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.     

Pentaiodide komplexer Alkalimetall‐Kronenether‐Kationen: Darstellung und strukturelle Charakterisierung der Verbindungen [M(Benzo‐15‐Krone‐5)2]I5 mit M = Na,K, Rb,Cs

Pentaiodides of Complex Alkaline Metal Crown Ether Cations: Synthesis and Structural Characterisation of the Compounds [M(benzo‐15‐crown‐5)₂]I₅, M = Na, K, Rb and Cs The isotypic compounds [M(benzo‐15‐crown‐5)₂]I₅, M = Na, K, Rb and Cs are obtained as single crystals via the reaction of benzo‐15‐crown‐5, MI and iodine (2 : 1 : 2) from ethanol/dichloromethane (1 : 1). These compounds crystallize in the monoclinic space group P2₁/n with four formula units in the unit cell. The cations form typical sandwich complexes. The volume of the unit cell increases by 4, 3 % from the sodium to the caesium compound, corresponding to the increasing space required by the cations. The pentaiodide units consist of a elongated triiodide unit and two iodine half‐molecules. These iodine molecules are completed by centres of symmetry. The interconnection between the pentaiodide units leads to the formation of zig‐zag chains that run along [001]. Considering the strongly different ionic radii of the alkali‐metal cations, the existence of this number of isotypic structures is rather surprising.     

Complexing properties of 3′,5′‐disubstituted‐4′‐hydroxybenzyl armed monoaza‐12‐crown‐4 and armed monoaza‐15‐crown‐5 ethers and crystal structures of the alkali metal ion complexes

A series of monoaza‐15‐crown‐5 ethers (2b‐2h) having 4′‐hydroxy‐3′,5′‐disubstituted benzyl groups have been prepared by the Mannich reaction of 2,6‐disubstituted phenols with the corresponding N‐methoxymethylmonoaza‐crown ethers. Competitive transport through a chloroform membrane by 12‐crown‐4 derivatives (lithium, potassium and cesium) and 15‐crown‐5 derivatives (sodium, potassium and cesium) were measured under basic‐source phase and acidic‐receiving phase conditions. All ligands transported size‐matched alkali‐metal cations. Ligands 1h and 2h with two fluorine atoms in the side arm gave higher metal ion transport rates than those of dimethyl‐ (1a and 2a), diisopropyl‐ (1b and 2b), and butylmethyl‐ (1d and 2d) derivatives. X‐ray crystal structures of six alkali metal complexes with monoaza‐12‐crown‐4‐derivatives ( 1b‐LiSCN, 1b‐KSCN, 1c‐NaSCN, 1d‐LiSCN, 1f‐RbSCN and 1h‐LiSCN ) and three alkali metal complexes with 15‐crown‐5 derivatives ( 2b‐KSCN, 2c‐KSCN , and 2e‐KSCN ) along with crystal structures of some new ligands (1b, 1c, 1d, 1f, and 2c) are also reported. These X‐ray analyses indicate that the crystal structures of the alkali metal ion complexes of these new armed‐crown ethers changed depending on the substituents at the 3′‐ and 5′‐positions of the appended hydroxybenzyl arms.     

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.     

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.     

Crown Ethers Bearing 18C6 Unit; Sensory Molecules for Fabricating PVC Membrane Lead Ion‐selective Electrodes

Crown ethers bearing 18C6 unit 18‐crown‐6 (18C6), dicyclohexyl18‐crown‐6 (DC18C6) and dibenzo18‐crown‐6 (DB18C6) have been examined as ion sensing materials for fabricating lead ion‐selective potentiometric sensors. Best performance of the electrode based upon 18C6 ionophore was achieved by using a membrane including 9% ionophore, 30% polyvinyl chloride (PVC), 2% oleic acid and 59% dibutylphthalate (DBP). The optimum composition for the sensors based on DC18C6 and DB18C6 was provided by the compositions: 9% DC18C6, 30% PVC, 1.5% sodium tetraphenyl borate (NaTBP), 59.5% DBP; and 5.9% DB18C6, 29.7% PVC, 2.5% NaTBP and 61.9% DBP, respectively. The linear response range of the electrode based on 18C6 (1 × 10^‐6‐1 × 10^‐3 M) differs from that presented by the DC18C6‐ and DB18C6‐based electrodes (1 × 10^‐5‐1 × 10^‐2 M). All the sensors were shown rapid response time (<12 s). The detection limit of the electrodes varies as 5.6 × 10^‐7, 6.3 × 10^‐6 and 7.1 × 10^‐6 M, for 18C6‐, DC18C6‐ and DB18C6‐based electrodes, respectively. The selectivity of the electrodes towards lead ions over some mono‐, di‐ and trivalent metal ions was evaluated. The lifetime of the electrode based on DC18C6 or DB18C6 ionophores was found to be more than three months, while it was shorter for 18C6‐based electrode. The application of the electrodes in aqueous samples was assessed.     

