catena‐Poly[[nickel(II)‐μ2‐[1,3‐bis(imidazol‐1‐ylmethyl)benzene‐κ2N3:N3′]‐μ2‐(5‐carboxybenzene‐1,3‐dicarboxylato‐κ4O1,O1′:O3,O3′)] 0.41‐hydrate]

The title compound, {[Ni(C₉H₄O₆)(C₁₄H₁₄N₄)]·0.41H₂O}_n, exhibits a three‐dimensional hydrogen‐bonded supramolecular framework. The Ni^II cation is six‐coordinated in a distorted triangular prism defined by two N atoms from two 1,3‐bis(imidazol‐l‐ylmethyl)benzene (bix) ligands and four O atoms from two 5‐carboxybenzene‐1,3‐dicarboxylate (HBTC) dianions. The bix molecules and HBTC dianions both act as bidentate ligands, linking the Ni^II cations to form a one‐dimensional coordination polymer. A two‐dimensional wave‐like net is constructed by O—H...O hydrogen bonds linking adjacent chains. Partially occupied solvent water molecules fill the cavities and link these layers to form a three‐dimensional supramolecular structure via O—H...O hydrogen bonds. The title compound was also characterized by powder X‐ray diffraction and thermogravimetric analysis.     

catena‐Poly[[[pentaaquathulium(III)]‐μ‐5‐sulfonatobenzene‐1,3‐dicarboxylato] 4,4′‐bipyridyl 1.5‐solvate hemihydrate]

The crystal structure of the title compound, {[Tm(C₈H₃O₇S)(H₂O)₅]·1.5C₁₀H₈N₂·0.5H₂O}_n, is built up from two [Tm(SIP)(H₂O)₅] molecules (SIP³⁻ is 5‐sulfonatobenzene‐1,3‐dicarboxylate), three 4,4′‐bipyridyl (bpy) molecules and one solvent water molecule. One of the bpy molecules and the solvent water molecule are located on an inversion centre and a twofold rotation axis, respectively. The Tm^III ion coordination is composed of four carboxylate O atoms from two trianionic SIP³⁻ ligands and five coordinated water molecules. The Tm³⁺ ions are linked by the SIP³⁻ ligands to form a one‐dimensional zigzag chain propagating along the c axis. The chains are linked by interchain O—H...O hydrogen bonds to generate a two‐dimensional layered structure. The bpy molecules are not involved in coordination but are linked by O—H...N hydrogen bonds to form two‐dimensional layers. The two‐dimensional layers are further bridged by the bpy molecules as pillars and the solvent water molecules through hydrogen bonds, giving a three‐dimensional supramolecular structure. π–π stacking interactions between the parallel aromatic rings, arranged in an offset fashion with a face‐to‐face distance of 3.566 (1) Å, are observed in the crystal packing.     

Three‐dimensional hydrogen‐bonded framework in bis(melamin‐1‐ium) naphthalene‐1,5‐disulfonate melamine pentahydrate

Crystals of the title compound, 2C₃H₇N₆⁺·C₁₀H₆O₆S₂²⁻·C₃H₆N₆·5H₂O, are built up of neutral 2,4,6‐triamino‐1,3,5‐triazine (melamine), singly protonated melaminium cations, naphthalene‐1,5‐disulfonate dianions and water molecules. Two independent anions lie across centres of inversion in the space group P. The melamine molecules are connected by N—H...N hydrogen bonds into two different one‐dimensional polymers almost parallel to the (010) plane, forming a stacking structure along the b axis. The centrosymmetric naphthalene‐1,5‐disulfonate anions interact with water molecules via O—H...O hydrogen bonds, forming layers parallel to the (001) plane. The cations and anions are connected by N—H...O and O—H...N hydrogen bonds to form a three‐dimensional supramolecular framework.     

A planar cyclic hexamer of water molecules in dichlorido(2,4,6‐tri‐2‐pyridyl‐1,3,5‐triazine)cadmium(II) trihydrate

In the title compound, [CdCl₂(C₁₈H₁₂N₆)]·3H₂O, the Cd atom has a distorted square‐pyramidal coordination geometry. The solvent water molecules are hydrogen bonded to each other to form planar cyclic water hexamers, which, together with other hydrogen bonds, interlink the Cd complex molecules to give one‐dimensional supramolecular ribbons that extend along the [111] direction. The chains are assembled into two‐dimensional layers parallel to (111) by π–π stacking interactions. Furthermore, interlayer π–π stacking interactions and weak C—H...Cl hydrogen bonds complete the formation of a three‐dimensional framework.     

