Poly[aquaneodymium(III)‐μ5‐2‐oxido‐5‐sulfonatobenzoato]

The title compound, [Nd(C₇H₃O₆S)(H₂O)]_n or [Nd(SSA)(H₂O)]_n (H₃SSA is 5‐sulfosalicylic acid), was synthesized by the hydrothermal reaction of Nd₂O₃ with H₃SSA in water. The compound forms a three‐dimensional network in which the asymmetric unit contains one Nd^III atom, one SSA ligand and one coordinated water mol­ecule. The central Nd^III ion is eight‐coordinate, bonded to seven O atoms from five different SSA ligands [Nd—O = 2.405 (4)–2.612 (4) Å] and one aqua O atom [Nd—OW = 2.441 (4) Å].     

Bis(2,6‐diamino‐1H‐purin‐3‐ium) di‐μ‐croconato‐κ3O,O′:O′′;κ3O:O′,O′′‐bis[tetraaqua(croconato‐κ2O,O′)neodymium(III)]

The structure of the ionic title compound, (C₅H₇N₆)₂[Nd₂(C₅O₅)₄(H₂O)₈], consists of anionic dimers built around an inversion centre and is made up of an Nd^III cation, two croconate (croco) dianions and four water molecules (plus their inversion images), with two noncoordinated symmetry‐related 2,6‐diamino‐1H‐purin‐3‐ium (Hdap⁺) cations providing charge balance. Each Nd^III atom is bound to nine O atoms from four water and three croco units. The coordination polyhedron has the form of a rather regular monocapped square antiprism. The croconate anions are regular and the Hdap⁺ cation presents a unique, thus far unreported, protonation state. The abundance of hydrogen‐bonding donors and acceptors gives rise to a complex packing scheme consisting of dimers interlinked along the three crystallographic directions and defining anionic `cages' where the unbound Hdap⁺ cations lodge, linking to the mainframe via (N—H)_Hdap...O_water/croco and (O—H)_water...N_Hdap interactions.     

catena‐Poly[[bis(μ‐2‐sulfonatobenzoato)bis[triaquagadolinium(III)]]‐μ‐oxalato]

The asymmetric unit of the title coordination polymer, [Gd₂(C₇H₄O₅S)₂(C₂O₄)(H₂O)₆]_n or [Gd(2‐SB)(ox)_0.5(H₂O)₃]_2n (2‐SB is 2‐sulfonatobenzoate and ox is oxalate), (I), consists of one Gd^III ion, one 2‐SB anion, three coordinated water molecules and one half of an ox ligand. The ox ligand is located on a crystallographic inversion centre. The Gd^III centre shows a distorted tricapped trigonal–prismatic coordination formed by nine O atoms from two 2‐SB anions, one ox ligand and three coordinated water molecules. The carboxylate and sulfonate groups of the 2‐SB anions adopt μ₂‐η¹:η² and μ₁‐η⁰:η⁰:η¹ coordination modes to link two Gd^III ions, generating a centrosymmetric binuclear [Gd₂(2‐SB)₂(H₂O)₆]²⁻ subunit. The ox ligand acts as a bridge, linking the binuclear [Gd₂(2‐SB)₂(H₂O)₆]²⁻ subunits into a one‐dimensional chain structure parallel to the b axis. Furthermore, extensive O—H...O hydrogen bonds connect the chains into a three‐dimensional supramolecular architecture.     

Poly[sodium(I)‐μ6‐hydrogen benzene‐1,4‐dicarboxylato]

Alkali metal salts of terephthalic acid are common reagents in the preparation of metal–ligand coordination complexes containing terephthalate anions. In the title compound, sodium hydrogen terephthalate, [Na(C₈H₅O₄)]_n, the cations occupy crystallographic inversion centres, and each bridging anion coordinates to six octahedral cations and vice versa. As seen in the known potassium derivative [Kaduk (2000). Acta Cryst. B 56 , 474–485; Miyakubo, Takeda & Nakamura (1994). Bull. Chem. Soc. Jpn, 67 , 2301–2303], sodium hydrogen terephthalate contains short O—H⋯O hydrogen bonds between anions [O⋯O = 2.4734 (17) Å]. The structure is centrosymmetric and exhibits disorder of the H‐atom position in the hydrogen bond and of the non‐bridging ring C atoms in the terephthalate ion.     

