2‐{[Tris(hydroxymethyl)methyl]aminomethylene}cyclohexa‐3,5‐dien‐1(2H)‐one and its 6‐hydroxy and 6‐methoxy derivatives

The title compounds, 2‐{[tris­(hydroxy­methyl)­methyl]­amino­methyl­ene}cyclo­hexa‐3,5‐dien‐1(2H)‐one, C₁₁H₁₅NO₄, (I), 6‐hydroxy‐2‐{[tris­(hydroxy­methyl)­methyl]­amino­methyl­ene}­cyclo­hexa‐3,5‐dien‐1(2H)‐one, C₁₁H₁₅NO₅, (II), and 6‐methoxy‐2‐{[tris­(hydroxy­methyl)­methyl]­amino­methyl­ene}­cyclo­hexa‐3,5‐dien‐1(2H)‐one, C₁₂H₁₇NO₅, (III), adopt the keto–amine tautomeric form, with the formal hydroxy H atom located on the N atom, and the NH group and oxo O atom display a strong intramolecular N—H⋯O hydrogen bond. The N—H⋯O hydrogen‐bonded rings are almost planar and coupled with the cyclo­hexa­diene rings. The carbonyl O atoms accept two other H atoms from the alcohol groups of adjacent mol­ecules in (I), and one from the alcohol and one from the phenol group in (II), but from only one alcohol H atom in (III).     

Hydro­gen bonding in 2-(hydroxy­methyl)-1,3-propane­diol and N,N′-bis­[2-hydroxy-1,1-bis­(hydroxy­methyl)­ethyl]­malon­amide

The mol­ecule of 2-(hydroxy­methyl)-1,3-propane­diol, C₄H₁₀O₃, lies across a mirror plane in space group P2₁/m, with disorder of both terminal hydroxyl H atoms. The molecules are linked by three O—H⋯O hydrogen bonds which combine to form sheets; in each O—H⋯O bond, the H atom resonates between the two O atoms. In the crystal structure of N,N′-­bis­[2-hydroxy-1,1-bis­(hydroxy­methyl)­ethyl]­malon­amide, C₁₁H₂₂N₂O₈, the molecule lies about a twofold axis and has four strong hydrogen bonds which form a mixture of chains and dimers; these combine to give a three-dimensional supramolecular framework.     

Bis(dimethyl sulfoxide‐S)tetrakis(μ‐p‐hydroxybenzoato‐O:O′)dirhodium(II)–tetrakis(μ‐butyrato‐O:O′)bis(dimethyl sulfoxide‐S)dirhodium(II) cocrystal ethanol disolvate

The title structure, [Rh₂(C₇H₅O₃)₄(C₂H₆OS)₂]·[Rh₂(C₄H₇­O₂)₄(C₂H₆OS)₂]·2C₂H₆O, contains two discrete neutral Rh–Rh dimers cocrystallized as the ethanol disolvate. Each dimer is situated on an inversion center. The butyrate chain displays disorder in one C‐atom position. In each dimer, the di­methyl sulfoxide ligand (dmso) is bound via S, as expected. The ethanol is a hydrogen‐bond acceptor for one p‐hydroxy­benzoate hydroxyl group and acts as a hydrogen‐bond donor to the dmso O atom of a neighboring p‐hydroxy­benzoate dirhodium complex. A third hydrogen bond is formed from the other p‐hydroxy­benzoate hydroxyl group to the dmso O atom of a butyrate–dirhodium complex.     