Diaquabis(quinoxaline‐2‐carboxylato‐κ2N1,O)copper(II)

In the title compound, [Cu(C₉H₅N₂O₂)₂(H₂O)₂], the Cu^II ion lies on an inversion centre and has an elongated centrosymmetric octahedral environment, equatorially trans‐coordinated by two N,O‐bidentate quinoxaline‐2‐carboxylate ligands and axially coordinated by two water O atoms. Symmetry‐related molecules are linked by strong O—H...O hydrogen bonds, involving the uncoordinated carboxyl O atom of the carboxylate group and the coordinated water molecules, to form a two‐dimensional network. Weak intermolecular C—H...N interactions also stabilize the crystal structure.     

A one‐dimensional heterometallic coordination polymer with a three‐dimensional supramolecular framework: poly[μ2‐aqua‐diaqua(2,2′‐bipyridyl)(μ5‐2‐sulfonatobutanedioato)copper(II)sodium(I)]

The title compound, [CuNa(C₄H₃O₇S)(C₁₀H₈N₂)(H₂O)₃]_n, consists of one Cu^II cation, one Na^I cation, one 2‐sulfonatobutanedioate trianion (SSC³⁻), one 2,2′‐bipyridyl (bpy) ligand and three coordinated water molecules as the building unit. The coordination of the Cu^II cation is composed of two pyridyl N atoms, one water O atom and two carboxylate O atoms in a distorted square‐pyramidal coordination geometry with an axial elongation. The Na^I cation is six‐coordinated by three water molecules and three carboxylate O atoms from three SSC³⁻ ligands in a distorted octahedral geometry. Two SSC³⁻ ligands link two Cu^II cations to form a Cu₂(SSC)₂(bpy)₂ macrocyclic unit lying across an inversion centre, which is further linked by Na^I cations via Na—O bonds to give a one‐dimensional chain. Interchain hydrogen bonds link these chains to form a two‐dimensional layer, which is further extended into a three‐dimensional supramolecular framework through π–π stacking interactions. The thermal stability of the title compound has also been investigated.     

Poly[[diaqua(μ3‐3‐nitrophthalato)calcium(II)] monohydrate]

The title 3‐nitrophthalate–calcium coordination polymer, {[Ca(C₈H₃NO₆)(H₂O)₂]·H₂O}_n, crystallizes as a one‐dimensional framework. The Ca^II centre has a distorted pentagonal–bipyramidal geometry, being seven‐coordinated by five O atoms from three different 3‐nitrophthalate groups and by two water molecules, resulting in a one‐dimensional zigzag chain along the a‐axis direction by the interconnection of the four O atoms from the two carboxylate groups. There is a D3 water cluster composed of the coordinated and the solvent water molecules within such chains. Adjacent chains are aggregated into two‐dimensional layers via hydrogen bonds in the c‐axis direction. The whole three‐dimensional structure is further stabilized by weak O—H...O hydrogen bonds between the O atoms of the nitro group and the water molecules.     

dl‐Alaninium semi‐oxalate monohydrate

The structure of the title compound, C₃H₈NO₂⁺·C₂HO₄⁻·H₂O, is formed by two chiral counterparts (l ‐ and d ‐alaninium cations), semi‐oxalate anions and water molecules, with a 1:1:1 cation–anion–water ratio. The structure is compared with that of the previously known anhydrous dl ‐alaninium semi‐oxalate [Subha Nandhini, Krishnakumar & Natarajan (2001). Acta Cryst. E 57 , o666–o668] in order to investigate the role of water molecules in the crystal packing. The structure of the hydrate resembles that of anhydrous alaninium semi‐oxalate, with the water molecule incorporated into the general three‐dimensional network of hydrogen bonds where it forms four hydrogen bonds with neighbours disposed tetrahedrally about it. Although the main structural motifs in the hydrate and in the anhydrous form are topologically similar, the incorporation of water molecules in the network results in significant geometric distortion. There are several types of hydrogen bond in the crystal structure of the hydrate, two of which (O—H...O bonds between the semi‐oxalate anions and O—H...O hydrogen bonds between water and alaninium cations) are very short. Such hydrogen bonds between semi‐oxalate anions are also present in the anhydrous form of this compound. Short distances between semi‐oxalate anions in neighbouring chains in the hydrate alternate with longer ones, whereas in the anhydrous structure they are equidistant. Despite the similarity of these compounds, dehydration of the hydrate on storage is not of a single‐crystal to single‐crystal type, but gives a polycrystalline pseudomorph, preserving the crystal habit. This transformation proceeds through the formation of an intermediate compound, presumably a hemihydrate.     

