Substituent effects on the structures of silver complexes with monoazatrithia-12-crown-4 ethers bearing substituted aromatic rings

New 4'-methoxybenzyl-, 4'-methylbenzyl-, benzyl-, 3',5'-difluorobenzyl-, 3',5'-dichlorobenzyl-, and 4'-nitrobenzyl-armed monoazatrithia-12-crown-4 ethers were prepared by the reductive amination of monoazatrithia-12-crown-4 with the appropriate benzenecarbaldehyde in the presence of NaBH(OAc)3. Cold electrospray ionization mass spectrometry and X-ray crystallography show that silver complexes with armed monoazatrithia-12-crown-4 ethers bearing aromatic side arms with electron-donating groups or electron-withdrawing groups are coordination polymers and trimers, respectively. The structures of the silver complexes were strongly dependent on the strength of the CH...pi interactions, which are controlled by substituent effects on the aromatic side arms.     

Synthesis and metal-ion binding properties of monoazathiacrown ethers

Synthetic procedures for monoazathiacrown ethers were explored, and monoazatrithia-12-crown-4, monoazatetrathia-15-crown-5, and monoazapentathia-18-crown-6 were obtained in moderate yields by the reaction of bis(2-chloroethyl)amine with the appropriate dithiols in the presence of lithium hydroxide in THF. To evaluate metal-ion binding properties of the monoazathiacrown ethers by solvent extraction, lipophilic dodecyl and dodecanoyl groups were incorporated onto the monoazathiacrown ethers. The solvent extraction experiments suggested that monoazathiacrown ethers have Ag(+) and Hg(2+) selectivities and that the relative selectivity between Ag(+) and Hg(2+) depends on their nitrogen atom properties and numbers of sulfur atoms reflecting the respective affinities of nitrogen and sulfur atoms to Hg(2+) and Ag(+). An interesting ability to bind Mg(2+) was observed in the case of N-dodecyl monoazatrithia-12-crown-4.     

Perfluoroalkylation of benzo crown ethers with sodium perfluoroalkanesulfinates in the presence of oxidant

Using Ce(SO4)2 or Mn(OAc)3 as oxidant, dibenzo crown ethers such as dibenzo-18-crown-6 (1) and dibenzo-24-crown-8 (5) and benzo-12-crown-4 (7) reacted smoothly with sodium perfluoroalkanesulfinates (2a-2e) to give the corresponding perfluoroalkylated products (3,4,6,7) in good yields with two isomers obtained in the case of dibenzo crown ethers. This provides a facile synthesis of perfluoroalkyl-containing crown ethers.     

碲杂冠醚及其铂配合物的合成

本文通过双(2-羟基乙基)碲醚与二醇的二对甲苯磺酸酯缩合, 首次合成了一类新型的冠醚-碲杂冠醚及其中一个碲杂冠醚与二氯化铂的配合物,并对碲杂冠醚的合成方法.结构特征以及配位性能等进行了讨论.     

Self-assembly, structures, and photophysical properties of 4,4'-bipyrazolate-linked metallo-macrocycles with dimetal clips

By employing functional diimine ligands coordinated dipalladium(II,II) or diplatinum(II,II) clips as corners and the coplanar 4,4'-bipyrazolate dianion (L(2-)) ligand as linker, a series of bipyrazolate-bridged metallo-macrocycles, namely, [M8L4](NO3)8 (M = Pd(dmbpy), 1; Pd(bpy), 2; Pt(bpy), 3a; Pd(phen), 4; Pt(phen), 5; Pd(15-crown-5-phen), 6; Pd(18-crown-6-phen), 8; Pd(benzo-24-crown-8-phen), 10a; Pt(15-crown-5-phen), 7a, Pt(18-crown-6-phen), 9a; Pt(benzo-24-crown-8-phen), 11a) and [M6L3](NO3)6 (M = Pt(bpy), 3b; Pt(15-crown-5-phen), 7b; Pt(18-crown-6-phen), 9b; Pd(benzo-24-crown-8-phen), 10b; Pt(benzo-24-crown-8-phen), 11b), have been synthesized through a directed self-assembly approach that involves spontaneous deprotonation of the 1H-bipyrazolyl ligands in aqueous solution. All these compounds have a crown-shaped cavity that can serve as host to solvent molecules and anions. The structures are characterized by elemental analysis, (1)H and (13)C NMR, ESI-MS, and in the cases of 1a (the BF4(-) salt of 1), 2a (the BF4(-) salt of 2), and 3b by single-crystal X-ray diffraction analysis. Photophysical properties for complexes 1 and 2 are discussed.     

