Stabilization of Substituted Triazenide Oxides: Synthesis and X‐ray Structural Features of Polymeric Potassium 3‐(4‐carboxylatophenyl)‐1‐methyltriazene N‐oxide‐hydrate, {K[O2C‐C6H4‐N(H)NN(CH3)O]·4H2O}n

3‐(4‐carboxyphenyl)‐1‐methyltriazene N‐oxide reacts with KOH in methanol/pyridine to give {K[O₂C‐C₆H₄‐N(H)NN(CH₃)O]·4H₂O}_n, Potassium‐3‐(4‐carboxylatophenyl)‐1‐methyltriazene N‐oxide). The terminal carboxylato group of the anion does not interact with the cation. In the crystal lattice of {K(C₈H₈N₃O₃)·4H₂O}_n each three of the four water molecules interact with two potassium cations, every K⁺ ion being the centre of six bridging K···O interactions. Potassium cations interact further with the terminal N‐oxigen atom of single [C₈H₈N₃O₃]^? anions achieving two parallel {C₈H₈N₃O₃^?K⁺}_n chains, which are linked through water molecules. The resulting polymeric, one‐dimensional chain, is operated by a screw axis 2₁ parallel to the crystallographic direction [010], along and equidistant to the K⁺ centres. The coordination of the K⁺ centres involves a distortion of the boat conformation of elementary sulfur (S₈) with the ideal C_2v symmetry.     

Synthesis,Structures, and Properties of Two Novel Supramolecular Architectures Constructed from [2,3‐f]Pyrazino[1,10]phenanthroline‐2,3‐dicarboxylic Acid

Two new compounds, [Ag(Hppdb)]_n ( 1 ) and {[Ag₂(Hppdb)₂(bpe)] · 5.5H₂O}_n( 2 ) [H₂ppdb = [2,3‐f]pyrazino[1,10]phenanthroline‐2,3‐dicarboxylic acid, bpe = trans‐1,2‐bis(4‐pyridyl)ethylene], were synthesized and characterized. In 1 , Hppdb^– ions link Ag^I cations to form an infinite 1D [–Ag–(Hppdb)–Ag–]_n chain, furthermore, the dimensionality is extended to 2D layers through synergistic π–π stacking, hydrogen‐bonding and weak Ag ··· O interactions. Correspondingly, the dimeric [(Ag)(Hppdb)]₂ subunits in 2 are connected by bpe ligands to generate a loop‐link‐shaped 1D chain motif, which is further joined through a R₂²(18)C–H ··· O hydrogen‐bonding ring to afford interesting diagonal/diagonal inclined catenation 2D + 2D → 3D supramolecular architectures. In addition, solid‐state properties such as photoluminescence and thermal stability of the two compounds were studied.     

Chemoselective Route for Synthesis of N‐Aryl‐3‐oxochromeno[2,3‐c]pyrazole‐2(3H)‐carbothioamide Derivatives

A chemoselective route for the synthesis of chromeno[2,3‐c]pyrazole‐2(3H)‐carbothioamide derivatives by a five‐component reaction of salicylaldehyde, malononitrile, NH₂NH₂?H₂O, aryl isothiocyanate, and H₂O in EtOH/AcOH mixture is reported. This new protocol has the advantages of high yields, short reaction times, ease of operation, and simple purification. All structures were confirmed by IR, ¹H‐ and ¹³C‐NMR, and MS analyses. A plausible mechanism for this type of reaction is proposed (Scheme 2).     

Zu den Kristallstrukturen der Übergangsmetall(II)‐Dodekahydro‐closo‐Dodekaborat‐Hydrate Cu(H2O)5,5[B12H12]·2,5 H2O und Zn(H2O)6[B12H12]·6 H2O

