Hydro­gen‐bonding patterns in 2‐amino‐4,6‐di­methyl­pyrimidinium hydrogen sulfate

In the title compound, C₆H₁₀N₃⁺·HSO₄⁻, the asymmetric unit consists of a hydrogen sulfate anion and a 2‐amino‐4,6‐di­methyl­pyrimidinium cation. The hydrogen sulfate anions self‐assemble through O—H⋯O hydrogen bonds, forming supramolecular chains along the b axis, while the organic cations form base pairs via N—H⋯N hydrogen bonds. The amino­pyrimidinium cations join to the sulfate anions via a pair of hydrogen bonds donated from the pyrimidinium protonation site and from the exo amine group cis to the protonated site.     

Tris(ethyl­ene­diamine)­nickel(II) bis­[2‐cyano‐2‐(oxidoimino)­acetamidato]­nickelate(II) monohydrate

The title compound, [Ni(C₂H₈N₂)₃][Ni(C₃HN₃O₂)₂]·H₂O, appears to be a modular associate consisting of two complex counter‐ions, containing bivalent nickel as the central atom in both cases, and a solvent water mol­ecule. The Ni^II ion in the complex cation lies on the C₂ crystallographic axis. Its coordination environment is formed by six N atoms of three ethyl­ene­diamine (en) mol­ecules, representing a distorted octa­hedral geometry. The Ni^II ion in the complex anion occupies a position at the center of inversion. It exhibits a distorted square‐planar coordination geometry formed by four N atoms belonging to the deprotonated oxidoimine and amide groups of the two doubly charged 2‐cyano‐2‐(oxidoimino)acetamidate anions, situated in trans positions with respect to each other. In the crystal packing, the complex anions are linked by water mol­ecules via hydrogen bonds between the amide O atoms and water H atoms, forming chains translated along the a direction. The [Ni(en)₃]²⁺ cations fill empty spaces between the translational chains, connecting them by hydrogen bonds between the oxime and amide O atoms of the anions and the amine H atoms of the cations, forming layers along the ac plane. The water mol­ecules provide connection between layers through N atoms of the cations, thus forming a three‐dimensional modular structure.     

Hydrogen‐bonded bilayers in ­piperazinium(2+) bis(mandelate) bis(methanol) solvate

In the title compound, C₄H₁₂N₂²⁺·2C₈H₇O₃^?·2CH₄O, the cations lie across centres of inversion and are disordered over two orientations with equal occupancy; there are equal numbers of (R)‐ and (S)‐mandelate anions present (mandelate is α‐hydroxy­benzene­acetate). The anions and the neutral water mol­ecules are linked by O—H?O hydrogen bonds [O?O 2.658 (3) and 2.682 (3) Å, and O—H?O 176 and 166°] into deeply folded zigzag chains. Each orientation of the cation forms two symmetry‐related two‐centre N—H?O hydrogen bonds [N?O 2.588 (4) and 2.678 (4) Å, and N—H?O 177 and 171°] and two asymmetric, but planar, three‐centre N—H?(O)₂ hydrogen bonds [N?O 2.686 (4)–3.137 (4) Å and N—H?O 137–147°], and by means of these the cations link the anion/water chains into bilayers.     

Two new structures in the glycine–oxalic acid system

Glycinium semi‐oxalate‐II, C₂H₆NO₂⁺·C₂HO₄⁻, (A), and diglycinium oxalate methanol disolvate, 2C₂H₆NO₂⁺·C₂O₄²⁻·2CH₃OH, (B), are new examples in the glycine–oxalic acid family. (A) is a new polymorph of the known glycinium semi‐oxalate salt, (C). Compounds (A) and (C) have a similar packing of the semi‐oxalate monoanions with respect to the glycinium cations, but in (A) the two glycinium cations and the two semi‐oxalate anions in the asymmetric unit are non‐equivalent, and the binding of the glycinium cations to each other is radically different. Based on this difference, one can expect that, although the two forms grow concomitantly from the same batch, a transformation between (A) and (C) in the solid state should be difficult. In (B), two glycinium cations and an oxalate anion, which sits across a centre of inversion, are linked via strong short O—H...O hydrogen bonds to form the main structural fragment, similar to that in diglycinium oxalate, (D). Methanol solvent molecules are embedded between the glycinium cations of neighbouring fragments. These fragments form a three‐dimensional network via N—H...O hydrogen bonds. Salts (B) and (D) can be obtained from the same solution by, respectively, slow or rapid antisolvent crystallization.     

