Polymorphism in 2‐(4‐hydroxy‐2,6‐dimethylanilino)‐5,6‐dihydro‐4H‐1,3‐thiazin‐3‐ium chloride

Details of the structures of two conformational polymorphs of the title compound, C₁₂H₁₇N₂OS⁺·Cl⁻, are reported. In form (I) (space group P), the two N—H groups of the cation are in a trans conformation, while in form (II) (space group P2₁/c), they are in a cis arrangement. This results in different packing and hydrogen‐bond arrangements in the two forms, both of which have extended chains lying along the a direction. In form (I), these chains are composed of centrosymmetric R₄²(18) (N—H...Cl and O—H...Cl) hydrogen‐bonded rings and R₂²(18) (N—H...O) hydrogen‐bonded rings. In form (II), the chains are formed by centrosymmetric R₄²(18) (N—H...Cl and O—H...Cl) hydrogen‐bonded rings and by R₄²(12) (N—H...Cl) hydrogen‐bonded rings.     

1‐(2‐{4‐[6‐Hydro­xy‐2‐(4‐hydroxy­phenyl)­benzo­[b]­thiol‐3‐yl­carbonyl]­phenoxy}ethyl)­piperidinium chloride

The title compound, raloxifene hydro­chloride, C₂₈H₂₈NO₄S⁺·Cl^?, belongs to the benzo­thio­phene class of antiosteoporotic drugs. In the molecular cation, the 2‐phenol ring sustains a dihedral angle of 45.3 (1)° relative to the benzo­[b]­thio­phene system. The benzo­[b]­thio­phene and phenyl ring planes are twisted with respect to the carbonyl plane, with the smallest twist component occurring between the phenyl and carbonyl planes. The N atom bears the positive charge in the molecular cation and the piperidine ring adopts an almost perfect chair conformation. The Cl^? anion is involved in the formation of N—H?Cl and O—H?Cl intermolecular hydrogen bonds, which lead to the formation of a layer of molecular cations.     

Hydrogen‐bonded networks in trans‐3‐(3‐pyridyl)acrylic acid and rctt‐3,3′‐(3,4‐dicarboxycyclobutane‐1,2‐diyl)dipyridinium dichloride

The structure of trans‐3‐(3‐pyridyl)acrylic acid, C₈H₇NO₂, (I), possesses a two‐dimensional hydrogen‐bonded array of supramolecular ribbons assembled via heterodimeric synthons between the pyridine and carboxyl groups. This compound is photoreactive in the solid state as a result of close contacts between the double bonds of neighbouring molecules [3.821 (1) Å] along the a axis. The crystal structure of the photoproduct, rctt‐3,3′‐(3,4‐dicarboxycyclobutane‐1,2‐diyl)dipyridinium dichloride, C₁₆H₁₆N₂O₄²⁺·2Cl⁻, (II), consists of a three‐dimensional hydrogen‐bonded network built from crosslinking of helical chains integrated by self‐assembly of dipyridinium cations and Cl⁻ anions via different O—H...Cl, C—H...Cl and N⁺—H...Cl hydrogen‐bond interactions.     

2,2′‐(Iminodimethylene)bis(1H‐benzimidazolium)(1+) chloride

The title compound, C₁₆H₁₆N₅⁺·Cl⁻ (nbbH⁺·Cl⁻), displays N—H⋯N, N—H⋯Cl and π–π inter­actions in the crystal packing. The Cl⁻ anion is chelated by the nbbH⁺ cation via two N—H⋯Cl hydrogen bonds. Inter‐ion N—H⋯N and N—H⋯Cl hydrogen bonds link ions related by 2₁ screw axes into chains along the c axis. These chains are further linked by glide‐plane operations to generate a three‐dimensional network, which is additionally stabilized by inter­chain π–π inter­actions.     

Intermolecular O—H⃛O hydrogen bonding in the three independent molecules of (2S)‐3‐(4‐hydroxyphenyl)‐2‐(1‐oxoisoindolin‐2‐yl)­propanoic acid

The title compound, C₁₇H₁₅NO₄, derived from l ‐tyrosine, crystallizes with three independent mol­ecules which differ in the conformation of the asymmetric unit: the N—C—C—C_ipso torsion angles are ?71.7 (5), ?63.6 (6) and ?52.5 (5)°, respectively. Deformations in the phenol ring hydroxy O—C—C angles of 116.5 (4)/123.9 (4), 121.7 (5)/118.1 (4) and 122.4 (5)/118.6 (5)°, respectively, result from their respective intermolecular hydrogen‐bonding environments. Intermolecular O_acid—H?O=C_indole, O_phenol—H?O—H_phenol and O_phenol—H?O=C_indole hydrogen bonds, with O?O distances in the range 2.607 (4)–2.809 (4) Å, are present in combination with C—H?O and C—H?π_arene interactions. The primary hydrogen‐bonding systems assemble with graph sets R₃³(8) and R₃²(22).     

