Alkali‐Metal ortho‐Hydroxyphenolates: Syntheses and Crystal Structures from Powder X‐Ray Diffraction

Colorless and highly air‐ and moisture‐sensitive powders of M[o‐C₆H₄O(OH)] with M = K, Rb, or Cs have been synthesized from reaction mixtures of the appropriate alkali metal and catechol in thf. All compounds were structurally characterized by means of powder X‐ray diffraction using the Rietveld profile refinement technique including restraints for the C—C/C—O bond distances and the C—C—C angles. The atomic arrangements of M[o‐C₆H₄O(OH)] (K: monoclinic P2₁/c; Rb/Cs: orthorhombic Pbcm) are characterized by polymeric chains of [M₁^[4]O₂^[2]η⁶] units connected by hydrogen bonds, thereby making up layered structures similar to the one of catechol. The coordinatively unsaturated alkali metals are forming edge‐sharing MO₄ pyramids and exhibit asymmetrical η⁶‐interactions with the phenylene rings. The symmetry of the unit cells increases with increasing size of the cation, and this results in a decrease of the monoclinic angle from 118.5° (catechol) to 93.7° (K compound), eventually leading to orthorhombic cells for the Rb and Cs compounds.     

Alkali‐Metal meta‐Hydroxyphenolates: Syntheses and Crystal Structures from Powder X‐Ray Diffraction

M[m‐C₆H₄O(OH)] (M = Li—Cs) have been obtained as highly air‐ and moisture‐sensitive powders from reaction mixtures of the appropriate alkali metals and resorcinol in thf. Both the potassium and rubidium compounds were structurally characterized by means of powder X‐ray diffraction using the Simulated Annealing method and the Rietveld profile refinement technique including C—C/C—O bond distance and C—C—C angle restraints. K[m‐C₆H₄O(OH)] (orthorhombic P2₁2₁2₁) forms infinite alternating chains of meta‐hydroxyphenolate anions connected by K—O bonds and short charge‐assisted hydrogen bonds, thereby generating a three‐dimensional network of corrugated layers similar to the structure of pure resorcinol. The potassium cations are surrounded by a triangle of oxygen and, moreover, coordinated by six adjacent phenylene rings to form a distorted octahedron. The complex crystal structure of Rb[m‐C₆H₄O(OH)] (monoclinic Pa) is characterized by layers of hydrogen‐bonded meta‐hydroxyphenolate triple units separated by corrugated rubidium layers. The three crystallographically different Rb atoms are coordinated by three, four, and five oxygens with irregular polyhedra, and the rubidiums are also involved in further electrostatic interactions by up to eight phenylene rings.     

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.     

The structures of the isomorphous potassium and rubidium salts of 4‐nitrobenzoic acid and an overview of the metal complex stereochemistries of the alkali metal salt series with this ligand

4‐Nitrobenzoic acid (PNBA) has proved to be a useful ligand for the preparation of metal complexes but the known structures of the alkali metal salts of PNBA do not include the rubidium salt. The structures of the isomorphous potassium and rubidium polymeric coordination complexes with PNBA, namely poly[μ₂‐aqua‐aqua‐μ₃‐(4‐nitrobenzoato)‐potassium], [K(C₇H₄N₂O₂)(H₂O)₂]_n, (I), and poly[μ₃‐aqua‐aqua‐μ₅‐(4‐nitrobenzoato)‐rubidium], [Rb(C₇H₄N₂O₂)(H₂O)₂]_n, (II), have been determined. In (I), the very distorted KO₆ coordination sphere about the K⁺ centres in the repeat unit comprise two bridging nitro O‐atom donors, a single bridging carboxylate O‐atom donor and two water molecules, one of which is bridging. In Rb complex (II), the same basic MO₆ coordination is found in the repeat unit, but it is expanded to RbO₉ through a slight increase in the accepted Rb—O bond‐length range and includes an additional Rb—O_carboxylate bond, completing a bidentate O,O′‐chelate interaction, and additional bridging Rb—O_nitro and Rb—O_water bonds. The comparative K—O and Rb—O bond‐length ranges are 2.7352 (14)–3.0051 (14) and 2.884 (2)–3.182 (2) Å, respectively. The structure of (II) is also isomorphous, as well as isostructural, with the known structure of the nine‐coordinate caesium 4‐nitrobenzoate analogue, (III), in which the Cs—O bond‐length range is 3.047 (4)–3.338 (4) Å. In all three complexes, common basic polymeric extensions are found, including two different centrosymmetric bridging interactions through both water and nitro groups, as well as extensions along c through the para‐related carboxylate group, giving a two‐dimensional structure in (I). In (II) and (III), three‐dimensional structures are generated through additional bridges involving the nitro and water O atoms. In all three structures, the two water molecules are involved in similar intra‐polymer O—H...O hydrogen‐bonding interactions to both carboxylate and water O‐atom acceptors. A comparison of the varied coordination behaviour of the full set of Li–Cs salts with 4‐nitrobenzoic acid is also made.     