On the Crystal Structures of the Transition‐Metal(II) Dodecahydro‐closo‐Dodecaborate Hydrates Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O and Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O By neutralization of an aqueous solution of the free acid (H₃O)₂[B₁₂H₁₂] with basic copper(II) carbonate or zinc carbonate, blue lath‐shaped single crystals of the octahydrate Cu[B₁₂H₁₂]·8 H₂O (≡ Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O) and colourless face‐rich single crystals of the dodecahydrate Zn[B₁₂H₁₂]·12 H₂O (≡ Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O) could be isolated after isothermic evaporation. Copper(II) dodecahydro‐closo‐dodecaborate octahydrate crystallizes at room temperature in the monoclinic system with the non‐centrosymmetric space group Pm (Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O: a = 768.23(5), b = 1434.48(9), c = 777.31(5) pm, β = 90.894(6)°; Z = 2), whereas zinc dodecahydro‐closo‐dodecaborate dodecahydrate crystallizes cubic in the likewise non‐centrosymmetric space group F23 (Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O: a = 1637.43(9) pm; Z = 8). The crystal structure of Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O can be described as a monoclinic distortion variant of the CsCl‐type arrangement. As characteristic feature the formation of isolated [Cu₂(H₂O)₁₁]⁴⁺ units as a condensate of two corner‐linked Jahn‐Teller distorted [Cu(H₂O)₆]²⁺ octahedra via an oxygen atom of crystal water can be considered. Since “zeolitic” water of hydratation is also present, obviously both classical H–O^δ?···^+δH–O and non‐classical B–H^δ?···^+δH–O hydrogen bonds play a significant role for the stabilization of the structure. A direct coordinative influence of the quasi‐icosahedral [B₁₂H₁₂]^2? anions on the Cu²⁺ cations has not been determined. The zinc compound Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O crystallizes in a NaTl‐type related structure. Two crystallographically different [Zn(H₂O)₆]²⁺ octahedra are present, which only differ in their relative orientation within the packing of the [B₁₂H₁₂]^2? anions. The stabilization of the crystal structure takes place mainly via H–O^δ?···^+δH–O hydrogen bonds, since again the hydrogen atoms of the [B₁₂H₁₂]^2? anions have no direct coordinative influence on the Zn²⁺ cations.     

A Convenient Synthesis of 2,3‐Dihydro‐4H‐thiopyrano[2,3‐b]‐, ‐[2,3‐c]‐, or ‐[3,2‐c]pyridin‐4‐ones by the Reaction of the Corresponding 1‐(Chloropyridinyl)alk‐2‐en‐1‐ones with NaSH

2,3‐Dihydro‐4H‐thiopyrano[2,3‐b]pyridin‐4‐ones 4 were prepared by a three‐step sequence from commercially available 2‐chloropyridine ( 1 ). Thus, successive treatment of 1 with ⁱPr₂NLi (LDA) and α,β‐unsaturated aldehydes gave 1‐(2‐chloropyridin‐3‐yl)alk‐2‐en‐1‐ols 2 , which were oxidized with MnO₂ to 1‐(2‐chloropyridin‐3‐yl)alk‐2‐en‐1‐ones 3 . The reactions of 3 with NaSH?n H₂O proceeded smoothly at 0° in DMF to provide the desired thiopyranopyridinones. Similarly, 2,3‐dihydro‐4H‐thiopyrano[2,3‐c]pyridin‐4‐ones 8 and 2,3‐dihydro‐4H‐thiopyrano[3,2‐c]pyridin‐4‐ones 12 were obtained starting from 3‐chloropyridine ( 5 ) and 4‐chloropyridine ( 9 ), respectively.     

Neutral 4‐phenyl‐1‐[phenyl(pyridin‐2‐yl)methylidene]semicarbazide and its salt forms with inorganic anions

Semicarbazones can exist in two tautomeric forms. In the solid state, they are found in the keto form. This work presents the synthesis, structures and spectroscopic characterization (IR and NMR spectroscopy) of four such compounds, namely the neutral molecule 4‐phenyl‐1‐[phenyl(pyridin‐2‐yl)methylidene]semicarbazide, C₁₉H₁₆N₄O, (I), abbreviated as HBzPyS, and three different hydrated salts, namely the chloride dihydrate, C₁₉H₁₇N₄O⁺·Cl^?·2H₂O, (II), the nitrate dihydrate, C₁₉H₁₇N₄O⁺·NO₃^?·2H₂O, (III), and the thiocyanate 2.5‐hydrate, C₁₉H₁₇N₄O⁺·SCN^?·2.5H₂O, (IV), of 2‐[phenyl({[(phenylcarbamoyl)amino]imino})methyl]pyridinium, abbreviated as [H₂BzPyS]⁺·X^?·nH₂O, with X = Cl^? and n = 2 for (II), X = NO₃^? and n = 2 for (III), and X = SCN^? and n = 2.5 for (IV), showing the influence of the anionic form in the intermolecular interactions. Water molecules and counter‐ions (chloride or nitrate) are involved in the formation of a two‐dimensional arrangement by the establishment of hydrogen bonds with the N—H groups of the cation, stabilizing the E isomers in the solid state. The neutral HBzPyS molecule crystallized as the E isomer due to the existence of weak π–π interactions between pairs of molecules. The calculated IR spectrum of the hydrated [H₂BzPyS]⁺ cation is in good agreement with the experimental results.     