catena‐Poly[[[1‐benzoyl‐2‐(2‐hydroxyethyl)‐3‐(2‐pyridyl)guanidine]chloridocopper(II)] chloride 0.61‐hydrate]

The title copper(II) complex, {[CuCl(C₁₅H₁₆N₄O₂)]Cl·0.61H₂O}_n, is a one‐dimensional zigzag coordination polymer structure extending along the (010) direction. The Cu^II atom has a square‐pyramidal geometry, where the basal plane is formed by two cis N atoms and one O atom from the ligand, and by a Cl atom. The apical position is occupied by a carbonyl O atom from a symmetry‐related molecule. In the crystal structure, there are O—H...Cl and N—H...Cl hydrogen bonds, which link parallel polymer chains along the c direction, so building a two‐dimensional structure via the interstitial Cl atoms.     

(R)‐N‐[(R)‐1‐(2‐Hydroxy‐5‐methyl­phenyl)‐2‐phenyl­ethyl]‐2‐methyl‐1‐phenyl­propyl­ammonium chloride

In the title compound, C₂₅H₃₀NO⁺·Cl⁻, the mol­ecules are linked by a combination of inter­molecular N—H⋯Cl and O—H⋯Cl hydrogen bonds and intra­molecular N—H⋯O hydrogen bonds. The absolute configuration of the new stereogenic centre (the C atom adjacent to the N atom on the phenol side) is determined to have an R configuration.     

(R)‐4‐(4‐Fluoro­phenyl)‐1‐[2‐hydroxy‐2‐(3‐methyl‐1‐benzo­furan‐2‐yl)­ethyl]­piperazinium chloride propan‐1‐ol solvate

The title compound, C₂₁H₂₄FN₂O₂⁺·Cl⁻·C₃H₈O, is a potential drug designed as a hybrid compound with antihypertensive, antioxidant and β‐adrenolytic activity. The cation contains nearly planar benzo­furan and fluoro­phenyl ring systems, as well as a piperazine ring adopting an almost perfect chair conformation. The benzo­furan and piperazine moieties are connected by an ethyl chain, the moieties forming a dihedral angle of 163.12 (13)°. In the crystal structure, ions and propanol solvent mol­ecules are linked via N—H⋯Cl and O—H⋯Cl bonds into linear (010) chains.     

3′,4′‐Bis(4‐chloro­phenyl)­spiro­[chroman‐3,5′(4′H)‐isoxazol]‐4‐one

The title compound, C₂₃H₁₅Cl₂NO₃, crystallizes with two independent mol­ecules in the asymmetric unit. The chroman­one moiety consists of a benzene ring fused with a six‐membered heterocyclic ring which adopts a sofa conformation. The five‐membered spiro­isoxazoline ring is in an envelope conformation. The p‐chloro­phenyl rings bridged by the five‐membered ring are nearly perpendicular to each other. The chromanone moiety of one mol­ecule packs into the cavity formed by the p‐chloro­phenyl rings of a second mol­ecule through the formation of C—H?π interactions. The structure is stabilized by weak C—H?O, C—H?Cl and C—H?π interactions.     

Two polymorphs of 2‐(4‐chlorophenyl)‐4‐methylchromenium perchlorate

Crystallization (from ethyl acetate solution) of 2‐(4‐chlorophenyl)‐4‐methylchromenium perchlorate, C₁₆H₁₂ClO⁺·;ClO₄⁻, (I), yields two monoclinic polymorphs with the space groups P2₁/n [polymorph (Ia)] and P2₁/c [polymorph (Ib)]; in both cases, Z = 4. Cations and anions, disordered in polymorph (Ib), form ion pairs in both polymorphs as a result of Cl—O...π interactions. Related by a centre of symmetry, neighbouring ion pairs in polymorph (Ia) are linked viaπ–π interactions between cationic fragments, and the resulting dimers are linked through a network of C—H...O(perchlorate) interactions between adjacent cations and anions. The ion pairs in polymorph (Ib), arranged in pairs of columns along the a axis, are linked through a network of C—H...O(perchlorate), C—Cl...π, π–π and C—Cl...O(perchlorate) interactions. The aromatic skeletons in polymorph (Ia) are parallel in the cationic fragments involved in dimers, but nonparallel in adjacent ion pairs not constituting dimers. In polymorph (Ib), these skeletons are parallel in pairs of columns, but nonparallel in adjacent pairs of columns; this is visible as a herring‐bone pattern. Differences in the crystal structures of the polymorphs are most probably the cause of their different colours.     