Chromium complexes bearing disubstituted organophosphate ligands and their use in ethylene polymerization

The crystal structures of three unusual chromium organophosphate complexes have been determined, namely, bis(μ‐butyl 2,6‐di‐tert‐butyl‐4‐methylphenyl hydrogen phosphato‐κO:κO′)di‐μ‐hydroxido‐bis[(butyl 2,6‐di‐tert‐butyl‐4‐methylphenyl hydrogen phosphato‐κO)(butyl 2,6‐di‐tert‐butyl‐4‐methylphenyl phosphato‐κO)chromium](Cr—Cr) heptane disolvate or {Cr₂(μ₂‐OH)₂[μ₂‐PO₂(OBu)(O‐2,6‐^tBu₂‐4‐MeC₆H₂)‐κO:κO′]₂[PO₂(OBu)(O‐2,6‐^tBu₂‐4‐MeC₆H₂)‐κO]₂[HOPO(OBu)(O‐2,6‐^tBu₂‐4‐MeC₆H₂)‐κO]₂}·2C₇H₁₆, [Cr₂(C₁₉H₃₂O₄P)₄(C₁₉H₃₃O₄P)₂(OH)₂]·2C₇H₁₆, denoted ( 1 )·2(heptane), [μ‐bis(2,6‐diisopropylphenyl) phosphato‐1κO:2κO′]bis[bis(2,6‐diisopropylphenyl) phosphato]‐1κO,2κO‐chlorido‐2κCl‐triethanol‐1κ²O,2κO‐di‐μ‐ethanolato‐1κ²O:2κ²O‐dichromium(Cr—Cr) ethanol monosolvate or {Cr₂(μ₂‐OEt)₂[μ₂‐PO₂(O‐2,6‐ⁱPr₂‐C₆H₃)₂‐κO:κO′][PO₂(O‐2,6‐ⁱPr₂‐C₆H₃)₂‐κO]₂Cl(EtOH)₃}·EtOH, [Cr₂(C₂H₅O)₂(C₂₄H₃₄O₄P)₃Cl(C₂H₆O)₃]·C₂H₆O, denoted ( 2 )·EtOH, and di‐μ‐ethanolato‐1κ²O:2κ²O‐bis{[bis(2,6‐diisopropylphenyl) hydrogen phosphato‐κO][bis(2,6‐diisopropylphenyl) phosphato‐κO]chlorido(ethanol‐κO)chromium}(Cr—Cr) benzene disolvate or {Cr₂(μ₂‐OEt)₂[PO₂(O‐2,6‐ⁱPr₂‐C₆H₃)₂‐κO]₂[HOPO(O‐2,6‐ⁱPr₂‐C₆H₃)₂‐κO]₂Cl₂(EtOH)₂}·2C₆H₆, [Cr₂(C₂H₅O)₂(C₂₄H₃₄O₄P)₂(C₂₄H₃₅O₄P)₂Cl₂(C₂H₆O)₂]·2C₆H₆, denoted ( 3 )·2C₆H₆. Complexes ( 1 )–( 3 ) have been synthesized by an exchange reaction between the in‐situ‐generated corresponding lithium or potassium disubstituted phosphates with CrCl₃(H₂O)₆ in ethanol. The subsequent crystallization of ( 1 ) from heptane, ( 2 ) from ethanol and ( 3 ) from an ethanol/benzene mixture allowed us to obtain crystals of ( 1 )·2(heptane), ( 2 )·EtOH and ( 3 )·2C₆H₆, whose structures have the monoclinic P2₁, orthorhombic P2₁2₁2₁ and triclinic P space groups, respectively. All three complexes have binuclear cores with a single Cr—Cr bond, i.e. Cr₂O₆P₂ in ( 1 ), Cr₂PO₄ in ( 2 ) and Cr₂O₂ in ( 3 ), where the Cr atoms are in distorted octahedral environments, formally having 16 ē per Cr atom. The complexes have bridging ligands μ₂‐OH in ( 1 ) or μ₂‐OEt in ( 2 ) and ( 3 ). The organophosphate ligands demonstrate terminal κO coordination modes in ( 1 )–( 3 ) and bridging μ₂‐κO:κO′ coordination modes in ( 1 ) and ( 2 ). All the complexes exhibit hydrogen bonding: two intramolecular O_phos…H—O_phos interactions in ( 1 ) and ( 3 ) form two {H[PO₂(OR)₂]₂} associates; two intramolecular Cl…H—O_Et hydrogen bonds additionally stabilize the Cr₂O₂ core in ( 3 ); two intramolecular O_phos…H—O_Et interactions and two O…H—O intermolecular hydrogen bonds with a noncoordinating ethanol molecule are observed in ( 2 )·EtOH. The presence of both basic ligands (OH^? or OEt^?) and acidic [H(phosphate)₂]^? associates at the same metal centres in ( 1 ) and ( 3 ) is rather unusual. Complexes may serve as precatalysts for ethylene polymerization under mild conditions, providing polyethylene with a small amount of short‐chain branching. The formation of a small amount of α‐olefins has been detected in this reaction.     

