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.     

6,6′‐Di­methoxy‐2,2′‐[(1R,2R)‐cyclo­hexane‐1,2‐diyl­bis­(nitrilo­methyl­idyne)]­diphenol: three C—H⃛O hydrogen bonds generate a three‐dimensional framework

Molecules of the title compound, alternatively called (R,R)‐N,N′‐bis(3‐methoxysalicylidene)‐trans‐cyclohexane‐1,2‐diamine, C₂₂H₂₆N₂O₄, contain two intramolecular O—H⃛N hydrogen bonds and adopt a conformation with approximate twofold rotational symmetry. The mol­ecules are linked by three C—H⃛O hydrogen bonds [H⃛O = 2.45–2.55 Å, C⃛O = 3.329 (2)–3.398 (2) Å and C—H⃛O = 142–172°] into a continuous framework.     

Supramolecular structures of bis‐thionooxalamic acid esters derived from (±)‐cyclohexane‐1,2‐diamine and (±)‐1,2‐diphenylethylenediamine

The bis‐thionooxalamic acid esters trans‐(±)‐diethyl N,N′‐(cyclohexane‐1,2‐diyl)bis(2‐thiooxamate), C₁₄H₂₂N₂O₄S₂, and (±)‐N,N′‐diethyl (1,2‐diphenylethane‐1,2‐diyl)bis(2‐thiooxamate), C₂₂H₂₄N₂O₄S₂, both consist of conformationally flexible molecules which adopt similar conformations with approximate C₂ rotational symmetry. The thioamide and ester parts of the thiooxamate group are significantly twisted along the central C—C bond, with the S=C—C=O torsion angles in the range 30.94 (19)–44.77 (19)°. The twisted s‐cis conformation of the thionooxamide groups facilitates assembly of molecules into a one‐dimensional polymeric structure via intermolecular three‐center C=S...NH...O=C hydrogen bonds and C—H...O interactions formed between molecules of the opposite chirality.     

Ethyl N‐phenyl­oxamate

The oxamate group in the title compound, C₁₀H₁₁NO₃, is almost coplanar with the phenyl ring because of intramol­ecular hydrogen‐bonding interactions, and the structure can be described as an anilide single bonded to an ethyl carboxyl­ate group. The supramolecular structure is achieved through intermolecular hard N—H⋯O and soft C—H⋯X (X = O and phenyl) hydrogen‐bonding interactions.     

2‐Benzyl­amino‐6‐benzyl­oxy­pyrimidin‐4(3H)‐one: hydrogen‐bonded chains of rings linked into sheets by a π–π‐stacking interaction

The title compound, C₁₈H₁₇N₃O₂, crystallizes with Z′ = 2 in space group P2₁/c, and the two independent mol­ecules are approximate, but not exact, mirror images. The molecular–electronic structure is strongly polarized, and the mol­ecules are linked by paired N—H⃛O hydrogen bonds [H⃛O = 2.00–2.23 Å, N⃛O = 2.798 (3)–2.992 (3) Å and N—H⃛O = 145–151°] into two independent C(4)C(6)[(6)] chains of rings, which are linked into sheets by a single aromatic π–π‐stacking interaction.     

4‐Ethynyl‐4‐hydroxycyclohexan‐1‐one and 4‐ethynyl‐4‐hydroxy‐2,3,5,6‐tetramethylcyclohexa‐2,5‐dien‐1‐one

The title compounds, C₈H₁₀O₂, (I), and C₁₂H₁₄O₂, (II), occurred as by‐products in the controlled synthesis of a series of bis­(gem‐alkynols), prepared as part of an extensive study of synthon formation in simple gem‐alkynol derivatives. The two 4‐(gem‐alkynol)‐1‐ones crystallize in space group P2₁/c, (I) with Z′ = 1 and (II) with Z′ = 2. Both structures are dominated by O—H?O=C hydrogen bonds, which form simple chains in the cyclo­hexane derivative, (I), and centrosymmetric dimers, of both symmetry‐independent mol­ecules, in the cyclo­hexa‐2,5‐diene, (II). These strong synthons are further stabilized by C[triple‐bond]C—H?O=C, C_methylene—H?O(H) and C_methyl—H?O(H) interactions. The direct intermolecular interactions between donors and acceptors in the gem‐alkynol group, which characterize the bis­(gem‐alkynol) analogues of (I) and (II), are not present in the ketone derivatives studied here.     