Melaminium acetate acetic acid solvate monohydrate

The crystals of the title new melaminium salt, 2,4,6‐tri­amino‐1,3,5‐triazin‐1‐ium acetate acetic acid solvate monohydrate, C₃H₇N₆⁺·CH₃COO^?·CH₃COOH·H₂O, are built up from singly protonated melaminium residues, acetate anions, and acetic acid and water mol­ecules. The melaminium residues are interconnected by N—H?N hydrogen bonds to form chains along the [010] direction. These chains of melaminium residues form stacks aligned along the a axis. The acetic acid mol­ecules interact with the acetate anions via the H atom of their carboxylic acid groups and, together with the water mol­ecules, form layers that are parallel to the (001) plane. The oppositely charged moieties interact via multiple N—H?O hydrogen bonds that stabilize a pseudo‐two‐dimensional stacking structure.     

Glycinium semi‐malonate and a glutaric acid–glycine cocrystal: new structures with short O—H...O hydrogen bonds

Glycinium semi‐malonate, C₂H₆NO₂⁺·C₃H₃O₄⁻, (I), and glutaric acid–glycine (1/1), C₂H₅NO₂·C₅H₈O₄, (II), are new examples of two‐component crystal structures containing glycine and carboxylic acids. (II) is the first example of a glycine cocrystal which cannot be classified as a salt, as glutaric acid remains completely protonated. In the structure of (I), there are chains formed exclusively by glycinium cations, or exclusively by malonate anions, and these chains are linked with each other. Two types of very short O—H...O hydrogen bonds are present in the structure of (I), one linking glycinium cations with malonate anions, and the other linking malonate anions with each other. In contrast to (I), no direct linkages between molecules of the same type can be found in (II); all the hydrogen‐bonded chains are heteromolecular, with molecules of neutral glutaric acid alternating with glycine zwitterions, linked by two types of short O—H...O hydrogen bonds.     

Cocrystallization of melaminium levulinate monohydrate

Crystals of 2,4,6‐tri­amino‐1,3,5‐triazin‐1‐ium levulinate (4‐oxo­pentanoate) monohydrate, C₃H₇N₆⁺·C₅H₇O₃⁻·H₂O, are formed via self‐assembled hydrogen bonding by cocrystallization of mel­amine and levulinic acid. Two N—H⋯N hydrogen bonds and four N—H⋯O hydrogen bonds connect two melaminium entities such that each of two pairs of N—H⋯O bonds bridges two H atoms belonging to the amine groups of two different melaminium cations via the carbonyl O atom of one levulinate mol­ecule.     

Hydrogen‐bonded sheets in 2‐(2‐aminophenyl)‐1H‐benzimidazol‐3‐ium dihydrogen phosphate

The title salt, C₁₃H₁₂N₃⁺·H₂PO₄⁻, contains a nonplanar 2‐(2‐aminophenyl)‐1H‐benzimidazol‐3‐ium cation and two different dihydrogen phosphate anions, both situated on twofold rotation axes in the space group C2. The anions are linked by O—H...O hydrogen bonds into chains of R₂²(8) rings. The anion chains are linked by the cations, via hydrogen‐bonding complementarities and electrostatic interactions, giving rise to a sheet structure with alternating rows of organic cations and inorganic anions. Comparison of this structure with that of the pure amine reveals that the two compounds generate characteristically different sheet structures. The anion–anion chain serves as a template for the assembly of the cations, suggesting a possible application in the design of solid‐state materials.     