Unusual hydrate stabilization in the two‐dimensional layered structure of quinacrinium bis(2‐carboxy‐4,5‐dichlorobenzoate) tetrahydrate,a proton‐transfer compound of the drug quinacrine

The crystal structure of the hydrated proton‐transfer compound of the drug quinacrine [rac‐N′‐(6‐chloro‐2‐methoxyacridin‐9‐yl)‐N,N‐diethylpentane‐1,4‐diamine] with 4,5‐dichlorophthalic acid, C₂₃H₃₂ClN₃O²⁺·2C₈H₃Cl₂O₄⁻·4H₂O, has been determined at 200 K. The four labile water molecules of solvation in the structure form discrete ...O—H...O—H... hydrogen‐bonded chains parallel to the quinacrine side chain, the two N—H groups of which act as hydrogen‐bond donors for two of the water acceptor molecules. The other water molecules, as well as the acridinium H atom, also form hydrogen bonds with the two anion species and extend the structure into two‐dimensional sheets. Between these sheets there are also weak cation–anion and anion–anion π–π aromatic ring interactions. This structure represents the third example of a simple quinacrine derivative for which structural data are available but differs from the other two in that it is unstable in the X‐ray beam due to efflorescence, probably associated with the destruction of the unusual four‐membered water chain structures.     

Multiple hydrogen bonds in cytosinium zoledronate trihydrate

The asymmetric unit of the title compound [systematic name: 4‐amino‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium 1‐hydroxy‐2‐(1H,3H‐imidazol‐3‐ium‐1‐yl)ethylidenediphosphonate trihydrate], C₄H₆N₃O⁺·C₅H₉N₂O₇P₂⁻·3H₂O, contains one cytosinium cation, one zoledronate anion and three water molecules. The zoledronate anion has a zwitterionic character, in which each phosphonate group is singly deprotonated and an imidazole N atom is protonated. Furthermore, proton transfer takes place from one of the phosphonic acid groups of the zoledronate anion to one of the N atoms of the cytosinium cation. The cytosinium cation forms a C(6) chain, while the zoledronate anion forms a rectangular‐shaped centrosymmetric dimer through N—H...O hydrogen bonds. The cations and anions are held together by N—H...O and O—H...O hydrogen bonds to form a one‐dimensional polymeric tape. The three water molecules play a crucial role in hydrogen bonding, resulting in a three‐dimensional hydrogen‐bonded network.     

Tris(2,2′‐bipyridine)iron(II) bis(1,1,3,3‐tetracyano‐2‐ethoxypropenide) dihydrate: chiral hydrogen‐bonded frameworks interpenetrate in three dimensions

In the title compound, [Fe(C₁₀H₈N₂)₃](C₉H₅N₄O)₂·2H₂O, the chiral cations lie across twofold rotation axes in the space group C2/c. The anions and the water molecules are linked by two independent O—H...N hydrogen bonds to form C₂²(8) chains, and these chains are linked by the cations via C—H...N and C—H...O hydrogen bonds to form two interpenetrating three‐dimensional frameworks, each of which contains only one enantiomeric form of the chiral cation.     

Two new polymorphs of 2,6‐diaminopyrimidin‐4(3H)‐one monohydrate

The title compound, C₄H₆N₄O·H₂O, crystallized simultaneously as a triclinic and a monoclinic polymorph from an aqueous solution of 2,4‐diaminopyrimidin‐6‐ol. Previously, an orthorhombic polymorph was isolated under the same experimental conditions. The molecular geometric parameters in the two present polymorphs and the previously reported orthorhombic polymorph are similar, but the structures differ in the details of their crystal packing. In the triclinic system, the diaminopyrimidinone molecules are connected to one another via N—H...O and N—H...N hydrogen bonding to form infinite chains in the [011] direction. The chains are further hydrogen bonded to the water molecules, resulting in a three‐dimensional network. In the monoclinic system, the diaminopyrimidinone molecules are hydrogen bonded together into two‐dimensional networks parallel to the bc plane. The water molecules link the planes to form a three‐dimensional polymeric structure.     

catena‐Poly[[[tetra­aqua­zinc(II)]‐μ‐4,4′‐bipyridine] bis­(4‐hydroxy­benzene­sulfonate) trihydrate]