π‐Stacked hydrogen‐bonded dimers in 2‐(2‐nitro­phenyl­amino­carbonyl)­benzoic acid,and hydrogen‐bonded sheets in orthorhombic and monoclinic polymorphs of 2‐(4‐nitro­phenyl­amino­carbonyl)­benzoic acid

Molecules of 2‐(2‐nitrophenylaminocarbonyl)benzoic acid, C₁₄H₁₀N₂O₅, are linked into centrosymmetric R(8) dimers by a single O—H⋯O hydrogen bond [H⋯O = 1.78 Å, O⋯O = 2.623 (2) Å and O—H⋯O = 178°] and these dimers are linked into sheets by a single aromatic π–π stacking interaction. The isomeric compound 2‐(4‐nitrophenylaminocarbonyl)benzoic acid crystallizes in two polymorphic forms. In the orthorhombic form (space group P2₁2₁2₁ with Z′ = 1, crystallized from ethanol), the mol­ecules are linked into sheets of R(22) rings by a combination of one N—H⋯O hydrogen bond [H⋯O = 1.96 Å, N⋯O = 2.833 (3) Å and N—H⋯O = 171°] and one O—H⋯O hydrogen bond [H⋯O = 1.78 Å, O⋯O = 2.614 (3) Å and O—H⋯O = 173°]. In the monoclinic form (space group P2₁/n with Z′ = 2, crystallized from acetone), the mol­ecules are linked by a combination of two N—H⋯O hydrogen bonds [H⋯O = 2.09 and 2.16 Å, N⋯O = 2.873 (4) and 2.902 (3) Å, and N—H⋯O = 147 and 141°] and two O—H⋯O hydrogen bonds [H⋯O = 1.84 and 1.83 Å, O⋯O = 2.664 (3) and 2.666 (3) Å, and O—H⋯O = 166 and 174°] into sheets of some complexity. These sheets are linked into a three‐dimensional framework by a single C—H⋯O hydrogen bond [H⋯O = 2.45 Å, C⋯O = 3.355 (4) Å and C—­H⋯O = 160°].     

Dimorphism in (2Z)‐2‐benzyl­idene‐N,7‐dimethyl‐3‐oxo‐5‐phenyl‐2,3‐dihydro‐5H‐1,3‐thia­zolo[3,2‐a]pyrimidine‐6‐carboxamide

The title compound, C₂₂H₁₉N₃O₂S, crystallizes in two polymorphic forms having the same space group, viz. P, with Z′ = 2 and Z′ = 1. In both polymorphs, the planar thia­zole ring is fused cis with the dihydro­pyrimidine ring, the carbamoyl group is in an extended conformation with an anti­clinal orientation with respect to the pyrimidine ring, and the phenyl ring is attached to the pyrimidine ring approximately at a right angle. The two polymorphs have different inter­planar angles between the phenyl and thia­zole rings. The mol­ecules are linked by N—H⋯O and C—H⋯O hydrogen bonds.     