l‐Leucinium perchlorate

Crystals of l ‐leucinium perchlorate, C₆H₁₄NO₂⁺·ClO₄⁻, are built up from protonated l ‐leucinium cations and perchlorate anions. l ‐Leucinium cations related by a twofold screw axis are inter­connected by N—H⋯O hydrogen bonds into zigzag chains parallel to [010]. The O atoms of the perchlorate anions act as acceptors of hydrogen bonds that link the l ‐leucinium chains into separated but inter­acting two‐dimensional layers parallel to (001). Since the title compound crystallizes in a non‐centrosymmetric space group, it can be useful as a material for non‐linear optics. The efficiency of second harmonic generation is about twice that of K₂[HPO₄].     

Supra­molecular hydrogen‐bonding networks in bis­(adeninium) phthalate phthalic acid 1.45‐hydrate

In the title compound, 2C₅H₆N₅⁺·C₈H₄O₄²⁻·C₈H₆O₄·1.45H₂O, the asymmetric unit comprises two adeninium cations, two half phthalate anions with crystallographic C₂ symmetry, one neutral phthalic acid mol­ecule, and one fully occupied and one partially occupied site (0.45) for water mol­ecules. The adeninium cations form N—H⋯O hydrogen bonds with the phthalate anions. The cations also form infinite one‐dimensional polymeric ribbons via N—H⋯N inter­actions. In the crystal packing, hydrogen‐bonded columns of cations, anions and phthalate anions extend parallel to the c axis. The water mol­ecules crosslink adjacent columns into hydrogen‐bonded layers.     

catena‐Poly[[bis(nicotinamide‐κN1)copper(I)]‐μ‐thiocyanato‐κ2N:S]

The Cu^I cations in the title compound, [Cu(NCS)(C₆H₆N₂O)₂]_n, are coordinated by N atoms from each of two mirror‐related nicotin­amide ligands, as well as by one N atom of one thio­cyanate ligand and one S atom of a symmetry‐related thio­cyanate ligand, within a slightly distorted tetrahedron. The Cu^I cations and the thio­cyanate anions are located on a crystallographic mirror plane and the nicotin­amide ligands occupy general positions. The Cu^I cations are connected by the thio­cyanate anions to form chains in the direction of the crystallographic a axis. These chains are connected by hydrogen bonds between the amide H atoms and the O atoms of adjacent nicotin­amide ligands, to give a three‐dimensional structure.     

1,1,3,3‐Tetra­methyl­guanidinium dihydrogen­orthophosphate

In the title compound, C₅H₁₄N₃⁺·H₂PO₄^?, the cation has a central guanidinium fragment with a planar geometry, as expected for a central Csp² atom with a small charge delocalization along the three C—N bonds. The crystal packing is governed by hydrogen bonds so that the phosphate anions are linked head to tail, forming chains running parallel to the c direction. These chains in turn are interconnected by hydrogen bonds to intermediate tetra­methyl­guanidinium cations forming hydrogen‐bonded molecular layers stacked parallel to the bc crystal planes.     

Tetra­butyl­ammonium α‐acetyl‐γ‐butyrolactonate containing a three‐dimensional hydrogen‐bonded network

The title compound, C₁₆H₃₆N⁺·C₆H₇O₃^?, crystallizes with two independent anions and two independent cations in the asymmetric unit. Each anion adopts an s‐trans conformation and forms O?H—C hydrogen bonds to the α‐methyl­ene groups of four neighbouring tetra­butyl­ammonium cations, to create a three‐dimensional hydrogen‐bonded network.     

Hierarchy of hydrogen bonding in bis­(1,4,7‐trioxa‐10‐azoniacyclo­dodecane) bis­(4‐amino­benzoate) trihydrate

In the title compound, 2C₈H₁₈NO₃⁺·2C₇H₆NO₂⁻·3H₂O, proton transfer occurs from the carboxylic acid group of the 4‐amino­benzoic acid (PABA) mol­ecule to the amine group of the macrocycle, resulting in the formation of a salt‐like adduct. The anions are combined into helical chains which are further bound by the water mol­ecules into sheets. The macrocyclic cations are situated between these layers and are bound to the anions both directly and via bridging water mol­ecules. The structure exhibits a diverse system of hydrogen bonding.     

