One‐dimensionally linked Chain Crown Ether Complexes. Syntheses and Crystal Structures of Complexes [K(18‐Crown‐6)]2[M(SeCN)4](H2O) (M = Pd,Pt)

18‐crown‐6(18‐C‐6) complexes with K₂[M(SeCN)₄] (M = Pd, Pt): [K(18‐C‐6)]₂[Pd(SeCN)₄] (H₂O) ( 1 ) and [K(18‐C‐6)]₂[Pt(SeCN)₄](H₂O) ( 2 ) have been isolated and characterized by elemental analysis, IR spectroscopy and single crystal X‐ray analysis. The complexes crystallize in the monoclinic space group P2₁/n with cell dimensions: 1 : a = 1.1159(3) Å, b = 1.2397(3) Å, c = 1.6003(4) Å, β = 92.798(4)°, V = 2.2111(8) ų, Z = 2, F(000) = 1140, R₁ = 0.0418, wR₂ = 0.0932 and 2 : a = 1.1167(3) Å, b = 1.2394(3) Å, c = 1.5968(4) Å, β = 92.945(4)°, V = 2.2071(9) ų, Z = 2, F(000) = 1204, R₁ = 0.0341, wR₂ = 0.0745. Both complexes form one‐dimensionally linked chains of [K(18‐C‐6)]⁺ cations and [M(SeCN)₄]^2— (M = Pd, Pt) anions bridged by K‐O‐K interactions between adjacent [K(18‐C‐6)]⁺ units.     

Bis(adamantan‐1‐aminium) tetrachloridozincate(II) 18‐crown‐6 monohydrate clathrate

The structure of the title compound [systematic name: bis(adamantan‐1‐aminium) tetrachloridozincate(II)–1,4,7,10,13,16‐hexaoxacyclooctadecane–water (1/1/1)], (C₁₀H₁₈N)₂[ZnCl₄]·C₁₂H₂₄O₆·H₂O, consists of supramolecular rotator–stator assemblies and ribbons of hydrogen bonds parallel to [010]. The assemblies are composed of one protonated adamantan‐1‐aminium cation and one crown ether molecule (1,4,7,10,13,16‐hexaoxacyclooctadecane) to give an overall [(C₁₀H₁₈N)(18‐crown‐6)]⁺ cation. The –NH₃⁺ group of the cation nests in the crown and links to the crown‐ether O atoms through N—H...O hydrogen bonds. The 18‐crown‐6 ring adopts a pseudo‐C_3v conformation. The second adamantan‐1‐aminium forms part of ribbons of adamantan‐1‐aminium–water–tetrachloridozincate units which are interconnected by O—H...Cl, N—H...O and N—H...Cl hydrogen bonds via three different continuous rings with R₅⁴(12), R₄³(10) and R₃³(8) motifs.     

Propane‐1,3‐diaminium tetrachloridozincate(II) 18‐crown‐6 clathrate

The reaction of propane‐1,3‐diamine hydrochloride, 18‐crown‐6 and zinc(II) chloride in methanol solution yields the title complex salt [systematic name: propane‐1,3‐diaminium tetrachloridozincate(II)–1,4,7,10,13,16‐hexaoxacyclooctadecane (1/1)], (C₃H₁₂N₂)[ZnCl₄]·C₁₂H₂₄O₆, with an unusual supramolecular structure. The diprotonated propane‐1,3‐diaminium cation forms an unexpected 1:1 supramolecular rotator–stator complex with the crown ether, viz. [C₃H₁₂N₂(18‐crown‐6)]²⁺, in which one of the –NH₃⁺ substituents nests in the crown and interacts through N—H...O hydrogen bonding. The other –NH₃⁺ group interacts with the [ZnCl₄]²⁻ anion via N—H...Cl hydrogen bonding, forming cation–crown–anion ribbons parallel to [010].     