N,N′‐Bis(2‐pyridylmeth­yl)ferrocene‐1,1′‐diyldicarboxamide and N,N′‐bis­(3‐pyridylmeth­yl)ferrocene‐1,1′‐diyldicarboxamide

The mol­ecules of N,N′‐bis­(2‐pyridylmeth­yl)ferrocene‐1,1′‐diyl­dicarboxamide, [Fe(C₁₂H₁₁N₂O)₂], contain intra­molecular N—H⋯N hydrogen bonds and are linked into sheets by three independent C—H⋯O hydrogen bonds. The mol­ecules of the isomeric compound N,N′‐bis­(3‐pyridylmeth­yl)ferrocene‐1,1′‐diyldicarboxamide lie across inversion centres, and the mol­ecules are linked into sheets by a combination of N—H⋯N hydrogen bonds and π–π stacking inter­actions between pyridyl groups.     

Three new [XC(O)NH]P(O)[N(CH2C6H5)2]2 phosphoric triamides (X = CClF2, 3‐F‐C6H4 and 3,5‐F2‐C6H3): a database analysis of tertiary N‐atom geometry in compounds with a C(O)NHP(O)[N]2 core

In the phosphoric triamides N,N,N′,N′‐tetrabenzyl‐N′′‐(2‐chloro‐2,2‐difluoroacetyl)phosphoric triamide, C₃₀H₂₉ClF₂N₃O₂P, (I), N,N,N′,N′‐tetrabenzyl‐N′′‐(3‐fluorobenzoyl)phosphoric triamide, C₃₅H₃₃FN₃O₂P, (II), and N,N,N′,N′‐tetrabenzyl‐N′′‐(3,5‐difluorobenzoyl)phosphoric triamide, C₃₅H₃₂F₂N₃O₂P, (III), the tertiary N atoms of the dibenzylamido groups have sp² character with minimal deviation from planarity. The sums of the three bond angles about the N atoms in (I)–(III) deviate by less than 8° from the planar value of 360°. The geometries of the tertiary N atoms in all phosphoric triamides with C(O)NHP(O)[N]₂ skeletons deposited in the Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B 58 , 380–388] have been examined and the bond‐angle sums at the two tertiary N atoms (SUM1 and SUM2) and the parameter ΔSUM (= SUM1 − SUM2) considered. It was found that in compounds with a considerable ΔSUM value, the more pyramidal N atoms are usually oriented so that the corresponding lone electron pair is anti with respect to the P=O group. In (I), (II) and (III), the phosphoryl and carbonyl groups, separated by an N atom, are anti with respect to each other. In the C(O)NHP(O) fragment of (I)–(III), the P—N bond is longer and the O—P—N angle is contracted compared with the other two P—N bonds and the O—P—N angles in the molecules. These effects are also seen in analogous compounds deposited in the CSD. Compounds with [C(O)NH]P(O)[N]X (X≠ N), such as compounds with a [C(O)NH]P(O)[N][O] skeleton, have not been considered here. Also, compounds with a [C(O)NH]₂P(O)[N] fragment have not been reported to date. In the crystal structures of all three title compounds, adjacent molecules are linked via pairs of P=O...H—N hydrogen bonds, forming dimers with C_i symmetry.     

2,2,2‐Trinitroethanol

2,2,2‐Trinitroethanol, C₂H₃N₃O₇, at 100 (2) K has Z′ = 2 in the space group P2₁/c. The structure displays intramolecular O—H...O hydrogen bonds, as well as intermolecular O—H...O and C—H...O hydrogen bonding; the O—H...O hydrogen bonds, forming R₄⁴(8) rings, and dipolar nitro–nitro interactions account for the high density of 1.839 Mg m⁻³.     

Hydrogen‐bonded supramolecular networks of N,N′‐bis(4‐pyridylmethyl)oxalamide and 4,4′‐{[oxalylbis(azanediyl)]dimethylene}dipyridinium dinitrate

The molecule of N,N′‐bis(4‐pyridylmethyl)oxalamide, C₁₄H₁₄N₄O₂, (I) or 4py‐ox, has an inversion center in the middle of the oxalamide group. Adjacent molecules are then linked through intermolecular N—H...N and C—H...O hydrogen bonds, forming an extended supramolecular network. 4,4′‐{[Oxalylbis(azanediyl)]dimethylene}dipyridinium dinitrate, C₁₄H₁₆N₄O₂²⁺·2NO₃⁻, (II), contains a diprotonated 4py‐ox cation and two nitrate counter‐anions. Each nitrate ion is hydrogen bonded to four 4py‐ox cations via intermolecular N—H...O and C—H...O interactions. Adjacent 4py‐ox cations are linked through weak C—H...O hydrogen bonding between an α‐pyridinium C atom and an oxalamide O atom, forming a two‐dimensional extended supramolecular network.     