Layered poly[μ2‐aqua‐μ3‐dimethyl­formamide‐di‐μ3‐phenyl­phosphon­ato‐dipotassium]

The first structurally characterized alkali metal phospho­nate, the title compound, [K₂(C₆H₆O₃P)₂(C₃H₇NO)(H₂O)]_n, has a complex structure, with layers parallel to the crystallographic bc plane consisting of two crystallographically independent K atoms sandwiched between the three types of ligands present in the structure, viz. water molecules, dimethyl­formamide molecules and two crystallographically independent phenyl­phospho­nate ligands. Six O atoms coordinate to one K atom and seven to the other. The interlayer distance is 15.327 (4) Å. The K—O distances are in the range 2.739 (2)–2.932 (2) Å for the seven‐coordinate K atom and 2.650 (2)–2.821 (2) Å for the six‐coordinate K atom.     

Tuning the Magnetization Dynamic Properties of Nd⋅⋅⋅Fe and Nd⋅⋅⋅Co Single‐Molecular Magnets by Introducing 3 d–4 f Magnetic Interactions

By using paramagnetic [Fe(CN)₆]^3? anions in place of diamagnetic [Co(CN)₆]^3? anions, two field‐induced mononuclear single‐molecular magnets, [Nd(18‐crown‐6)(H₂O)₄][Co(CN)₆] ? 2 H₂O ( 1 ) and [Nd(18‐crown‐6)(H₂O)₄][Fe(CN)₆] ? 2 H₂O ( 2 ), have been synthesized and characterized. Single‐crystal X‐ray diffraction analysis revealed that compounds 1 and 2 were ionic complexes. The Nd^III ions were located inside the cavities of the 18‐crown‐6 ligands and were each bound by four water molecules on either side of the crown ether. Magnetic investigations showed that these compounds were both field‐induced single‐molecular magnets. By comparing the slow relaxation behaviors of compounds 1 and 2 , we found significant differences between the direct and Raman processes for these two complexes, with a stronger direct process in compound 2 at low temperatures. Complete active space self‐consistent field (CASSCF) calculations were also performed on two [Nd(18‐crown‐6)(H₂O)₄]³⁺ fragments of compounds 1 and 2 . Ab initio calculations showed that the magnetic anisotropies of the Nd^III centers in complexes 1 and 2 were similar to each other, which indicated that the difference in relaxation behavior was not owing to the magnetic anisotropy of Nd^III. Our analysis showed that the magnetic interaction between the Nd^III ion and the low‐spin Fe^III ion in complex 2 played an important role in enhancing the direct process and suppressing the Raman process of the single‐molecular magnet.     

[{Na(7‐Nitro‐5‐sulfonate‐naphthalene‐1,4‐dicarboxy‐acid (H2O)2}·H2O]n: A Water‐Soluble 2D Layer Polymeric Complex with Microporous Molecular Channels

The X‐ray crystallographic studies are reported for a water‐soluble sodium complex of organic acid, {[Na(NSNDC)(H₂O)₂]·H₂O}_n, (NSNDC = 7‐Nitro‐5‐sulfonate‐napthalene‐1,4‐dicarboxy‐acid). It contains layers of vertically oriented NNSDC‐anions sandwiching cations and water molecules. The rows of anions are linked in a direction by sodium ions and along b by hydrogen bonding, which have microporous channels (9.410 × 3.210Ų) along the crystallographic b‐axis. Considering the Na coordination environments, π‐π stacking interaction between aryl ring and hydrogen bonds, the title compound represents a stably 2D infinitely extended structure.     

pH Dependent Synthesis of NdIII Coordination Compounds Based on Bifunctional 5‐(4‐Pyridyl)tetrazole‐2‐acetic Acid

The Nd^III coordination compounds [Nd(4‐pytza)₃(H₂O)₂] · 2H₂O ( 1 ) and [Nd(4‐pytza)₂(H₂O)₄]Cl · 2H₂O ( 2 ) [H4‐pytza = 5‐(4‐pyridyl)tetrazole‐2‐acetic acid] were synthesized by reactions of K4‐pytza and NdCl₃ · 6H₂O at different pH values. Single crystal X‐ray diffraction analysis reveals that 4‐pytza ligands in 1 in a μ_1,3‐COO syn‐syn or μ_1,1,3‐COO bridging mode coordinate to two central Nd^III atoms to display a dinuclear unit, which is connected by one of these 4‐pytza ligands acting in end‐to‐end bridging mode to form a 1D ladder‐like chain. Different from 1 , each 4‐pytza in 2 with a μ_1,3‐COO syn‐anti bridging mode coordinates to two Nd^III atoms to display a 1D zigzag chain. Furthermore, the luminescence properties of 1 and 2 were investigated at room temperature in the solid state.     

