Anion Controlled Supramolecular Self‐Assembly of Tetraprotonated Tris[2‐(benzylamino)ethyl]amine

The novel supramolecular assembly of composition [{(bz₃tren)H₄}⁴⁺ · (ReO₄)^— · 3(Cl)^—] resulted from the self‐organization of a mixture of tris[2‐(benzylamino)ethyl]amine (bz₃tren), HCl and NH₄ReO₄ at a molar ratio of 1:4.7:1 in methanol. The crystal architecture is characterized by stacks of repeating sandwich‐type building blocks that contain charge‐assisted N—H···O(Re) hydrogen bonds [N···O 2.81‐2.86Å] and weaker C—H···O(Re) interactions [C···O 3.11Å]. The stacks are further linked by N—H···Cl [N···Cl 3.03Å] and weaker C—H···Cl [C···Cl 3.47‐3.74Å] interactions into two‐dimensional layers bordered by the benzyl groups of the [(bz₃tren)H₄]⁴⁺ cations. Edge‐to‐face C—H···π interactions involving the aromatic rings occur within and between the layers. The protonation constants of bz₃tren in methanol were determined by potentiometric titration. The corresponding structures of the ligand in its different protonation states were calculated at the DFT‐level.     

Mechanochemical synthesis and X‐ray structural characterization of three 3‐nitrophenol cocrystals with three aminal cage azaadamantanes: the role of the stereoelectronic effect on intermolecular hydrogen‐bonding patterns

The structures of the cocrystalline adducts of 3‐nitrophenol (3‐NP) with 1,3,5,7‐tetraazatricyclo[3.3.1.1^3,7]decane [HMTA, ( 1 )] as the 2:1:1 hydrate, 2C₆H₅NO₃·C₆H₁₂N₄·H₂O, ( 1a ), with 1,3,6,8‐tetraazatricyclo[4.3.1.1^3,8]undecane [TATU ( 2 )] as the 2:1 cocrystal, 2C₆H₅NO₃·C₇H₁₄N₄, ( 2a ), and with 1,3,6,8‐tetraazatricyclo[4.4.1.1^3,8]dodecane [TATD, ( 3 )] as the 2:1 cocrystal, 2C₆H₅NO₃·C₈H₁₆N₄, ( 3a ), are reported. In the binary crystals ( 2a ) and ( 3a ), the 3‐nitrophenol molecules are linked via O—H…N hydrogen bonds into aminal cage azaadamantanes. In ( 1a ), the structure is stabilized by O—H…N and O—H…O hydrogen bonds, and generates ternary cocrystals. There are C—H…O hydrogen bonds present in all three cocrystals, and in ( 1a ), there are also C—H…O and C—H…π interactions present. The presence of an ethylene bridge in the structures of ( 2 ) and ( 3 ) defines the formation of a hydrogen‐bonded motif in the supramolecular architectures of ( 2a ) and ( 3a ). The differences in the C—N bond lengths of the aminal cage structures, as a result of hyperconjugative interactions and electron delocalization, were analysed. These three cocrystals were obtained by the solvent‐free assisted grinding method. Crystals suitable for single‐crystal X‐ray diffraction were grown by slow evaporation from a mixture of hexanes.     

Hydrogen‐bonded assemblies of 5,10,15,20‐tetrakis(4‐hydroxyphenyl)porphyrin with dimethylformamide,dimethylacetamide and water

The title free base porphyrin compound forms hydrogen‐bonded adducts with N,N‐dimethylformamide, C₄₄H₃₀N₄O₄·4C₃H₇NO, (I), a mixture of N,N‐dimethylformamide and water, C₄₄H₃₀N₄O₄·4C₃H₇NO·H₂O, (II), and a mixture of N,N‐dimethylacetamide and water, C₄₄H₃₀N₄O₄·6C₃H₇NO·2H₂O, (III). Total solvation of the four hydroxy functions of the porphyrin molecules characterizes all three compounds, thus preventing its supramolecular association into extended network architectures. In (I), the asymmetric unit consist of two five‐component adduct species, while in (III), the nine‐component entities reside on centres of inversion. This report provides the first structural characterizations of the free base tetra(hydroxyphenyl)porphyrin. It also demonstrates that the presence of strong Lewis bases, such as dimethylformamide or dimethylacetamide, in the crystallization mixture prevents direct supramolecular networking of the porphyrin ligands via O—H...O—H hydrogen bonds, due to their competing O—H...N(base) interaction with the hydroxy functions. The crystal packing of compounds (I)–(III) resembles that of other hydrogen‐bonding‐assisted tetraarylporphyrin clathrates.     