Weak C—H...O and C—H...π hydrogen bonds and π–π stacking interactions in a series of four N′‐[(E)‐(aryl)methylidene]‐N‐methyl‐2‐oxo‐1,3‐oxazolidine‐4‐carbohydrazides

Oxazolidin‐2‐ones are widely used as protective groups for 1,2‐amino alcohols and chiral derivatives are employed as chiral auxiliaries. The crystal structures of four differently substituted oxazolidinecarbohydrazides, namely N′‐[(E)‐benzylidene]‐N‐methyl‐2‐oxo‐1,3‐oxazolidine‐4‐carbohydrazide, C₁₂H₁₂N₃O₃, (I), N′‐[(E)‐2‐chlorobenzylidene]‐N‐methyl‐2‐oxo‐1,3‐oxazolidine‐4‐carbohydrazide, C₁₂H₁₂ClN₃O₃, (II), (4S)‐N′‐[(E)‐4‐chlorobenzylidene]‐N‐methyl‐2‐oxo‐1,3‐oxazolidine‐4‐carbohydrazide, C₁₂H₁₂ClN₃O₃, (III), and (4S)‐N′‐[(E)‐2,6‐dichlorobenzylidene]‐N,3‐dimethyl‐2‐oxo‐1,3‐oxazolidine‐4‐carbohydrazide, C₁₃H₁₃Cl₂N₃O₃, (IV), show that an unexpected mild‐condition racemization from the chiral starting materials has occurred in (I) and (II). In the extended structures, the centrosymmetric phases, which each crystallize with two molecules (A and B) in the asymmetric unit, form A+B dimers linked by pairs of N—H...O hydrogen bonds, albeit with different O‐atom acceptors. One dimer is composed of one molecule with an S configuration for its stereogenic centre and the other with an R configuration, and possesses approximate local inversion symmetry. The other dimer consists of either R,R or S,S pairs and possesses approximate local twofold symmetry. In the chiral structure, N—H...O hydrogen bonds link the molecules into C(5) chains, with adjacent molecules related by a 2₁ screw axis. A wide variety of weak interactions, including C—H...O, C—H...Cl, C—H...π and π–π stacking interactions, occur in these structures, but there is little conformity between them.     

Hydro­gen‐bonded adducts of ferrocene‐1,1′‐diyl­bis­(di­phenyl­methanol): monomeric and dimeric 1:1 adducts with 1,2‐bis(4‐pyridyl)­ethane and 1,2‐­diamino­ethane

In ferrocene‐1,1′‐diyl­bis­(di­phenyl­methanol)–4,4′‐ethyl­enedi­pyridine (1/1), [Fe(C₁₈H₁₅O)₂]·C₁₂H₁₂N₂, there is an intra­molecular O—H?O hydrogen bond in the ferrocenediol component and a single O—H?N hydrogen bond linking the two components into a finite monomeric adduct. Ferrocene‐1,1′‐diyl­bis­(di­phenyl­methanol)–ethyl­enedi­amine (1/1), [Fe(C₁₈H₁₅O)₂]·C₂H₈N₂, crystallizes with Z′ = 2 in space group P, and there are two independent four‐component aggregates in the structure, both of which are centrosymmetric. In the first type of aggregate, the molecular components are linked by O—H?N and N—H?O hydrogen bonds, in which both di­amine N atoms participate; in the second type of aggregate, the di­amine component is disordered over two sets of sites, but only one N atom is involved in the hydrogen bonding.     