Model porphyrin precursors: 1,2,4,5‐tetrakis(cyanomethyl)­benzene,methyl 3,4,5‐triacetoxy­benzoate and 2‐(N‐phthalimidomethyl)benzoic acid

In the crystalline state, the centrosymmetric mol­ecule 1,2,4,5‐tetrakis­(cyano­methyl)­benzene, C₁₄H₁₀N₄, has one cyano­methyl group in the benzene plane and one cyano­methyl group rotated 67.2 (2)° out of the benzene plane. Molecules of methyl 3,4,5‐tri­acetoxy­benzoate, C₁₄H₁₄O₈, form chains with each mol­ecule twisted 89.6 (1)° from the preceding mol­ecule. In this orientation, a close C—H?O contact is formed, with an H?O distance of 2.34 Å. The structure of 2‐(N‐phthalimido­methyl)­benzoic acid, C₁₆H₁₁NO₄, reveals hydrogen‐bonded dimers linked by the carboxyl groups of adjacent mol­ecules. The O4?O3 distance is 2.636 (2) Å and the O4—H?O3 angle is 171 (2)°.     

Bis(2,5‐dimethoxy‐4‐methylphenyl)methane and bis(2,5‐dimethoxy‐3,4,6‐trimethylphenyl)methane

Bis(2,5‐di­methoxy‐4‐methyl­phenyl)­methane, C₁₉H₂₄O₄, (IIa), was obtained and characterized as a minor product from the reaction of tolu­hydro­quinone di­methyl ether (1,4‐dimethoxy‐2‐methylbenzene) with N‐(hydroxy­methyl)­tri­fluoro­acet­amide. Similarly, bis(2,5‐di­methoxy‐3,4,6‐tri­methyl­phenyl)­methane, C₂₃H₃₂O₄, (IIb), was prepared from the corresponding reaction of tri­methyl­hydro­quinone di­methyl ether (2,5‐dimethoxy‐1,3,4‐trimethylbenzene). The mol­ecules of (IIa) and (IIb) each lie on a twofold axis passing through the methyl­ene group. The dihedral angle between the planar phenyl rings is 73.4 (1)° in (IIa) and 77.9 (1)° in (IIb). The external bond angles around the bridging methyl­ene group are 116.6 (2) and 117.3 (2)° for (IIa) and (IIb), respectively. In (IIa), the methoxy substituents lie in the plane of the ring and are conjugated with the aromatic system, whereas in (IIb), they are almost perpendicular to the phenyl ring and are positioned on opposite sides.     

2,4‐Di­methoxy­benzoic acid and 2,5‐di­methoxy­benzoic acid

The title compounds (both C₉H₁₀O₄) have nearly planar structures, and the methyl and/or carboxylic acid groups lie out of the molecular plane, as dictated by steric interactions. 2,5‐Di­methoxy­benzoic acid (2,5‐DMBA) forms an unusual intramolecular hydrogen bond between the carboxylic acid group and the O atom of the methoxy group in the 2‐position [O⋯O = 2.547 (2) Å and O—H⋯O = 154 (3)°]. 2,4‐DMBA forms a typical hydrogen‐bond dimer with a neighboring mol­ecule.     

Two bis­(ammonium) 1,5‐naphthalene­disulfonate salts

The title compounds, bis­(ammonium) naphthalene‐1,5‐di­sul­fon­ate, 2NH₄⁺·C₁₀H₆O₆S₂²⁻, and bis­[1‐(hydroxy­methyl)‐3,5,7‐tri­aza‐1‐azoniatri­cyclo­[3.3.1.1^3,7]­decane] 1,5‐naphthalene­di­sul­fon­ate, 2C₇H₁₅N₄O⁺·C₁₀H₆O₆S₂²⁻, were prepared from the acid‐promoted reaction of hexa­methyl­enetetr­amine. In both structures, the di­sulfonate anion is positioned on an inversion center, with each sulfonate group contributing to the supramolecular assemblies via hydrogen bonds. The ammonium cations are linked to sulfonate groups by four distinct N⁺—H⃛⁻O—S contacts [N⃛O = 2.846 (2)–2.898 (2) Å and N—H⃛O = 160 (2)–175 (2)°], whereas the 1‐(hydroxy­methyl)‐3,5,7‐tri­aza‐1‐azoniatri­cyclo­[3.3.1.1^3,7]­decane cations form one O—H⃛⁻O—S [O⃛O = 2.628 (2) Å and O—H⃛O = 176°] and three C—H⃛⁻O—S [C⃛O = 3.359 (2)–3.380 (2) Å and C—H⃛O = 148–155°] interactions to neighboring sulfonate groups.     