In the title compound, {[Zn(C₁₀H₈N₂)(H₂O)₄](C₆H₅O₄S)₂·3H₂O}_n, the Zn atom, the bipyridine ligand and one of water mol­ecules are located on twofold rotation axes. The Zn atom is coordinated by four O atoms from four water mol­ecules and two N atoms from two 4,4′‐bipyridine mol­ecules in a distorted octa­hedral geometry. The Zn²⁺ ions are linked by the 4,4′‐bipyridine mol­ecules to form a one‐dimensional straight chain propagating along the c axis. The 4‐hydroxy­benzene­sulfonate counter‐ions are bridged by the solvent water mol­ecules through hydrogen bonds to generate a two‐dimensional layer featuring large pores. In the crystal packing, the intra­layer pores form one‐dimensional channels along the c axis, in which the one‐dimensional [Zn(C₁₀H₈N₂)(H₂O)₄]²⁺ chains are encapsulated. Electrostatic inter­actions between cations and anions and extensive hydrogen bonds result in a three‐dimensional supra­molecular structure.     

2,6‐Diamino‐9H‐purine monohydrate and bis(2,6‐diamino‐9H‐purin‐1‐ium) 2‐(2‐carboxylatophenyl)acetate heptahydrate: two simple structures with very complex hydrogen‐bonding schemes

Two structures presenting an uncomplexed 2,6‐diaminopurine (dap) group are reported, namely 2,6‐diamino‐9H‐purine monohydrate, C₅H₆N₆·H₂O, (I), and bis(2,6‐diamino‐9H‐purin‐1‐ium) 2‐(2‐carboxylatophenyl)acetate heptahydrate, 2C₅H₇N₆⁺·C₉H₆O₄²⁻·7H₂O, (II). Both structures are rather featureless from a molecular point of view, but present instead an outstanding hydrogen‐bonding scheme. In compound (I), this is achieved through a rather simple independent unit content (one neutral dap and one water molecule) and takes the form of two‐dimensional layers tightly connected by strong hydrogen bonds, and interlinked by much weaker hydrogen bonds and π–π interactions. In compound (II), the fundamental building blocks are more complex, consisting of two independent 2,6‐diamino‐9H‐purin‐1‐ium (Hdap⁺) cations, one homophthalate [2‐(2‐carboxylatophenyl)acetate] dianion and seven solvent water molecules. The large number of hydrogen‐bond donors and acceptors produces 26 independent interactions, leading to an extended and complicated network of hydrogen bonds in a packing organization characterized by the stacking of interleaved anionic and cationic planar arrays. These structural characteristics are compared with those of similar compounds in the literature.     

Tris(1,10‐phenanthroline‐κ2N,N′)cadmium(II) bis(perchlorate) 3.5‐hydrate: a water chain stabilized by perchlorate anions

The title compound, [Cd(C₁₂H₈N₂)₃](ClO₄)₂·3.5H₂O, contains a cross‐shaped one‐dimensional channel along the c axis which encapsulates an ordered water chain. This water chain features a centrosymmetric cyclic water hexamer unit with a chair‐like conformation. Neighbouring hexamers are linked by bridging water molecules. The host perchlorate anions recognize and stabilize the guest water chain via three kinds of hydrogen‐bond patterns, leading to the formation of a complex one‐dimensional {[(H₂O)₇(ClO₄)₄]⁴⁻}_n anionic chain. One perchlorate acts as a single hydrogen‐bond acceptor dangling on the chain, the second perchlorate on the chain serves as a double hydrogen‐bond acceptor for only one water molecule to form an R₂²(6) ring, where both entities lie on a twofold axis, while the third perchlorate, which also lies on a twofold axis, accepts two hydrogen bonds from two equivalent water molecules and is involved in the construction of an R₆⁵(14) ring.     

Bis[diaquabis(2,2‐bipyridine N,N′‐dioxide‐κ2O,O′)cobalt(II)] ξ‐octamolybdate dihydrate

The title organic–inorganic hybrid compound, [Co(C₁₀H₈N₂O₂)₂(H₂O)₂]₂[Mo₈O₂₆]·2H₂O, consists of [Co(bpdo)₂(H₂O)₂]²⁺ (bpdo is 2,2‐bipyridine N,N′‐dioxide) and ξ‐[Mo₈O₂₆]⁴⁻ groups in a 2:1 ratio, plus two water solvent molecules. The independent Co atom in the cation is coordinated by four O atoms from two bpdo ligands and two water molecules, in a distorted octahedral geometry. The counter‐anions, built up around a symmetry center, are linked by solvent water molecules through O—H...O hydrogen bonds to generate two‐dimensional layers, which are in turn linked by coordinated water molecules from the cationic units through further O—H...O hydrogen bonds, forming a three‐dimensional supramolecular structure.     