Trimethyl[3‐methyl‐1‐(o‐tolenesulfonyl)indol‐2‐ylmethyl]ammonium iodide and benzyl[3‐bromo‐1‐(phenylsulfonyl)indol‐2‐ylmethyl]tolylamine

The title compounds, C₂₀H₂₅N₂O₂S⁺·I^?, (I), and C₂₉H₂₅BrN₂O₂S, (II), respectively, both crystallize in space group P. The pyrrole ring subtends an angle with the sulfonyl group of 33.6° in (I) and 21.5° in (II). The phenyl ring of the sulfonyl substituent makes a dihedral angle with the best plane of the indole moiety of 81.6° in (I) and 67.2° in (II). The lengthening or shortening of the C—N bond distances in both compounds is due to the electron‐withdrawing character of the phenyl­sulfonyl group. The S atoms are in distorted tetrahedral configurations. The molecular structures are stabilized by C—H?O and C—H?I interactions in (I), and by C—H?O and C—H?N interactions in (II).     

Dichloro­[(6R,7S,8S,14S)‐(–)‐sparteine‐κ2N,N′]mercury(II)

In the title compound, [HgCl₂(C₁₅H₂₆N₂)], the chiral alkaloid (6R,7S,8S,14S)‐(−)‐l ‐sparteine acts as a bident­ate ligand, with two Cl⁻ ligands occupying the remaining coordination sites, producing a distorted tetra­hedron. The N—Hg—N plane is twisted by 81.1 (2)° from the Cl—Hg—Cl plane. The mid‐point of the N⋯N line does not lie exactly on the Cl—Hg—Cl plane but is tilted towards one of the N atoms by 0.346 Å. Similarly, the mid‐point of the Cl⋯Cl line is tilted toward one of the Cl atoms by 0.163 Å. The packing structure shows that the complex is stabilized by two inter­atomic Cl⋯H contacts involving both Cl atoms and the methyl­ene or methine H atoms of the (−)‐sparteine ligand.     

Dichloro­[(1E,1′E)‐1,1′‐(pyridine‐2,6‐diyl)diethanone bis­(O‐methyl­oxime)‐κ3N1,N2,N6]copper(II)

In the title compound, [CuCl₂(C₁₁H₁₅N₃O₂)], the Cu^II ion is five‐coordinated in a strongly distorted trigonal–bipyramidal arrangement, with the two methyl­oxime N atoms located in the apical positions, and the pyridine N and the Cl atoms located in the basal plane. The two axial Cu—N distances are almost equal (mean 2.098 Å) and are substantially longer than the equatorial Cu—N bond [1.9757 (15) Å]. It is observed that the N(oxime)—M—N(pyridine) bond angle for five‐membered chelate rings of 2,6‐diacetyl­pyridine dioxime complexes is inversely related to the magnitude of the M—N(pyridine) bond. The structure is stabilized by intra‐ and inter­molecular C—H⋯Cl hydrogen bonds which involve the methyl H atoms, except for one of the two acetyl­methyl groups.     

N,N′‐Bis(2‐hydroxycyclohexyl)‐N,N′‐bis(2‐hydroxyethyl)ethane‐1,2‐diaminium dichloride

The achiral meso form of the title compound, C₁₈H₃₈N₂O₄²⁺·2Cl⁻, crystallizes to form undulating layers consisting of chains linked via weak hydroxyalkyl C—H...Cl contacts. The chains are characterized by centrosymmetric hydrogen‐bonded dimers generated via N—H...Cl and hydroxycycloalkyl O—H...Cl interactions. trans‐N‐Alkyl bridges subdivide the chains into hydrophilic segments flanked by hydrophobic cycloalkyl stacks along [001].     

trans‐Di­chloro­tetrakis(4‐methylpyrimidine‐N1)­ruthenium(II)

The title compound, trans‐[Ru^IICl₂(N¹‐mepym)₄] (mepym is 4‐methylpyrimidine, C₅H₆N₂), obtained from the reaction of trans,cis,cis‐[Ru^IICl₂(N¹‐mepym)₂(SbPh₃)₂] (Ph is phenyl) with excess mepym in ethanol, has fourfold crystallographic symmetry and has the four pyrimidine bases coordinated through N¹ and arranged in a propeller‐like orientation. The Ru—N and Ru—Cl bond distances are 2.082 (2) and 2.400 (4) Å, respectively. The methyl group, and the N³ and Cl atoms are involved in intermolecular C—H?N and C—­H?Cl hydrogen‐bond interactions.     

