Exploring the interaction of mercury(II) by N(2)S(2) and NS(3) anthracene-containing macrocyclic ligands: photophysical, analytical, and structural studies.

The complexation properties toward Hg(II) of six macrocyclic ligands, 3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L1), 7-(9-anthracenylmethyl)-3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L2), 7-(10-methyl-9-anthracenylmethyl)-3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L3), 7,7'-[9,10-anthracenediylbis(methylene)]bis-3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L4), 1,4,7-trithia-11-azacyclotetradecane (L5), and 11,-(anthracen-9-ylmethyl)-1,4,7-trithia-11-azacyclotetradecane (L6), were studied. The stoichiometries of the formed species were determined from absorption and fluorescence titrations. In these anthracene-containing macrocycles, a fluorescent quenching of the emission was found upon Hg(II) addition. The X-ray crystal structure of [HgCl2(L2)] x 1/2CH2Cl2 was determined. The asymmetric unit contains two independent [HgCl2(L2)] molecules and one dichloromethane molecule. Each Hg(II) ion is coordinated by the pyridine nitrogen, the two sulfur atoms of one L2 molecule, and two chloride ions. Analytical studies using solvent extraction separation of Hg(II) from aqueous solutions were performed to determine the Hg(II) extraction capability of ligands L1, L2, and L5.

Structural and EPR studies on single-crystal and polycrystalline samples of copper(II) and cobalt(II) complexes with N2S2-based macrocyclic ligands.

The properties of Cu(II) and Co(II) complexes with oxygen- or nitrogen-containing macrocycles have been extensively studied; however, less attention has been paid to the study of complexes containing sulfur atoms in the first coordination sphere. Herein we present the interaction between these two metal ions and two macrocyclic ligands with N2S2 donor sets. Cu(II) and Co(II) complexes with the pyridine-containing 14-membered macrocycles 3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L) and 7-(9-anthracenylmethyl)-3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L1) have been synthesized. The X-ray structural analysis of {[Co(ClO4)(H2O)(L)][Co(H2O)2(L)]}(ClO4)3 shows two different metal sites in octahedral coordination. The EPR spectra of powdered samples of this compound are typical of distorted six-coordinated Co(II) ions in a high-spin (S=3/2) configuration, with the ground state being S=1/2 (g1=5.20, g2=3.20, g3=1.95). The EPR spectrum of [Cu(ClO4)(L)](ClO4) was simulated assuming an axial g tensor (g1=g2=2.043, g3=2.145), while that of [Cu(ClO4)(L1)](ClO4) slightly differs from an axial symmetry (g1=2.025, g2=2.060, g3=2.155). These results are compatible with a Cu(II) ion in square-pyramidal coordination with N2S2 as basal ligands. Single-crystal EPR experiment performed on [Cu(ClO4)(L1)](ClO4) allowed determining the eigenvalues of the molecular g tensor associated with the copper site, as well as the two possible orientations for the tensor. On the basis of symmetry arguments, an assignment in which the eigenvectors are nearly along the Cu(II)-ligand bonds is chosen.

Structural and magnetic properties of a complete halide series of Ni(II) complexes with a pyridine-containing 14-membered macrocycle.

The complete halide series of Ni(II) complexes containing the tetradentate macrocyclic ligand 3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L), was fully characterized by X-ray diffraction. The fluoro, chloro, and bromo complexes are dinuclear species with formula [{Ni(L)}2(mu-X)2]2+ (X = halide), whereas only mononuclear species with formula [Ni(Y)(solv)(L)]n+ (Y = halide or solvent molecule), were obtained with I. To date, the fluoro derivative is the first nonorganometallic coordination compound containing the Ni(mu-F)2Ni core. The magnetic properties of these halo complexes have been studied. Intramolecular interactions were observed in the three dinuclear complexes, being antiferromagnetic in the fluoro derivative and ferromagnetic in both the chloro and bromo ones. The two iodo derivatives are paramagnetic species, as would be expected for mononuclear octahedral Ni(II) complexes. Density functional theory calculations led us to relate the magnetic behaviors of these compounds to the values of the corresponding Ni-X-Ni(i) angle. The analysis of the singly occupied molecular orbitals gave a clear comprehension of the different magnetic exchange interactions found in these Ni(II) complexes.

Color tuning of a nickel complex with a novel N2S2 pyridine-containing macrocyclic ligand.