Twist‐chair conformation of the tetraoxepane ring remains unchanged in tetraoxaspirododecane diamines

A detailed structural analysis has been performed for N,N′‐bis(4‐chlorophenyl)‐7,8,11,12‐tetraoxaspiro[5.6]dodecane‐9,10‐diamine, C₂₀H₂₂Cl₂N₂O₄, (I), N,N′‐bis(2‐fluorophenyl)‐7,8,11,12‐tetraoxaspiro[5.6]dodecane‐9,10‐diamine, C₂₀H₂₂F₂N₂O₄, (II), and N,N′‐bis(4‐fluorophenyl)‐7,8,11,12‐tetraoxaspiro[5.6]dodecane‐9,10‐diamine, C₂₀H₂₂F₂N₂O₄, (III). The seven‐membered ring with two peroxide groups adopts a twist‐chair conformation in all three compounds. The lengths of the C—N and O—O bonds are slightly shorter than the average statistical values found in the literature for azepanes and 1,2,4,5‐tetraoxepanes. The geometry analysis of compounds (I)–(III), the topological analysis of the electron density at the (3, ?1) bond critical points within Bader's quantum theory of `Atoms in molecules' (QTAIM) and NBO (natural bond orbital) analysis at the B3LYP/6‐31G(d,2p) level of theory showed that there are n_O→σ*(C—O), n_N→σ*(C—O) and n_O→σ*(C—N) stereoelectronic effects. The molecules of compounds (I) and (III) are packed in the crystals as zigzag chains due to strong N—H…O and C—H…O hydrogen‐bond interactions, whereas the molecules of compound (II) form chains in the crystals bound by N—H…O, C—H…π and C—H…O contacts. All these data show that halogen atoms and their positions have a minimal effect on the geometric parameters, stereoelectronic effects and crystal packing of compounds (I)–(III), so that the twist‐chair conformation of the tetraoxepane ring remains unchanged.     

Assembling an isomer grid: the isomorphous 4‐, 3‐ and 2‐fluoro‐N′‐(4‐pyridyl)benzamides

The three title isomers, 4‐, (I), 3‐, (II), and 2‐fluoro‐N′‐(4‐pyridyl)benzamide, (III), all C₁₂H₉FN₂O, crystallize in the P2₁/c space group (No. 14) with similar unit‐cell parameters and are isomorphous and isostructural at the primary hydrogen‐bonding level. An intramolecular C—H...O=C interaction is present in all three isomers [C...O = 2.8681 (17)–2.884 (2) Å and C—H...O117–118°], with an additional N—H...F [N...F = 2.7544 (15) Å] interaction in (III). Intermolecular amide–pyridine N—H...N hydrogen bonds link molecules into one‐dimensional zigzag chains [graph set C(6)] along the [010] direction as the primary hydrogen bond [N...N = 3.022 (2), 3.049 (2) and 3.0213 (17) Å]. These are augmented in (I) by C—H...π(arene) and cyclic C—F...π(arene) contacts about inversion centres, in (II) by C—F...F—C interactions [C...F = 3.037 (2) Å] and weaker C—H...π(arene)/C—H...F contacts, and in (III) by C—H...π(arene) and C=O...O=C interactions, linking the alternating chains into two‐dimensional sheets. Typical amide N—H...O=C hydrogen bonds [as C(4) chains] are not present [N...O = 3.438 (2) Å in (I), 3.562 (2) Å in (II) and 3.7854 (16) Å in (III)]; the C=O group is effectively shielded and only participates in weaker interactions/contacts. This series is unusual as the three isomers are isomorphous (having similar unit‐cell parameters, packing and alignment), but they differ in their interactions and contacts at the secondary level.     

