The synthesis and thermotropic liquid crystal (LC) properties of gemini imidazolium salts comprising Cl−, BF4−, PF6−, AuCl4− counteranions, varied alkenyl spacer lengths and terminal alkyl chains are described. LC properties are investigated by differential scanning calorimetry, polarizing optical microscopy, and powder X-ray diffraction studies. It should be noted that, salts of short spacers favor the formation of mesophase. A SmA with wide mesophase range and high thermal stability are identified. The Cl− salts have shown an odd-even effect on phase transition temperatures as the length and parity of the spacer is varied. The use of [(CH2)4(C18-Im)2][AuCl4]2 salt as precursor for the fabrication of Au nano/micro particles via chemical reduction, photo irradiation, and thermolysis methods is presented. A clear vision of morphology change is observed in Au structures by varying the reduction method, however the mesophase does not control over the size and morphology of Au particles in the thermolysis method. The colloidal AuNPs prepared in this study showed remarkable stability for over six months. These results offer great insight into the counter anion and spacer effects on LC nature of gemini Im salts, which broadens the scientific understanding to develop advanced soft materials.

The rationally designed polydentate ligands, L 1 and L 2 , based on the pyridinyl moiety and the hydrazone fragment have been synthesized to coordinate zinc(II) ions. We utilize pyridine as a rigid core connecting two bipyridines as ligand building blocks with a hydrozone linker for the L 1 . The L 2 has a reversed design in which a bipyridine was used as a hinging-available building block of the ligand core, connecting two pyridazine arms with a hydrazone linker. Two novel helical dizinc(II) complexes were obtained by the reaction of L 1 and L 2 with zinc(II) perchlorate in acetonitrile. The structures of both helicates were confirmed by X-ray diffractometry. Single-stranded helicate Zn 2 L 1 contains two zinc ions bridged by an oxygen atom. Except for the L 2 ligand, no other bridging species were found between the two zinc ions in the double-stranded helicate Zn 2 L 2 2 . The self-assembling process of helicate Zn 2 L 1 in solution state was studied by UV–Vis spectrometric titration experiments. The stepwise formation constants imply a slightly positive cooperative behavior for the formation of helicates.

Examples of polynuclear metallomesogens are few. Herein,1,2,4-triazole ligands were used to prepare mono- and polynuclear silver(I) triazole metallomesogens. Besides showing an SmA phase in the mesophase, two interesting properties were observed. First, higher ion conductivity is always found for the polynuclear complexes than for the mononuclear complexes with the same anion, an observation contrary to the knowledge that migration of a monomeric cation should be faster than that of a polymeric cation. Second, thermolysis of the polynuclear silver(I) triazole complexes in the assembled mesophase yielded Ag nanowires, in an excellent demonstration of the assembled nature of the polynuclear silver(I) ions in the thermolysis process.

Photoactive platinum complexes of stoichiometry [Pt((CCCR)-C-R) L](0/+) (R=Me, nBu and L= -CN, -C=CPh, -N=CCH3, -Py, -CO) featuring pincer-type bis N-heterocyclic carbene (NHC) ligands (RCCCR) were synthesized. Organometallic syntheses of these complexes are facile and achievable through standard laboratory procedures. Control of intermolecular Pt center dot center dot center dot Pt interaction, pi-pi stacking, and emission tuning is achieved through suitable choice of the NHC-wingtip substituent (R) and the auxiliary ligand (L). Exposure to specific volatile organic compounds (VOCs) or mechanical grinding triggers changes in emission colors, which render these complexes photofunctional. Solid-state structures and photoluminescence results are described herein.

Cobalt complexes of Co((3)Cn)(2)(MeOH)(4), derived from 3,4,5-trialkyloxybenzoate ligand (noted as 3Cn) with n = 10, 12, 14 and 16, were synthesized and characterized. The crystal of Co(1C(12))(2)(MeOH)(4) were determined by means of x-ray single crystal analysis. It crystallizes in the monoclinic P21/c space group with a = 24.3271(19) angstrom, b = 14.0058(11) angstrom, c = 6.4612(4) angstrom, alpha = gamma = 90 degrees, beta = 94.368(4)degrees, and Z = 2. The phase texture and mesogenic properties were detected by polarized optical microscopic and powder x-ray diffraction technique. It was found that these compounds display the cubic phases. Differential scanning calorimetric data indicated that these compounds were nearly room temperature liquid crystalline and with a very wide mesogenic phase range.