The novel pyridine-containing 14-membered macrocycle 3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L), which contains an N2S2 donor set, was synthesized, and its protonation behavior was studied by absorption titration with CH3SO3H. The reaction of L with Pd(II) was studied spectroscopically, and the square-planar complex [Pd(L)](BF4) was isolated and characterized. The reactions between L and NiX2 x 6 H2O (X = BF4, ClO4) in ethanol or acetonitrile afforded the octahedral complexes [Ni(CH3CN)(H2O)(L)](X)2 and [Ni(H2O)2(L)](X)2, respectively. The square-planar complexes [Ni(L)](X)2 were obtained by heating these octahedral complexes. Spectrophotometric titrations of [Ni(L)](BF4)2 were performed with neutral and negatively charged ligands. The color of nitromethane solutions of this square-planar complex turns from red to cyan, purple, blue, yellow-green, and pink following addition of halides, acetonitrile, water, pyridine, and 2,2'-bipyridine, respectively. X-ray structural analyses were carried out on the {[Ni(ClO4)(H2O)(L)][Ni(H2O)2(L)]}(ClO4)3, [Ni(CH3CN)(H2O)(L)](ClO4)2, [{Ni(L)}2(mu-Cl)2](ClO4)2, and [{Ni(L)}2(mu-Br)2]Br2 x 2 CH3NO2 complexes.

New fluorescence PET systems based on N2S2 pyridine-anthracene-containing macrocyclic ligands. spectrophotometric, spectrofluorimetric, and metal ion binding studies.

Three new fluorescent devices for protons and metal ions have been synthesized and characterized, and their photophysical properties have been explored; these are the macrocycles 7-(9-anthracenylmethyl)-3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L1) and 7-(10-methyl-9-anthracenylmethyl)-3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L2) and the bis macrocycle 7,7'-[9,10-anthracenediylbis(methylene)]bis-3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L3). All these systems have a pyridil-thioether-containing macrocycles as a binding site and an anthracene moiety as a signaling agent. The coordination properties of these ligands toward Cu(II), Co(II), Ni(II), Zn(II), and Pd(II) have been studied in solution and in the solid state. The addition of these metal ions to dichloromethane solutions of L1, L2, and L3 produce strong changes in the absorption and emission spectra of these ligands. The stoichiometry of the species, formed at 298 K, have been determined from absorption and fluorescence titrations. The Co(II) and Cu(II) complexes of L1 have been studied by EPR spectroscopy. This last complex and its free ligand have also been characterized by X-ray crystallography.

Synthesis and Reactivity of Nickel(II) Complexes of the Pyridine-Based Phosphorus-Containing Macrocycle 6-Phenyl-15-aza-6-phospha-3,9- dithiabicyclo[9,3,1]pentadeca-1(15),11,13-triene.

The reactivity of the phosphomacrocycle 6-phenyl-15-aza-6-phospha-3,9-dithiabicyclo[9,3,1]pentadeca-1(15), 11,13-triene (L) toward different Ni(II) salts has been studied. The reaction of L with 1 molar equiv of Ni(II) perchlorate in acetonitrile solution gives the complex [Ni(L)(CH(3)CN)(2)](ClO(4))(2) (1), which crystallizes in the monoclinic space group P2(1)/c (No. 14) with a = 12.704(2) Å, b = 13.538(2) Å, c = 17.377(2) Å, beta = 107.554(8) degrees, and Z = 4. The Ni(II) atom in 1 shows an octahedral environment defined by the four donor atoms of L and two acetonitrile molecules in a cis disposition. The reaction of L with Ni(II) perchlorate in 2:1 molar ratio yields the green complex [Ni(Lox)(2)](ClO(4))(2) (2) in which the phosphine groups of the ligand L are in their phosphine-oxide form (Lox). The same complex is also obtained by adding more ligand L to an acetonitrile solution of 1. Complex 2 crystallizes in the triclinic space group P&onemacr; (No. 2) with a = 10.564(1) Å, b = 11.975(2) Å, c = 9.124(2) Å, alpha = 109.79(1) degrees, beta = 95.67(2) degrees, gamma = 109.19(1) degrees, and Z = 1. The octahedral coordinated Ni(II) atom in 2 lies on a crystallographic center of symmetry, and it is surrounded by two pyridine nitrogen atoms, two thioether sulfur atoms, and two phosphine-oxide oxygen atoms provided by two facially coordinated Lox ligands. The reaction of L with Ni(II) chloride and Ni(II) thiocyanate yields the complexes [NiCl(2)(L)] (3) and [Ni(NCS)(2)(L)] (4), respectively, which are also obtained by adding Me(4)NCl or KSCN to an acetonitrile solution of 1. Complex 4 crystallizes in the monoclinic space group P2(1)/n (No. 14), with a = 11.139(2) Å, b = 13.270(2) Å, c = 14.885(1) Å, beta = 92.34(1) degrees, and Z = 4, and its structure is similar to that of complex 1, simply replacing the two acetonitrile molecules by two SCN(-) anions. The reactions of the complex 1 with different chelating (en, bipy, o-phen) and nonchelating (py) N-donor ligands have also been carried out. In all cases the two acetonitrile molecules of 1 are easly replaced by the N-donor ligands, but the macrocycle L molecule remains coordinated to the Ni(II) atom. The crystal structure of the complex [Ni(L)(py)(2)](ClO(4))(2) (5) is also elucidated. Crystal data: monoclinic space group P2(1)/c (No. 14) a = 13.063(2) Å, b = 16.615(3) Å, c = 14.973(3) Å, beta = 91.76(2) degrees, Z = 4.