Cationic organotin cluster [t‐Bu2Sn(OH)(H2O)]22+2OTf−‐catalyzed one‐pot three‐component syntheses of 5‐substituted 1H‐tetrazoles and 2,4,6‐triarylpyridines in water

The cationic organotin cluster [t‐Bu₂Sn(OH)(H₂O)]₂²⁺2OTf^? is easy to prepare and stable in air. The catalytic activity of [t‐Bu₂Sn(OH)(H₂O)]₂²⁺2OTf^? as a neutral organotin Lewis acid catalyst is probed through the one‐pot three‐component syntheses of 5‐substituted 1H‐tetrazoles from aldehydes, hydroxylamine hydrochloride and sodium azide, and of 2,4,6‐triarylpyridines from aromatic aldehydes, substituted acetophenones and ammonium acetate. The reactions proceed well in the presence of 1 mol% of [t‐Bu₂Sn(OH)(H₂O)]₂²⁺2OTf^? in water and provide the corresponding 5‐substituted 1H‐tetrazoles and 2,4,6‐triarylpyridines in good to excellent yields. The method reported has several advantages such as the catalyst being neutral, low catalyst loading and use of water as a green solvent.     

7‐Methoxy‐2,3‐dioxo‐1,4‐dihydroquinoxalin‐6‐aminium chloride monohydrate

Single crystals of the title compound, C₉H₁₀N₃O₃⁺·Cl⁻·H₂O, were obtained by recrystallization from hydrochloric acid. The cations stack along the crystallographic a direction. The 2,3‐dioxo‐1,4‐dihydroquinoxaline group shows a significant deviation from planarity [r.m.s. deviation from the best plane = 0.063 (2) Å]. Hydrogen bonding links the cations, chloride anions and water molecules to form an extended three‐dimensional architecture.     

(8‐Dimethylamino‐1‐naphthyl)dimethylammonium 3‐carboxy‐1,4,5,‐6,7,7‐hexachlorobicyclo[2.2.1]hept‐5‐ene‐2‐carboxylate hydrate

The structure of the title compound, C₁₄H₁₉N₂⁺·C₉H₃Cl₆O₄^?·H₂O, consists of singly ionized 1,4,5,6,7,7‐hexachlorobicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxylic acid anions and protonated 1,8‐bis(dimethylamino)naphthalene cations. In the (8‐dimethylamino‐1‐napthyl)dimethylammonium cat­ion, a strong disordered intramolecular hydrogen bond is formed with N?N = 2.589 (3) Å. The geometry and occupancy obtained in the final restrained refinement suggest that the disordered hydrogen bond may be asymmetric. Water mol­ecules link the anion dimers into infinite chains via hydrogen bonding.     

Das Lanthan‐Dodekahydro‐closo‐Dodekaborat‐Hydrat [La(H2O)9]2[B12H12]3·15 H2O und sein Oxonium‐Chlorid‐Derivat [La(H2O)9](H3O)Cl2[B12H12]·H2O

