a material that displays an intense blue luminescence.

A charge-transfer salt composed of methyl viologen and hexa­cyanidoferrate(II)

In bis­(1,1′-dimethyl-4,4′-bipyridine-1,1′-diium) hexa­cyanidoferrate(II) octa­hydrate, the cation is located on a general position and adopts a noncoplanar structure, with a dihedral angle of 40.32 (7)° between the planes of the pyridine rings. In the crystal, layers of electron-donor [Fe(CN)₆]⁴⁻ anions and layers of electron-acceptor cations are stacked in an alternating manner.

Supra­molecular architectures in two 1:1 cocrystals of 5-fluoro­uracil with 5-bromo­thio­phene-2-carbox­ylic acid and thio­phene-2-carb­oxy­lic acid

In cocrystals of 5-fluoro­uracil with 5-bromo­thio­phene-2-carb­oxy­lic acid and thio­phene-2-carb­oxy­lic acid, two types of base pairs [(8) homosynthon] and carb­oxy­lic acid dimers [(8) homosynthon] are formed. Both cocrystals display robust (8) supra­molecular synthons, π–π stacking and C—F⋯π inter­actions, leading to supra­molecular architectures.

A new phospho­rescent heteroleptic cuprous complex with a neutral 2-methyl­quinolin-8-ol ligand: synthesis, structure characterization, properties and TD–DFT calculations

In the heteroleptic cuprous complex [Cu(Xantphos)(8-HOXQ)]PF₆ [Xantphos is 9,9-dimethyl-4,5-bis­(di­phenyl­phosphan­yl)-9H-xanthene and 8-HOXQ is 2-methyl­quinolin-8-ol], the hy­droxy group of the N,O-chelating 8-HOXQ ligand remains protonated. TD–DFT (time-dependent density functional theory) studies demonstrate that the yellow phospho­rescence is most likely derived from the emissive (M+L′)→LCT (LCT is ligand charge transfer) excited state.

Dinuclear cobalt(II) complexes with double phosphate ester bridges and tetra­dentate ligands having anisole or quinoline appendages

Two dinuclear Co^II complexes incorporating tetra­dentate 2-meth­oxy-N,N-bis­[(pyridin-2-yl)meth­yl]aniline and N,N-bis­[(pyridin-2-yl)meth­yl]quinolin-8-amine ligands, with the metal centres doubly bridged by two diphenyl phosphate ester groups, have similar structures with distorted octa­hedral geometries around the metal centres. A number of aromatic–aromatic inter­actions present in the crystal lattices stabilize the solid-state structures.

A one-dimensional silver(I) coordination polymer based on 5-methyl-1,3,4-thia­diazol-2-amine and pyridine-2,3-di­carboxyl­ate

In a novel Ag^I coordination polymer based on a dinuclear Ag^I cluster consisting of three bridging 5-methyl-1,3,4-thia­diazol-2-amine ligands and one bridging pyridine-2,3-di­carboxyl­ate ligand, one Ag^I atom is located in a four-coordinated AgN₄ tetra­hedral geometry and the other Ag^I atom is in a tetra­hedral AgN₃O geometry. Inter­chain N—H⋯O hydrogen bonds extend the one-dimensional chains into an undulating two-dimensional sheet. The sheets are further packed into a three-dimensional supra­molecular framework by inter­chain N—H⋯O hydrogen bonds.