Poly[diaqua[μ‐1,4‐bis(imidazol‐1‐ylmethyl)benzene‐κ2N3:N3′](μ‐trans‐cyclohexane‐1,4‐carboxylato‐κ2O1:O4)manganese(II)]: a three‐dimensional hydrogen‐bonding α‐polonium net

In the title coordination compound, [Mn(C₈H₁₀O₄)(C₁₄H₁₄N₄)(H₂O)₂]_n, each Mn^II centre occupies an inversion centre. The 1,4‐bis(imidazol‐1‐ylmethyl)benzene (1,4‐bix) ligand and the trans‐cyclohexane‐1,4‐dicarboxylate dianion (chdc) both function in bridging modes, linking adjacent Mn^II centres into a two‐dimensional four‐connected (4,4) network. These two‐dimensional layers are stacked in a parallel mode. Hydrogen bonds between water molecules and carboxylate O atoms link neighbouring (4,4) networks, yielding a three‐dimensional α‐polonium net.     

catena‐Poly[[silver(I)‐μ‐1,3‐bis(4‐pyridyl)propane] hemi(naphthalene‐1,5‐disulfonate) dihydrate]: a three‐dimensional metallo‐supramolecular sandwich lamellar network

The title compound, {[Ag(C₁₃H₁₄N₂)](C₁₀H₆O₆S₂)_0.5·2H₂O}_n, (I), features a three‐dimensional supramolecular sandwich architecture that consists of two‐dimensional cationic layers composed of polymeric chains of silver(I) ions and 1,3‐bis(4‐pyridyl)propane (bpp) ligands, linked by Ag...Ag and π–π interactions, alternating with anionic layers in which uncoordinated naphthalene‐1,5‐disulfonate (nds²⁻) anions and solvent water molecules form a hydrogen‐bonded network. The asymmetric unit consists of one Ag^I cation linearly coordinated by N atoms from two bpp ligands, one bpp ligand, one half of an nds²⁻ anion lying on a centre of inversion and two solvent water molecules. The two‐dimensional {[Ag(bpp)]⁺}_n cationic and {[(nds)·2H₂O]²⁻}_n anionic layers are assembled into a three‐dimensional supramolecular framework through long secondary coordination Ag...O interactions between the sulfonate O atoms and Ag^I centres and through nonclassical C—H...O hydrogen bonds.     

An angularly fused three‐ring precursor to phytuberin

The title compound, 3,3a,5,5a,6,7,8,9‐octahydro‐3a‐hydroxy‐5a‐methyl‐8‐(2‐prop­enyl)­furo­[3,2‐c]­iso­benzo­furan‐2‐one, C₁₄H₂₀O₄, crystallizes with two independent molecules in the asymmetric unit. The molecules have similar metric parameters but differ in the conformations of the isopropenyl groups. The hydroxyl groups form one‐dimensional chains of hydrogen bonds.     

A new polymorph of 1,4‐bis(imidazol‐1‐ylmethyl)benzene dihydrate and its hydrogen‐bonded fivefold interpenetrated CdSO4 network

Single crystals of a new polymorph of 1,4‐bis(imidazol‐1‐ylmethyl)benzene dihydrate (bix·2H₂O), C₁₄H₁₄N₄·2H₂O, have been obtained by the hydrothermal method. The asymmetric unit is composed of two independent half‐bix molecules, one on an inversion center and one on a twofold axial site, and two water molecules. The disordered water molecules link into discrete tetrameric water units via two O—H...O hydrogen bonds, forming planar R₄⁴(8) rings. These tetrameric water units and bix molecules are further linked by two O—H...N hydrogen bonds into a three‐dimensional network in which an (106) hydrogen‐bonded ring is observed. These large rings lead to the formation of a fivefold interpenetrated network. If both the tetrameric water units and the bix molecules can be regarded as connected nodes, one single three‐dimensional net can then be rationalized as a CdSO₄ network. This study indicates that topological methodology can be applied in some cases in order to understand the inherent characteristics of some hydrogen‐bonded supramolecular assemblies.