The Lanthanum Dodecahydro‐closo‐Dodecaborate Hydrate [La(H₂O)₉]₂[B₁₂H₁₂]₃·15 H₂O and its Oxonium‐Chloride Derivative [La(H₂O)₉](H₃O)Cl₂[B₁₂H₁₂]·H₂O By neutralization of an aqueous solution of the free acid (H₃O)₂[B₁₂H₁₂] with basic La₂O₃ and after isothermic evaporation colourless, face‐rich single crystals of a water‐rich lanthanum(III) dodecahydro‐closo‐dodecaborate hydrate [La(H₂O)₉]₂[B₁₂H₁₂]₃·15 H₂O are isolated. The compound crystallizes in the trigonal system with the centrosymmetric space group (a = 1189.95(2), c = 7313.27(9) pm, c/a = 6.146; Z = 6; measuring temperature: 100 K). The crystal structure of [La(H₂O)₉]₂[B₁₂H₁₂]₃·15 H₂O can be characterized by two of each other independent, one into another posed motives of lattice components. The [B₁₂H₁₂]²⁻ anions (d(B–B) = 177–179 pm; d(B–H) = 105–116 pm) are arranged according to the samarium structure, while the La³⁺ cations are arranged according to the copper structure. The lanthanum cations are coordinated in first sphere by nine oxygen atoms from water molecules in form of a threecapped trigonal prism (d(La–O) = 251–262 pm). A coordinative influence of the [B₁₂H₁₂]²⁻ anions on La³⁺ has not been determined. Since “zeolitic” water of hydratation is also present, obviously the classical H–O^δ–···^+δH–O‐hydrogen bonds play a significant role in the stabilization of the crystal structure. During the conversion of an aqueous solution of (H₃O)₂[B₁₂H₁₂] with lanthanum trichloride an anion‐mixed salt with the composition [La(H₂O)₉](H₃O)Cl₂[B₁₂H₁₂]·H₂O is obtained. The compound crystallizes in the hexagonal system with the non‐centrosymmetric space group (a = 808.84(3), c = 2064.51(8) pm, c/a = 2.552; Z = 2; measuring temperature: 293 K). The crystal structure can be characterized as a layer‐like structure, in which [B₁₂H₁₂]²⁻ anions and H₃O⁺ cations alternate with layers of [La(H₂O)₉]³⁺ cations (d(La–O) = 252–260 pm) and Cl⁻ anions along [001]. The [B₁₂H₁₂]²⁻ (d(B–B) = 176–179 pm; d(B–H) = 104–113 pm) and Cl⁻ anions exhibit no coordinative influence on La³⁺. Hydrogen bonds are formed between the H₃O⁺ cations and [B₁₂H₁₂]²⁻ anions, also between the water molecules of [La(H₂O)₉]³⁺ and Cl⁻ anions, which contribute to the stabilization of the crystal structure.     

First Coordination Polymer of 1,4‐Dihydro‐2,3‐Quinoxalinedione in Ketoamine Tautomeric Form

The first coordination compound of 1,4‐dihydro‐2,3‐quinoxalinedione in ketoamine tautomeric form (denoted as H₂qdione) was reported. H₂qdione was obtained by a solid‐state reaction of o‐phenylenediamine and oxalic acid. Reaction of this ligand with CdCl₂ solvothermally yielded a coordination polymer [Cd(H₂qdione)Cl₂]_n, which was structurally characterized by X‐ray diffraction and IR spectroscopy. Continuous Cd₂Cl₂ diamonds form a double‐sided comb with terminal H₂qdione‐κ²O,O′ as the comb teeth. Interaction of these combs through very extensive π–π stacking, C–H ··· Cl, and N–H ··· Cl hydrogen bonds leads to a novel 3D architecture and significant enhancement of solid‐state luminescence of about 10 times compared to the free H₂qdione ligand.     

Mechanistic insights on DBU catalyzed β‐amination of nbs to chalcone driving by water: Multiple roles of water

DFT calculations were conducted to pursue deeper understandings on the mechanism and the explicit role of trace water in the DBU‐catalyzed β‐amination of NBS to chalcone. Being different from previously proposed by Liang et al., a cooperative participation of both DBU and water is noticed in the preferred mechanism. The preferential mechanistic scenario assisted by water undergoes three major steps: the formation of succinimide and HBrO, concerted nucleophilic addition and H‐shift, and keto‐enol tautomerization. Moreover, we found that DBU‐HBrO is unnecessary in the third step and three‐water‐cluster assisted keto‐enol tautomerization is the most advantageous case. It is further noted that the catalytic position of the third water molecule and the proton shift orientation to some extent affect step 3 via O···H O and O H···π interactions, which is confirmed by AIM analysis. The computational results suggest that water molecules play pivotal roles as reactant, catalyst, and stabilizer to promote the reaction of chalcone and NBS. The origin of the more stable transition state structure in the rate‐determining step of DBU‐water catalyzed mechanism is ascribed to noncovalent interactions, halogen bond, and electrostatic interactions than DBU only ones. © 2017 Wiley Periodicals, Inc.     

Sodium 2‐oxo‐3‐semicarbazono‐2,3‐dihydro‐1H‐indole‐5‐sulfonate dihydrate

The title compound, Na⁺·C₉H₇N₄O₅S⁻·2H₂O, presents a Z configuration around the imine C=N bond and an E configuration around the C(O)NH₂ group, stabilized by two intra­molecular hydrogen bonds. The packing is governed by ionic inter­actions between the Na⁺ cation and the surrounding O atoms. The ionic unit, Na⁺ and 2‐oxo‐3‐semicarbazono‐2,3‐dihydro‐1H‐indole‐5‐sulfonate, forms layers extending in the bc plane. The layers are connected by hydrogen bonds involving the water mol­ecules.     