A Study of the Solubility of Hydrated Orthophosphates of Yttrium,Lanthanum, Cerium,and Neodymium in Sulfuric-Phosphoric Acid Solutions at 20°C

The solubility of YPO₄ · 2H₂O, LaPO₄ · 1.5H₂O, CePO₄ · 1.5H₂O, and NdPO₄ · H₂O 10–60 wt % in sulfuric-phosphoric acid solutions containing 10–60 wt % H₂SO₄ and 13.8–41.4 H₃PO₄ was studied.     

Solubility in the LaCl<Subscript>3</Subscript>-LnCl<Subscript>3</Subscript>-HCl-H<Subscript>2</Subscript>O (Ln = Pr,Nd) Systems at 25°C

The solubility in the quaternary water-salt systems LaCl₃-NdCl₃-HCl-H₂O (1) and LaCl₃-PrCl₃-HCl-H₂O (2) at 25°C was studied in the section of 40 wt % hydrochloric acid, a system with a eutonic discontinuity. The composition at the point of discontinuity for the eutonic solution is the following. In system 1: 4.67 wt % LaCl₃ · 7H₂O, 0.37 wt % PrCl₃ · 7H₂O, 37.98 wt % HCl, and 56.98 wt % H₂O; in system 2: 4.37 wt % LaCl₃ · 7H₂O, 0.93 wt % NdCl₃ · 6H₂O, 37.88 wt % HCl, and 56.82 wt % H₂O.     

Tris(1H‐benzimidazol‐2‐yl­meth­yl)­amine–solvent adducts

The tris­(1H‐benzimidazol‐2‐yl­meth­yl)­amine (ntb) mol­ecule crystallizes in different solvent systems, resulting in two kinds of adduct, namely the monohydrate, C₂₄H₂₁N₇·H₂O or ntb·H₂O, (I), and the acetonitrile–methanol–water (1/0.5/1.5) solvate, C₂₄H₂₁N₇·C₂H₃N·0.5CH₄O·1.5H₂O or ntb·1.5H₂O·0.5MeOH·MeCN, (II). In both cases, ntb adopts a tripodal mode to form hydrogen bonds with a solvent water mol­ecule via two N—H⋯O and one O—H⋯N hydrogen bond. In (I), the ntb·H₂O adduct is further assembled into a two‐dimensional network by N—H⋯N and O—H⋯N hydrogen bonds, while in (II), a double‐stranded one‐dimensional chain structure is assembled via N—H⋯O and O—H⋯O hydrogen bonds, with the acetonitrile mol­ecules located inside the cavities of the chain structure.     

Polysulfonylamine. CLXIII [1] Kristallstrukturen von Metall‐di(methansulfonyl)amiden. 12 [1] Das orthorhombische Doppelsalz Na2Cs2[(CH3SO2)2N]4·3H2O: Ein dreidimensionales Koordinationspolymer aus (Caesium‐Anion‐Wasser)‐Schichten und intercalierten Natriumionen