catena‐Poly[[diaquazinc(II)]‐μ‐4,4′‐sulfonyldibenzoato‐κ2O:O′]

The title compound, [Zn(C₁₄H₈O₆S)(H₂O)₂]_n, is the first reported metal complex of the 4,4′‐sulfonyldibenzoate anion. The structure comprises zigzag chains of alternating [Zn(H₂O)₂]²⁺ and sulfonyldibenzoate units, the central Zn and S atoms of which lie on crystallographic twofold axes. The Zn^II centre occupies a strongly distorted tetrahedral environment [O—Zn—O = 83.30 (7)–136.19 (8)°], coordinated by the two water O atoms [Zn—O = 1.986 (2) Å] and one O atom from each of two carboxylate groups [Zn—O = 1.9942 (19) Å], with much longer contacts to the other O atoms of these carboxylates [Zn—O = 2.528 (2) Å]. Hydrogen bonds between carboxylate O atoms and coordinated water molecules in adjacent chains lead to the formation of a three‐dimensional network structure.     

Poly[[diaquabis(μ2‐crotonato‐κ3O:O,O′)(crotonato‐κ2O,O′)lanthanum(III)] adenine monosolvate monohydrate]

The asymmetric unit of the title compound, {[La(C₄H₅O₂)₃(H₂O)₂]·C₅H₅N₅·H₂O}_n, consists of an La^III cation, three crotonate (but‐2‐enoate) anions and two coordinated water molecules forming the neutral complex, completed by an external adenine molecule and one hydration water molecule. The LaO₁₀ coordination polyhedra, connected through the sharing of a single edge, form isolated chains running along the [100] direction. These one‐dimensional structures are characterized by two different centrosymmetric La₂O₂ loops, with La...La distances of 4.5394 (6) and 4.5036 (6) Å. The unbound adenine and water solvent molecules form a highly planar hydrogen‐bonded array parallel to (110) (r.m.s. deviation from the mean plane < 0.10 Å) which intersects the isolated La–crotonate chains in a slanted fashion to form an extremely connected hydrogen‐bonded three‐dimensional structure.     

A novel three‐dimensional heterometallic coordination polymer: poly[[diaquadi‐μ3‐chlorido‐μ2‐chlorido‐tri‐μ3‐nicotinato‐tricopper(I)gadolinium(III)] hemihydrate]

In the title polymeric heterometallic compound, {[Cu₃Gd(C₆H₄NO₂)₃Cl₃(H₂O)₂]·0.5H₂O}_n, comprising copper(I) and gadolinium(III) cations bridged by nicotinate (nic) ligands and chloride anions, the Gd^III centers display a bicapped trigonal prismatic geometry, defined by six carboxylate O atoms and two water molecules. For copper(I), one Cu center is three‐coordinated by three chloride ions and displays a trigonal–planar geometry; the other two Cu centers are four‐coordinated and display a very distorted tetrahedral geometry. The chloride anions act in μ₂‐ and μ₃‐bridging modes, linking the Cu^I ions into an infinite chain. The nic ligand exhibits a tridentate coordination mode, with the carboxylate O atoms linking to two Gd^III ions and the N atom linking to one Cu^I ion. Thus, a novel three‐dimensional heterometallic coordination polymer is constructed from Gd–carboxylate subunits and Cu—Cl chains. In addition, intra‐ and intermolecular O—H...O and O—H...Cl hydrogen bonds are also observed within the three‐dimensional structure. Topologically, the framework represents an unusual 3,6‐connected (4.8²)₃(4¹⁰.6⁵) net.     

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.     

catena‐Poly[bis[1‐chloromethyl‐1,4‐diazoniabicyclo[2.2.2]octane] [cadmium(II)‐tri‐μ‐chlorido‐[chloridocadmium(II)]‐di‐μ‐chlorido‐[chloridocadmium(II)]‐tri‐μ‐chlorido] tetrahydrate]