An unprecedented 3D framework, [Ag(Ag-6(C2-Me-(Mepdz)(2))(3)(CH3CN)(2)](ClO4)(13), has been synthesized by using a ligand with both rigid pyridazine and flexible hydrazone segments, which represents to the best of our knowledge, the first example of metallosupramolecule built by the triple- stranded helixes sharing the same penta- silver core.

A novel double helical dicopper(II) complex was synthesized by reaction of a polydentate ligand L = 2,2'-bipyridy1-6,6'-bis(2-acetylpyrazinohydrazone) with copper(II) perchlorate in CH3CN. The self-assembling process was studied by UV-Vis spectrometric titration experiments which revealed the formation of dinuclear complexes [Cu2L2](ClO4)(4). The structure of dicopper double-helicate was confirmed by X-ray diffractometry. Each copper(II) center occupies a distorted octahedral environment. Variable-temperature magnetic measurements reveal weak antiferromagnetic interactions between Cu(II) ion centers with J = -0.63 cm(-1).

A family of acyclic aza-bridged bis-1,10-phenanthroline compounds has been synthesized in a convenient way. The resulting compounds 2 and 2 HCl were fully characterized and their solid state structures and NMR spectroscopic properties were investigated to assess how the structural units affect the alkylation reactions. The results reveal the transoid structure for 2. The broadening NMR peak in 2 is shown to be due to an unusual intramolecular CH center dot center dot center dot N hydrogen bond. This unique conformation offers an efficient and regioselective method to prepare the amino-substituted bis-2,2'-1,10-phenanthroline derivatives and 1,10-phenanthrolino-N-alkylated compounds. (C) 2010 Elsevier Ltd. All rights reserved.

A novel polydentate ligand, L = 2,2'-bipyridyl-6,6'-bis(2-acetylpyrazinohydrazone), was synthesized by condensation of 6,6'-dihydrazine-2,2'-bipyridine and 2-acetylpyrazine. Reaction of L ligand strands with nickel(II) perchlorate in CH3CN generates a double helical dinuclear complex. Its complexation behavior was studied by UV-Vis spectrophotometric titration experiments that revealed the formation of dinuclear complexes [Ni2L2](CIO4)(4). Moreover, the double-helical structure of [Ni2L2](ClO4)(4) was confirmed by X-ray diffractometer. Each nickel(II) center occupies a distorted octahedral environment. Variable-temperature magnetic measurements revealed weak antiferromagnetic interactions between Ni(II) ion centers with J = -0.34 cm(-1).

A new ruthenium complex, [Ru(L)(bpy)(2)]center dot 2PF(6), (L = 3,5-di(2'-pyridy1)-1,2,4-oxadiazole), was synthesized and characterized. The assignment of chemical shift for [Ru(L)(bpy)(2)]center dot 2PF(6) was accomplished by HHCOSY technique. The cyclic voltammogram of [Ru(L)(bpy)(2)]center dot 2PF(6) shows a metal-centered Ru-II/Ru-III oxidation with potential at 1.35 V, as well as four reversible reduction waves with the former two potentials at -1.24 and -1.60 V, attributed to two bpy/bpy(-) process, and the latter two potentials at -1.86 and -2.16 V, attributed to L/L- and L-L2-, respectively. The absorption spectrum of the ruthenium complex was dominated by metal-to-ligand charge transfer (MLCT) band in the visible range, with absorption maxima appearing at 442 nm and molar extinction coefficient of 13 x 10(3) M(-1)cm(-1). The phosphorescent emission band has been attributed to from MLCT triplet state.

