Exceptionally Inert Lanthanide(III) PARACEST MRI Contrast Agents Based on an 18-Membered Macrocyclic Platform.

We report a macrocyclic ligand based on a 3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane platform containing four hydroxyethyl pendant arms (L(1)) that forms extraordinary inert complexes with Ln(3+) ions. The [EuL(1)](3+) complex does not undergo dissociation in 1 M HCl over a period of months at room temperature. Furthermore, high concentrations of phosphate and Zn(2+) ions at room temperature do not provoke metal-complex dissociation.

Lanthanide(III) complexation with an amide derived pyridinophane.

Herein we report a detailed investigation of the solid state and solution structures of lanthanide(III) complexes with the 18-membered pyridinophane ligand containing acetamide pendant arms TPPTAM (TPPTAM = 2,2',2″-(3,7,11-triaza-1,5,9(2,6)-tripyridinacyclododecaphane-3,7,11-triyl)triacetamide). The ligand crystallizes in the form of a clathrated hydrate, where the clathrated water molecule establishes hydrogen-bonding interactions with the amide NH groups and two N atoms of the macrocycle. The X-ray structures of 13 different Ln(3+) complexes obtained as the nitrate salts (Ln(3+) = La(3+)-Yb(3+), except Pm(3+)) have been determined.

Polyamine ligand-mediated self-assembly of gold and silver nanoparticles into chainlike structures in aqueous solution: towards new nanostructured chemosensors.

Polyamine ligands are very versatile compounds due to their water solubility and flexibility. In the present work, we have exploited the binding ability of a polyamine molecular linker (L (2-)) bearing different functional groups, which favors the self-assembling of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) into 1D nanochains in aqueous solution. The chainlike assemblies of AuNPs and AgNPs were structurally stable for a long period of time, during which their characteristic optical properties remained unchanged.

Bis(o-methylserotonin)-containing iridium(III) and ruthenium(II) complexes as new cellular imaging dyes: synthesis, applications, and photophysical and computational studies.

We report the synthesis, characterization, and scope of a new versatile emissive molecular probe functionalized with a 1,10-phenanthroline moiety containing methylserotonin groups as binding sites for metal ion recognition. The synthesis, characterization, and evaluation of the in vitro imaging capability of the iridium(III) and ruthenium(II) complexes [Ir(ppy)2(N-N)](+) and [Ru(bpy)2(N-N)](2+), in which ppy is 2-phenylpyridine, bpy is 2,2'-bipyridine, and N-N is a 1,10-phenanthroline ligand functionalized with two methylserotonin groups to serve as binding sites for metal ion recognition, is reported. The uptake of these compounds by living freshwater fish (Carassius auratus) was studied by fluorescence microscopy, and the cytotoxicity of ligand N-N and [Ru(bpy)2(N-N)](2+) in this species was also investigated.

Pyridinophane platform for stable lanthanide(III) complexation.

A detailed investigation of the solid state and solution structures of lanthanide(III) complexes with the macrocyclic ligand 2,11,20-triaza[3.3.3](2,6)pyridinophane (TPP) is reported.

A chemosensor for dihydrogenphosphate based on an oxoazamacrocycle possessing three thiourea arms.

We report a new H-bond macrocyclic chromogenic chemosensor in organic media, H(3)L, which displayed drastic changes in its UV-vis spectra revealing selectivity for dihydrogenphosphate over other inorganic anions, such as acetate or fluoride. The X-ray crystal structures of the [H(4)L···NO(3)]·(CH(3)CN)(4) and [H(4)L···CF(3)CO(2)]·(CH(3)CN)(2) salt complexes are also reported.

Dinuclear cobalt(II) and copper(II) complexes with a Py2N4S2 macrocyclic ligand.

The interaction between Co(II) and Cu(II) ions with a Py(2)N(4)S(2)-coordinating octadentate macrocyclic ligand (L) to afford dinuclear compounds has been investigated. The complexes were characterized by microanalysis, conductivity measurements, IR spectroscopy and liquid secondary ion mass spectrometry. The crystal structure of the compounds [H(4)L](NO(3))(4), [Cu(2)LCl(2)](NO(3))(2) (5), [Cu(2)L(NO(3))(2)](NO(3))(2) (6), and [Cu(2)L(μ-OH)](ClO(4))(3)·H(2)O (7) was also determined by single-crystal X-ray diffraction.

Structural, MALDI-TOF-MS, magnetic and spectroscopic studies of new dinuclear copper(II), cobalt(II) and zinc(II) complexes containing a biomimicking μ-OH bridge.

The Py(2)N(4)S(2) octadentate coordinating ligand afforded dinuclear cobalt, copper and zinc complexes and the corresponding mixed metal compounds. The overall geometry and bonding modes have been deduced on the basis of elemental analysis data, MALDI-TOF-MS, IR, UV-vis and EPR spectroscopies, single-crystal X-Ray diffraction, conductivity and magnetic susceptibility measurements. In the copper and zinc complexes, a μ-hydroxo bridge links the two metal ions.

