A Pd₄Br₄ macrocycle trapped by cocrystallization from a highly dynamic equilibrium of η³-cyclo­hepta­trienide complexes

The structure of a cocrystal formed by dimers and tetra­mers of an imidazolium-functionalized η³-cyclo­hepta­trienide–palladium(II) complex is reported and discussed with regard to the dynamic equilibrium between these species in solution.

Diminished electron density in the Vaska-type rhodium(I) complex trans-[Rh(NCBH₃)(CO)(PPh₃)₂]

The synthesis, IR and NMR spectroscopic data, and single-crystal X-ray diffraction analysis of trans-[Rh(NCBH₃)(CO)(PPh₃)₂] are reported. The cyano­trihydridoborate ligand coordinates to the Rh^I atom through the N atom in a trans position with respect to the carbonyl ligand. The IR and NMR data indicate a diminished electron density on the central Rh^I atom.

A study of the planarity of the pyrrolone fragment in 2-iso­propyl-2,3-di­hydro-1H-isoindol-1-one

The single-crystal X-ray structure of 2-isopropyl-2,3-di­hydro-1H-isoindol-1-one is discussed and compared with known structures. The aromaticity of the five-membered ring is discussed with the help of structures retrieved from the Cambridge Structural Database.

Inter­molecular Pb⋯N inter­actions in lead(II) dimers producing a supra­molecular two-dimensional metal–organic compound: bis­[μ₂-N′-(2-oxido­benzyl­idene)benzohydrazidato-κ⁴O:O,N′,O′]dilead(II)

The first compound of Pb^II with the benzoyl­hydrazone derivative of salicyl­aldehyde shows a supra­molecular two-dimensional network in which the phenolate O atom bridges two metal centres and the resulting dimers are connected by Pb⋯N inter­actions. The net topology is represented by a [3².5²,3.5³] Schläfli symbol.

A new three-dimensional zinc(II) coordination polymer involving 2-[(1H-1,2,4-triazol-1-yl)meth­yl]-1H-benzimidazole and benzene-1,4-di­carboxyl­ate ligands

A new zinc(II) coordination polymer based on multidentate N-donor 2-[(1H-1,2,4-triazol-1-yl)meth­yl]-1H-benzimidazole and bridging O-donor benzene-1,4-di­carboxyl­ate ligands has been prepared and structurally characterized. Helices with different handedness are connected by crystallographically distinct benzene-1,4-di­carboxyl­ate ligands resulting in a three-dimensional framework.

A phase transition from monoclinic C2 with Z′ = 1 to triclinic P1 with Z′ = 4 for the quasiracemate L-2-amino­butyric acid–D-me­thio­nine (1/1)

A phase transition taking place at 229 K upon cooling produces twinned crystals with triclinic symmetry. Massive side-chain disorder due to steric conflict under ambient conditions is avoided at low temperature by adopting a high Z′ packing arrangement with a heterogeneous mix of side-chain conformations.

A novel binuclear copper complex incorporating a nalidixic acid derivative displaying a one-dimensional coordination polymeric structure

In the structure of a one-dimensional polymeric copper(II) complex with a carbonyl hydrazone derivative of nalidixic acid, square-pyramidal and octa­hedral Cu^II ions alternate along the polymer chain.

Diastereoisomeric forms of 11-ethyl-6,11-di­hydro-5H-dibenzo[b,e]azepine-6-carboxamide: syntheses and the mol­ecular and supra­molecular structure of the minor form (6RS,11RS)-11-ethyl-6,11-di­hydro-5H-dibenzo[b,e]azepine-6-carboxamide

A synthesis is reported for the diastereoisomers of 11-ethyl-6,11-di­hydro-5H-dibenzo[b,e]azepine-6-carboxamide, a potentially useful precursor in the synthesis of analogues of some anti-allergenic, anti­depressant and anti­histaminic drugs currently in use. Structure analysis of the minor isomer shows that it has the (6RS,11RS) configuration, implying that the major form has the (6RS,11SR) configuration.

A cyanide-bridged heterometallic coordination polymer constructed from square-planar [Ni(CN)₄]²⁻: synthesis, crystal structure, thermal decomposition, electron paramagnetic resonance (EPR) spectrum and magnetic properties

The square-planar [Ni(CN)₄]²⁻ unit has been developed using O-donor ligands to form the coordination polymer [Cu^IINi^II(CN)₄(H₂O)₂]·H₂O, in which two-dimensional layers are constructed by anionic [Ni(CN)₄]²⁻ units that bridge to four adjacent cationic [Cu(H₂O)₂]²⁺ units through four μ₂-cyanide groups. A magnetic investigation showed the presence of a very weak anti­ferromagnetic inter­action between the Cu^II atoms through the diamagnetic [Ni(CN)₄]²⁻ ion.

Li₄Ge₂B as a new derivative of the Mo₂B₅ and Li₅Sn₂ structure types

The structure of tetra­lithium digermanium boride exhibits a new structure type, in the noncentrosymmetric space group R3m, in which all the Li, Ge and B atoms occupy sites with 3m symmetry. All the atoms are coordinated by rhombic dodeca­hedra (coordination number = 14). According to electronic structure calculations, strong covalent Ge—Ge and Ge—B inter­actions were established.

Conformational dimorphism in o-nitro­benzoic acid: alternative ways to avoid the O⋯O clash

Coplanarity impossible! In both crystal forms of o-nitro­benzoic acid, unfavourably short O⋯O contacts between the vicinal substituents are avoided by tilting either the NO₂ or the COOH group.

A polymeric silver thio­saccarinate complex with a two-dimensional triply entangled mesh and argentophilic inter­actions

A two-dimensional Ag^I–thio­saccharinate coordination polymer exhibits an unusually short Ag⋯Ag separation of 2.8859 (10) Å. The inter­penetrated crystal structure consists of threefold entangled 2D→2D arrays (2D is two-dimensional).

Di- and tri­phenyl­acetate complexes of yttrium and europium

The X-ray structures of the non-isomorphic [Eu(Ph₂CHCOO)₃(dme)]₂ and [Y(Ph₂CHCOO)₃(dme)]₂ complexes (dme is 1,2-di­meth­oxy­ethane) exhibit three coordination modes of the anionic di­phenyl­acetate ligands. The {[Eu(Ph₃CCOO)₃(CH₃OH)₄]·2CH₃OH}₂ dimer, formed by inter­molecular O—H⋯O hydrogen bonds via two bridging methanol mol­ecules, displays two types of tri­phenyl­acetate ligand coordination.

X-ray characterization and magnetic properties of di­oxy­gen-bridged Cu^II and Mn^III Schiff base complexes

Two new di­oxy­gen-bridged Cu^II and Mn^III Schiff base complexes have been synthesized and their crystal structures have been determined by X-ray diffraction analysis. The variable-temperature (2–300 K) magnetic susceptibilities have been investigated for both complexes.

Monitoring photo-induced transformations in crystals of 2,6-di­fluoro­cinnamic acid under ambient conditions

The crystal and mol­ecular structure of 2,6-di­fluoro­cinnamic acid was determined and analysed in terms of a photochemical [2 + 2] dimerization. The mol­ecules are arranged in stacks along the a axis and the values of the inter­molecular geometrical parameters indicate that they may undergo this photochemical reaction. The reaction was carried out in situ and the changes of the unit-cell parameters during crystal irradiation by a UV beam were monitored.

Handbook of Inorganic Substances 2015