Polysulfonylamines. CLXIII. Crystal Structures of Metal Di(methanesulfonyl)amides. 12. The Orthorhombic Double Salt Na₂Cs₂[(CH₃SO₂)₂N]₄·3H₂O: A Three‐Dimensional Coordination Polymer Built up from Cesium‐Anion‐Water Layers and Intercalated Sodium Ions The packing arrangement of the three‐dimensional coordination polymer Na₂Cs₂[(MeSO₂)₂N]₄·3H₂O (orthorhombic, space group Pna2₁, Z′ = 1) is in some respects similar to that of the previously reported sodium‐potassium double salt Na₂K₂[(MeSO₂)₂N]₄·4H₂O (tetragonal, P4₃2₁2, Z′ = 1/2). In the present structure, four multidentately coordinating independent anions, three independent aquo ligands and two types of cesium cation form monolayer substructures that are associated in pairs to form double layers via a Cs(1)—H₂O—Cs(2) motif, thus conferring upon each Cs⁺ an irregular O₈N₂ environment drawn from two N, O‐chelating anions, two O, O‐chelating anions and two water molecules. Half of the sodium ions occupy pseudo‐inversion centres situated between the double layers and have an octahedral O₆ coordination built up from four anions and two water molecules, whereas the remaining Na⁺ are intercalated within the double layers in a square‐pyramidal and pseudo‐C₂ symmetric O₅ environment provided by four anions and the water molecule of the Cs—H₂O—Cs motif. The net effect is that each of the four independent anions forms bonds to two Cs⁺ and two Na⁺, two independent water molecules are involved in Cs—H₂O—Na motifs, and the third water molecule acts as a μ₃‐bridging ligand for two Cs⁺ and one Na⁺. The crystal cohesion is reinforced by a three‐dimensional network of conventional O—H···O=S and weak C—H···O=S/N hydrogen bonds.     

A whole zoo of hydrogen bonds in one crystal structure: tris(isonicotinium) hydrogensulfate sulfate monohydrate

Depending on the reaction partner, the organic ditopic molecule isonicotinic acid (Hina) can act either as a Brønsted acid or base. With sulfuric acid, the pyridine ring is protonated to become a pyridinium cation. Crystallization from ethanol affords the title compound tris(4‐carboxypyridinium) hydrogensulfate sulfate monohydrate, 3C₆H₆NO₂⁺·HSO₄⁻·SO₄²⁻·H₂O or [(H₂ina)₃(HSO₄)(SO₄)(H₂O)]. This solid contains 11 classical hydrogen bonds of very different flavour and nonclassical C—H…O contacts. All N—H and O—H donors find at least one acceptor within a suitable distance range, with one of the three pyridinium H atoms engaged in bifurcated N—H…O hydrogen bonds. The shortest hydrogen‐bonding O…O distance is subtended by hydrogensulfate and sulfate anions, viz. 2.4752 (19) Å, and represents one of the shortest hydrogen bonds ever reported between these residues.     

Pentazol‐Derivate und daraus entstehende Azide: [O3S—p‐C6H4—N5]— und [O3S—p‐C6H4—N3]— als Kalium‐Kronenether‐Salze

Pentazole Derivates and Azides Formed from them: Potassium‐Crown‐Ether Salts of [O₃S—p‐C₆H₄—N₅]^— and [O₃S—p‐C₆H₄—N₃]^{— —}O₃S—p‐C₆H₄—N₂⁺ was reacted with sodium azide at —50 °C in methanol, yielding a mixture of 4‐pentazolylbenzenesulfonate and 4‐azidobenzenesulfonate (amount‐of‐substance ratio 27:73 according to NMR). By addition of KOH in methanol at —50 °C a mixture of the potassium salts K[O₃S—p‐C₆H₄—N₅] and K[O₃S—p‐C₆H₄—N₃] was precipitated (ratio 60:40). A solution of this mixture along with 18‐crown‐6 in tetrahydrofurane yielded the crystalline pentazole derivate [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₅]·THF by addition of petrol ether at —70 °C. From the same solution upon evaporation and redissolution in THF/petrol ether the crystalline azide [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·THF was obtained. A solution of the latter in chloroform/toluene under air yielded [K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·1/3H₂O. According to their X‐ray crystal structure determinations [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₅]·THF and [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·THF have the same kind of crystal packing. Differences worth mentioning exist only for the atomic positions of the pentazole ring as compared to the azido group and for one THF molecule which is coordinated to the potassium ion; different orientations of the THF molecule take account for the different space requirements of the N₅ and the N₃ group. In [K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·1/3H₂O there exists one unit consisting of one [K‐18‐crown‐6]⁺ and one [O₃S‐C₆H₄—N₃]^— ion and another unit consisting of two [O₃S‐C₆H₄—N₃]^— ions joined via two [K‐18‐crown‐6]⁺ ions and one water molecule. The rate constants for the decomposition [O₃S‐C₆H₄—N₅]^— → [O₃S‐C₆H₄—N₃]^— + N₂ in methanol were determined at 0 °C and —20 °C.     

