Pyridine 1:1 adducts of urea (Z′ = 1) and thio­urea (Z′ = 8)

The 1:1 adduct of pyridine and urea crystallizes in the P2₁/c space group with Z = 4 (Z′ = 1). The structure is of a standard type for urea adducts, whereby the urea mol­ecules form a ribbon consisting of linked (8) rings and the pyridine mol­ecules are attached to the periphery of the ribbon by bifurcated (N—H⋯)₂N hydrogen bonds. The 1:1 adduct of pyridine and thio­urea crystallizes in the P2₁/n space group with Z = 32 (Z′ = 8). The structure displays similar ribbons to those of the urea adduct.

Synthesis, structure characterization, photoluminescence properties and TD–DFT calculations for two new borates

The synthesis and structural determination of the di­ethyl­ammonium and propyl­ammonium salts of bis­(salicylato)borate are reported. The crystal structures are stabilized by N—H⋯O, C—H⋯O and C—H⋯π/N—H⋯O hydrogen bonds. The salts displays a strong blue-light emission with maxima around 490 nm which appears to be derived from the intramolecular charge transfer (ICT) excited state.

A three-dimensional twofold inter­penetrated cobalt(II) MOF containing a flexible carboxyl­ate-based ligand: synthesis, structure and magnetic properties

A novel Co^II-containing twofold inter­penetrated coordination polymer was assembled with the flexible ligand 5-[(4-carb­oxy­phen­oxy)meth­yl]isophthalic acid. The polymer adopts a (3,5)-connected topology and shows anti­ferromagnetic inter­actions between the two Co^II cations in the asymmetric unit.

[1-(Pyrazin-2-yl)ethyl­idene]hydrazine: a new multitopic ligand for the design of hybrid mol­ecular frameworks

The mol­ecule [1-(pyrazin-2-yl)ethyl­idene]hydrazine consists of an imine linkage with an N—N bond length of 1.3540 (14) Å. This asymmetric compound is nearly planar and adopts an E configuration about the azomethine C=N double bond. In the solid state, there are two inter­molecular N—H⋯N inter­actions that inter­connect the mol­ecules into a two-dimensional network.

Involvement of conformational isomerism in the complexity of the crystal network of 1-(4-nitro­phen­yl)-1H-1,3-benzimidazole derivatives driven by C—H⋯A (A = NO₂, N_py and π) and orthogonal N_py⋯NO₂ and ONO⋯Csp² inter­actions

Participation of π– and n–π* (n = O and N_py; π* = Csp² and ) inter­actions in the equi-energetic conformations of 1-(4-nitro­phen­yl)-1H-1,3-benzimidazoles.

Two polymorphs of 2,5-di­chloro-3,6-bis­(di­benzyl­amino)-p-hydro­quinone with flexible di­benzyl­amino groups

Two conformational polymorphs of a hydro­quinone derivative with flexible di­benzyl­amino groups were obtained. A partial conformational difference in the mol­ecular structures leads to significant structural differences in their mol­ecular arrangements.

Mol­ecular structures of a series of substituted bis­(η⁵-cyclo­penta­dien­yl)titanium dihalides Cp^R₂TiX₂ [X = F, Cl, Br and I; R = CHPh₂, CH(p-Tol)₂ and adamant­yl]

Eleven crystal structures of a series of substituted titanocene dihalides are reported and characterized by single-crystal X-ray diffraction and additional analytical data.

Supra­molecular arrangement and photophysical properties of a dinuclear cyano­phenyl­boronic acid ester

The novel dinuclear cyano­phenyl­boronic ester 4,4′-(2,4,8,10-tetra­oxa-3,9-dibora­spiro­[5.5]undecane-3,9-di­yl)dibenzo­nitrile was prepared by condensation of 4-cyano­phenyl­boronic acid and penta­erythritol. Density functional theory (DFT) calculations with ethanol as solvent reproduced reasonably well the HOMO and LUMO.

The vanadate garnet Ca₂NaCd₂V₃O₁₂: a single-crystal X-ray diffraction study

Single crystals of the vanadate garnet Ca₂NaCd₂V₃O₁₂ were synthesized using the floating-zone method and the crystal structure was investigated using single-crystal X-ray diffraction. The effectiveness of substitution of the garnet Y-site cation with reference to previous structural studies of vanadate garnets was considered.

Prevalent polymorphism in benzo­phenones

The benzo­phenone structural unit is shown to be polymorphic regardless of the substituents around the hydro­carbon core.

Salt forms of sulfadiazine with alkali metal and organic cations

The structures of four alkali metal salt forms of sulfadiazine and two organic salt forms of sulfadiazine are described and the bonding modes of the sulfadiazine ligand are discussed.

The [4 + 4] thermocyclization of 9-anthraldehyde: synthesis, crystal structure, experimental and theoretical UV spectra, natural bonding orbital analysis and prediction of third-order nonlinear optical properties

The synthesis and crystal structure of a monoclinic polymorph of the dimer of 9-anthraldehyde have been investigated, together with a theoretical evaluation of its natural bonding orbitals, electronic transitions and second-order hyperpolarizability. The crystal structure shows the formation of one-dimensional chains through inter­molecular C—H⋯O hydrogen bonds linked by C—H⋯π(ring) inter­actions.

Supra­molecular hydrogen-bonding patterns in salts of the anti­folate drugs trimethoprim and pyrimethamine

In the crystal structures of nine new salts of the anti­folate drugs trimethoprim and pyrimethamine, the pyrimidine N1 atom is protonated. The cation inter­acts with the corresponding anion primarily via a pair of N—H⋯O hydrogen bonds, generating the robust (8) supra­molecular heterosynthon. The pyrimidinium cation also forms base pairs via a pair of N—H⋯N hydrogen bonds, generating a ring motif [(8) supra­molecular homosynthon]. Quadruple DDAA/DADA arrays of hydrogen bonds and noncovalent Cl⋯Cl, Cl⋯O, C—Br⋯π, C—Cl⋯π, C—H⋯π and π–π inter­actions further stabilize the crystal structures.

Two new Co^II coordination polymers with multifunctional 5-amino-2,4,6-tri­bromo­isophthalic acid and flexible isomeric bis­(imidazole) ligands: preparation, crystal structure and characterization

Two new Co^II coordination polymers with multifunctional 5-amino-2,4,6-tri­bromo­isophthalic acid (H₂ATBIP) and isomeric bis­(imidazole) ligands have been prepared and characterized.

The structures of 1,4-di­aryl-5-tri­fluoro­methyl-1H-1,2,3-triazoles related to J147, a drug for treating Alzheimer's disease

Seven new 1,4-diaryl-5-tri­fluoro­methyl-1H-1,2,3-triazoles have been synthesized and their X-ray structures determined and compared to that of J147, a recently reported promising new drug for the treatment of Alzheimer's disease. B3LYP/6-311++G(d,p) calculations have been performed to determine the potential surface and the mol­ecular electrostatic potential (MEP) of J147, and to examine the correlation between hydrazone J147 and the 1,2,3-triazoles.