4-Nitro­phenyl 2-chloro­benzoate

The aromatic rings in the title compound, C₁₃H₈ClNO₄, enclose a dihedral angle of 39.53 (3)°. The nitro group is almost coplanar with the ring to which it is attached [dihedral angle = 4.31 (1)°]. In the crystal, mol­ecules are connected by C—H...O hydrogen bonds into chains running along [001].

Tetra­aceto­nitrile­lithium tetra­iso­thio­cyanato­borate

The crystal structure of the title salt, [Li(CH₃CN)₄][B(NCS)₄], is composed of discrete cations and anions. Both the Li and B atoms show a tetra­hedral coordination by four equal ligands. The aceto­nitrile and iso­thio­cyanate ligands are linear. The bond angles at the B atom are close to the ideal tetra­hedral value [108.92 (18)-109.94 (16)°], but the bond angles at the Li atom show larger deviations [106.15 (17)-113.70 (17)°].

Di-μ-bromido-bis­[(diethyl ether-κO)(2,4,6-tri­methyl­phen­yl)magnesium]: the mesityl Grignard reagent

The crystal structure of the title compound, [Mg₂Br₂(C₉H₁₁)₂(C₄H₁₀O)₂], features a centrosymmetric two-centre magnesium complex with half a mol­ecule in the asymmetric unit. The Mg atom is in a considerably distorted Br₂CO coordination. Bond lengths and angles are comparable with already published values. The crystal packing is stabilized by C—H...π inter­actions linking the complexes into sheets parallel to (0-11).

[μ-3,3′-Bis(tri­hydro­bor­yl)[3]ferroceno­phane]bis­(chlorido­zirconocene)

The title compound, [FeZr₂(C₅H₅)₄Cl₂(C₁₃H₁₈B₂)], is a heteronuclear complex that consists of a [3]ferrocenophane moiety substituted at each cyclo­penta­dienyl (Cp) ring by a BH₃ group; the BH₃ group is bonded via two H atoms to the Zr atom of the zirconocene chloride moiety in a bidentate fashion. The two Cp rings of the [3]ferrocenophane moiety are aligned at a dihedral angle of 8.9 (4)° arising from the strain of the propane-1,3-diyl bridge linking the two Cp rings. [One methyl­ene group is disordered over two positions with a site-occupation factor of 0.552 (18) for the major occupied site.] The dihedral angles between the Cp rings at the two Zr atoms are 50.0 (3) and 51.7 (3)°. The bonding Zr...H distances are in the range 1.89 (7)–2.14 (7) Å. As the two Cp rings of the ferrocene unit are connected by an ansa bridge, the two Zr atoms approach each other at 6.485 (1) Å. The crystal packing features C—H...Cl inter­actions.

4,4′-Dimethyl-2,2′-{[2,3,3a,4,5,6,7,7a-octa­hydro-1H-benzimidazole-1,3-di­yl]bis­(methyl­ene)}diphenol

The asymmetric unit of the title compound, C₂₃H₃₀N₂O₂, contains one half-mol­ecule, with a twofold axis splitting the mol­ecule in two identical halves. The structure of the racemic mixture has been reported previously [Rivera et al. (2009) J. Chem. Crystallogr. 39, 827–830] but the enanti­omer reported here crystallized in the ortho­rhom­bic space group P2₁2₁2 (Z = 2), whereas the racemate occurs in the triclinic space group P-1 (Z = 2). The observed mol­ecular conformation is stabilized by two intra­molecular O—H...N hydrogen bonds, which generate rings with graph-set motif S(6). In the crystal, mol­ecules are linked via non-classical C—H...O inter­actions, which stack the mol­ecules along the b axis.

4,4′-Di-tert-butyl-2,2′-[imidazolidine-1,3-diylbis(methyl­ene)]diphenol

In the title compound, C₂₅H₃₆N₂O₂, the two tert-butyl-substituted benzene rings are inclined at an angle of 53.5 (3)° to one another. The imidazolidine ring has an envelope conformation with with one of the C atoms of the ethylene fragment as the flap. The structure displays two intra­molecular O—H...N hydrogen bonds that generate S(6) ring motifs. The crystal studied was a non-merohedral twin with a fractional contribution of 0.281(6) for the minor domain.