Ethyl N‐[2‐(hydroxy­acetyl)­phenyl]­carbamate,ethyl N‐[2‐(hydroxy­acetyl)‐4‐iodo­phenyl]­carbamate and ethyl N‐[2‐(hydroxy­acetyl)‐4‐methyl­phenyl]­carbamate

In ethyl N‐[2‐(hydroxy­acetyl)phenyl]carbamate, C₁₁H₁₃NO₄, all of the non‐H atoms lie on a mirror plane in the space group Pnma; the mol­ecules are linked into simple chains by a single C—H⋯O hydrogen bond. The mol­ecules of ethyl N‐[2‐(hydroxy­acetyl)‐4‐iodo­phenyl]carbamate, C₁₁H₁₂INO₄, are linked into sheets by a combination of O—H⋯I and C—H⋯O hydrogen bonds and a dipolar I⋯O contact. Ethyl N‐­[2‐(hydroxy­acetyl)‐4‐methyl­phenyl]carbamate, C₁₂H₁₅NO₄, crystallizes with Z′ = 2 in the space group P; pairs of mol­ecules are weakly linked by an O—H⋯O hydrogen bond and these aggregates are linked into chains by two independent aromatic π–π stacking inter­actions.     

Conformational preferences in 2‐­nitrophenylthiolates: S‐(2‐nitro­phenyl) 4‐toluenethiosulfonate

In the title compound, C₁₃H₁₁NO₄S₂, the nitro group is rotated by 44.1 (1)° out of the plane of the adjacent aryl ring and the toluene­thio­sulfonate group is almost orthogonal to the plane of the nitrated aryl ring. There are three types of C—H?O hydrogen bond in the structure [C?O range 3.324 (3)–3.503 (3) Å; C—H?O range 160–173°] and these link the mol­ecules into a three‐dimensional framework.     

2‐Pyridone–tartronic acid (1/1), 3‐hydroxy­pyridinium hydrogen tartronate and 4‐hydroxy­pyridinium hydrogen tartronate

Tartronic acid forms a hydrogen‐bonded complex, C₅H₅NO·C₃H₄O₅, (I), with 2‐pyridone, while it forms acid salts, namely 3‐hydroxy­pyridinium hydrogen tartronate, (II), and 4‐hy­droxy­pyridinium hydrogen tartronate, (III), both C₅H₆NO⁺·C₃H₃O₅⁻, with 3‐hydroxy­pyridine and 4‐hydroxy­pyridine, respectively. In (I), the pyridone mol­ecules and the acid mol­ecules form R(8) and R(10) hydrogen‐bonded rings, respectively, around the inversion centres. In (II) and (III), the cations and anions are linked by N—H⋯O and O—H⋯O hydrogen bonds to form a hydrogen‐bonded chain. In each of (I), (II) and (III), an intermolecular hydrogen bond is formed between a carboxyl group and the hydroxyl group attached to the central C atom, and in (I), the hydroxyl group participates in an intramolecular hydrogen bond with a carbonyl group. No intermolecular hydrogen bond is formed between the carboxyl groups in (I), or between the carboxyl and carboxyl­ate groups in (II) and (III).     

cis‐Bis(3,6‐di­hydro‐2H‐1,2‐oxazine‐N)­di­iodo­platinum(II) and cis‐bis(3,4,5,6‐tetra­hydro‐2H‐1,2‐oxazine‐N)­di­iodo­platinum(II)

