Poly[[diaqua­bis­(μ₂-crotonato-κ³O:O,O′)(crotonato-κ²O,O′)lanthanum(III)] adenine monosolvate monohydrate]

The asymmetric unit of the title compound, {[La(C₄H₅O₂)₃(H₂O)₂]·C₅H₅N₅·H₂O}_n, consists of an La^III cation, three crotonate (but-2-enoate) anions and two coordinated water mol­ecules forming the neutral complex, completed by an external adenine mol­ecule and one hydration water mol­ecule. The LaO₁₀ coordination polyhedra, connected through the sharing of a single edge, form isolated chains running along the [100] direction. These one-dimensional structures are characterized by two different centrosymmetric La₂O₂ loops, with La...La distances of 4.5394 (6) and 4.5036 (6) Å. The unbound adenine and water solvent mol­ecules form a highly planar hydrogen-bonded array parallel to (110) (r.m.s. deviation from the mean plane < 0.10 Å) which inter­sects the isolated La–crotonate chains in a slanted fashion to form an extremely connected hydrogen-bonded three-dimensional structure.

Two isomorphous lanthanide crotonate complexes: di-[mu]-but-2-enoato-bis­[diaqua­bis­(but-2-enoato)dysprosium(III)] adenine monosolvate hepta­hydrate and the samarium(II) analogue

The asymmetric unit of the title dimeric compounds, [Ln₂(C₄H₅O₂)₆(H₂O)₄]·C₅H₅N₅·7H₂O, with Ln = Dy, (I), and Sm, (II), consists of an Ln^III cation, three crotonate (but-2-enoate) anions and two coordinated water mol­ecules forming the neutral complex, cocrystallized with half of an external adenine mol­ecule and 3.5 water mol­ecules. The metal complex has crystallographic inversion symmetry. The LnO₉ coordination polyhedra are connected through the sharing of a single edge to form isolated dimeric units, with Ln...Ln separations of 4.1766 (12) Å for (I) and 4.2340 (12) Å for (II). The unbound adenine mol­ecule and one of the solvent water mol­ecules are disordered around an inversion centre into two overlapping, equally populated, units. The structure is sustained by a complex hydrogen-bonding scheme involving all possible O-H and N-H groups as donors, and crotonate and water O and adenine N atoms as acceptors. The system is compared with recently published related compounds.

Bis(2-amino-1H-benzimidazol-3-ium) tetra­kis­(μ-but-2-en­oato)-κ⁴O:O′;κ³O,O′:O;κ³O:O,O′-bis­[bis­(but-2-en­oato-κ²O,O′)holmium(III)]

The title ionic compound, (C₇H₈N₃)₂[Ho₂(C₄H₅O₂)₈], is con­structed from two almost identical independent centrosymmetric anionic dimers balanced by two independent 2-amino-1H-benzimid­azol-3-ium (Habim⁺) cations. The asymmetric part of each dimer is made up of one Ho^III cation and four crotonate (crot or but-2-enoate) anions, two of them acting in a simple η²-chelating mode and the remaining two acting in two different μ₂:η² fashions, viz. purely bridging and bridging–chelating. Symmetry-related Ho^III cations are linked by two Ho—O—Ho and two Ho—O—C—O—Ho bridges which lead to rather short intra­cationic Ho...Ho distances [3.8418 (3) and 3.8246 (3) Å]. In addition to the obvious Coulombic inter­actions linking the cations and anions, the isolated [Ho₂(crot)₈]²⁻ and Habim⁺ ions are linked by a number of N—H...O hydrogen bonds, in which all N—H groups of the cation are involved as donors and all (simple chelating) crot O atoms are involved as acceptors. These inter­actions result in compact two-dimensional structures parallel to (110), which are linked to each other by weaker π–π contacts between Habim⁺ benzene groups.

Isoquinolin-5-amine

The title compound, C₉H₈N₂, presents two almost identical independent mol­ecules in the asymmetric unit, both of them exhibiting an extremely planar isoquinoline core (maximum r.m.s. deviation = 0.014 Å). The most significant deviation is found in the -NH₂ groups, which present a noticeable pyramidalization around the N atom, a feature also present in related structures containing the mol­ecule as a ligand. The supra­molecular structure is based on pairs of parallel hydrogen-bonded chains formed by just one mol­ecular type each, defined by the strongest hydrogen bonds in the structure, which are of the N-H...N type. These parallel chains are linked into pairs (or strips) via weaker C-H...N hydrogen bonds. Related strips generated by the c-glide plane define two families running along [10] and [110], giving rise to an inter­esting system of inter­woven chains stabilized by a number of weaker contacts of the C-H...[pi] type.