Adducts of hexa­methyl­ene­tetr­amine with ferrocene­carboxyl­ic acid and ferrocene-1,1'-di­carboxyl­ic acid: multiple disorder in space groups Fmm2 and Cmcm

Hexa­methyl­ene­tetr­amine, C₆H₁₂N₄, and ferrocene­carboxyl­ic acid, C₁₁H₁₀FeO₂, form a 1:2 adduct, (I), which is a salt, viz. hexa­methyl­ene­tetramin­ium(2+) bis(ferro­cene­car­box­yl­ate), (C₆H₁₄N₄)[Fe(C₅H₅)(C₆H₄O₂)]₂. The dication in (I) is disordered with two orientations at a site of mm2 symmetry in space group Fmm2, while the anion lies across a mirror plane with its unsubstituted cyclo­penta­dienyl ring disordered over two sets of sites. With ferrocene-1,1'-di­carboxyl­ic acid, C₁₂H₁₀FeO₄, hexa­methyl­enetetr­amine forms a 1:1 adduct, (II), in which both components are neutral, viz. hexa­methyl­ene­tetramine-ferro­cene-1,1'-di­car­box­ylic acid (1/1), [Fe(C₆H₅O₂)₂]·C₆H₁₂N₄. The amine component in (II) is disordered with two orientations at a site of mm2 symmetry in space group Cmcm, while the acid component is disordered with two orientations at a site of 2/m symmetry. The components in (I) are linked into a finite three-ion aggregate by a single N-H...O hydrogen bond, while the components of (II) are linked into continuous chains by a single O-H...N hydrogen bond.

Bis­[6-amino-3-methyl-5-nitro­so­pyrimidine-2,4(1H,3H)-dionato]­di­aqua­zinc(II) dihydrate, redetermined at 120 K: a three-dimensional hydrogen-bonded framework

The title compound, whose structure has been redetermined at 120 K, contains almost centrosymmetric trans-[Zn(C₅H₅N₄O₃)₂(H₂O)₂]·2H₂O units, together with two uncoordinated water mol­ecules. An extensive series of O—H...O, O—H...N and N—H...O hydrogen bonds gives rise to a three-dimensional framework structure.

6,6'-Di­methoxy-2,2'-[(1R,2R)-cyclo­hexane-1,2-diyl­bis­(nitrilo­methyl­idyne)]­diphenol: three C-H...O hydrogen bonds generate a three-dimensional framework

Molecules of the title compound, alternatively called (R,R)-N,N'-bis(3-methoxysalicylidene)-trans-cyclohexane-1,2-diamine, C₂₂H₂₆N₂O₄, contain two intramolecular O-H...N hydrogen bonds and adopt a conformation with approximate twofold rotational symmetry. The mol­ecules are linked by three C-H...O hydrogen bonds [H...O = 2.45-2.55 Å, C...O = 3.329 (2)-3.398 (2) Å and C-H...O = 142-172°] into a continuous framework.

2-Benzyl­amino-6-benzyl­oxy­pyrimidin-4(3H)-one: hydrogen-bonded chains of rings linked into sheets by a [pi]-[pi]-stacking interaction

The title compound, C₁₈H₁₇N₃O₂, crystallizes with Z' = 2 in space group P2₁/c, and the two independent mol­ecules are approximate, but not exact, mirror images. The molecular-electronic structure is strongly polarized, and the mol­ecules are linked by paired N-H...O hydrogen bonds [H...O = 2.00-2.23 Å, N...O = 2.798 (3)-2.992 (3) Å and N-H...O = 145-151°] into two independent C(4)C(6)[R₂¹(6)] chains of rings, which are linked into sheets by a single aromatic [pi]-[pi]-stacking interaction.