Dinuclear neodymium and lanthanum bis(2,6‐diisopropylphenyl) phosphate complexes bearing a hydroxide ligand: catalytic activity of the Nd complex in 1,3‐diene polymerization

The reactions of K[(2,6‐ⁱPr₂C₆H₃‐O)₂POO] either with LaCl₃(H₂O)₇ or with Nd(NO₃)₃(H₂O)₆ in a 3:1 molar ratio, followed by vacuum drying and recrystallization from alkanes, have led to the formation of diaquapentakis[bis(2,6‐diisopropylphenyl) phosphato]‐μ‐hydroxido‐dilanthanum hexane disolvate, [La₂(C₂₄H₃₄O₄P)₅(OH)(H₂O)₂]·2C₆H₁₄, ( 1 )·2(hexane), and tetraaquatetrakis[bis(2,6‐diisopropylphenyl) phosphato]‐μ‐hydroxido‐dineodymium bis(2,6‐diisopropylphenyl) phosphate heptane disolvate, [Nd₂(C₂₄H₃₄O₄P)₄(OH)(H₂O)₄]·2C₆H₁₄, ( 2 )·2(heptane). The compounds crystalize in the P2₁/n and P space groups, respectively. The diaryl‐substituted organophosphate ligand exhibits three different coordination modes, viz. κ²O,O′‐terminal [in ( 1 ) and ( 2 )], κO‐terminal [in ( 1 )] and μ₂‐κ¹O:κ¹O′‐bridging [in ( 1 ) and ( 2 )]. Binuclear structures ( 1 ) and ( 2 ) are similar and have the same unique Ln₂(μ‐OH)(μ‐OPO)₂ core. The structure of ( 2 ) consists of an [Nd₂{(2,6‐ⁱPr₂C₆H₃‐O)₂POO}₄(OH)(H₂O)₄]⁺ cation and a [(2,6‐ⁱPr₂C₆H₃‐O)₂POO]⁻ anion, which are bound via four intermolecular O—H…O hydrogen bonds. The molecular structure of ( 1 ) displays two O—H…O hydrogen bonds between OH/H₂O ligands and a κ¹O‐terminal organophosphate ligand, which resembles, to some extent, the `free' [(2,6‐ⁱPr₂C₆H₃‐O)₂POO]⁻ anion in ( 2 ). NMR studies have shown that the formation of ( 1 ) undoubtedly occurs due to intramolecular hydrolysis during vacuum drying of the aqueous La tris(phosphate) complex. Catalytic experiments have demonstrated that the presence of the coordinated hydroxide anion and water molecules in precatalyst ( 2 ) substantially lowered the catalytic activity of the system prepared from ( 2 ) in butadiene and isoprene polymerization compared to the catalytic system based on the neodymium tris[bis(2,6‐diisopropylphenyl) phosphate] complex, which contains neither OH nor H₂O ligands.     

