rac-(S,S)-Bis(1-ferrocenylbut-3-en­yl) ether

The title complex, [Fe₂(C₅H₅)₂(C₁₈H₂₀O)], formed by dehydration of 1-ferrocenylbut-3-en-1-ol, crystallizes as a racemic compound. The central C-O-C fragment, in which the C atoms are the chiral centers, is characterized by an angle of 116.26 (10)° at the O atom. One ferrocene group shows a staggered conformation whereas the other shows an eclipsed conformation.

The monoclinic form of trilithium dichromium(III) tris­(orthophosphate)

The monoclinic form of trilithium dichromium(III) tris­(ortho­phosphate), Li₃Cr₂(PO₄)₃, was prepared by the reactive halide flux method. The structure of the title compound is composed of a three-dimensional anionic framework with composition _∞ ³[Cr₂(PO₄)₃]³⁻ and Li⁺ ions situated in the empty channels. The rigid framework built up from CrO₆ octa­hedra and PO₄ tetra­hedra is the same as that found in other monoclinic Li₃M₂(PO₄)₃ (M = Fe, Sc, V) phases. The three Li⁺ cations of Li₃Cr₂(PO₄)₃ are unequally disordered over six crystallographically different sites. The classical charge balance of the title compound can be represented as [Li⁺]₃[Cr³⁺]₂[P⁵⁺]₃[O²⁻]₁₂. Solid-state UV/Vis spectra indicate that the crystal filed splitting (Δ₀) of the Cr³⁺ ion is around 2.22 eV.

4-Meth­oxy-3-(meth­oxy­meth­yl)benzalde­hyde

In the title compound, C₁₀H₁₂O₃, the dihedral angle between the benzene ring and the meth­oxy­methyl side chain is 9.7 (2)°. The O atom of the aldehyde group and the C atom of the meth­oxy group deviate from the plane of the ring by 0.039 (3) and 0.338 (4) Å, respectively. The only inter­molecular inter­actions are very weak C—H...π inter­actions.

4-Nitro-N^2^-(pyridin-4-ylmethylidene)benzene-1,2-diamine

In the title compound, C₁₂H₁₀N₄O₂, the dihedral angle between the aromatic rings is 43.18 (16)°. The nitro group is rotated from its attached ring by 7.8 (2)° and a short intra­molecular N—H...N contact occurs. In the crystal, the mol­ecules are linked by N—H...N and C—H...O hydrogen bonds, generating a three-dimensional network.