The sulfamide derivative of triphenylmethanol, 3-[hydroxy(diphenyl)methyl]benzenesulfonamide (H2NSO2Ph)Ph2COH was synthesized and, alongside with the parent triphenylmethanol and triphenylmethylamine, was investigated for selective interactions with crown ethers of different dimensionality (12-18-membered cycles). The molecule of 12-crown-4 (12C4) appeared to be the best candidate for Ph3COH, Ph3CNH2 and Ph3CNH3·NCS, while (H2NSO2Ph)Ph2COH forms the complex exclusively with 18-crown-6 (18C6). The triphenylammonia trifluoroacetate, Ph3CNH3·CF3COO, selectively forms the complex only with 2-methoxyethanol. The crystalline products of the compositions (Ph3COH)2·12C4, (Ph3CNH2)2·12C4, (Ph3CNH3·NCS)2·12C4, [(H2NSO2Ph)Ph2COH]2·18C6 and Ph3CNH3·CF3COO CH3OCH2CH2OH were obtained and studied by X-ray single crystal diffraction.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Four novel complexes of 2,4-dithiouracil (pyrimidine-2,4(1 H ,3 H )-dithione, DTU) with 18-membered benzo- and dibenzo-crown ethers were synthesized in approximately the same conditions and studied by single crystal diffraction. Hydrogen bonding was observed to be the most important for the complexation in the solid state but π–π interactions also contribute to it. The crystalline monohydrates of the 1:1:1 stoichiometry are recorded for 4-bromo- and 4-nitrobenzo-18-crown-6 (complexes 1 and 2 ), while complexes with [2.4]dibenzo- and thia[1.5]dibenzo-18-crown-6 (complexes 3 and 4 ) represent anhydrous adducts of the 2:2 ratio. The crystal structures reveal three supramolecular structural motifs: the alternative chain for the ternary complex 1 and two types of capsules for complexes 2 − 4 where the DTU dimers are encapsulated inside the space restricted by two crown molecules.

Reaction of the hexadentate N4O2-donor ligand 6,6′-bis(3-hydrazonobutan-2-one)-2,2′-bipyridine (L) with Ag(I) and Zn(II) affords a dinuclear double stranded helicate species [Ag2L2]2+ (1a) and [Zn2L2]2+ (1b), in which partitioning of the ligand into two bis-tridentate pyridyl-ketoimine chelating units allow each ligand to bridge both metal centres. X-ray crystallography, ESI-MS and UV–Vis spectrophotometric titration experiments reveal that the complex (1a) retains its solid-state structure in solution. The crystal structure of (1a) provides the first example of dinuclear silver(I) complex in which both of the metal centres can be approximated as a seven coordinate distorted mono-capped trigonal prism in which the Ag⋯Ag close contact of 3.034(4)Å is taken into account and forms the cap. The counter-ions do not interact with metal centres but hydrogen bond to N–H protons of the hydrazonic arms from the separate strands. The adjacent helical units are cross-linked together via NH⋯Oketo hydrogen bonding to maintain the supramolecular structure.

Hexanitro[60]-fullerene was synthesized. Hexahydroxy[60]-fullerene was obtained by hydrolysis of the resulting hexanitro[60]-fullerene in situ. The electrochemical properties have been investigated by using cyclic voltammetry and controlled potential electrolysis technique. Two reduction peaks of C-60(OH)(6) with quasi-reversibility in DMF solution were observed. No electrochemical response was observed for the C-60 (OH)(12) compound in a variety of solvent. An electrode following chemical reaction occurred for C-60(NO2)(6) after the first reduction at -0.96 V. The trace amount residue of C-60(NO2)(6) shows quasi-reversible redox behavior. The results from the controlled potential electrolysis show that the C-60(NO2)(6) has six sequential electron transfer at -0.96 V (vs. Fc/Fc(+)) to produce free C-60 and NO2- anion. (c) 2008 Elsevier B.V. All rights reserved.

The reaction of thionicotinamide (3-thioamidopyridine) with 18-membered crown ethers, 18-crown-6 (18C6), benzo-18-crown-6 (B18C6) and cis–anti–cis-dicyclohexyl-18-crown-6 (D18C6) results in the molecular complexes of 1:1 ratio for 18C6 (complex 1) and B18C6 (complex 2) and monohydrate of 2:1:1 ratio for D18C6 (complex 3), respectively. The complexes are sustained by combination of N–H⋯O, O–H⋯N and C–H⋯O hydrogen bonds, and the components are associated into molecular adduct (1) or infinite chain (2 and 3).