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.     

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.     

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.     

ACE applied to the quantitative characterization of benzo‐18‐crown‐6‐ether binding with alkali metal ions in a methanol–water solvent system

ACE was applied to the quantitative evaluation of noncovalent binding interactions between benzo‐18‐crown‐6‐ether (B18C6) and several alkali metal ions, Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺, in a mixed binary solvent system, methanol–water (50/50 v/v). The apparent binding (stability) constants (K_b) of B18C6–alkali metal ion complexes in the hydro‐organic medium above were determined from the dependence of the effective electrophoretic mobility of B18C6 on the concentration of alkali metal ions in the BGE using a nonlinear regression analysis. Before regression analysis, the mobilities measured by ACE at ambient temperature and variable ionic strength of the BGE were corrected by a new procedure to the reference temperature, 25°C, and the constant ionic strength, 10 mM . In the 50% v/v methanol–water solvent system, like in pure methanol, B18C6 formed the strongest complex with potassium ion (log K_b=2.89±0.17), the weakest complex with cesium ion (log K_b=2.04±0.20), and no complexation was observed between B18C6 and the lithium ion. In the mixed methanol–water solvent system, the binding constants of the complexes above were found to be about two orders lower than in methanol and about one order higher than in water.     

Fine‐tuning of electromembrane extraction selectivity using 18‐crown‐6 ethers as supported liquid membrane modifiers

Selectivity of electromembrane extractions (EMEs) was fine‐tuned by modifications of supported liquid membrane (SLM) composition using additions of various 18‐crown‐6 ethers into 1‐ethyl‐2‐nitrobenzene. Gradually increased transfer of K⁺, the cation that perfectly fits the cavity of 18‐crown‐6 ethers, was observed for EMEs across SLMs modified with increasing concentrations of 18‐crown‐6 ethers. A SLM containing 1% w/v of dibenzo‐18‐crown‐6 in 1‐ethyl‐2‐nitrobenzene exhibited excellent selectivity for EMEs of K⁺. The established host–guest interactions between crown ether cavities in the SLM and potassium ions in donor solution ensured their almost exhaustive transfer into acceptor solution (extraction recovery ～92%) within 30 min of EME at 50 V. Other inorganic cations were not transferred across the SLM (Ca²⁺ and Mg²⁺) or were transferred negligibly (NH₄⁺, Na⁺; extraction recovery < 2%) and had only subtle effect on EMEs of K⁺. The high selectivity of the tailor‐made SLM holds a great promise for future applications in EMEs since the range of similar selective modifiers is very broad and may be applied in various fields of analytical chemistry.     

Pb(18‐crown‐6)Cl2 and Hg(18‐crown‐6)I2: Molecular Dihalides Trapped in a Crown Ether

Pb(18‐crown‐6)Cl₂ and Hg(18‐crown‐6)I₂ are obtained as transparent colourless crystals of needle and hexagonal shape, respectively, by isothermal evaporation of their dichloromethane solutions. Pb(18‐crown‐6)Cl₂ crystallizes with the trigonal crystal system [ , no. 148, a = b = 1176.3(2), c = 1191.8(3) pm, V = 1428.2(5) 10⁶·pm³, Z = 3] whereas Hg(18‐crown‐6)I₂ crystallizes with the orthorhombic crystal system (Pnma, no. 62, a = 1613.9(2) pm, b = 2822.2(5) pm, c = 841.3(1) pm, V = 3832(1)10⁶·pm³, Z = 8). Both compounds are characterized by linear MX₂ (HgI₂ or PbCl₂) molecular units which are encrypted by the crown ether. In both cases, the divalent metal ion resides in the middle of the crown ether resulting in a hexagonal bipyramidal coordination environment for the metal cations. The molecular symmetry comes close to D_3d. Hg(18‐crown‐6)I₂ and Pb(18‐crown‐6)Cl₂ differ in the way the single MX₂@18‐crown‐6 units are packed. Whereas the Hg(18‐crown‐6)I₂ molecules are arranged in a (distorted) cubic closest packing, the Pb(18‐crown‐6)Cl₂ molecules adopt a hexagonal closest packing.     