The title complexes, [Pt(C₄H₇NO)₂I₂], (I), and [Pt(C₄H₉NO)₂I₂], (II), possess similar square‐planar coordination geometries with modest distortions from ideality. For (I), the cis‐L—Pt—L angles are in the range 87.0 (4)–94.2 (3)°, while the trans angles are 174.4 (3) and 176.4 (3)°. For (II), cis‐L—Pt—L are 86.1 (8)–94.2 (6)° and trans‐L—Pt—L are 174.4 (6) and 177.4 (5)°. One 3,6‐di­hydro‐2H‐1,2‐oxazine ligand in (I) is rotated so that the N—O bond is out of the square plane by approximately 70°, while the N—C bond is only ca 20° out of the plane. The other oxazine ligand is rotated so that the N—C bond is about 80° out of the plane, while the N—O bond is out of the plane by approximately 24°. In (II), the 3,4,5,6‐tetra­hydro‐2H‐1,2‐oxazine ligands are also positioned with one having the N—O bond further out of the plane and the other having the N—C bond positioned in that fashion. Both ligands, however, are rotated approximately 90° compared with their positions in (I). In both complexes, this results in an unsymmetrical distortion of the I—Pt—N bond angles in which one is expanded and the other contracted. These features are compared to those of reported cis‐di­amine­di­iodo­platinum(II) complexes.     

Self‐assembled hydrogen‐bonded bilayers in 1,4‐diazabicyclo[2.2.2]octane–N‐(phosphonomethyl)iminodiacetic acid–water (1/1/1.5)

The title compound is a hydrated salt, 1,4‐diazo­nia­bi­cyclo­[2.2.2]­octane–N‐[(hydroxy­phosphinato)­methyl]­iminiodi­acetate–water (1/1/1.5), C₆H₁₄N₂²⁺·C₅H₈NO₇P^2?·1.5H₂O, in which one of the water mol­ecules lies across a twofold rotation axis in space group P2/n. The ionic components are linked into sheets by a combination of a three‐centre N—H?(O)₂ hydrogen bond and two‐centre O—H?O and N—H?O hydrogen bonds, and these sheets are pairwise linked by the water mol­ecules into bilayers, by means of further O—H?O hydrogen bonds.     

Melaminium bis(4‐hydroxybenzenesulfonate) dihydrate

The crystals of a new melaminium salt, 2,4,6‐tri­amino‐1,3,5‐triazine‐1,3‐diium bis(4‐hydroxy­benzene­sulfonate) dihydrate, C₃H₈N₆²⁺·2C₆H₅O₄S^?·2H₂O, are built up from doubly proton­ated melaminium(2+) residues, dissociated p‐phenol­sulfonate anions and water mol­ecules. The doubly protonated melaminium dication lies on a twofold axis. The hydroxyl group of the p‐hydroxybenzenesulfonate residue is roughly coplanar with the phenyl ring [dihedral angle 13 (2)°]. A combination of ionic and donor–acceptor hydrogen‐bond interactions link the melaminium and p‐hydroxybenzenesulfonate residues and the water mol­ecules to form a three‐dimensional network.     

Two new conformationally restricted 4,5‐dihydroxynorvaline analogues with a norbornane skeleton

The structures of two conformationally restricted 4,5‐di­hydroxy­norvaline analogues with a norbornane skeleton, namely methyl (1S,2S,3R,4R)‐2‐benz­amido‐3‐(1,2‐di­hydroxy­ethyl)­bi­cyclo[2.2.1]­heptane‐2‐carboxyl­ate, C₁₈H₂₃NO₅, and methyl (1R,2S,3R,4S)‐2‐benz­amido‐3‐(1,2‐di­hydroxy­ethyl)­bi­cyclo[2.2.1]­heptane‐2‐carboxyl­ate, C₁₈H₂₃NO₅, exhibit a conformation in the helical region of the ?,ψ map but their handedness is opposite. In both cases, the torsion angles (χ^1,1) giving the relative orientation of the 1,2‐di­hydroxy­ethyl group of the amino acid side chain and the benz­amide group of the peptide chain indicate that these groups adopt a nearly eclipsed conformation. Both compounds show a complex hydrogen‐bonding pattern.     