Two crown‐ether‐coordinated caesium halogen salts

The crystal structures of two crown‐ether‐coordinated caesium halogen salt hydrates, namely di‐μ‐bromido‐bis[aqua(1,4,7,10,13,16‐hexaoxacyclooctadecane)caesium(I)] dihydrate, [Cs₂Br₂(C₁₂H₂₄O₆)₂(H₂O)₂]·2H₂O, (I), and poly[[diaquadi‐μ‐chlorido‐μ‐(1,4,7,10,13,16‐hexaoxacyclooctadecane)dicaesium(I)] dihydrate], {[Cs₂Cl₂(C₁₂H₂₄O₆)(H₂O)₂]·2H₂O}_n, (II), are reported. In (I), all atoms are located on general positions. In (II), the Cs⁺ cation is located on a mirror plane perpendicular to the a axis, the chloride anion is located on a mirror plane perpendicular to the c axis and the crown‐ether ring is located around a special position with site symmetry 2/m, with two opposite O atoms exactly on the mirror plane perpendicular to the a axis; of one water molecule, only the O atom is located on a mirror plane perpendicular on the a axis, while the other water molecule is completely located on a mirror plane perpendicular to the c axis. Whereas in (I), hydrogen bonds between bromide ligands and water molecules lead to one‐dimensional chains running along the b axis, in (II) two‐dimensional sheets of water molecules and chloride ligands are formed which combine with the polymeric caesium–crown polymer to give a three‐dimensional network. Although both compounds have a similar composition, i.e. a Cs⁺ cation with a halogen, an 18‐crown‐6 ether and a water ligand, the crystal structures are rather different. On the other hand, it is remarkable that (I) is isomorphous with the already published iodide compound.     

Kristallstrukturen „supramolekularer”︁ (Benzo‐18‐krone‐6)kaliumtetrathiocyanatometallate: Ein dimerer Komplex {[K(Benzo‐18‐krone‐6)]2[Hg(SCN)4]}2 und zwei isomere Komplexe [K(Benzo‐18‐krone‐6)][Cd(SCN)3] mit kettenförmigen Trithiocyanatocadmat‐Anionen

Crystal Structures of „Supramolecular”︁ Benzo‐18‐crown‐6 Potassium Tetrathiocyanato Metallates: A Dimeric Complex {[K(Benzo‐18‐crown‐6)]₂[Hg(SCN)₄]}₂ and Two Isomeric Complexes [K(Benzo‐18‐crown‐6)][Cd(SCN)₃] Containing Trithiocyanato Cadmate Anions with Chain Structures By reaction of potassium thiocyanatomercurate(II) complexes with benzo‐18‐crown‐6 (2,3‐benzo‐1,4,7,10,13,16‐hexaoxacyclooctadec‐2‐ene) crystals of {[K(benzo‐18‐crown‐6)]₂[Hg(SCN₄)]}₂ ( 1 ) were obtained. 1 crystallizes monoclinic, space group P2₁/n (non‐standard setting of P2₁/c), a = 1737.35(2), b = 1377.16(2), c = 1984.12(3) pm, β = 100.637(1)°, Z = 2. With potassium tetrathiocyanatocadmate(II) two modifications of a complex [K(benzo‐18‐crown‐6)][Cd(SCN)₃] ( 2 , 3 ), of different symmetry were formed. 2 crystallizes monoclinic, P2₁/c, a = 1158,31(3), b = 1096,55(2), c = 2028,46(2) pm, β = 99,5261(2)°, Z = 4, 3  orthorhombic, P2₁cn, a = 1105,95(3), b = 1413,07(4), c = 1617,10(5) pm, Z = 4. 1 has a dimeric structure, built up from a dication K₂(benzo‐18‐crown‐6)₂]²⁺ and two [K(benzo‐18‐crown‐6)]⁺ cations, which are bridged by two [Hg(SCN)₄]^2– anions. In 2 and 3 triply bridged infinite [{Cd(SCN)₃^–}_n] zigzag chains, stretching along screw axes, are to be found as anions. In 2 these chains exist in two conformations related by inversion symmetry, whereas in 3 only one form can be found. [K(benzo‐18‐crown‐6)]⁺ cations are linked to the anion chains via K · · · S interactions of different lengths.     

