Bis[4-(dimethyl­amino)­pyridinium] octa­aqua­chloridolanthanum(III) tetra­chloride trihydrate

The title organic–inorganic salt, (C₇H₁₁N₂)₂[LaCl(H₂O)₈]Cl₄·3H₂O, consists of two 4-(dimethyl­amino)­pyridinium and one [La(H₂O)₈Cl]²⁺ cations, four chloride anions and three solvent water mol­ecules. In the crystal, the various units are connected by N—H...Cl, O—H...Cl, O—H...O and N—H...O hydrogen bonds, forming a network of alternating organic and inorganic layers. The 4-(dimethyl­amino)­pyridinium cations stack along the c axis, while the inorganic layers lie parallel to the ac plane. The chloride anions are located between these entities, forming hydrogen bonds with the NH atom of the pyridinium ions and the water mol­ecules. There are also C—H...Cl hydrogen bonds present involving one of the 4-(dimethyl­amino)­pyridinium cations, resulting in the formation of a three-dimensional supra­molecular architecture.

Tris[4-(dimethyl­amino)­pyridinium][(bis-μ-dichlorido)-deca­aqua­dichlorido­dineodymium(III)] penta­chloride dihydrate

The title compound, (C₇H₁₁N₂)₃[Nd₂Cl₄(H₂O)₁₀]Cl₅·2H₂O, consists of three 4-(dimethyl­amino)­pyridinium cations, one of which is disordered about an inversion center, one [Nd₂Cl₄(H₂O)₁₀]²⁺ dication possessing inversion symmetry, five chloride anions, one of which is disordered over two inversion centers, and two lattice water mol­ecules. The 4-(dimethyl­amino)­pyridinium cations are protonated at the pyridine N atoms and form N—H...Cl hydrogen bonds with Cl⁻ counter-ions. The dimethyl­amino groups (C/N/C) lie close to the plane of the pyridinium rings, making dihedral angles of 1.6 (6)° and 6.5 (3)°. In the crystal, the [Nd₂Cl₄(H₂O)₁₀]²⁺ dications are linked via O—H...O and O—H...Cl hydrogen bonds, forming sheets lying parallel to the bc plane. These sheets are linked via O—H...Cl hydrogen bonds, forming a three-dimensional network. The 4-(dimethyl­amino)­pyridinium cations are located in the cavities and linked to the framework by C—H...Cl interactions.

4-(Dimethyl­amino)­pyridinium octa­aqua­erbium(III) tetra­chloride monohydrate

In the title compound, (C₇H₁₁N₂)[Er(H₂O)₈]Cl₄·H₂O, the asymmetric unit consists of one 4-(dimethyl­amino)­pyridinium and one octa­aqua­erbium cation balanced by four Cl⁻ anions, and one water mol­ecule. The 4-(dimethyl­amino)­pyridinium cation is protonated at the pyridine N atom. The dimethyl­amino group (C/N/C) lies close to the plane of the pyridinium ring, making a dihedral angle of 4.5 (3)°. In the crystal, the [Er(H₂O)₈]³⁺ cations are linked via O—H...O and O—H...Cl hydrogen bonds, forming two-dimensional networks propagating in the ab plane. These networks are linked via O—H...O and O—H...Cl hydrogen bonds, forming a three-dimensional network. The 4-(dimethyl­amino)­pyridinium cations are located in the cavities and are linked to the framework via N—H...Cl, C—H...O and C—H...Cl hydrogen bonds.