The title compound, {(C₇H₁₅N₂Cl)₂[Cd₃Cl₁₀]·4H₂O}_n, consists of 1‐chloromethyl‐1,4‐diazoniabicyclo[2.2.2]octane dications, one‐dimensional inorganic chains of {[Cd₃Cl₁₀]⁴⁻} anions and uncoordinated water molecules. Each of the two independent Cd^II ions, one with site symmetry 2/m and the other with site symmetry m, is octahedrally coordinated by chloride ions (two with site symmetry m and one with site symmetry 2), giving rise to novel polymeric zigzag chains of corner‐sharing Cd‐centred octahedra parallel to the c axis. The organic cations, bisected by mirror planes that contain the two N atoms, three methylene C atoms and the Cl atom, are ordered. Hydrogen bonds (O—H...Cl and O—H...O) between the water molecules (both with O atoms in a mirror plane) and the chloride anions of neighbouring chloridocadmate chains form a three‐dimensional supramolecular network.     

catena‐Poly[[[pentaaquathulium(III)]‐μ‐5‐sulfonatobenzene‐1,3‐dicarboxylato] 4,4′‐bipyridyl 1.5‐solvate hemihydrate]

The crystal structure of the title compound, {[Tm(C₈H₃O₇S)(H₂O)₅]·1.5C₁₀H₈N₂·0.5H₂O}_n, is built up from two [Tm(SIP)(H₂O)₅] molecules (SIP³⁻ is 5‐sulfonatobenzene‐1,3‐dicarboxylate), three 4,4′‐bipyridyl (bpy) molecules and one solvent water molecule. One of the bpy molecules and the solvent water molecule are located on an inversion centre and a twofold rotation axis, respectively. The Tm^III ion coordination is composed of four carboxylate O atoms from two trianionic SIP³⁻ ligands and five coordinated water molecules. The Tm³⁺ ions are linked by the SIP³⁻ ligands to form a one‐dimensional zigzag chain propagating along the c axis. The chains are linked by interchain O—H...O hydrogen bonds to generate a two‐dimensional layered structure. The bpy molecules are not involved in coordination but are linked by O—H...N hydrogen bonds to form two‐dimensional layers. The two‐dimensional layers are further bridged by the bpy molecules as pillars and the solvent water molecules through hydrogen bonds, giving a three‐dimensional supramolecular structure. π–π stacking interactions between the parallel aromatic rings, arranged in an offset fashion with a face‐to‐face distance of 3.566 (1) Å, are observed in the crystal packing.     

Poly[[(μ2‐biphenyl‐2,4′‐dicarboxylato)[μ2‐1,4‐bis(imidazol‐1‐ylmethyl)benzene]cadmium(II)] 0.15‐hydrate]

The asymmetric unit of the title two‐dimensional coordination polymer, {[Cd(C₁₄H₈O₄)(C₁₄H₁₄N₄)]·0.15H₂O}_n, is composed of one Cd^II cation, one biphenyl‐2,4′‐dicarboxylate (bpdc) anion, one 1,4‐bis(imidazol‐1‐ylmethyl)benzene (bix) ligand and 0.15 solvent water molecules. The coordination environment of the Cd^II cation is defined by four carboxylate O atoms from two different bpdc anions in a chelating mode and two N atoms from two distinct bix ligands, constructing a distorted trigonal prism polyhedron. Two inversion‐related Cd^II cations are bridged together by two positionally disordered bpdc anions, forming a 22‐membered ring with a Cd...Cd distance of 9.1966 (9) Å. These rings are then further linked by two bix ligands, extending into a two‐dimensional layer along (102) with 6³ topology.     

Poly[[di‐μ3‐acetato‐di‐μ2‐aqua‐diaqua‐di‐μ3‐hydroxo‐tricopper(II)] naphthalene‐1,5‐disulfonate]

The crystal structure of the title complex, {[Cu₃(C₂H₃O₂)₂(OH)₂(H₂O)₄](C₁₀H₆O₆S₂)}_n, is built of infinite polymeric cationic {[Cu₃(C₂H₃O₂)₂(H₂O)₄(OH)₂]²⁺}_n chains stretching along the a axis, with naphthalene‐1,5‐disulfonate (1,5‐nds) anions in between. One independent Cu^II cation and the 1,5‐nds anion occupy special positions on crystallographic inversion centres. Each Cu^II cation has an octa­hedral coordination environment formed by two carboxyl O atoms, two hydroxo O atoms and two water mol­ecules. The carboxyl­ate and hydroxo groups perform a bridging function, linking adjacent Cu atoms in the chain, with a shortest Cu⋯Cu distance of 2.990 (3) Å. The chains are further linked into a three‐dimensional supra­molecular framework via hydrogen‐bonding inter­actions involving the sulfonate groups of the 1,5‐­nds dianions.     