Neue Polyiodide des Caesiums mit Doppel‐ und Tripeldecker‐Kationen, [Cs(Benzo‐18‐Krone‐6)2]Ix und [Cs2(Benzo‐18‐Krone‐6)3](Ix)2 (x = 3, 5)

New Polyiodides of Cesium containing Double and Triple Decker Cations, [Cs(benzo‐18‐crown‐6)₂]I_x and [Cs₂(benzo‐18‐crown‐6)₃](I_x)₂ (x = 3, 5) [Cs(b18c6)₂]I_x (x = 3 (1) , 5 (3) ) and [Cs₂(b18c6)₃](I_x)₂ (x = 3 (2) , 5 (4) ) (b18c6 = benzo‐18‐crown‐6) have been synthesized by the reaction of benzo‐18‐crown‐6 (C₁₆H₂₄O₆), cesium iodide (CsI) and iodine (I₂) in acetonitrile ( 1 ), ethanol/dichloromethane ( 2 , 4 ) and 2‐methoxyethanol ( 3 ). Their crystal structures were determined on the basis of single crystal X‐ray data {( 1 ): monoclinic, C2/c, Z = 4, a = 2048.8(5), b = 1329.5(5), c = 1588.7(5) pm, β = 110.23(1)°; ( 2 ): monoclinic, C2/c, Z = 4, a = 2296.0(1), b = 2092.7(1), c = 1373.6(1) pm, β = 100.21(1)°; ( 3 ): monoclinic, P2₁/n, Z = 4, a = 1586.3(1), b = 1745.5(1), c = 1608.6(1) pm, β = 92.37(1)°; ( 4 ): triclinic, , Z = 2, a = 1241.7(1), b = 1539.8(2), c = 1938.4(2) pm, α = 91.15(1), β = 100.53(1), γ = 95.26(1)°}. As expected, double decker cations centered by Cs atoms, [Cs(b18c6)₂]⁺, are found in the structures of ( 1 ) and ( 3 ). In contrast, the triple decker cation found in ( 2 ) and ( 4 ) is less common. The triiodide anions of ( 1 ) and ( 2 ) can be regarded as normal and the chain‐type pentaiodide anions of ( 3 ) and ( 4 ) fall into the known systematic sequence of these anions. The differences in the connectivity of the crystallographically independent I₅^? anions in ( 4 ) are surprising with respect to the fact that, so far, independent pentaiodide anions do not show variations in their scheme of connectivity within one crystal structure.     

Complexation of Alkali Triflates by Crown Ethers: Synthesis and Crystal Structure of [Na(12‐crown‐4)2][SO3CF3], [Na(15‐crown‐5)][SO3CF3], [Rb(18‐crown‐6)][SO3CF3], and [Cs(18‐crown‐6)][SO3CF3]

Complexes of trifluoromethanesulfonates (triflates) with alkali metals Na, Rb, Cs have been prepared in the presence of various macrocyclic polyether crowns [(12‐crown‐4), (15‐crown‐5) and (18‐crown‐6)]. Depending on the combination of alkali ion with crown, the complexes include separated ion pairs [Na(12‐crown‐4)₂] [SO₃CF₃] ( 1 ) and contact ion pairs [Na(15‐crown‐5)] [SO₃CF₃] ( 2 ), [Rb(18‐crown‐6)] [SO₃CF₃] ( 3 ), and [Cs(18‐crown‐6)] [SO₃CF₃] ( 4 ), in which the triflate acts as a bidentate ligand. It is shown that the choice of crown ether is of paramount importance in determining the solid‐state structural outcome. The complex resulting from the pairing of crown ether ( 1 ) develops, when the crown ether is too small in relation to the alkali ion radius. When the cavity size of the crown ether is matched with the alkali ion radius, simple monomeric structures are identified in 2 , 3 and 4 . The title compounds crystallize in the monoclinic crystal system: 1 : space group P2/c with a = 9.942(3), b = 11.014(2), c = 10.801(3) Å, β = 97.30(2)°, V = 1173.1(4) ų, Z = 2, R1 = 0.0812, wR2 = 0.1133: 2 : space group P2₁/m with a = 7.949(2), b = 12.063(3), c = 9.094(2) Å, β = 105.98(2)°, V = 838.3(4) ų, Z = 2, R1 = 0.0869, wR2 = 0.1035: 3 : space group P2₁/c with a = 12.847(5), b = 8.448(2), c = 22.272(6) Å, β = 122.90(3)°, V = 2029.5(1) ų, Z = 4, R1 = 0.0684, wR2 = 0.1044: 4 : space group P2₁/n with a = 12.871(3), b = 8.359(1), c = 19.019(4) Å, β = 92.61(2)°, V = 2044.2(6) ų, Z = 4, R1 = 0.0621, wR2 = 0.0979.     