A ferric-cyanide-bridged one-dimensional dirhodium complex with (18-­crown-6)­potassium cations

The crystal structure of the title compound, catena-poly[bis[aqua(18-crown-6)­potassium] di­aqua(18-crown-6)­potassium [[tetra-μ-benzoato-2:3κ⁸O:O′-μ-cyano-1:2κ²C:N-tetra­cyano-1κC-irondirhodium(Rh—Rh)]-μ-cyano-1κC:3′κN] octahydrate], [K(18-crown-6)(H₂O)]₂[K(18-crown-6)(H₂O)₂]­[FeRh₂(C₇H₅O₂)₄(CN)₆]·8H₂O, where (18-crown-6) is 1,4,7,10,13,16-hexaoxa­cyclo­octa­decane (C₁₂H₂₄O₆), has been determined. Ferric cyanides connect the dirhodium units to form a one-dimensional chain compound. [K(18-crown-6-ether)(H₂O)₂] cations (with inversion symmetry) and [K(18-crown-6-ether)(H₂O)] cations (in general positions) are located between the chains.     

Synthesis,Crystal Structure and Properties of Rubidium Dihydrogentricyanomelaminate Semihydrate Rb[H2C6N9] · 1/2 H2O

Rubidium dihydrogentricyanomelaminate semihydrate Rb[H₂C₆N₉] · ¹/₂ H₂O was obtained as colorless rod‐like single crystals from a solution of Rb₃[C₆N₉] · H₂O and 0.1 M HCl after water evaporation at room temperature. According to the X‐ray single‐crystal structure determination (Rb[H₂C₆N₉] · ¹/₂ H₂O: C2/c (no. 15), a = 2007.4(3) pm, b = 512.2(1) pm, c = 2168.0(4) pm, β = 111.66(2)°, Z = 8, R1 = 0.059, 2391 independent reflections, 159 parameters) Rb⁺ and cyclic planar [H₂C₆N₉]^— ions as well as hydrate water molecules occur in the crystal. Rb[H₂C₆N₉] · ¹/₂ H₂O was investigated by FTIR and Raman spectroscopy, TG measurements and temperature‐dependent X‐ray powder diffraction. According to the thermoanalytic investigations, dehydration of Rb[H₂C₆N₉] · ¹/₂ H₂O starts above 60 °C and is finished below 250 °C.     