Unusual centrosymmetric structure of [M(18‐crown‐6)]+ (M = Rb,Cs and NH4) complexes stabilized in an environment of hexachloridoantimonate(V) anions

In (1,4,7,10,13,16‐hexaoxacyclooctadecane)rubidium hexachloridoantimonate(V), [Rb(C₁₂H₂₄O₆)][SbCl₆], (1), and its isomorphous caesium {(1,4,7,10,13,16‐hexaoxacyclooctadecane)caesium hexachloridoantimonate(V), [Cs(C₁₂H₂₄O₆)][SbCl₆]}, (2), and ammonium {ammonium hexachloridoantimonate(V)–1,4,7,10,13,16‐hexaoxacyclooctadecane (1/1), (NH₄)[SbCl₆]·C₁₂H₂₄O₆}, (3), analogues, the hexachloridoantimonate(V) anions and 18‐crown‐6 molecules reside across axes passing through the Sb atoms and the centroids of the 18‐crown‐6 groups, both of which coincide with centres of inversion. The Rb⁺ [in (1)], Cs⁺ [in (2)] and NH₄⁺ [in (3)] cations are situated inside the cavity of the 18‐crown‐6 ring; they are situated on axes and are equally disordered about centres of inversion, deviating from the centroid of the 18‐crown‐6 molecule by 0.4808 (13), 0.9344 (7) and 0.515 (8) Å, respectively. Interaction of the ammonium cation and the 18‐crown‐6 group is supported by three equivalent hydrogen bonds [N...O = 2.928 (3) Å and N—H...O = 162°]. The centrosymmetric structure of [Cs(18‐crown‐6)]⁺, with the large Cs⁺ cation approaching the centre of the ligand cavity, is unprecedented and accompanied by unusually short Cs—O bonds [2.939 (2) and 3.091 (2) Å]. For all three compounds, the [M(18‐crown‐6)]⁺ cations and [SbCl₆]⁻ anions afford linear stacks along the c axis, with the cationic complexes embedded between pairs of inversion‐related anions.     

Crystal Structures and Redox Responses Coupled with Ion Recognition of p‐Benzoquinone‐ and Hydroquinone‐Fused [18]crown‐6

The crystal structures and redox properties of p‐benzoquinone (BQ)‐fused [18]crown‐6 1 and bis‐BQ‐fused [18]crown‐6 2 were examined. The anion radicals of these BQ molecules were stabilized by addition of metal ions, through effective electrostatic interactions between the negatively charged BQ moiety and positively charged ion‐capturing [18]crown‐6 unit. The electrostatic interactions and solvation energy played important roles in determining the magnitudes of anodic redox shifts in the reduction potentials. Regular π‐stacking of BQ units and regular arrays of [18]crown‐6 units were observed in crystal 2 , in which one‐dimensional π‐electron columns were separated by ionic channels. The hydroquinone‐fused [18]crown‐6 molecule 3 and a new BQ‐ and phenol‐fused [18]crown‐6 derivative 4 were obtained as single crystals. The molecular conformations of [18]crown‐6 in crystal 3 and hydrated crystal 3 ?H₂O were different from each other.     

DFT study of the carbon‐ and nitrogen‐pivot lariat crown ethers and their complexes with alkali metal cations: Na+, K+

In this work, a quantum mechanical research of five lariat crown ethers(LCEs), 2‐methoxy‐15‐crown‐5( A ), N‐methoxy‐4‐aza‐15‐crown‐5( B ), N‐methoxy‐4‐aza‐18‐crown‐6( C ), N‐methoxyethyl‐4‐aza‐18‐crown‐6( D ), N,N′‐bis(2‐metho xyethyl)‐4,13‐diaza‐18‐crown‐6( E ), which are based on either 15‐crown‐5 or 18‐crown‐6 frameworks and contain various pendant arms extending from either carbon or nitrogen atoms on the crown frameworks, had been done using density functional theory with B3LYP/6‐31G* method to obtain the electronic and geometrical structures of the LCEs and their complexes with alkali metal ions: Na⁺ and K⁺. The nucleophilicity of LCEs had been investigated by the Fukui functions. For complexes, the match between the cation and cavity size, the status of interaction between alkali metal ions and donor atoms in the LCEs, and the sidearm effect of the LCEs had been analyzed through the other calculated parameters, such as, highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy, and energy gaps. In addition, the enthalpies of complexation reaction had been studied by the calculated thermodynamic data (298 K). The calculated results are all in a good agreement with the experimental data for the complexes. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009     

Double‐Armed Benzo‐15‐crown‐5 Ligands and Complexes and Single Crystal Structure Determination

This work describes the syntheses and characterizations of double‐armed benzo‐15‐crown‐5 containing nitro ( 1 ), amine ( 2 ), and imine ( 3–5 ) groups, and their sodium complexes ( 1a–5a ). Structures of the ligands ( 1–5 ) and sodium complexes ( 1a–5a ) were identified via elemental analyses, and infrared, ¹H‐ nuclear magnetic resonance (NMR), ¹³C‐NMR, and mass spectrometry. The metal extractions were examined by using ultravoilet–visible spectrophotometry. Single crystal for 2 was successfully obtained, and its X‐ray crystal structure was resolved. The compound 2 crystallizes in triclinic, space group p‐1 with a = 9.1420(3), b = 14.9580(4), c = 20.4110(5), and Z = 4.     