Preparation of macrocyclic di- and tetraamides containing unsubstituted macroring nitrogen atoms,tertiary amine sidearms and/or piperazine subcyclic units

Seven new macrocyclic di- and tetramides have been prepared by the cyclization reaction of various polyamines or, in one case, a dimercaptan with a bis(α-chloroamide) or diethyl malonate. Three of the resulting macrocyclic diamides were reduced with borane to form the corresponding polyaza-crown analogs. Macrocycles prepared include two tetraaza-12-crown-4, two tetraaza-13-crown-4, two tetraaza-14-crown-4, one dithiadiaza-14-crown-4, one tetraaza-15-crown-4 with a piperazine subcyclic group, one dibenzotetraaza-24-crown-8 and one octaaza-30-crown-8 with two piperazine subcyclic groups.     

Oxonium ions from aqua regia: isolation by hydrogen bonding to crown ethers

The preparation and structures of a variety of oxonium ion tetrachloroaurate(III) salts isolated from aqua regia are reported. The new compounds are [(H(5)O(2))(2)(12-crown-4)(2)][AuCl(4)](2) (1), [(H(7)O(3))(15-crown-5)][AuCl(4)] (2), [(H(5)O(2))(benzo-15-crown-5)(2)][AuCl(4)] (3), [(H(3)O)(18-crown-6)][AuCl(4)] (4), [(H(5)O(2))(dibenzo-24-crown-8)][AuCl(4)] (5), [(H(5)O(2))(4-nitrobenzo-15-crown-5)(2)][AuCl(4)] (6), [(H(3)O)(4-nitrobenzo-18-crown-6)][AuCl(4)] (7), [(H(11)O(5))(tetrachlorodibenzo-18-crown-6)(2)][AuCl(4)] (8), and [(H(7)O(3))(dinitrodibenzo-30-crown-10)][AuCl(4)] (9). A significant correlation between the degree of proton hydration and crown ether size is observed. Aryl crown ethers are nitrated in concentrated aqua regia, but nonnitrated products may be obtained in a dilute solution of aqua regia by reaction with aqueous HAuCl(4).     

Spin trapping of free radicals generated by gammaradiolysis of crown ethers and their analogues

Gamma-radiolytically generated radicals of crown ethers /12-crown-4, 1; 15-crown-5, 2; dicyclohexano-24-crown-8, 3/ and the model compounds /tetrahydrofurane, 4 and 1,4-dioxane, 5/ were studied by the spin-trapping method using C-phenyl-N-methylnitrone /PBN/ as a spin-trapping agent giving rise to the sufficiently stable nitroxyl radicals. The spin adducts of radicals 2 and 3 are relatively stable up to the temperature 253 K and 453 K, respectively.     

Cationic rare-earth metal trimethylsilylmethyl complexes supported by THF and 12-crown-4 ligands: synthesis and structural characterization