Investigation of Structural Relationships between Racemic Alkali and Ammonium Hydrogen Tartrates and their Chiral Counterparts

Single crystals of racemic anhydrous alkali and ammonium hydrogen tartrates of the composition M(C₄H₅O₆) with M = K, Rb, Cs, NH₄ as well as M_xM′_1?x(C₄H₅O₆) with {M = K, M′ = Rb, x = 0.5}, {M = K, M′ = NH₄, x = 0.56} and {M = Rb, M′ = NH₄, x = 0.61} were obtained from the reaction of D,L‐tartaric acid with the corresponding hydroxides MOH and / or M′OH. These compounds form an isostructural series (monoclinic, P2₁/c, Z = 4). The structures consist of alternating tartrate anion layers and cation layers. Each tartrate layer is held together by a number of hydrogen bonds and contains exclusively either the D or the L‐form of the tartrate. Structural analogies between these crystals and their chiral counterparts are investigated. The smilarity of cell parameters between racemic and chiral structures is shown to be a consequence of certain packing features that occur in both groups.     

Formation of lithium,sodium and potassium complexes with 1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol (taci)

Single crystals of (1,3‐diamino‐5‐azaniumyl‐1,3,5‐trideoxy‐cis‐inositol‐κ³O²,O⁴,O⁶)(1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol‐κ³O²,O⁴,O⁶)lithium(I) diiodide dihydrate, [Li(C₆H₁₆N₃O₃)(C₆H₁₅N₃O₃)]I₂·2H₂O or [Li(Htaci)(taci)]I₂·2H₂O (taci is 1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol), (I), bis(1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol‐κ³O²,O⁴,O⁶)sodium(I) iodide, [Na(C₆H₁₅N₃O₃)₂]I or [Na(taci)₂]I, (II), and bis(1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol‐κ³O²,O⁴,O⁶)potassium(I) iodide, [K(C₆H₁₅N₃O₃)₂]I or [K(taci)₂]I, (III), were grown by diffusion of MeOH into aqueous solutions of the complexes. The structures of the Na and K complexes are isotypic. In all three complexes, the taci ligands adopt a chair conformation with axial hydroxy groups, and the metal cations exhibit exclusive O‐atom coordination. The six O atoms of the resulting MO₆ unit define a centrosymmetric trigonal antiprism with approximate D_3d symmetry. The interligand O...O distances increase significantly in the order Li < Na < K. The structure of (I) exhibits a complex three‐dimensional network of R—NH₂—H...NH₂—R, R—O—H...NH₂—R and R—O—H...O(H)—H...NH₂—R hydrogen bonds. The structures of the Na and K complexes consist of a stack of layers, in which each taci ligand is bonded to three neighbours via pairwise O—H...NH₂ interactions between vicinal HO—CH—CH—NH₂ groups.     

Two new transition metal inorganic–organic hybrid borates: [tris(2‐aminoethoxy)trihydroxyhexaborato]cobalt(II) and its nickel(II) analogue

The two isomorphous title compounds, [1,5,9‐tris(2‐aminoethoxy)‐3,7,11‐trihydroxy‐3,7,11‐tribora‐1,5,9‐triborata‐2,4,6,8,10,12‐hexaoxa‐13‐oxoniatricyclo[7.3.1.0^5,13]tridecane]cobalt(II), [Co(C₆H₂₁B₆N₃O₁₃)] or Co{B₆O₇(OH)₃[O(CH₂)₂NH₂]₃}, and the Ni^II analogue, [Ni(C₆H₂₁B₆N₃O₁₃)], each consist of an M^II cation and an inorganic–organic hybrid {B₆O₇(OH)₃[O(CH₂)₂NH₂]₃}²⁻ anion. The M^II cation lies on a crystallographic threefold axis (as does one O atom) and is octahedrally coordinated by three N atoms from the organic component. Three O atoms covalently link the B–O cluster and the organic component. Molecules are connected to one another through N—H...O and O—H...O hydrogen bonds, forming a three‐dimensional supramolecular network.     