Poly[[diaquabis[μ2‐2‐(4‐pyridinio)propane‐1,3‐dionato‐κ2O:O′]cobalt(II)] dinitrate]

The title compound, {[Co(C₈H₇NO₂)₂(H₂O)₂](NO₃)₂}_n, is the first d‐metal ion complex involving bidentate bridging of a β‐dialdehyde group. The Co²⁺ ion is situated on an inversion centre and adopts an octahedral coordination with four equatorial aldehyde O atoms [Co—O = 2.0910 (14) and 2.1083 (14) Å] and two axial aqua ligands [Co—O = 2.0631 (13) Å]. The title compound has a two‐dimensional square‐grid framework structure supported by propane‐1,3‐dionate O:O′‐bridges between the metal ions. The organic ligand itself possesses a zwitterionic structure, involving conjugated anionic propane‐1,3‐dionate and cationic pyridinium fragments. Hydrogen bonding between coordinated water molecules, the pyridinium NH group and the nitrate anions [O...O = 2.749 (2) and 2.766 (3) Å, and N...O = 2.864 (3) Å] is essential for the crystal packing.     

Hydrogen‐bonded frameworks of bis(2‐carboxypyridinium) hexafluorosilicate and bis(2‐carboxyquinolinium) hexafluorosilicate dihydrate

In bis(2‐carboxypyridinium) hexafluorosilicate, 2C₆H₆NO₂⁺·SiF₆²⁻, (I), and bis(2‐carboxyquinolinium) hexafluorosilicate dihydrate, 2C₁₀H₈NO₂⁺·SiF₆²⁻·2H₂O, (II), the Si atoms of the anions reside on crystallographic centres of inversion. Primary inter‐ion interactions in (I) occur via strong N—H...F and O—H...F hydrogen bonds, generating corrugated layers incorporating [SiF₆]²⁻ anions as four‐connected net nodes and organic cations as simple links in between. In (II), a set of strong N—H...F, O—H...O and O—H...F hydrogen bonds, involving water molecules, gives a three‐dimensional heterocoordinated rutile‐like framework that integrates [SiF₆]²⁻ anions as six‐connected and water molecules as three‐connected nodes. The carboxyl groups of the cation are hydrogen bonded to the water molecule [O...O = 2.5533 (13) Å], while the N—H group supports direct bonding to the anion [N...F = 2.7061 (12) Å].     

1‐Carboxymethyl‐3‐methyl‐1H‐imidazol‐3‐ium chloride 2‐(3‐methyl‐1H‐imidazol‐3‐ium‐1‐yl)acetate monohydrate: a crystal stabilized by imidazolium zwitterions

The title compound, C₆H₉N₂O₂⁺·Cl⁻·C₆H₈N₂O₂·H₂O, contains one 2‐(3‐methyl‐1H‐imidazol‐3‐ium‐1‐yl)acetate inner salt molecule, one 1‐carboxymethyl‐3‐methyl‐1H‐imidazol‐3‐ium cation, one chloride ion and one water molecule. In the extended structure, chloride anions and water molecules are linked via O—H...Cl hydrogen bonds, forming an infinite one‐dimensional chain. The chloride anions are also linked by two weak C—H...Cl interactions to neighbouring methylene groups and imidazole rings. Two imidazolium moieties form a homoconjugated cation through a strong and asymmetric O—H...O hydrogen bond of 2.472 (2) Å. The IR spectrum shows a continuous D‐type absorption in the region below 1300 cm⁻¹ and is different to that of 1‐carboxymethyl‐3‐methylimidazolium chloride [Xuan, Wang & Xue (2012). Spectrochim. Acta Part A, 96 , 436–443].     

Tris[2‐(1,3‐thiazol‐2‐yl‐κN)‐1H‐benzimidazole‐κN3]zinc(II) dinitrate ethanol hemisolvate monohydrate at 100 K

The Zn^II center in the dicationic complex of the title compound, [Zn(C₁₀H₇N₃S)₃](NO₃)₂·0.5C₂H₅OH·H₂O, is in a distorted octahedral environment with imperfect noncrystallographic C₃ symmetry. Each 2‐(1,3‐thiazol‐2‐yl)‐1H‐benzimidazole ligand coordinates in a bidentate manner, with the Zn—N(imidazole) bond lengths approximately 0.14 Å shorter than the Zn—N(thiazole) bond lengths. Charge‐assisted hydrogen bonds connect cations, anions and water molecules. A lattice void is occupied by an ethanol solvent molecule disordered about a crystallographic inversion center and π‐stacking is observed between one type of symmetry‐related benzene rings.