Hydrogen‐bonded chains in 2,2,2‐trichloro‐N,N′‐bis(4‐methoxyphenyl)ethane‐1,1‐diamine and a three‐dimensional hydrogen‐bonded framework in 2,2,2‐trichloro‐N,N′‐bis(4‐chlorophenyl)ethane‐1,1‐diamine

In 2,2,2‐trichloro‐N,N′‐bis(4‐methoxyphenyl)ethane‐1,1‐diamine, C₁₆H₁₇Cl₃N₂O₂, molecules are linked into helical chains by N—H...O hydrogen bonds. Molecules of 2,2,2‐trichloro‐N,N′‐bis(4‐chlorophenyl)ethane‐1,1‐diamine, C₁₄H₁₁Cl₅N₂, are connected into a three‐dimensional framework by two independent Cl...Cl interactions and one C—H...Cl hydrogen bond.     

Hydro­gen bonding in substituted nitro­anilines: isolated nets in 1,3‐­diamino‐4‐nitrobenzene and continuously interwoven nets in 3,5‐­dinitro­aniline

Molecules of 1,3‐diamino‐4‐nitrobenzene, C₆H₇N₃O₂, are linked by N—H?O hydrogen bonds [N?O 2.964 (2) and 3.021 (2) Å; N—H?O 155 and 149°] into (4,4) nets. In 3,5‐di­nitro­aniline, C₆H₅N₃O₄, where Z′ = 2, the mol­ecules are linked by three N—H?O hydrogen bonds [N?O 3.344 (2)–3.433 (2) Å and N—H?O 150–167°] into deeply puckered nets, each of which is interwoven with its two immediate neighbours.     

Three new phosphoric triamides with a [C(O)NH]P(O)[N(C)(C)]2 skeleton: a database analysis of C—N—C and P—N—C bond angles

In N,N,N′,N′‐tetraethyl‐N′′‐(4‐fluorobenzoyl)phosphoric triamide, C₁₅H₂₅FN₃O₂P, (I), and N‐(2,6‐difluorobenzoyl)‐N′,N′′‐bis(4‐methylpiperidin‐1‐yl)phosphoric triamide, C₁₉H₂₈F₂N₃O₂P, (II), the C—N—C angle at each tertiary N atom is significantly smaller than the two P—N—C angles. For the other new structure, N,N′‐dicyclohexyl‐N′′‐(2‐fluorobenzoyl)‐N,N′‐dimethylphosphoric triamide, C₂₁H₃₃FN₃O₂P, (III), one C—N—C angle [117.08 (12)°] has a greater value than the related P—N—C angle [115.59 (9)°] at the same N atom. Furthermore, for most of the analogous structures with a [C(=O)NH]P(=O)[N(C)(C)]₂ skeleton deposited in the Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B 58 , 380–388], the C—N—C angle is significantly smaller than the two P—N—C angles; exceptions were found for four structures with the N‐methylcyclohexylamide substituent, similar to (III), one structure with the seven‐membered cyclic amide azepan‐1‐yl substituent and one structure with an N‐methylbenzylamide substituent. The asymmetric units of (I), (II) and (III) contain one molecule, and in the crystal structures, adjacent molecules are linked via pairs of N—H...O=P hydrogen bonds to form dimers.     

Two N,N′‐diaryl‐2,2,2‐trichloroethane‐1,1‐diamines: hydrogen‐bonded supramolecular structures in one and two dimensions

The molecules of 2,2,2‐trichloro‐N,N′‐diphenylethane‐1,1‐diamine, C₁₄H₁₃Cl₃N₂, are linked into (040) sheets by a combination of C—H...Cl and C—H...π(arene) hydrogen bonds. In 2,2,2‐trichloro‐N,N′‐bis(4‐methylphenyl)ethane‐1,1‐diamine, C₁₆H₁₇Cl₃N₂, the molecules are linked into C(7) chains by two independent C—H...Cl hydrogen bonds and one Cl...Cl contact.