Two isomorphous azastilbene derivatives: 1‐(2‐chlorobenzyl)‐4‐[(E)‐2‐(4‐hydroxyphenyl)ethenyl]pyridinium chloride and 1‐(2‐bromobenzyl)‐4‐[(E)‐2‐(4‐hydroxyphenyl)ethenyl]pyridinium bromide

The crystal structures of the two title (E)‐stilbazolium halogenates, C₂₀H₁₇ClNO⁺·Cl⁻ and C₂₀H₁₇BrNO⁺·Br⁻, are isomorphous, with an isostructurality index of 0.985. The azastyryl fragments are almost planar, with dihedral angles between the benzene and pyridine rings of ca 4.5°. The rings of the benzyl groups are, in turn, almost perpendicular to the azastyryl planes, with dihedral angles larger than 80°. The cations and anions are connected by O—H...X⁻ (X = halogen) hydrogen bonds. The halide anions are `sandwiched' between the charged pyridinium rings of neighbouring molecules, and weak C—H...O hydrogen bonds and C—H...X and C—H...π interactions also contribute to the crystal structures.     

2,8‐Di­hydroxy‐1,3,7,9‐tetra­methyl‐6,12‐di­hydro­dipyrido­[1,2‐a:1′,2′‐d]pyrazine­diyl­ium dichloride dihydrate

The 2,8‐di­hydroxy‐1,3,7,9‐tetra­methyl‐6,12‐di­hydro­di­pyrido[1,2‐a:1′,2′‐d]pyrazine­diyl­ium dication possesses 2/m symmetry and lies in the mirror plane together with a chloride anion and the water O atom. The dication also lies on an inversion centre, i.e. C₁₆H₂₀N₂O₂²⁺·2Cl^?·2H₂O. Due to these symmetry constrictions the dication adopts an unexpected planar conformation. Molecules are linked by O—H?O and O—H?Cl hydrogen bonds to form chains, which are cross‐connected by C—H?Cl attractive interactions forming a complex three‐dimensional hydrogen‐bond network.     

Intermolecular interactions in the chiral and racemic forms of 3‐­hydroxy‐2‐(1‐oxoisoindolin‐2‐yl)­butanoic acid derived from threonine

The title compounds, C₁₂H₁₃NO₄, are derived from l ‐threonine and dl ‐threonine, respectively. Hydro­gen bonding in the chiral derivative, (2S/3R)‐3‐hydroxy‐2‐(1‐oxoisoindolin‐2‐yl)­butanoic acid, consists of O—H_acid?O_alkyl—H?O=C_indole chains [O?O 2.659 (3) and 2.718 (3) Å], Csp³—H?O and three C—H?π_arene interactions. In the (2R,3S/2S,3R) racemate, conventional carboxylic acid hydrogen bonding as cyclical (O—H?O=C)₂ [graph set R₂²(8)] is present, with O_alkyl—H?O=C_indole, Csp³—H?O and C—H?π_arene interactions. The COOH group geometry differs between the two forms, with C—O, C=O, C—C—O and C—C=O bond lengths and angles of 1.322 (3) and 1.193 (3) Å, and 109.7 (2) and 125.4 (3)°, respectively, in the chiral structure, and 1.2961 (17) and 1.2210 (18) Å, and 113.29 (12) and 122.63 (13)°, respectively, in the racemate structure. The O—C=O angles of 124.9 (3) and 124.05 (14)° are similar. The differences arise from the contrasting COOH hydrogen‐bonding environments in the two structures.     

1,1′‐(Ethenyl­idene)bis­(4‐chloro­benzene)

The title compound, C₁₄H₁₀Cl₂, crystallizes as colourless prisms with two symmetry‐independent mol­ecules in the unit cell. Numerous inter­molecular C—H⋯π inter­actions dominate in the crystal structure, where C—H⋯Cl and long Cl⋯Cl contacts are also observed.     

Dichloro­(O‐ethyl 3‐methyl­pyridine‐2‐carboximidic acid‐κ2N,N′)copper(II)

In the title compound, [CuCl₂(C₉H₁₂N₂O)], the Cu^II atom is coordinated by two Cl⁻ anions and two N atoms of one O‐ethyl 3‐methyl­pyridine‐2‐carboximidic acid mol­ecule in a slightly distorted square‐planar geometry, with Cu—N distances of 2.0483 (17) and 1.9404 (18) Å, and Cu—Cl distances of 2.2805 (10) and 2.2275 (14) Å. In addition, each Cu^II atom is connected by one Cl⁻ anion and the Cu^II atom from a neighbouring mol­ecule, with Cu⋯Cl and Cu⋯Cu distances of 2.9098 (13) and 3.4022 (12) Å, respectively, and, therefore, a centrosymmetric dimer is formed. Adjacent mol­ecular dimers are connected by π–π stacking inter­actions between pyridine rings to form a zigzag mol­ecular chain. The mol­ecular chains are also enforced by N—H⋯Cl and C—H⋯Cl inter­actions.