[VO(SeO3)(H2O)2]·0.5H2O

In poly[[diaquaoxido[μ₃‐trioxidoselenato(2−)]vanadium(IV)] hemihydrate], {[VO(SeO₃)(H₂O)₂]·0.5H₂O}_n, the octahedral V(H₂O)₂O₄ and pyramidal SeO₃ building units are linked by V—O—Se bonds to generate ladder‐like chains propagating along the [010] direction. A network of O—H...O hydrogen bonds helps to consolidate the structure. The O atom of the uncoordinated water molecule lies on a crystallographic twofold axis. The title compound has a similar structure to those of the reported phases [VO(OH)(H₂O)(SeO₃)]₄·2H₂O and VO(H₂O)₂(HPO₄)·2H₂O.     

Synthesis,Crystal Structure,and Magnetic Properties of {[Cu(phen)]2(C4H2O4)2} · 4.5H2O with C4H4O4 = Maleic Acid

Reaction of CuCl₂ · 2H₂O, phenanthroline, maleic acid and NaOH in CH₃OH/H₂O (1:1 v/v) at pH = 7.0 yielded blue {[Cu(phen)]₂(C₄H₂O₄)₂} · 4.5H₂O, which crystallizes in the monoclinic space group C2/c (no. 15) with cell dimensions: a = 18.127(2)Å, b = 12.482(2)Å, c = 14.602(2)Å, β = 103.43(1)°, U = 3213.5(8)ų, Z = 4. The crystal structure consists of the centrosymmetric dinuclear {[Cu(phen)]₂(C₄H₂O₄)₂} complex molecules and hydrogen bonded H₂O molecules. The Cu atoms are each square‐pyramidally coordinated by two N atoms of one phen ligand and three carboxyl O atoms of two maleato ligands with one carboxyl O atom at the apical position (d(Cu‐N) = 2.008, 2.012Å, equatorial d(Cu‐O) = 1.933, 1.969Å, axial d(Cu‐O) = 2.306Å). Two square‐pyramids are condensed via two apical carboxyl O atoms with a relatively larger Cu···Cu separation of 3.346(1)Å. The dinuclear complex molecules are assembled via the intermolecular π—π stacking interactions into 1D ribbons. Crossover of the resulting ribbons via interribbon π—π stacking interactions forms a 3D network with the tunnels occupied by H₂O molecules. The title complex behaves paramagnetically between 5—300 K, following the Curie‐Weiss law _χm(T—θ) = 0.435 cm³ · mol^—1 · K with θ = 1.59 K.     