A three‐component cocrystal: benzoyl(hydroxyimino)acetonitrile–18‐crown‐6–water (2/1/4)

In the title compound, 2C₉H₆N₂O₂·C₁₂H₂₄O₆·4H₂O, the 18‐crown‐6 (1,4,7,10,13,16‐hexaoxacyclooctadecane) molecule resides across a centre of inversion. The adduct exists as a molecular hydrogen‐bonded complex featuring integration of two kinds of synthons, viz. [(18‐crown‐6)(H₂O)₄] [O...O = 2.8645 (18)–2.9014 (18) Å] and an oxime/aqua ensemble, PhC(O)C(CN)NOH...OH₂ [O...O = 2.5930 (18) Å]. The reliability of the oxime/aqua motif, sustained by the highly acidic cyanooxime, is an essential factor in the construction of multicomponent cocrystals and the accommodation of oxime species in macrocyclic hosts. The supramolecular structure is generated by the alternation of hydrophilic [(18‐crown‐6)(H₂O)₄] layers and bilayers of benzoyl(hydroxyimino)acetonitrile molecules, resulting in stacking interactions between the phenyl and cyano groups of 3.666 (2) Å.     

Potassium di­cyano­argentate(I) 1,4,7,10,13,16‐hexaoxa­cyclo­octadecane

The crystal structure of the title compound, K[Ag(CN)₂]·C₁₂H₂₄O₆, conventionally denoted K(18‐crown‐6)Ag(CN)₂, where 18‐crown‐6 is 1,4,7,10,13,16‐hexa­oxa­cyclo­octa­decane, is characterized by closely packed linear chains formed by the coordination of the nitrile N atoms of the [Ag(CN)₂]⁻ anions to the K⁺ cations. The K atoms lie on centers of inversion and are additionally bound to the six O atoms of the crown ether.     

4‐Carboxypyridinium perchlorate 18‐crown‐6 dihydrate clathrate and 4‐carboxypyridinium tetrafluoroborate 18‐crown‐6 dihydrate clathrate

Mixtures of 4‐carboxypyridinium perchlorate or 4‐carboxypyridinium tetrafluoroborate and 18‐crown‐6 (1,4,7,10,13,16‐hexaoxacyclooctadecane) in ethanol and water solution yielded the title supramolecular salts, C₆H₆NO₂⁺·ClO₄⁻·C₁₂H₂₄O₆·2H₂O and C₆H₆NO₂⁺·BF₄⁻·C₁₂H₂₄O₆·2H₂O. Based on their similar crystal symmetries, unit cells and supramolecular assemblies, the salts are essentially isostructural. The asymmetric unit in each structure includes one protonated isonicotinic acid cation and one crown ether molecule, which together give a [(C₆H₆NO₂)(18‐crown‐6)]⁺ supramolecular cation. N—H...O hydrogen bonds between the protonated N atoms and a single O atom of each crown ether result in the 4‐carboxypyridinium cations `perching' on the 18‐crown‐6 molecules. Further hydrogen‐bonding interactions involving the supramolecular cation and both water molecules form a one‐dimensional zigzag chain that propagates along the crystallographic c direction. O—H...O or O—H...F hydrogen bonds between one of the water molecules and the anions fix the anion positions as pendant upon this chain, without further increasing the dimensionality of the supramolecular network.     