New dinuclear nickel(II) and iron(II) complexes with a macrocyclic ligand containing a N6S2 donor-set: synthesis, structural, MALDI-TOF-MS, magnetic and spectroscopic studies.

A series of dinuclear Ni(II) and Fe(II) complexes with a Py(2)N(4)S(2) coordinating octadentate macrocyclic ligand L prepared by direct reactions have been studied. The overall geometry and bonding mode have been deduced on the basis of elemental analysis data, infrared, MALDI-TOF-MS, UV-vis spectroscopy, X-ray diffraction, conductivity and magnetic susceptibility measurements. In general both M(2+) centres are sited into the macrocyclic cavity coordinated to a pyridinic nitrogen atom, one sulfur atom, two secondary amine groups from the macrocyclic backbone and completing the coordination spheres with two solvent or anionic molecules in a distorted octahedral geometry, except in the case of [Ni(2)L(mu-Cl)(H(2)O)(2)](BF(4))(3).

A hexaaza macrocyclic ligand containing acetohydrazide pendants for Ln(III) complexation in aqueous solution. Solid-state and solution structures and DFT calculations.

Lanthanide complexes of a hexaaza macrocyclic ligand containing acetohydrazide pendants (L) have been synthesised (Ln = La-Er, except Pm), and structural studies have been carried out both in the solid state and in aqueous solution. Attempts to isolate the complexes of the heaviest Ln(iii) ions (Ln = Tm-Lu) were unsuccessful. The crystal structures of the ligand and its lanthanum complex have been determined by single-crystal X-ray crystallography.

A novel zinc(II) complex with the ligand 2,2',2''-(1,4,7-triazanonane-1,4,7-triyl)triacetate (NOTA).

The zinc(II) complex with NOTA [2,2',2''-(1,4,7-triazanonane-1,4,7-triyl)triacetate] has previously been synthesized and studied in solution, but was not isolated. The corresponding title Zn(II) complex penta-sodium(I) bis-{[2,2',2''-(1,4,7-triazanonane-1,4,7-triyl)triacetato]zinc(II)} tris-(perchlorate) methanol solvate, Na(5)[Zn(C(12)H(18)N(3)O(6))](2)(ClO(4))(3)·CH(3)OH, was crystallized as a sodium perchlorate double salt in methano-l solution. The asymmetric unit contains two independent [Zn(NOTA)](-) complex anion entities, five sodium cations, three perchlorate anions and a methanol solvent mol-ecule.

Different nuclearity silver(I) complexes with novel tetracyano pendant-armed hexaazamacrocyclic ligands.

A new series of different nuclearity silver(I) complexes with a variety of tetracyano pendant-armed hexaazamacrocyclic ligands containing pyridine rings (Ln) has been prepared starting from the nitrate and perchlorate Ag(I) salts in acetonitrile solutions. The ligands and complexes were characterized by microanalysis, conductivity measurements, IR, Raman, electronic absorption and emission spectroscopy, and L-SIMS spectrometry. (1)H NMR titrations were employed to investigate silver complexation by ligands L3 and L.

Pentanuclear Ba(II) complex of a macrocyclic ligand.

We report here the first pentanuclear Ba(II) complex of a new tri-aza, tri-oxa macrocycle with two carboxymethyl "arms" pending from two N atoms, H2L2. The crystal structure corresponds to the formula [Ba5(H0.375L2)4(ClO4)(CH3CH2OH)(H2O)2](ClO4)2.

Metal complexes with a new N(4)O(3) amine pendant-armed macrocyclic ligand: synthesis, characterization, crystal structures, and fluorescence studies.

The synthesis of a new oxaaza macrocyclic ligand, L, derived from O(1),O(7)-bis(2-formylphenyl)-1,4,7-trioxaheptane and tren containing an amine terminal pendant arm, and its metal complexation with alkaline earth (M = Ca(2+), Sr(2+), Ba(2+)), transition (M = Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+)), post-transition (M = Pb(2+)), and Y(3+) and lanthanide (M = La(3+), Er(3+)) metal ions are reported. Crystal structures of [H(2)L](ClO(4))(2).3H(2)O, [PbL](ClO(4))(2), and [ZnLCl](ClO(4)).

Barium Templating Schiff-Base Lateral Macrobicycles.

Schiff-base lateral macrobicycles containing two different binding units, a rigid and unsaturated N(2)X set (X: N, O) and a flexible and cyclic N(2)O(n)() set, linked by two aromatic bridges, have been prepared by reaction of the appropriate bibracchial diamines N,N'-bis(aminobenzyl)-diaza-crown and diformyl precursors in the presence of Ba(II) as templating agent. The expected cryptands do not form in the absence of the cation; the presence of this metal ion is necessary to orient the diamine precursor in a syn conformation. Comparison of the X-ray crystal structures of the barium complex of the bibracchial diamine N,N'-bis(2-aminobenzyl)-1,10-diaza-15-crown-5 and the barium complex of the cryptand derived from it incorporating a pyridine unit indicates that the encapsulation of the metal ion is clearly more effective in the case of the cryptand.