Iodine‐Catalyzed Synthesis of Spiro[1,3,4‐benzotriazepine‐2,3′‐indole]‐2′,5(1H,1′H)‐diones under Mild Conditions

The I₂‐catalyzed preparation of spiro[1,3,4‐benzotriazepine‐2,3′‐indole]‐2′,5(1H,1′H)‐diones from 2‐aminobenzohydrazide and isatins in MeCN at room temperature in good‐to‐excellent yields is described. The structure of 3 was corroborated spectroscopically (IR, ¹H‐ and ¹³C‐NMR, and EI‐MS data). A plausible mechanism for this type of reaction is proposed (Scheme 2).     

Impact of the anion and chalcogen on the crystal structure and properties of 4,6‐dimethyl‐2‐pyrimido(thio)nium halides

By the reaction of urea or thiourea, acetylacetone and hydrogen halide (HF, HBr or HI), we have obtained seven new 4,6‐dimethyl‐2‐pyrimido(thio)nium salts, which were characterized by single‐crystal X‐ray diffraction, namely, 4,6‐dimethyl‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium bifluoride, C₆H₉N₂O⁺·HF₂^? or (dmpH)F₂H, 4,6‐dimethyl‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium bromide, C₆H₉N₂O⁺·Br^? or (dmpH)Br, 4,6‐dimethyl‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium iodide, C₆H₉N₂O⁺·I^? or (dmpH)I, 4,6‐dimethyl‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium iodide–urea (1/1), C₆H₉N₂O⁺·I^?·CH₄N₂O or (dmpH)I·ur, 4,6‐dimethyl‐2‐sulfanylidene‐2,3‐dihydropyrimidin‐1‐ium bifluoride–thiourea (1/1), C₆H₉N₂S⁺·HF₂^?·CH₄N₂S or (dmptH)F₂H·tu, 4,6‐dimethyl‐2‐sulfanylidene‐2,3‐dihydropyrimidin‐1‐ium bromide, C₆H₉N₂S⁺·Br^? or (dmptH)Br, and 4,6‐dimethyl‐2‐sulfanylidene‐2,3‐dihydropyrimidin‐1‐ium iodide, C₆H₉N₂S⁺·I^? or (dmptH)I. Three HCl derivatives were described previously in the literature, namely, 4,6‐dimethyl‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium chloride, (dmpH)Cl, 4,6‐dimethyl‐2‐sulfanylidene‐2,3‐dihydropyrimidin‐1‐ium chloride monohydrate, (dmptH)Cl·H₂O, and 4,6‐dimethyl‐2‐sulfanylidene‐2,3‐dihydropyrimidin‐1‐ium chloride–thiourea (1/1), (dmptH)Cl·tu. Structural analysis shows that in 9 out of 10 of these compounds, the ions form one‐dimensional chains or ribbons stabilized by hydrogen bonds. Only in one compound are parallel planes present. In all the structures, there are charge‐assisted N⁺—H…X^? hydrogen bonds, as well as weaker C_Ar⁺—H…X^? and π⁺…X^? interactions. The structures can be divided into five types according to their hydrogen‐bond patterns. All the compounds undergo thermal decomposition at relatively high temperatures (150–300 °C) without melting. Four oxopyrimidinium salts containing a π⁺…X^?…π⁺ sandwich‐like structural motif exhibit luminescent properties.     

ZrOCl2·8H2O as an efficient and recyclable catalyst for the one‐pot multicomponent synthesis of novel [1,3]oxazino[5,6‐c]quinolin‐5‐one derivatives

A simple, efficient and eco‐friendly procedure has been developed using ZrOCl₂·8H₂O as catalyst for the synthesis of novel [1,3]oxazino[5,6‐c]quinolin‐5‐one derivatives in aqueous ethanol at room temperature. The present methodology offers several advantages such as operational simplicity, use of ZrOCl₂·8H₂O as a green, non‐toxic, inexpensive and reusable catalyst, reusability of reaction media, high yields, mild and environmentally benign reaction conditions.     