Metallophilic interactions in iodido(2,2′:6′,2′′‐terpyridine)platinum(II) diiodidoaurate(I)

In the title compound, [PtI(C₁₅H₁₁N₃)][AuI₂], the [PtI(terpy)]⁺ cations (terpy is 2,2′:6′,2′′‐terpyridine) stack in pairs about inversion centers through Pt...Pt interactions of 3.5279 (5) Å. The [AuI₂]⁻ anions also exhibit pairwise stacking, with Au...I distances of 3.7713 (5) Å. The [PtI(terpy)]⁺ cations and [AuI₂]⁻ anions aggregate forming infinite arrays of stacked ...({[PtI(terpy)]⁺...[PtI(terpy)]⁺}...{[AuI₂]⁻...[AuI₂]⁻})... units.     

Alkaliisocyanacetate. Synthese und Struktur von [K(18‐Krone‐6)](O2CCH2NC)

Alkali‐isocyanoacetates. Synthesis and Structure of [K(18‐crown‐6)](O₂CCH₂NC) The alkali isocyanoacetates M⁺[O₂CCH₂NC]^? (M = Li,Na,K,Cs) ( 1a ‐ d ) are synthesized by reaction of ethyl isocyanoacetate with the respective alkali hydroxides in ethanol and characterized by IR, NMR (¹H, ¹³C), and mass spectrometry (FAB). In alcoholic solution as well as in the gas phase ion pairs and higher aggregated species are observed. In contrast, [K(18‐crown‐6)][O₂CCH₂NC] ( 2 ) which is obtained from 1c and 18‐crown‐6, turns out to be a 1:1 electrolyte in solution (acetone); in the solid, the isocyanoacetate anion binds to K⁺ via the two carboxylate oxygen atoms resulting in an O₈‐coordinated metal atom.     

Isolated pentaiodide anions in [K(18‐crown‐6)]I5

(1,4,7,10,13,16‐Hexaoxa­cyclo­octa­decane‐κ⁶O)­potassium penta­iodide, [K(C₁₂H₂₄O₆)]I₅, obtained by slow evaporation of an ethanol solution of KI, 18‐crown‐6 and I₂, contains [K(18‐crown‐6)]⁺ cations (C_i symmetry) and I₅⁻ anions (C₂ symmetry), which are arranged in alternating layers parallel to (001). In contrast to the well known tendency of I₅⁻ ions to form chains and nets, the I₅⁻ units in the title compound are isolated.     

Novel Cesium‐Selective Electrodes Based on Lipophilic 1,3‐Bisbridged Cofacial‐calix[6]crowns

Five bisbridged calix[6]crowns have been investigated as Cs⁺ ionophore in PVC membrane electrodes. As ionophores, three 1,3‐bisbridged calix[6]crown‐4‐ethers( I–III ), 1,3‐bisbridged calix[6]crown‐5‐ether( IV ), and 1,3‐bisbridged calix[6]crown‐6‐ether( V ) have been evaluated. The membranes all give good Nernstian response in the concentration range from 1×10^?7 to 1×10^?1 M of cesium ion. The best detection limits (?log aequation/tex2gif-inf-1.gif=7.08–7.36) are obtained for electrode membranes containing 1,3‐bisbridged cofacial‐calix[6]crown‐4‐ethers( I‐III ), and the values are the lowest compared with those reported previously. The highest selectivity coefficients [ 3.74(Cs/K), 2.63(Cs/Rb)] are obtained for the membrane of 1,3‐bisbridged calix[6]crown‐4‐ether( II ), and these values are also the highest compared with previous reports for Cs⁺‐ISEs. The highest selectivity towards cesium ion is attributed to the geometrically cofacial positions of two crown‐ethers in calix[6]crowns in order to provide the complex of cesium ion and eight oxygens of cofacial crowns.     

