Head‐to‐head dimers in the zwitterion of 1‐hydroxy‐3‐(pyrrolidin‐1‐yl)pro­pyl­idene‐1,1‐bis­phospho­nic acid (EB 1053)

The title compound, 1‐hydroxy‐1‐phospho­no‐3‐(1‐pyr­rol­idin­io)­propyl­idene‐1‐phospho­nate, C₇H₁₇NO₇P₂, is a member of the bis­phospho­nate class of drugs. As a zwitterion, it possesses a negative charge on one of the PO₃ groups and a positive charge on the pyrrolidine N atom. A zwitterion makes a contact with a neighbouring ion through the hydroxyl O atom and two phospho­nyl O atoms, one each from two different PO₃ groups. Hydro­gen bonding involves O—H⋯O and N—H⋯O interactions; the former are involved in the formation of head‐to‐head dimers, while the latter join the dimers into a chain running along the crystallographic b axis.     

2‐(Hydro­xy­methyl)­pyridinium di­hydrogenphosphate

The title compound, C₆H₈NO⁺·H₂PO₄⁻, consists of 2‐(hy­droxy­methyl)­pyridinium and di­hydrogen­phosphate ions. The di­hydrogen­phosphate moieties are linked into chains by pairs of P—O—H⃛O—P hydrogen bonds. The 2‐(hydroxy­methyl)­pyridinium cations are connected to the di­hydrogen­phosphate units by O—H⃛O and N—H⃛O hydrogen bonds. Weak π–π interactions help to determine the interchain packing.     

Di­aza­bi­cyclo­[2.2.2]­octane‐1,4‐diium dichromate

The title compound, (C₆H₁₄N₂)[Cr₂O₇], consists of a di­aza­bi­cyclo­[2.2.2]­octane‐1,4‐diium cation and a discrete dichromate anion, which are linked in the crystal by N—H⋯O hydrogen bonds. The cation is ordered and distorted, owing to the confinement and twist of the hydrogen bonds involved. Two CrO₄ tetrahedra are joined through a shared O atom to form the dichromate anion. Chiral supramolecular chains of the title compound are built up via N—H⋯O hydrogen bonds, and C—H⋯O interactions play subordinate roles in forming the structure.     

Tri­phenyl­phosphine oxide–1‐naphthoic acid (1/1)

In the title compound, C₁₈H₁₅OP·C₁₁H₈O₂, co‐crystallization of tri­phenyl­phosphine oxide with 1‐naphthoic acid yields a supramolecular structure held together by one O—H⋯O and three C—H⋯O hydrogen bonds. The O—H⋯O hydrogen bond [O⋯O = 2.592 (2) Å] has little effect on the O=P bond distance.     

N‐(2,4‐Dimethoxy­benzyl­idene­amino)­guanidinium dihydrogenphosphate

In the asymmetric unit of the title compound, C₁₀H₁₅N₄O₂⁺·H₂PO₄⁻, there are two protonated amino­guanidinium cations and two dihydrogenphosphate anions. The positive charge on the protonated amidine group is delocalized over the three C—N bonds in a manner similar to that found in guanidinium salts. The amino­guanidinium cations are found to be the E‐isomer structures. Intra­molecular inter­actions of the N—H⋯N type are observed, leading to the formation of five‐membered rings. Extensive networks of O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds stabilize the three‐dimensional network. In the crystal structure, π–π inter­actions between the benzene rings, with a distance of 3.778 (2) Å between the ring centroids, also affect the packing of the mol­ecules.     

Self‐assembly of 2‐pivaloyl‐6‐chloro­pterin

In the title compound, N‐(6‐chloro‐4‐oxo‐3,4‐di­hydro­pteridin‐2‐yl)­‐2,2‐di­methyl­propan­amide, C₁₁H₁₂ClN₅O₂, the rings in the pterin moiety are planar. The amide carbonyl O atom is in syn‐periplanar conformation while the C—N—C—C propanamide linkage is antiperiplanar. The N—H?N and N—H?O intermolecular hydrogen bonds transform the mol­ecules into infinite chains.     

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.     