Reaction of the Pincer‐type Ligand {2, 6‐[P(O)(OEt)2]2‐4‐tert‐Bu‐C6H2}— with [Ph3C]+[PF6]—. Unprecedented Rearrangement and Carbon‐Carbon Bond Formation

The reaction of the organolithium derivative {2, 6‐[P(O)(OEt)₂]₂‐4‐tert‐Bu‐C₆H₂}Li ( 1 ‐Li) with [Ph₃C]⁺[PF₆]^— gave the substituted biphenyl derivative 4‐[(C₆H₅)₂CH]‐4′‐[tert‐Bu]‐2′, 6′‐[P(O)(OEt)₂]₂‐1, 1′‐biphenyl ( 5 ) which was characterized by ¹H, ¹³C and ³¹P NMR spectroscopy and single crystal X‐ray analysis. Ab initio MO‐calculations reveal the intramolecular O···C distances in 5 of 2.952(4) and 2.988(5)Å being shorter than the sum of the van der Waals radii of oxygen and carbon to be the result of crystal packing effects. Also reported are the synthesis and structure of the bromine‐substituted derivative {2, 6‐[P(O)(OEt)₂]₂‐4‐tert‐Bu]C₆H₂}Br ( 9 ) and the structure of the protonated ligand 5‐tert‐Bu‐1, 3‐[P(O)(OEt)₂]₂C₆H₃ ( 1 ‐H). The structures of 1 ‐H, 5 , and 9 are compared with those of related metal‐substituted derivatives.     

Hydrogen bonding in polyamino‐polyalcohols: a monohydrated cocrystal of 1,3‐diamino‐5‐azaniumyl‐1,3,5‐trideoxy‐cis‐inositol iodide and 1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol

In the title monohydrated cocrystal, namely 1,3‐diamino‐5‐azaniumyl‐1,3,5‐trideoxy‐cis‐inositol iodide–1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol–water (1/1/1), C₆H₁₆N₃O₃⁺·I⁻·C₆H₁₅N₃O₃·H₂O, the neutral 1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol (taci) molecule and the monoprotonated 1,3‐diamino‐5‐azaniumyl‐1,3,5‐trideoxy‐cis‐inositol cation (Htaci⁺) both adopt a chair conformation, with the three O atoms in axial and the three N atoms in equatorial positions. The cation, but not the neutral taci unit, exhibits intramolecular O—H...O hydrogen bonding. The entire structure is stabilized by a complex three‐dimensional network of intermolecular hydrogen bonds. The neutral taci entities and the Htaci⁺ cations are each aligned into chains along [001]. In these chains, two O—H...N interactions generate a ten‐membered ring as the predominant structural motif. The rings consist of vicinal 2‐amino‐1‐hydroxyethylene units of neighbouring molecules, which are paired via centres of inversion. The chains are interconnected into undulating layers parallel to the ac plane, and the layers are further held together by O—H...N hydrogen bonds and additional interactions with the iodide counter‐anions and solvent water molecules.     

Pseudopolyrotaxanes of Cucurbit[6]uril: A Three‐Dimensional Network Self‐assembled by ClO4−(H2O)2 Water Clusters

A pseudorotaxane of cucurbit[6]uril (CB[6]) with guest molecule N,N′‐hexamethylenebis (pyrazinyl perchlorate) (BPHP) was synthesized and characterized by ¹H NMR spectra, IR, single crystal X‐ray diffraction analysis and thermogravimetric analysis. The structure of the pseudorotaxane (CB[6]·BPHP) is stabilized by host‐guest hydrogen bonds. Self‐assembly of the pseudorotaxane produces infinite one‐dimensional and two‐dimensional networks with intermolecular hydrogen bonds. In the molecular packing of the CB[6]·BPHP, ClO₄^?(H₂O)₂ water clusters serve as bridges to associate these pseudorotaxanes and form three‐dimensional networked pseudopolyrotaxane.     

Hydrogen‐bonded and π‐interaction assembly in two 8‐alkoxycarbonyl‐1,8‐diazabicyclo[5.4.0]undec‐7‐enium chloride salts

The crystal structures of 8‐phenoxycarbonyl‐1,8‐diazabicyclo[5.4.0]undec‐7‐enium chloride, C₁₆H₂₁N₂O₂⁺·Cl⁻, (I), and 8‐methoxycarbonyl‐1,8‐diazabicyclo[5.4.0]undec‐7‐enium chloride monohydrate, C₁₁H₁₉N₂O₂⁺·Cl⁻·H₂O, (II), recently reported by Carafa, Mesto & Quaranta [Eur. J. Org. Chem. (2011), pp. 2458–2465], are analysed and discussed with a focus on crystal interaction assembly. Both compounds crystallize in the space group P2₁/c. The crystal packings are characterized by dimers linked through π–π stacking interactions and intermolecular nonclassical hydrogen bonds, respectively. Additional intermolecular C—H...Cl interactions [in (I) and (II)] and classical O—H...Cl hydrogen bonds [in (II)] are also evident and contribute to generating three‐dimensional hydrogen‐bonded networks.