Kronenetherkomplexe von Blei(II). Die Kristallstrukturen von [PbCl(18-Krone-6)][SbCl6], [Pb(18-Krone-6)(CH3CN)3][SbCl6]2, and [Pb(15-Krone-5)2][SbCl6]2

Crown Ether Complexes of Lead(II). The Crystal Structures of [PbCl(18-Krone-6)][SbCl₆], [Pb(18-Krone-6)(CH₃CN)₃][SbCl₆]₂ und [Pb(15-Krone-5)₂][SbCl₆]₂ . [PbCl(18-crown-6)][SbCl₆] has been prepared in low yield besides [Pb(CH₃)₂(18-crown-6)][SbCl₆]₂ by the reaction of Pb(CH₃)₂Cl₂ with antimony pentachloride in acetonitrile solution in the presence of 18-crown-6, forming pale-yellow crystals. The other two title compounds are formed as colourless crystals by the reaction of PbCl₂ with antimony pentachloride in acetonitrile solutions in the presence of 18-crown-6 and 15-crown-5, respectively. The complexes were characterized by IR spectroscopy and by crystal structure determinations. [PbCl(18-crown-6)][SbCl₆]: Space group P2₁/c, Z = 8, 5 003 observed unique reflections, R = 0.046. Lattice dimensions at - 80°C: a = 1 386.9; b = 1 642.7; c = 2 172.1 pm, β = 92.95°. The lead atom in the cation [PbCl(18-crown-6)]⁺ is surrounded in an almost hexagonal-planar construction by the six oxygen atoms of the crown ether and an axially oriented Cl atom. [Pb(18-crown-6)(CH₃CN)₃][SbCl₆]₂: Space group P1 , Z = 2, 6 128 observed unique reflections, R = 0.076. Lattice dimensions at - 70°C: a = 1 228.0; b = 1 422.9; c = 1 463.2 pm, α = 69.08°; β = 65.71°; γ = 64.51°. In the cation [Pb(18-crown-6)(CH₃CN)₃]²⁺ the lead atom is coordinated by the six oxygen atoms of the crown ether and by the three nitrogen atoms of the acetonitrile molecules. The structure determination is restricted by disorder. [Pb( 15-crown-5)₂][SbCI₆]₂: Space group P6₃/m, Z = 6, 5 857 observed unique reflections, R = 0.059. Lattice dimensions at -70°C: a = b = 2 198.5; c = 1499.4 pm, α = β = 90°, γ = 120°. In the cation [Pb(l5-crown-5)₂]² the lead atom is sandwich-like coordinated by the ten oxygen atoms of the two crown ether molecules. The structure determination is restricted by disorder.     

Two—dimensional Network Crown Ether Complex.Synthesis and Crystal Structure of 18—Crown—6 Complex：[K（18—C—6）]2[Cd—（nmt）2]

The novel complex [K(18-C-6)]2[Cd(mnt)2][18-C-6-18-crown-6,nmt=1,2-dicyanoethene-1,2-dithiolate,C2S2-(CN)2^2-] was synthesized and characterized by elemental analysis,IR spectrum and X-ray diffraction analysis.The complex displays two-dimensional network structure of [K(18-C-6)] complex segments and [Cd(nmt)2] complex segment bridged by S-K-S,S-K-N and N-K-N interactions between adjacent[K(18-C-6)] and [Cd(mnt)2]units.     

Synthesis and characterization of (cryptand‐222)potassium (2‐methylimidazolato)(meso‐tetraphenylporphinato)ferrate(II)–2‐methylimidazole–tetrahydrofuran (1/1/2)

Metalloporphyrin complexes containing an additional imidazole ligand can provide information about the effect of deprotonation or hydrogen bonding on the axial histidine unit in heme proteins. The title high‐spin five‐coordinate imidazolate‐ligated iron(II) porphyrinate, [K(C₁₈H₃₆N₂O₆)][Fe(C₄H₅N₂)(C₄₄H₂₈N₄)]·C₄H₆N₂·2C₄H₈O, has been synthesized and investigated. The solvated salt crystallizes with one 2‐methylimidazole molecule, two tetrahydrofuran solvent molecules and a potassium cation chelated inside a cryptand‐222 (4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane) molecule. The imidazolate ligand is ordered. The average Fe—Np (Np is a porphyrin N atom) bond length is 2.113 (11) Å and the axial Fe—N_Im (N_Im is an imidazolate N atom) is 2.0739 (13) Å. The out‐of‐plane displacement of the Fe^II atom from the 24‐atom mean plane is 0.6098 (5) Å, indicating an apparent doming of the porphyrin core.     