Two synthetic pathways, the interaction of Nb2O5 or Ta2O5 with an aqueous solution of hydrofluoric acid, HF, in the presence of 18-crown-6 (18C6), 15-crown-5 (15C5), benzo-15-crown-5 (B15C5) or benzo-12-crown-4 (B12C4), and the direct interaction of the corresponding pentafluorides, MF5 (M=Ta, Nb), in the presence of HF with the same crown ethers result in crystalline complexes of the same composition, [18C6·H3O][NbF6] (1), [18C6·H3O][TaF6] (2), [15C5·H5O2][TaF6] (3), [(B15C5)2·H5O2][(B15C5)2·H3O][TaF6]2 (4) and [(B12C4)2·H3O][TaF6] (5). Complexes 1–5 were identified by elemental and X-ray structural analysis. Compounds 1 and 2 are isostructural, with the [H3O]+ oxonium ion embedded in one crown molecule via OH⋯O hydrogen bonds. Complexes 3–5 represent sandwich-like adducts with the [H3O]+ or [H5O2]+ cations encapsulated. A plethora of weak C–H⋯F interactions with NbF6- and TaF6- anions is responsible for the extended supramolecular architectures.

Two cuprous complexes Cu(L1)(PPh3)1 (1) and Cu(L2)(PPh3)I (2) were obtained by reaction of Cu(PPh3)(3)I (PPh3 = triphenylphosphine) with two different alpha-diimine ligands L-1(3,5-di(2-pyridyl)-4-amino-1,2,4-triazole) and L-2(N-benzylidene-3,5-di (2'-pyridyl)-4-amino-1,2,4-triazole, respectively. These two complexes have been characterized by UV-Vis, luminescence, H-1 NMR spectroscopy and cyclic voltammetric studies. The structures are confirmed by the single crystal X-ray diffraction study. The compound Cu(L1)(PPh3)I (1) crystallizes in the triclinic space group P-1 with a=8.3188(14), b=9.2243(15), c=21.177(4), a=78.156(3), beta=86.45(3), gamma=65.966(3), Z=2 and the compound Cu(L2)(PPh3)I (2) crystallizes in the triclinic space group P-1 with a 8.9671(7), b = 13.9737(11), c = 14.6850(12), alpha = 82.2580(10), beta = 75.7020(10), gamma = 72.2790(10), Z = 2. Both complexes show an MLCT band at 340 similar to 545 nm region and complex 2 exhibits luminescence at room temperature in a dichloromethane solution. The cyclic voltammogram of Cu(L1)(PPh3)I shows the redox couples at + 0.36 and - 0.545 V.

The crystal structures of [(benzo-18-crown-6) · H3O]TaF6 and [(benzo-18-crown-6) · H3O]NbF6 complex compounds are determined by X-ray diffraction. It is revealed that the tantalum complex has two polymorphic modifications, namely, the monoclinic (I) and orthorhombic (II) modifications. The unit cell parameters of these compounds are as follows: a = 14.784(2) Å, b = 8.390(4) Å, c = 18.005(6) Å, β = 95.78(2)°, Z = 4, and space group P21/n for modification I; and a = 8.456(2) Å, b = 21.967(5) Å, c = 24.122(5) Å, Z = 8, and space group Pbca for modification II. The orthorhombic niobium complex [(benzo-18-crown-6) · H3O]NbF6 with the unit cell parameters a = 8.454(1) Å, b = 21.943(3) Å, c = 24.127(4) Å, Z = 8, and space group Pbca (III) is isostructural with tantalum complex II. The oxonium cation in complexes I–III is encapsulated by the crown ether and thus forms one ordinary and two bifurcate hydrogen bonds with the oxygen atoms of the crown ether. This macrocyclic cation is bound to the anions through the C-H ...F contacts (H...F, 2.48–2.58 Å).