Synthese,Kristallstruktur und thermischer Abbau von Mg(H2O)6[B12H12] · 6 H2O

Synthesis, Crystal Structure, and Thermal Decomposition of Mg(H₂O)₆[B₁₂H₁₂] · 6 H₂O By reaction of an aqueous solution of the free acid (H₃O)₂[B₁₂H₁₂] with MgCO₃ and subsequent isothermic evaporation of the resulting solution to dryness, colourless, bead‐shaped single crystals of the dodecahydrate of magnesium dodecahydro closo‐dodecaborate Mg(H₂O)₆[B₁₂H₁₂] · 6 H₂O (cubic, F4₁32; a = 1643.21(9) pm, Z = 8) emerge. The crystal structure is best described as a NaTl‐type arrangement in which the centers of gravity of the quasi‐icosahedral [B₁₂H₁₂]^2— anions (d(B—B) = 178—180 pm, d(B—H) = 109 pm) occupy the positions of Tl^— while the Mg²⁺ cations occupy the Na⁺ positions. A direct coordinative influence of the [B₁₂H₁₂]^2— units at the Mg²⁺ cations is however not noticeable. The latter are octahedrally coordinated by six water molecules forming isolated hexaaqua complex cations [Mg(H₂O)₆]²⁺ (d(Mg—O) = 206 pm, 6×). In addition, six “zeolitic” water molecules are located in the crystal structure for the formation of a strong O—H^δ+···^δ—O‐hydrogen bridge‐bonding system. The evidence of weak B—H^δ—···^δ+H—O‐hydrogen bonds between water molecules and anionic [B₁₂H₁₂]^2— clusters is also considered. Investigations on the dodecahydrate Mg[B₁₂H₁₂] · 12 H₂O (≡ Mg(H₂O)₆[B₁₂H₁₂] · 6 H₂O) by DTA/TG measurements showed that its dehydration takes place in two steps within a temperature range of 71 and 76 °C as well as at 202 °C, respectively. Thermal treatment eventually leads to the anhydrous magnesium dodecahydro closo‐dodecaborate Mg[B₁₂H₁₂].     

Polyol‐Metall‐Komplexe. 491) μ‐Dulcitolato‐O2, 3;4, 5‐Komplexe mit Amin‐Kupfer(II)‐ und ‐Nickel(II)‐Metallfragmenten

Polyol Metal Complexes. 49¹⁾ μ‐Dulcitolato‐O^{2, 3;4, 5} Complexes with Cu^II(en) and Ni^II(tren) Metal Fragments The dinuclear ethylenediamine‐copper(II) complex of the tetra‐anion of the achiral alditol dulcitol (galactitol) is remarkable, since it was the first crystalline carbohydrate—metal complex ever reported (W. Traube, G. Glaubitt, V. Schenck, Ber. Dtsch. Chem. Ges. 1930 , 63, 2083—2093). Although its existence is recognized for many decades, its structure remained unknown due to a kind of crystal packing that promotes twinning. Crystal growth at low temperatures now yielded crystalline specimens of [(en)₂Cu₂(Dulc2, 3, 4, 5H_—4)] · 7 H₂O ( 1 ) that have allowed us to unravel both the crystal structure and the twinning law. Closely related molecular structures are adopted by [(tren)₂Ni₂(Dulc2, 3, 4, 5H_—4)] · 20 H₂O ( 2 ) and [(Me₃tren)₂Ni₂(Dulc2, 3, 4, 5H_—4)] · 16 H₂O ( 3 ), the latter showing the shortest hydrogen bond towards a polyolate acceptor ever found (O···O distance: 2.422Å).     

rac‐3‐Benzoyl‐2‐methylpropionic acid and its organic salts: possibilities of Yang photocyclization in crystals

The analysis of the crystal structures of rac‐3‐benzoyl‐2‐methylpropionic acid, C₁₁H₁₂O₃, (I), morpholinium rac‐3‐benzoyl‐2‐methylpropionate monohydrate, C₄H₁₀NO⁺·C₁₁H₁₁O₃⁻·H₂O, (II), pyridinium [hydrogen bis(rac‐3‐benzoyl‐2‐methylpropionate)], C₅H₆N⁺·(H⁺·2C₁₁H₁₁O₃⁻), (III), and pyrrolidinium rac‐3‐benzoyl‐2‐methylpropionate rac‐3‐benzoyl‐2‐methylpropionic acid, C₄H₁₀N⁺·C₁₁H₁₁O₃⁻·C₁₁H₁₂O₃, (IV), has enabled us to predict and understand the behaviour of these compounds in Yang photocyclization. Molecules containing the Ar—CO—C—C—CH fragment can undergo Yang photocyclization in solvents but they can be photoinert in the crystalline state. In the case of the compounds studied here, the long distances between the O atom of the carbonyl group and the γ‐H atom, and between the C atom of the carbonyl group and the γ‐C atom preclude Yang photocyclization in the crystals. Molecules of (I) are deprotonated in a different manner depending on the kind of organic base used. In the crystal structure of (III), strong centrosymmetric O...H...O hydrogen bonds are observed.     