To expand the limited range of rare-earth metal cationic alkyl complexes known, a series of mono- and dicationic trimethylsilylmethyl complexes supported by THF and 12-crown-4 ligands with [BPh4]-, [BPh3(CH2SiMe3)]-, [B(C6F5)4]-, [B(C6F5)3(CH2SiMe3)]-, and [Al(CH2SiMe3)4]- anions were prepared from corresponding neutral precursors [Ln(CH2SiMe3)3Ln] (Ln = Sc, Y, Lu; L = THF, n = 2 or 3; L = 12-crown-4, n = 1) as solvent-separated ion pairs. The syntheses of the monocationic derivatives [Ln(CH2SiMe3)2(12-crown-4)n(THF)m]+[A]- are all high yielding and proceed rapidly in THF solution at room temperature. A "one pot" procedure using the neutral species directly for the syntheses of a number of lutetium and yttrium dicationic derivatives [Ln(CH2SiMe3)(12-crown-4)n(THF)m]2+[A]-2 with a variety of different anions, a class of compounds previously limited to just a few examples, is presented. When BPh3 is used to generate the ion triple, the presence of 12-crown-4 is required for complete conversion. Addition of a second equiv of 12-crown-4 and a third equiv of [NMe2PhH]+[B(C6F5)4]- abstracts a third alkyl group from [Ln(CH2SiMe3)(12-crown-4)2(THF)x]2+[B(C6F5)4]-2 (Ln = Y, Lu). X-ray crystallography and variable-temperature (VT) NMR spectroscopy reveal a structural diversity within the known series of neutral 12-crown-4 supported tris(trimethylsilylmethyl) complexes [Ln(CH2SiMe3)3(12-crown-4)] (Ln = Sc, Y, Sm, Gd-Lu) in the solid and solution states. The X-ray structure of [Sc(CH2SiMe3)3(12-crown-4)] exhibits incomplete 12-crown-4 coordination. VT NMR spectroscopy indicates fluxional 12-crown-4 coordination on the NMR time scale. X-ray crystallography of only the second structurally characterized dicationic rare-earth metal alkyl complex [Y(CH2SiMe3)(12-crown-4)(THF)3]2+[BPh4]-2 shows exocyclic 12-crown-4 coordination at the 8-coordinate metal center with well separated counteranions. 11B and 19F NMR spectroscopy of all mono- and dicationic rare-earth metal complexes reported demonstrate that the anions are symmetrical and noncoordinating on the NMR time scale. A series of trends within the 1H and 13C{1H} NMR resonances arising from the Ln-CH2 groups and, in the case of yttrium, the 1JYC coupling constants at the Y-CH2 group and the 89Y chemical shift values are discussed.     

冠醚共缩聚物的合成与性能

双冠醚化合物对某些金属离子比单冠醚具有更好的络合性能和选择性,它们合成、应用研究越来越受到人们的重视,本工作采用2,6-二羟甲基对甲氧基苯酚为缩合剂与芳香族冠醚缩聚,得到一系列具有双冠醚结构特征的新酚醛型聚苯并冠醚(简称聚冠醚),聚冠醚合成容易,并呈现了比相应单冠醚更优越的络合萃取能力和富集效率。     

Dimetallo[3.3]para- and metacyclophanes by self-assembly of pyridylmethyl armed-monoazatrithia- and monoazadithiaoxa-12-crown-4 ethers with Ag+ ions

New pyridylmethyl armed-monoazadithiaoxa- and monoazatrithia-12-crown-4 have been prepared. The structures of the Ag+ complexes of the new ligands were investigated by X-ray crystallography, 1H NMR titrations, and FAB-MS measurements. In all cases, the Ag+ complexes form dimetallo[3.3]para- or metacyclophane structures depending on the position of the N atom of the pyridine rings.     

Liquid crystal polymers containing macroheterocyclic ligands. III. Side chain liquid crystalline polymethacrylates containing mesogenic units based on diarylacetylenes and benzo-15-crown-5

The synthesis and polymerization of 4′-[4-ethynyl-1-(11-methacryloylundecan-1-yloxy) benzene] benzo-15-crown-5 ( 8 ), 4′-[4-ethynyl-4′-(11-methacryloylundecan-1-yloxy) biphenyl] benzo-15-crown-5 ( 15 ), 4′-[2-ethynyl-6-(11-methacryloylundecan-1-yloxy) naphthalene] benzo-15-crown-5 ( 24 ), and 4′-[2-ethynyl-6-(11-methacryloylundecan-1-yloxy)naphthalene]-5′-ethylbenzo-15-crown-5 ( 35 ) is described. The synthesis and characterization of 4′-[4-(4-ethynyl-1-(2-ethynyl-6-(6-hydroxyhexan-1-yloxy)naphthathalene)benzene]) benzo-15-crown-5 ( 29 ) is also presented. Both monomers and polymers were characterized for their mesomorphic behavior. 8 , poly( 8 ), and 15 are crystalline. Due to the insolubility of 15 , poly( 15 ) could not be synthesized. 24 is crystalline, while poly( 24 ) displays a monotropic nematic mesophase. 29 exhibits also a monotropic nematic mesophase. 35 is crystalline, while poly( 35 ) displays an enantiotropic nematic mesophase which is kinetically controlled due to its close proximity to the glass transition temperature.     