Supramolecular aggregation of two hydroxy­carboxylic acid derivatives

The crystal structures of 7,7‐dicyclo­but­yl‐5‐hydroxy­meth­yl‐6‐oxabicyclo­[3.2.1]octa­ne‐1‐carboxylic acid, C₁₇H₂₆O₄, (I), and 1‐(hydroxy­meth­yl)‐7‐oxaspiro­[bicyclo­[3.2.1]octa­ne‐6,1′‐cyclo­penta­ne]‐5‐carboxylic acid, C₁₃H₂₀O₄, (II), determined at 170 K, show that the conformation of the hydroxy­meth­yl group (anti or gauche) affects the dimensionality (one‐ or two‐dimensional) of the supramolecular structures via O—H⋯O hydrogen bonds. In (I), the carbox­yl and hydroxy­meth­yl groups inter­act with themselves, forming a one‐dimensional step‐ladder, while in (II), a two‐dimensional structure is made up of carboxylic acid centrosymmetric R₂²(8) dimers connected by hydrox­yl‐to‐ether contacts.     

Methyl 4‐O‐β‐d‐galacto­pyran­osyl α‐d‐gluco­pyran­oside (methyl α‐lactoside)

Methyl α‐lactoside, C₁₃H₂₄O₁₁, (I), is described by glycosidic torsion angles ϕ (O5_gal—C1_gal—O1_gal—C4_glc) and ψ (C1_gal—O1_gal—C4_glc—C5_glc), which have values of −93.52 (13) and −144.83 (11)°, respectively, where the ring atom numbering conforms to the convention in which C1 is the anomeric C atom and C6 is the exocyclic hydroxy­methyl (–CH₂OH) C atom in both residues. The linkage geometry is similar to that observed in methyl β‐lactoside methanol solvate, (II), in which ϕ is −88.4 (4)° and ψ is −161.3 (4)°. As in (II), an inter­molecular O3_glc—H⋯O5_gal hydrogen bond is observed in (I). The hydroxy­methyl group conformation in both residues is gauche–trans, with torsion angles ω_gal (O5_gal—C5_gal—C6_gal—O6_gal) and ω_glc (O5_glc—C5_glc—C6_glc—O6_glc) of 69.15 (13) and 72.55 (14)°, respectively. The latter torsion angle differs substantially from that found for (II) [−54.6 (2)°; gauche–gauche]. Cocrystallization of methanol, which is hydrogen bonded to O6_glc in the crystal structure of (II), presumably affects the hydroxy­methyl conformation in the Glc residue in (II).     

Phenyl‐ and mesitylglyoxylic acids: catemeric hydrogen bonding in two α‐keto acids

α‐Oxo­benzene­acetic (phenyl­glyoxy­lic) acid, C₈H₆O₃, adopts a transoid di­carbonyl conformation in the solid state, with the carboxyl group rotated 44.4 (1)° from the nearly planar benzoyl moiety. The heterochiral acid‐to‐ketone catemers [O?O = 2.686 (3) and H?O = 1.78 (4) Å] have a second, longer, intermolecular O—H?O contact to a carboxyl sp³ O atom [O?O = 3.274 (2) and H?O = 2.72 (4) Å], with each flat ribbon‐like chain lying in the bc plane and extending in the c direction. In α‐oxo‐2,4,6‐tri­methyl­benzene­acetic (mesityl­glyoxy­lic) acid, C₁₁H₁₂O₃, the ketone is rotated 49.1 (7)° from planarity with the aryl ring and the carboxyl group is rotated a further 31.2 (7)° from the ketone plane. The solid consists of chiral conformers of a single handedness, aggregating in hydrogen‐bonding chains whose units are related by a 3₁ screw axis, producing hydrogen‐bonding helices that extend in the c direction. The hydrogen bonding is of the acid‐to‐acid type [O?O = 2.709 (6) and H?O = 1.87 (5) Å] and does not formally involve the ketone; however, the ketone O atom in the acceptor mol­ecule has a close polar contact with the same donor carboxyl group [O?O = 3.005 (6) and H?O = 2.50 (5) Å]. This secondary hydrogen bond is probably a major factor in stabilizing the observed cisoid di­carbonyl conformation. Several intermolecular C—H?O close contacts were found for the latter compound.     