Synthese und Charakterisierung von 2‐O‐funktionalisierten Ethylrhodoximen und ‐cobaloximen

Synthesis and Characterization of 2‐O‐Functionalized Ethylrhodoximes and ‐cobaloximes 2‐Hydroxyethylrhodoxime and ‐cobaloxime complexes L—[M]—CH₂CH₂OH (M = Rh, L = PPh₃, 1 ; M = Co, L = py, 2 ; abbr.: L—[M] = [M(dmgH)₂L] (dmgH₂ = dimethylglyoxime, L = axial base) were obtained by reaction of L—[M]^— (prepared by reduction of L—[M]—Cl with NaBH₄ in methanolic KOH) with BrCH₂CH₂OH. H₂O—[Rh]^—, prepared by reduction of H[RhCl₂(dmgH)₂] with NaBH₄ in methanolic KOH, reacted with BrCH₂CH₂OH followed by addition of pyridine yielding py—[Rh]—CH₂CH₂OH ( 3 ). Complexes 1 and 3 were found to react with (Me₃Si)₂NH forming 2‐(trimethylsilyloxy)ethylrhodoximes L—[Rh]—CH₂CH₂OSiMe₃ (L = PPh₃, 4 ; L = py, 5 ). Treatment of complex 1 with acetic anhydride resulted in formation of the 2‐(acet oxy)ethyl complex Ph₃P—[Rh]—CH₂CH₂OAc ( 6 ). All complexes 1 — 6 were isolated in good yields (55—71 %). Their identities were confirmed by NMR spectroscopic investigations ( 1 — 6 : ¹H, ¹³C; 1 , 4 , 6 : ³¹P) and for [Rh(CH₂CH₂OH)(dmgH)₂(PPh₃)]·CHCl₃·1/2H₂O ( 1 ·CHCl₃·1/2H₂O) and py—[Rh]—CH₂CH₂OSiMe₃ ( 5 ) by X‐ray diffraction analyses, too. In both molecules the rhodium atoms are distorted octahedrally coordinated with triphenylphosphine and the organo ligands (CH₂CH₂OH and CH₂CH₂OSiMe₃, respectively) in mutual trans position. Solutions of 1 in dmf decomposed within several weeks yielding a hydroxyrhodoxime complex “Ph₃P—[Rh]—OH”. X‐ray diffraction analysis exhibited that crystals of this complex have the composition [{Rh(dmg)(dmgH) (H₂O)(PPh₃)}₂]·4dmf ( 7 ) consisting of centrosymmetrical dimers. The rhodium atom is distorted octahedrally coordinated. Axial ligands are PPh₃ and H₂O. One of the two dimethylglyoximato ligands is doubly deprotonated. Thus, only one intramolecular O—H···O hydrogen bridge (O···O 2.447(9)Å) is formed in the equatorial plane. The other two oxygen atoms of dmgH^— and dmg^2—, respectively, act as hydrogen acceptors each forming a strong (intermolecular) O···H′—O′ hydrogen bridge to the H′₂O′ ligand of the other molecule (O···O′ 2.58(2)/2.57(2)Å).     