Crown Ether Phase Transfer Catalysts for An Ionic Polymerization of Bisphenol A / 4,4′‐Dichlorodiphenyl Sulfone

Various crown ethers were prepared and applied as phase transfer catalysts for the an ionic copolymerization of bisphenol A and 4,4′‐dichlorodiphenyl sulfone monomers with alkali salts, e.g., NaNH₂, NaOH and KOH, as initiators. The catalytic abilities of various crown ethers for the an ionic polymerization of bisphenol A / 4,4′‐dichlorodiphenyl sulfone were found to be in the order: 15‐crown‐5 ? monobenzo‐15‐crown‐5 > 18‐crown‐6 > Dicyclohexano‐18‐crown‐6 > Dibenzo‐18‐crown‐6 > 12‐crown‐4 with sodium amide (NaNH₂) as initiator. Sodium amide was shown to be a better initiator than NaOH or KOH with monobenzo‐ 15‐crown‐5 as a catalyst. Effects of solvents and temperature on the crown ether catalytic polymerization were also investigated. Dimethyl sulfoxide (DMSO) exhibited much better for the polymerization than other organic solvents, e.g., toluene, p‐xylene, dimethyl formamide and dioxane. Higher polymerization was found at higher temperatures and about 100% yield of poly(bisphenol A / sulfone) was obtained at 125 °C in 3 hr. The molecular weight of poly(bisphenol A / sulfone) as a function of reaction time was determined with gel permeation chromatography. Concentration effects of crown ether on % yield and molecular weight of poly(bisphenol A / sulfone) were also investigated and discussed.     

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.     

Complexes of Crown Ether‐Containing N‐Phosphorylated Thioamides and Thioureas with CoII,ZnII and PdII Cations

The reaction of the potassium salts of N‐phosphorylated thioureas [4′‐benzo‐15‐crown‐5]NHC(S)NHP(Y)(OiPr)₂ (Y = S, HL^I ; Y = O, HL^II ) with Zn^II and Co^II cations in aqueous EtOH leads to complexes of formulae Zn(L^I,II‐S,Y)₂ (Y = S, 1 ; Y = O, 2 ) and Co(L^I‐S,S′)₂ ( 3 ), while interaction of the potassium salt of N‐phosphorylated thioamide [4′‐benzo‐15‐crown‐5]C(S)NHP(O)(OiPr)₂ ( HL^III ) with Zn^II in the same conditions leads to the complex Zn(HL^III)(L^III‐S,O)₂ ( 4 ). The reaction of the potassium salt of crown ether‐containing N‐phosphorylated bis‐thiourea N,N′‐[C(S)NHP(O)(OiPr)₂]₂‐1,10‐diaza‐18‐crown‐6 ( H₂L ) with Co^II, Zn^II and Pd^II cations in anhydrous CH₃OH leads to complexes M₂(L‐O,S)₂ (M = Co, 5 ; Zn, 6 ; M = Pd, 7 ). Thioamide HL^III was investigated by single‐crystal X‐ray diffraction.     

Die Molekül‐ und Kristallstruktur des Rubidium(Dibenzo‐18‐Krone‐6)‐pentaiodids [Rb(C20H24O6)]I5

Molecular and Crystal Structure of Rubidium(dibenzo‐18‐crown‐6)pentaiodide [Rb(C₂₀H₂₄O₆)]I₅ [Rb(Dibenzo‐18‐crown‐6)]₂(I₅)₂ is obtained as dark brown columns by reacting dibenzo‐18‐crown‐6, rubidium iodide, and iodine in a molar ratio of 1 : 1 : 6 in ethanole / dichlormethane (1:1). [Rb(C₂₀H₂₄O₆)]₂(I₅)₂ crystallizes with four formula units per unit cell in the orthorhombic space group Pnma with a = 1725.15(2) pm, b = 1863.76(3) pm and c = 1885.19(3) pm. The crystal structure consists of pentaiodide units I₅^—, which are linked to one another by head‐to‐tail‐contacts. The I₂ units, which stick out of the chain, are twisted against each other, in a way that neither a cis or a trans configuration is formed. By secondary bonding, the iodine atoms form nets of 18‐member planar rings with an almost rectangular form. This net‐like structural element has not been described up to now.