Pb2(OH)2[p‐O2C‐C6H4‐CO2]: Synthese und Kristallstruktur

Pb₂(OH)₂[p‐O₂C‐C₆H₄‐CO₂]: Synthesis and Crystal Structure Single crystals of Pb₂(OH)₂[p‐O₂C‐C₆H₄‐CO₂] ( 1 ) were obtained by hydrothermal reaction of terephthalic acid and PbCO₃ at 180 °C (10 days). 1 crystallizes in the monoclinic space group P2₁/c with Z = 2 (a = 1115.6(2) pm, b = 380.10(4) pm, c = 1141.3(2) pm, β = 93.39(1)°, V = 0.4831(1) nm³). The crystal structure is characterized by ladder‐type Pb(OH)_3/3 double chains, which are connected to a three‐dimensional framework by terephthalate dianions.     

Berberine formate–succinic acid (1/1)

The title compound [systematic name: 9,10‐di­methoxy‐2,3‐methyl­ene­dioxy‐5,6‐di­hydro­dibenzo­[a,g]­quinolizinium form­ate–succinic acid (1/1)], C₂₀H₁₈NO₄⁺·CHO₂⁻·C₄H₆O₄, con­tains centrosymmetric pairs of almost planar berberine cations, and hydrogen‐bonded (C₄H₆O₄⋯HCOO⁻)₂ rings of succinic acid with formate anions, bonded by O—H⋯O hydrogen bonds with O⋯O distances of 2.4886 (15) and 2.5652 (16) Å. Pairs of cations and mol­ecules of succinic acid are connected by non‐conventional weak C—H⋯O hydrogen bonds, with C⋯O distances of 3.082 (2) and 3.178 (2) Å.     

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.     

1:1 Adducts of 2,2′‐[isopropylidenebis(p‐phenyleneoxy)]diacetic acid with dimethylammonium and 4,4′‐bipyridine

The title compounds, dimethylammonium 2‐{4‐[1‐(4‐carboxymethoxyphenyl)‐1‐methylethyl]phenoxy}acetate, C₂H₈N⁺·C₁₉H₁₉O₆⁻, (I), and 2,2′‐[isopropylidenebis(p‐phenyleneoxy)]diacetic acid–4,4′‐bipyridine (1/1), C₁₉H₂₀O₆·C₁₀H₈N₂, (II), are 1:1 adducts of 2,2′‐[isopropylidenebis(p‐phenyleneoxy)]diacetic acid (H₂L) with dimethylammonium or 4,4′‐bipyridine. The component ions in (I) are linked by N—H...O, O—H...O and C—H...O hydrogen bonds into continuous two‐dimensional layers parallel to the (001) plane. Adjacent layers are stacked via C—H...O hydrogen bonds into a three‐dimensional network with an –ABAB– alternation of the two‐dimensional layers. In (II), two H₂L molecules, one bipy molecule and two half bipy molecules are linked by O—H...N hydrogen bonds into one‐dimensional chains and rectanglar‐shaped rings. They are assembled viaπ–π stacking interactions and C—H...O hydrogen bonds into an intriguing zero‐dimensional plus one‐dimensional poly(pseudo)rotaxane motif.     

Calcium(II) meso‐2,3‐di­phenyl­succinate heptahydrate

The title compound, [Ca(C₁₆H₁₂O₄)(H₂O)₆]·H₂O, adopts a conformation about the central C—C bond that places the two carboxylate groups in an anti orientation. The crystal consists of layers of two‐dimensional arrays of 2,3‐di­phenyl­succinate dianions which are linked by bridging Ca²⁺ cations. The unit cell contains two Ca²⁺ cations in an unusual four‐membered Ca—O—Ca—O ring in which the bridging O atoms belong to water mol­ecules rather than carboxyl­ates, i.e. poly­[[[di‐μ‐aqua‐bis­[penta­aqua­calcium(II)]]‐μ‐(meso‐2,3‐di­phenyl­succinato‐O:O′)] succinate dihydrate].     