A hydrated ethyl­ene­di­ammonium salt of a new polymeric polyoxoanion: (H2en)4[Co(H2O)2(OH)2(VO)6(HPO4)4(PO4)4]·3H2O

The title compound, tetrakis­(ethyl­enedi­ammonium) tetra‐μ‐hydrogenphosphato‐di‐μ‐hydro­xo‐ tetra‐μ‐phosphato‐bis­(aqua­cobalt)­hexakis­(oxovanadium) trihydrate, was synthesized hydro­thermally at moderate temperature. The structure consists of diprotonated ethyl­enedi­ammonium cations and layers of the polyanions. The polyanion contains four PO₄ tetrahedra and three VO₅ square pyramids that are linked through corner‐sharing by alternating P—O—V, which gives rise to a chain. The chains, connected by CoO₄(H₂O)₂ octahedra, form layers, resulting in a two‐dimensional layered structure. The Co—O distances are in the range 1.984 (3)–2.038 (4) Å, the P—O distances 1.508 (3)–1.575 (3) Å and the V—O distances 1.585 (3)–2.010 (3) Å.     

N,N′,N′′‐Tris(p‐methoxy­phenyl)­phospho­ric triamide

The title compound, C₂₁H₂₄N₃O₄P, is a self‐complementary hydrogen‐bond (HB) building unit, with (P=)O as the primary HB acceptor and N—H as the HB donor. Each of the four crystallographically distinct and nearly parallel mol­ecules of the unit cell has a net dipole moment along the P=O bond direction and all of the dipoles are directed in the same general crystallographic direction. Head‐to‐tail N—H⋯O=P double‐HB strands stack adjacent mol­ecules into one‐dimensional infinite polar columns. Each polar column is a 2₁ helix and all columns are essentially parallel, resulting in polar order throughout the entire crystal.     

2,4′‐Iso­propyl­idene­diphenol

Molecules of the title compound [systematic name: 2,4′‐(propane‐2,2‐diyl)diphenol], C₁₅H₁₆O₂, are linked through intermolecular O—H·O hydrogen bonds into infinite zigzag chains. The molecular structure is compared with that of the related compound 4,4′‐iso­propyl­idene­diphenol.     

Poly[[diaqua­cadmium(II)]‐μ4‐[N‐(phosphonato­methyl)ammonio]acetato]

The title compound, [Cd(C₃H₆NO₅P)(H₂O)₂]_n, is a three‐dimensional polymeric complex. The asymmetric unit contains one Cd atom, one N‐(phosphono­methyl)glycine zwitterion [(O⁻)₂OPCH₂NH₂⁺CH₂COO⁻] and two water mol­ecules. The coordination geometry is a distorted CdO₆ octa­hedron. Each N‐(phosphono­methyl)glycine ligand bridges four adjacent water‐coordinated Cd cations through three phospho­nate O atoms and one carboxyl­ate O atom, like a regular PO₄³⁻ group in zeolite‐type frameworks. One‐dimensional zigzag (–O—P—C—N—C—C—O—Cd–)_n chains along the [101] direction are linked to one another via Cd—O—P bridges and form a three‐dimensional network motif with three types of channel systems. The variety of O—H⋯O and N—H⋯O hydrogen bonds is likely to be responsible for stabilizing the three‐dimensional network structure and preventing guest mol­ecules from entering into the channels.     

(Z)‐1‐Ferrocenyl‐3‐(3‐hydroxy­anilino)­but‐2‐en‐1‐one and (Z)‐1‐ferrocenyl‐3‐(4‐hydroxy­anilino)­but‐2‐en‐1‐one

The title compounds, both [Fe(C₅H₅)(C₁₅H₁₄NO₂)], crystallize with Z′ = 2 in the centrosymmetric space group P. In each compound, there is an intra­molecular N—H⋯O=C hydrogen bond, and pairs of inter­molecular O—H⋯O=C hydrogen bonds link the mol­ecules into chains, parallel to [10] in the 3‐hydr­oxy compound and parallel to [10] in the 4‐hydr­oxy compound.     

Tri­benzyl­phosphine oxide

The title compound, (C₆H₅CH₂)₃PO, is an organic tertiary phosphine oxide. The mol­ecule has threefold symmetry, with the P—O bond along the threefold axis. Main dimensions include P—O 1.488 (4), P—C 1.823 (3) Å and O—P—C 114.7 (1)°. The crystals were accidentally obtained when preparing complexes of nickel(II) with di­benzyl­phosphine.     

5‐Chloro‐N‐(2‐hydroxy‐5‐methyl­phenyl)­salicyl­ald­imine

The title compound, N‐(5‐chloro‐2‐oxido­benzyl­idene)‐2‐hydroxy‐5‐methyl­anilinium, C₁₄H₁₂ClNO₂, is a tridentate Schiff base with almost planar molecules. Each mol­ecule contains a strong intramolecular N—H?O hydrogen bond [2.576 (2) Å]. There is also an intermolecular O—H?O hydrogen bond [2.695 (2) Å] linking neighbouring mol­ecules into infinite chains along the [101] direction.     