Assembly of 3‐D Network Structures Containing Oxydiacetate and CeIII or CeIV

Reaction of CeCl₃·7H₂O with Na₂(oda) (oda = O(CH₂CO₂)₂^2— oxydiacetate) in a 2:3 ratio gives the neutral cerium(III) complex [Ce₂(oda)₃(H₂O)₃]·9H₂O ( 1 ). Treatment of a 1:3 mixture of CeCl₃·7H₂O and H₂oda in water with 4 molar equivalents of NaOH also gives 1 but, with a larger excess of NaOH, the tri‐sodium salt Na₃[Ce(oda)₃]·9H₂O ( 2 ) is isolated. Formation of a tri‐ammonium analogue of 2 can be achieved by neutralisation of an aqueous solution of CeCl₃·7H₂O and H₂(oda) in a 1:3 ratio by NH₄OH, giving (NH₄)₃[Ce(oda)₃]·7H₂O ( 3 ). Use of the cerium(IV) reagent (NH₄)₂[Ce(NO₃)₆] with Na₂(oda) results in reduction to cerium(III) under ambient conditions and isolation of 1 . However, in the absence of light this reaction yields crystals of the novel cerium(IV) heterobimetallic [Ce(oda)₃Na₄(NO₃)₂] ( 4 ). Each of these complexes exhibit a 3‐D network structure having a common nine‐coordinate [Ce(oda)₃]^n— (n = 2 or 3) subunit, irrespective of the oxidation state of cerium. In 1 , six [Ce(oda)₃]^3— anions are connected, through bridging bidentate carboxylates, to a second Ce³⁺ site further coordinated by three water molecules. In contrast, the ammonium salt 2 , displays isolated [Ce(oda)₃]^3— anions, devoid of further carboxylate bonding, but enmeshed within a network of hydrogen‐bonded NH₄⁺ cations and water molecules. The remarkable structure of 4 consists of infinite 2‐D sheets of [Na₂(NO₃)]⁺ pillared by [Ce(oda)₃]^2— units, the connectivity arising by multidentate nitrate and carboxylate bridging.     

Adducts of 1,1,1‐tris(4‐hydroxy­phenyl)­ethane with 1,2‐bis(4‐pyridyl)­ethane and 1,2‐bis(4‐pyridyl)­ethene: continuously interwoven structures in three dimensions

In the adduct 1,2‐bis(4‐pyridyl)­ethane–1,1,1‐tris(4‐hydroxy­phenyl)­ethane (1/2), C₁₂H₁₂N₂·2C₂₀H₁₈O₃, the bipyridyl component lies across an inversion centre in P. The tris‐phenol mol­ecules [systematic name: 4,4′,4′′‐(ethane‐1,1,1‐triyl)­triphenol] are linked by O—H?O hydrogen bonds to form sheets built from R(38) rings, and symmetry‐related pairs of sheets are linked by the bipyridyl mol­ecules via O—H?N hydrogen bonds to form open bilayers. Each bilayer is interwoven with two adjacent bilayers, forming a continuous three‐dimensional structure. In the adduct 1,2‐bis(4‐pyridyl)­ethene–1,1,1‐tris(4‐hydroxy­phenyl)­ethane–methanol (1/1/1), C₁₂H₁₀N₂·C₂₀H₁₈O₃·CH₄O, the mol­ecules are linked by O—H?O and O—H?N hydrogen bonds into three interwoven three‐dimensional frameworks, generated by single spiral chains along [010] and [001] and a triple‐helical spiral along [100].     

Two succinic acid derivatives of 2‐ethyl‐6‐methylpyridin‐3‐ol

Crystals of bis(2‐ethyl‐3‐hydroxy‐6‐methylpyridinium) succinate–succinic acid (1/1), C₈H₁₂NO⁺·0.5C₄H₄O₄²⁻·0.5C₄H₆O₄, (I), and 2‐ethyl‐3‐hydroxy‐6‐methylpyridinium hydrogen succinate, C₈H₁₂NO⁺·C₄H₅O₄⁻, (II), were obtained by reaction of 2‐ethyl‐6‐methylpyridin‐3‐ol with succinic acid. The succinate anion and succinic acid molecule in (I) are located about centres of inversion. Intermolecular O—H...O, N—H...O and C—H...O hydrogen bonds are responsible for the formation of a three‐dimensional network in the crystal structure of (I) and a two‐dimensional network in the crystal structure of (II). Both structures are additionally stabilized by π–π interactions between symmetry‐related pyridine rings, forming a rod‐like cationic arrangement for (I) and cationic dimers for (II).     