Synthesis of New Crown Ethers Containing Appended Pyridine, 10-hydroxybenzoquinoline, 8-hydroxyquinoline and 2-amino-1-hydroxybiphenyl Sidearms

Twelve crown ethers containing one or two arms were synthesized. Two methods were used to attach arms to the azacrown ethers. Ligands 4 - 12 were prepared by a nucleophilic substitution of secondary macrocyclic amine functions on RX ( X=bromide or tosylate groups). Ligands 13 - 15 were obtained via a Mannich reaction of secondary macrocyclic amines with 5-chloro-8-hydroxyquinoline or a substituted-phenol. Diaza-18-crown-6 was treated with 2-bromomethyl-9-methyl-1,10-phenanthroline at the same conditions in which 4 - 8 and 10 - 12 were prepared. In this case, the main product was the diazacrown ether containing one arm. Twelve new aza-crown ethers bearing aromatic and aliphatic side arms were prepared by nucleophilic substitution by secondary macrocyclic amine functions on halide or tosylates or via a Mannich reaction of the macrocyclic secondary amines with phenolic compounds. R=derivatives of pyridine, 8-hydroxyquiniline, and 1-hydroxybiphenyl. Crown ether include aza-15-crown-5 diaza-18-crown-6 diazatrithia-15 (and 16)-crown-6 and diaza-21-crown-7     

New 13-vertex metallacarborane sandwich compounds; synthetic and structural studies

Reduction of 1,12-closo-C2B10H12 followed by reaction with the appropriate metal halide and metathesis with either [K(18-crown-6)]Br or [BTMA]Cl ([BTMA] = [C6H5CH2N(CH3)3]+) affords isolable salts of the supraicosahedral metallacarborane sandwich anions [4,4-M-(1,10-closo-C2B10H12)2]n- in moderate to good yield. Compounds prepared are [BTMA][4,4-Co-(1,10-closo-C2B10H12)2] ( 1), [K(18-crown-6)][4,4-Co-(1,10-closo-C2B10H12)2] ( 2), [K(18-crown-6)]2[4,4-Ni-(1,10-closo-C2B10H12)2] ( 3), [K(18-crown-6)]2[4,4-Fe-(1,10-closo-C2B10H12)2] ( 4), [BTMA]2[4,4-Fe-(1,10-closo-C2B10H12)2] ( 5) and [K(18-crown-6)]2[4,4-Ti-(1,10-closo-C2B10H12)2] ( 6). Oxidation of the iron(II) species 4 and 5 with FeCl3 in THF generates the iron(III) analogues [K(18-crown-6)][4,4-Fe-(1,10-closo-C2B10H12)2] ( 7) and [BTMA][4,4-Fe-(1,10-closo-C2B10H12)2] ( 8), respectively. All diamagnetic compounds were characterised spectroscopically and the structures of 1, 3, 4, 6, 7 and 8 were established by single crystal X-ray diffraction. All anions have the anticipated cluster structures with two docosahedral 13-vertex cages joined at the central metal atom (the common degree-six vertex 4). Carbon atoms occupy the degree-four vertex 1 and the degree-five vertex 10. 11B NMR spectroscopy suggests the anions have, on the NMR timescale, C2h symmetry in solution at room temperature, consistent with free rotation, or at least substantial libration, of cage units about the long molecular axis. In the solid state the relative conformations of the two cages may be rationalised by simple bonding arguments, the single exception being the conformation of 4, in which both cages are subject to directional B-H...K+ interactions to the [K(18-crown-6)]+ counterion. The salts 3, 6 and 7 also show B-H...K+ interactions but involving one cage only.     