A novel metallo‐organically templated pentaborate: acetato[N,N′‐bis(2‐aminoethyl)ethane‐1,2‐diamine]zinc(II) 4,4′,6,6′‐tetrahydroxy‐2,2′‐spirobi[cyclotriboroxane](1−)

The title compound, [Zn(C₂H₃O₂)(C₆H₁₈N₄)][B₅O₆(OH)₄], contains mixed‐ligand [Zn(CH₃COO)(teta)]⁺ complex cations (teta is triethylenetetramine) and pentaborate [B₅O₆(OH)₄]⁻ anions. The [B₅O₆(OH)₄]⁻ anions are connected to one another through hydrogen bonds, forming a three‐dimensional supramolecular network, in which the [Zn(CH₃COO)(teta)]⁺ cations are located.     

Komplexe der Alkalimetalltetraphenylborate mit makrocyclischen Kronenethern

Complexes of the Alkali Metal Tetraphenylborates with Macrocyclic Crown Ethers Alkali metal tetraphenylborates, MB(C₆H₅)₄ (M = Li to Cs), react in tetrahydrofuran with macrocyclic crown ethers to give complexes of the general formula MB(C₆H₅)₄(crown)_m(THF)_n. Suitable single crystals for X‐ray structure analysis were grown from a solvent mixture of tetrahydrofuran and n‐hexane. The salt like complexes [Li(12‐crown‐4)(thf)][B(C₆H₅)₄] ( 1 ), [Na(15‐crown‐5)(thf)][B(C₆H₅)₄] ( 2 ), and [Cs(18‐crown‐6)₂][B(C₆H₅)₄] · THF ( 6 ), the mononuclear molecular complexes [KB(C₆H₅)₄(18‐crown‐6)(thf)] ( 3 ), [RbB(C₆H₅)₄(18‐crown‐6)] ( 4 ), and [CsB(C₆H₅)₄(18‐crown‐6)] · THF ( 5 ), and the compound [CsB(C₆H₅)₄(18‐crown‐6)]₂[Cs(18‐crown‐6)₂][B(C₆H₅)₄] ( 7 ), which contains a binuclear molecule ([CsB(C₆H₅)₄(18‐crown‐6)]₂) beside a [Cs(18‐crown‐6)₂]⁺ cation and a [B(C₆H₅)₄]^? anion, are described. All compounds are charactarized by infrared spectra, elemental analysis, NMR‐spectroscopy, and X‐ray single crystal structure analysis.     

Syntheses and Structures of Two New Cu/Nb/pyrazine Complexes: Three dimensional CuNb(pyz)2OF5 · (pyz)(H2O) and two dimensional [Cu(pyz)2.5]+ [NbF6]− · (pyz)

Crystals of CuNb(pyz)₂OF₅ · (pyz)(H₂O) ( 1 ) and [Cu(pyz)_2.5]⁺ [NbF₆]^? · (pyz) ( 2 ) were grown (150°C and autogeneous pressures) from CuO, 1/2(Nb₂O₅), (HF)_x · pyridine, and H₂O in excess pyrazine. Light blue single crystals of ( 1 ) are orthorhombic, crystallizing in space group Cccm (No. 66), with a = 14.547(1) Å, b = 16.135(2) Å, c = 13.803(2) Å, and Z = 8. The structure of ( 1 ) contains corner shared [Cu(pyz)_4/2F_2/2]⁺, [Cu(pyz)_4/2O_2/2], and [NbF₄O_1/2F_1/2]^?0.5 octahedra. Orange crystals of ( 2 ) are monoclinic, crystallizing in space group C2/c (No. 15), with a = 11.792(8) Å, b = 17.123(3) Å, c = 17.051(5) Å, β = 90.04(4)°, and Z = 8. The structure of ( 2 ) contains puckered rings of corner shared [Cu(pyz)(pyz)_3/2]⁺ tetrahedra and isolated [NbF₆]^? anions within the rings.