A zwitterion of 1,5‐bis­(2‐hydroxy­benzamido)‐3‐aza­pentane: a two‐dimensional hydrogen‐bonding network involving dimers

The title compound, 2‐{N‐[2‐(2‐hydroxy­benzamido)ethyl­ammonio­ethyl]amino­carbon­yl}phenolate, C₁₈H₂₁N₃O₄, crystallizes in a zwitterionic form as a result of inter­molecular proton transfer and possesses a negatively charged phenolate group and a protonated amino group. The 2‐hydroxy­benzamide and 2‐(amino­carbonyl)­phenolate moieties attached to the two ends of the C—C—N—C—C backbone adopt a cis conformation in relation to this backbone. All N‐ and O‐bound H atoms are involved in hydrogen‐bond formation; the zwitterions are first linked into head‐to‐tail dimers, which are further organized into a two‐dimensional network parallel to the crystallographic bc plane.     

Adducts of 1,1,1‐tris(4‐hydroxyphenyl)ethane with diamines: three‐dimensional hydrogen‐bonded frameworks formed with 1,6‐diaminohexane and 2,2′‐bipyridyl

The adduct 1,6‐di­amino­hexane–1,1,1‐tris(4‐hydroxy­phenyl)­ethane (1/2) is a salt {hexane‐1,6‐diyldiammonium–4‐[1,1‐bis(4‐hydroxyphenyl)ethyl]phenolate (1/2)}, C₆H₁₈N₂²⁺·2C₂₀H₁₇O₃^?, in which the cation lies across a centre of inversion in space group P. The anions are linked by two short O—H?O hydrogen bonds [H?O 1.74 and 1.76 Å, O?O 2.5702 (12) and 2.5855 (12) Å, and O—H?O 168 and 169°] into a chain containing two types of R(24) ring. Each cation is linked to four different anion chains by three N—H?O hydrogen bonds [H?O 1.76–2.06 Å, N?O 2.6749 (14)–2.9159 (14) Å and N—H?O 156–172°]. In the adduct 2,2′‐bipyridyl–1,1,1‐tris(4‐hydroxy­phenyl)­ethane (1/2), C₁₀H₈N₂·2C₂₀H₁₈O₃, the neutral di­amine lies across a centre of inversion in space group P2₁/n. The tris­(phenol) mol­ecules are linked by two O—H?O hydrogen bonds [H?O both 1.90 Å, O?O 2.7303 (14) and 2.7415 (15) Å, and O—H?O 173 and 176°] into sheets built from R(38) rings. Pairs of tris­(phenol) sheets are linked via the di­amine by means of a single O—H?N hydrogen bond [H?N 1.97 Å, O?N 2.7833 (16) Å and O—H?N 163°].     

4‐Fluoro‐2‐(phospho­no­methyl)­benzene­sulfonic acid monohydrate

The title compound, C₇H₈FO₆PS·H₂O, contains both phospho­nic and sulfonic acid functionalities. An extensive network of O—H?O hydrogen bonds is present in the crystal structure. The three acidic protons are associated with the phospho­nate group. Two protons experience typical hydrogen‐bond contacts with the sulfonate‐O atoms, while the third has a longer covalent bond of 1.05 (3) Å to the phospho­nate‐O atom and a short hydrogen‐bond contact of 1.38 (3) Å to the water O atom (all O—H?O angles are in the range 162–175°). The sulfonate group is positioned so that one S—O bond is nearly coplanar with the phenyl ring [torsion angle O—S—C—C ?8.6 (2)°]. The phospho­nate group is oriented approximately perpendicular to the ring [torsion angle P—C—C—C 99.2 (2)°] with one P—O bond anti to the benzyl C—C bond. The mol­ecules pack in layers in the b–c plane with the water mol­ecules in between adjacent pairs of inverted layers.