Iodide, azide, and cyanide complexes of (N,C), (N,N), and (N,O) metallacycles of tetra- and pentavalent uranium

In contrast to the neutral macrocycle [UN*(2)(N,C)] (1) [N* = N(SiMe(3))(3); N,C = CH(2)SiMe(2)N(SiMe(3))] which was quite inert toward I(2), the anionic bismetallacycle [NaUN*(N,C)(2)] (2) was readily transformed into the enlarged monometallacycle [UN*(N,N)I] (4) [N,N = (Me(3)Si)NSiMe(2)CH(2)CH(2)SiMe(2)N(SiMe(3))] resulting from C-C coupling of the two CH(2) groups, and [NaUN*(N,O)(2)] (3) [N,O = OC(═CH(2))SiMe(2)N(SiMe(3))], which is devoid of any U-C bond, was oxidized into the U(V) bismetallacycle [Na{UN*(N,O)(2)}(2)(μ-I)] (5). Sodium amalgam reduction of 4 gave the U(III) compound [UN*(N,N)] (6). Addition of MN(3) or MCN to the (N,C), (N,N), and (N,O) metallacycles 1, 4, and 5 led to the formation of the anionic azide or cyanide derivatives M[UN*(2)(N,C)(N(3))] [M = Na, 7a or Na(15-crown-5), 7b], M[UN*(2)(N,C)(CN)] [M = NEt(4), 8a or Na(15-crown-5), 8b or K(18-crown-6), 8c], M[UN*(N,N)(N(3))(2)] [M = Na, 9a or Na(THF)(4), 9b], [NEt(4)][UN*(N,N)(CN)(2)] (10), M[UN*(N,O)(2)(N(3))] [M = Na, 11a or Na(15-crown-5), 11b], M[UN*(N,O)(2)(CN)] [M = NEt(4), 12a or Na(15-crown-5), 12b]. In the presence of excess iodine in THF, the cyanide 12a was converted back into the iodide 5, while the azide 11a was transformed into the neutral U(V) complex [U(N{SiMe(3)}SiMe(2)C{CHI}O)(2)I(THF)] (13). The X-ray crystal structures of 4, 7b, 8a-c, 9b, 10, 12b, and 13 were determined.     

Differential pulse polarographic studies of mercury complexes with some crown ethers in nonaqueous solvents

The complex formation of Hg(2+) with some macrocyclic crown ethers in nitrobenzene, acetonitrile and dimethylformamide solutions was studied by differential pulse polarography at 25 degrees C. The stoichiometry and stability of the complexes were determined by monitoring the shift in the Hg(2+) differential pulse peak potential against the ligand concentration. The stability of the resulting 1:1 complexes vary in the order dicyclohexyl-18-crown-6 > 18-crown-6 > 15-crown-5 > dibenzo-18-crown-6 > dibenzo-24-crown-8 > benzo-15-crown-5 > 12-crown-4. There is an inverse relationship between the complex stability and the Gutmann donor number of solvents.     

Conformational analysis of 12-crown-3 and sodium ion selectivity of electrodes based on bis(12-crown-3) derivatives with malonate spacers

A conformational analysis was performed on two crown ethers (12-crown-3 and 12-crown-4) using a combination of semi-empirical and ab initio methods. The lowest conformations of 12-crown-3 and 12-crown-4 were found to have exodentate C_3v and C₂ structure, respectively. In the case of the sandwich-type complexation, the nucleophilic cavity of 12-crown-3 rather than that of 12-crown-4 seemed to be optimal for complexation with the Na⁺ ion. Four new bis(12-crown-3) derivatives (1–4) were examined as potential sodium ion-selective ionophores in poly(vinylchloride) (PVC) membrane electrodes. The ion-selective electrode (ISE) based on di(1,5,9-trioxacyclododecanylmethyl) 2-dodecyl-2-methylmalonate (1) had the highest selectivity for the sodium ion among the alkali and alkaline earths studied. The sodium ion selectivity of the ISE based on bis(12-crown-3) derivative 1 was superior to that of the ISE based on the bis(12-crown-4) analogue.     