Low‐dimensional hydrogen‐bonded structures in the 1:1 and 1:2 proton‐transfer compounds of 4,5‐dichlorophthalic acid with the aliphatic Lewis bases triethylamine,diethylamine, n‐butylamine and piperidine

The structures of the proton‐transfer compounds of 4,5‐dichlorophthalic acid (DCPA) with the aliphatic Lewis bases triethylamine, diethylamine, n‐butylamine and piperidine, namely triethylaminium 2‐carboxy‐4,5‐dichlorobenzoate, C₆H₁₆N⁺·C₈H₃Cl₂O₄⁻, (I), diethylaminium 2‐carboxy‐4,5‐dichlorobenzoate, C₄H₁₂N⁺·C₈H₃Cl₂O₄⁻, (II), bis(butanaminium) 4,5‐dichlorobenzene‐1,2‐dicarboxylate monohydrate, 2C₄H₁₂N⁺·C₈H₂Cl₂O₄²⁻·H₂O, (III), and bis(piperidinium) 4,5‐dichlorobenzene‐1,2‐dicarboxylate monohydrate, 2C₅H₁₂N⁺·C₈H₂Cl₂O₄²⁻·H₂O, (IV), have been determined at 200 K. All compounds have hydrogen‐bonding associations, giving discrete cation–anion units in (I) and linear chains in (II), while (III) and (IV) both have two‐dimensional structures. In (I), a discrete cation–anion unit is formed through an asymmetric R₁²(4) N⁺—H...O₂ hydrogen‐bonding association, whereas in (II), chains are formed through linear N—H...O associations involving both aminium H‐atom donors. In compounds (III) and (IV), the primary N—H...O‐linked cation–anion units are extended into a two‐dimensional sheet structure via amide–carboxyl N—H...O and amide–carbonyl N—H...O interactions. In the 1:1 salts (I) and (II), the hydrogen 4,5‐dichlorophthalate anions are essentially planar with short intramolecular carboxyl–carboxyl O—H...O hydrogen bonds [O...O = 2.4223 (14) and 2.388 (2) Å, respectively]. This work provides a further example of the uncommon zero‐dimensional hydrogen‐bonded DCPA–Lewis base salt and the one‐dimensional chain structure type, while even with the hydrate structures of the 1:2 salts with the primary and secondary amines, the low dimensionality generally associated with 1:1 DCPA salts is also found.     

Comparison of the hydrogen‐bond patterns in 2‐amino‐1,3,4‐thiadiazolium hydrogen oxalate, 2‐amino‐1,3,4‐thiadiazole–succinic acid (1/2), 2‐amino‐1,3,4‐thiadiazole–glutaric acid (1/1) and 2‐amino‐1,3,4‐thiadiazole–adipic acid (1/1)

The X‐ray single‐crystal structure determinations of the chemically related compounds 2‐amino‐1,3,4‐thiadiazolium hydrogen oxalate, C₂H₄N₃S⁺·C₂HO₄⁻, (I), 2‐amino‐1,3,4‐thiadiazole–succinic acid (1/2), C₂H₃N₃S·2C₄H₆O₄, (II), 2‐amino‐1,3,4‐thiadiazole–glutaric acid (1/1), C₂H₃N₃S·C₅H₈O₄, (III), and 2‐amino‐1,3,4‐thiadiazole–adipic acid (1/1), C₂H₃N₃S·C₆H₁₀O₄, (IV), are reported and their hydrogen‐bonding patterns are compared. The hydrogen bonds are of the types N—H...O or O—H...N and are of moderate strength. In some cases, weak C—H...O interactions are also present. Compound (II) differs from the others not only in the molar ratio of base and acid (1:2), but also in its hydrogen‐bonding pattern, which is based on chain motifs. In (I), (III) and (IV), the most prominent feature is the presence of an R₂²(8) graph‐set motif formed by N—H...O and O—H...N hydrogen bonds, which are present in all structures except for (I), where only a pair of N—H...O hydrogen bonds is present, in agreement with the greater acidity of oxalic acid. There are nonbonding S...O interactions present in all four structures. The difference electron‐density maps show a lack of electron density about the S atom along the S...O vector. In all four structures, the carboxylic acid H atoms are present in a rare configuration with a C—C—O—H torsion angle of ∼0°. In the structures of (II)–(IV), the C—C—O—H torsion angle of the second carboxylic acid group has the more common value of ∼|180|°. The dicarboxylic acid molecules are situated on crystallographic inversion centres in (II). The Raman and IR spectra of the title compounds are presented and analysed.