Melaminium chloride hemihydrate

The crystals of a new melaminium salt, 2,4,6‐tri­amino‐1,3,5‐triazin‐1‐ium chloride hemihydrate, C₃H₇N₆⁺·Cl^?·0.5H₂O, are built up from single‐protonated melaminium residues, chloride anions and water mol­ecules. The protonated melaminium cations lie on a twofold axis, while the chloride anions and water mol­ecule lie on the m plane. The melaminium residues are interconnected by N—H?N hydrogen bonds, forming chains parallel to the (001) plane. The chains of melaminium residues form a three‐dimensional network through hydrogen‐bond interactions with chloride anions and water mol­ecules.     

Pseudosymmetry in ammonium [(carboxymethyl)sulfanyl]acetate

The structure of the title compound, NH₄⁺·C₄H₅O₄S⁻, is composed of mono­carboxyl­ate anions of [(carboxymethyl)sulfanyl]acetic acid linked into infinite chains via strong O—H⋯O⁻ hydrogen bonds. The three‐dimensional structure is completed by the ammonium cations, which interlink neighbouring chains via N—H⋯O hydrogen bonds. Solution and refinement in the true space group Pn led to an unambiguous position for the single carboxyl H atom. In the higher symmetry space group P2/n, the carboxylate anion would be located on a twofold axis.     

The one‐dimensional structure of Cu(dmen)2Pd(CN)4 (dmen is N,N‐di­methyl­ethyl­enedi­amine)

The title compound, catena‐poly­[[μ‐cyano‐1:2κ²C:N‐dicyano‐1κ²C‐bis(N,N‐di­methyl­ethyl­enedi­amine‐2κ²N,N′)­pallad­ium(II)­copper(II)]‐μ‐cyano‐1:2′κ²C:N], [CuPd(CN)₄(C₄H₁₂N₂)₂]_n, consists of infinite quasi‐linear chains with all metal positions on centers of symmetry. The paramagnetic [Cu(dmen)₂]²⁺ cations are linked by diamagnetic [Pd(CN)₄]²⁻ anions via bridging cyano groups, which occupy trans positions in both cation and anion, giving rise to 2,2‐TT‐type chains. The coordination polyhedron of the paramagnetic Cu atom is an octahedron exhibiting typical elongation due to the Jahn–Teller effect, with two longer Cu—N([triple‐bond]C) bonds in the axial positions [2.5528 (13) Å] and four shorter Cu—N_dmen bonds (dmen is N,N‐dimethylethylenediamine) in the equatorial plane [1.9926 (11) and 2.1149 (12) Å]. The Cu—N[triple‐bond]C angle is 138.03 (12)°. Neighboring chains form weak N—H⋯NC hydrogen bonds.     

Glycinium trifluoroacetate

In the title compound, C₂H₆NO₂⁺·C₂F₃O₂^?, the main N—C—COOH skeleton of the glycinium cation is almost perfectly planar. The tri­fluoro­acetate anion has a staggered conformation with typical bond distances and angles. The CF₃ group is slightly disordered. The structure is stabilized by an extensive network of strong O—H?O hydrogen bonds and weaker N—H?O bonds.     

Sodium trichloro­methane­sulfonate monohydrate

Sodium trichloro­methane­sulfonate monohydrate, Na⁺·CCl₃SO₃⁻·H₂O, crystallizes in P2₁/a with all the atoms located in general positions. The trichloro­methane­sulfonate (trichlate) anion consists of pyramidal SO₃ and CCl₃ groups connected via an S—C bond in a staggered conformation with approximate C_3v symmetry. The water mol­ecule is hydrogen bonded to the sulfonate O atoms, with one water H atom forming weak bifurcated O—H⋯O hydrogen bonds to two different trichlate ions. Two water O atoms and three O atoms from different SO₃ groups form a square‐pyramidal arrangement around the sodium ion.