Gamma-radiolysis of some crown ethers and their analogues. Electron spin resonance specra of free radicals

The method of low temperature ESR spectroscopy was used to study the free radicals generated by -irradiation of crown ethers: 12-crown-4 /1/; 15-crown-5 /2/; dicyclohexane-24-crown-8 /3/; and their analogues: tetrahydrofurane /4/ and 1,4-dioxane /5/. ESR spectra of radicals 4 and 5 taken at 77 K represent a simple singlet; ESR spectra of radicals generated from 1, 2 and 3 have a complex, multiplet structure. The kinetics of thermal decay of free radicals 4 in dependence on temperature starting from 103 K was investigated. The radicals 4 decay very fast at 253 K.     

Reactivity of a heterocyclic As-Se compound with metal salts: syntheses and structures of the first copper complexes and of new alkali metal salts containing As-Se anions

The structures of the new compounds [Cu8(Ph2As2Se2)2(PhAsSe2)2(dppm)4] (1) (dppm = bis-diphenylphosphinomethane), [Cu4(Ph2As2Se2)2(PPh3)4] (2), [{K(18-crown-6)}2(PhAsSe3)] (3), [Na12(PhAsSe3)6(15-crown-5)6] (4) and 1/x[Na2(PhAsSe3)(thf)(H2O)3]x (5) are reported. 2-5 were prepared by reactions of metal thiolates with [(PhAs)2(mu-Se)(mu-Se2)].     

Synthesis, structure and hydrosilylation activity of neutral and cationic rare-earth metal silanolate complexes

Rare-earth metal alkyl tri(tert-butoxy)silanolate complexes [Ln{mu,eta2-OSi(O(t)Bu)3}(CH2SiMe3)2]2 (Ln = Y (1), Tb (2), Lu (3)) were prepared via protonolysis of the appropriate tris(alkyl) complex [Ln(CH2SiMe3)3(thf)2] with tri(tert-butoxy)silanol in pentane. Crystal structure analysis revealed a dinuclear structure for with square pyramidal geometry at the yttrium centre. The silanolate ligand coordinates in an eta2-bridging coordination mode giving a 4-rung truncated ladder and non-crystallographic inversion centre. Addition of two equiv. of 12-crown-4 to a pentane solution of 1 or 3 respectively gave [Ln{OSi(O(t)Bu)(3)}(CH2SiMe3)2(12-crown-4)].12-crown-4 (Ln = Y (4), Lu (5)). Crystal structure analysis of 5 showed a slightly distorted octahedral geometry at the lutetium centre. The silanolate ligand adopts an eta(1)-terminal coordination mode, whilst the crown ether unit coordinates in an unusual kappa3-fashion. Reaction of 1-3 with [NEt3H]+[BPh4]- in thf yielded the cationic derivatives [Ln{OSi(O(t)Bu)3}(CH2SiMe3)(thf)4]+[BPh4]- (Ln = Y (6), Tb (7) and Lu (8)); coordination of crown ether led to compounds of the form [Ln{OSi(O(t)Bu)3}(CH2SiMe3)(L)(thf)n]+[BPh4]- (Ln = Y, Lu, L = 12-crown-4, n = 1 (9,10); Ln = Y, Lu, L = 15-crown-5, n = 0 (11,12)). Reaction of 1 with [NMe2PhH]+[B(C6F5)4]-, [Al(CH2SiMe3)3] or BPh3 in thf gave the ion pairs [Y{OSi(O(t)Bu)3}(CH2SiMe3)(thf)4]+[A]- ([A]- = [B(C6F5)4]- (13), [Al(CH2SiMe3)4]- (14), [BPh3(CH2SiMe3)]- (15)), whilst two equiv. [NMe2PhH]+[BPh4]- with 1 in thf produced the dicationic ion triple [Y{OSi(O(t)Bu)3}(thf)6]2+[BPh4]-2 (16). Crystal structure analysis revealed that 16 is mononuclear with pentagonal bipyramidal geometry at the yttrium centre. The silanolate ligand coordinates in an eta(1)-terminal fashion. All diamagnetic compounds have been characterized by NMR spectroscopy. 1, 3, 4, 6 and 13 were tested as olefin hydrosilylation pre-catalysts with a variety of substrates; 1 was found to be highly active in 1-decene hydrosilylation.