Charge‐assisted N—H·I and C—H·I hydrogen bonding in (1R,2S)‐1‐(ferrocenylmethyl)‐2‐(methoxymethyl)pyrrolidinium iodide

In the title compound, [Fe(C₅H₅)(C₁₂H₁₉NO)]I, the ferrocene moiety has an eclipsed conformation, with mean Fe—C bond lengths of 2.031 (4) and 2.020 (6) Å for the substituted and unsubstituted cyclo­penta­dienyl rings. The pyrrolidinium heterocycle adopts an envelope conformation and has its 1‐ and 2‐substituents in a relative trans disposition. Strong (+/−)‐charge‐assisted N—H·I and C—H·I hydrogen bonds are present. The crystal structure is also stabilized by weak C—H·O interactions.     

[(4,4‐Dimethyl‐2‐oxo‐1,3‐oxazolidin‐3‐yl)methyl]phosphonic acid

The title compound, C₆H₁₂NO₅P, was synthesized as an inter­mediate phase in a search for new N‐(phosphono­methyl)glycine derivatives. The mol­ecules are held together by O—H⋯O hydrogen bonds, forming chains along the b axis in the crystal structure. The observed mol­ecular structure is compared with that calculated by the density functional theory method.     

4‐[N,N‐Bis(2‐hydroxy­imino‐2‐phenyl­ethyl)­amino]‐1,5‐di­methyl‐2‐phenyl‐2,3‐di­hydro‐1H‐pyrazol‐3‐one monohydrate

The title compound, C₂₇H₂₇N₅O₃·H₂O, is built up from pyrazolinone, phenyl and aceto­phenone oxime moieties. The 2‐­phenyl substituent is nearly perpendicular to the pyrazo­linone ring, with a dihedral angle of 87.66 (1)°. The aceto­phenone oxime moieties are twisted out of the pyrazolinone‐ring plane by 47.04 (1)°. The mol­ecules in the crystal pack in an antiparallel fashion and are held together by hydrogen‐bonded water mol­ecules and intermolecular O—H⋯O and O—H⋯N hydrogen bonds.     

2′,4′‐Di­hydroxy‐3‐methoxy‐α,β‐di­hydro­chalcone and 2′,4‐di­hydroxy‐α,β‐di­hydro­chalcone: supramolecular structures formed by O—H⋯O,C—H⋯O and stacking interactions

The crystal structures of 2′,4′‐di­hydroxy‐3‐methoxy‐α,β‐di­hydro­chalcone, C₁₆H₁₆O₄, and 2′,4‐di­hydroxy‐α,β‐di­hydro­chalcone, C₁₅H₁₄O₃, have been determined. In both compounds, the structure consists of two nearly planar six‐membered aromatic rings connected by a propanal chain, which is bent in the methoxy compound and almost straight in the other compound. In the crystal structures, the molecular units of both compounds are linked by O—H⋯O hydrogen bonds to form infinite one‐dimensional chains. Hydro­gen bonds and C—H⋯O contacts in the crystal structures were studied by topological analysis of charge density based on Hartree–Fock calculations. Almost all of the investigated C—H⋯O contacts should be characterized as weak hydrogen bonds.     

Ethyl (E)‐3‐(2‐hydroxy­phenyl)‐2‐(morpholino­carbonyl)­propenoate

The title compound, C₁₆H₁₉NO₅, crystallizes as a centrosymmetric dimer through strong O—H⋯O hydrogen‐bonding interactions between the hydroxy­phenyl and morpholino­carbonyl groups. The morpholino­carbonyl group is almost perpendicular to the propenoate moiety. Electron delocalization in the N—C(=O) fragment leads to the formation of hydrogen‐bonded S(5) ring motifs through C—H⋯O interactions.     

Triphenylphosphine oxide–3‐chlorobenzoic acid (1/1)

In the title compound, C₁₈H₁₅OP·C₇H₅ClO₂, the tri­phenyl­phosphine oxide molecule forms a single directed hydrogen bond with the 3‐chloro­benzoic acid molecule, with an O⃛O=P distance of 2.607 (2) Å. The C—Cl and C=O bonds adopt a cisoid conformation in the 3‐chloro­benzoic acid molecule.