The 2:1 complex of maleic acid and 1,4‐diazabicyclo[2.2.2]octane: hydrogen‐bonded sheets linked by C–H⋯O hydrogen bonds

In the title complex, 1,4‐diazo­niabi­cyclo­[2.2.2]­octane bis­(hy­drogen maleate), C₆H₁₄N₂²⁺·2C₄H₃O₄^?, the C₄H₃O₄^? and C₆H₁₄N₂²⁺ ions, derived from maleic acid and 1,4‐di­aza­bi­cyclo­[2.2.2]­octane, respectively, are disordered across a mirror plane in space group Cmc2₁, and they are linked by two nearly linear N—H?O hydrogen bonds, with N?O distances of 2.662 (3) and 2.614 (4) Å, and N—H?O angles of 173°. The crystal structure consists of sheets with reticulations of 3.3792 (4) Å in stratum and 7.3892 (8) Å in width. The sheets are linked by C—H?O hydrogen bonds.     

A donor–acceptor compound composed of a di­nuclear zinc(II) complex of a Robson macro­cycle with 8‐methyl­quino­line

A donor–acceptor compound, di­aqua‐1κO,2κO‐[μ‐11,23‐dimethyl‐3,7,15,19‐tetra­aza­tri­cyclo­[19.3.1.1^9,13]hexacosa‐1(25),2,7,9,11,13(26),14,19,21,23‐decaene‐25,­26‐diolato‐1κ⁴N³,N⁷,O²⁵,O²⁶:­2κ⁴N¹⁵,N¹⁹,O²⁵,O²⁶]­dizinc(II) diperchlorate bis(8‐methyl­quinoline) ethanol disolvate, [Zn₂(C₂₄H₂₆N₄O₂)(H₂O)₂](ClO₄)₂·2C₁₀H₉N·2C₂H₆O, obtained by the reaction of a dinuclear zinc(II) complex of a Robson macrocycle (acceptor) and 8‐methyl­quinoline (donor), lies about an inversion centre and the coordination about the unique Zn atom is a distorted square pyramid. The fifth coordination site is occupied by the water mol­ecule, Zn—O = 2.016 (2) Å, and the average macrocyclic Zn—O and Zn—N distances are 2.059 (6) and 2.059 (3) Å, respectively.     

Mössbauer study on solid state photolysis of alkali tris(malonato)ferrates(III)

Solid state photolysis of alkali tris(malonato)ferrates(III), i.e., M₃[Fe(CH₂C₂O₄)₃]xH₂O (M=Li, Na, K, NH₄) has been studied employing Mössbauer, infrared and reflectance spectroscopic techniques. The complexes were irradiated for 300 hours using a medium pressure mercury vapour lamp of 250 W, Photodecomposition led to the formation of an iron(II) intermediate, M₂[Fe^II(CH₂C₂O₄)₂(H₂O)₂] (M=Li, Na, K) which on prolonged standing in air oxidized to M[Fe^III(CH₂C₂O₄)₂(H₂O)₂]. However, in case of ammonium complex, Fe^IICH₂C₂O₄·2H₂O once formed remained stable. The extent of photoreduction showed the sequence: NH₄, K>Li>Na. The results have been compared with those of alkali tris (oxalato) ferrates(III).     

Picolinamidium squarate and di‐p‐toluidinium squarate dihydrate

The crystal structure determinations of picolinamidium squarate, C₆H₇N₂O⁺·C₄O₄⁻, (I), and di‐p‐toluidinium squarate dihydrate, 2C₇H₁₀N⁺·C₄O₄²⁻·2H₂O, (II), are reported. While salt formation occurs by donation of one H atom from squaric acid to the picolin­amide mol­ecule in (I), in compound (II), each squaric acid mol­ecule donates one H atom to the p‐toluidine N atom of two trans p‐toluidine molecules. In (I), the pyridine ring is coplanar with the squarate monoanion through imposed crystallographic mirror symmetry; in (II), the dihedral angle between the p‐toluidine moiety and the squarate dianion is 70.71 (1)°. In (I), a three‐dimensional structure is formed via van der Waals interactions between parallel planes of mol­ecules, with hydrogen‐bond interactions (N—H⋯O and O—H⋯O) acting within the planes; hydrogen bonds form a three‐dimensional network in (II).