Liang Ping Wu

Toward the Construction of Functional Solid-State Supramolecular Metal Complexes Containing Copper(I) And Silver(I)

Publisher Summary This chapter discusses construction of functional solid-state supramolecular metal complexes containing copper (I) and silver (I). The copper(I) and silver(I) ions are regarded as extremely soft acids favoring coordination to soft bases, such as ligands containing S and unsaturated N. Copper(I) and silver(I) complexes with these soft ligands give rise to an interesting array of stereochemistries and geometric configurations, with the coordination numbers of two to six all occurring. The most common stereochemistries for both ions are the linear two-coordinate and the tetrahedral four-coordinate geometries with some distortions of the environment, particularly in the presence of chelating type ligands, attributable to the spherical dl0 configuration. On the basis of resonance Raman spectra, the lowest excited state in the polymer is assigned to the Cu(I)-topyrazine metal-to-ligand charge-transfer excited state. Successful construction of multidimensional frameworks largely relies on ligand design to suit different geometries and coordination numbers of the metal ions.

Synthesis, crystal structures and magnetic behavior of polymeric lanthanide complexes with benzenehexacarboxylic acid (mellitic acid)

Abstract Three lanthanide complexes with mellitic acid [Ce2{C6(COO)6}(H2O)8]·H2O (1), [Eu2{C6(COO)6}(H2O)8]·H2O (2) and [Yb2{C6(COO)6}(H2O)10]·2H2O (3), have been synthesized and structurally characterized by X-ray crystallography and magnetic properties. The three compounds crystallize in the monoclinic space space P21/n, with unit cell dimensions of: a = 8.627(2), b = 13.218(2), c = 9.650(1) A , β = 95.93(1)° and Z = 2 for 1 ;a = 8.505(2), b = 13.145(1), c=9.536(2) A , β=94.73(2)° and Z=2 for 2 ; a = 8.420(1), b = 9.224(4), c = 16.229(1) A , β = 100.267(9)° and Z = 2 for 3. All three structures consist of an extended network of metal ions, coordinated to mellitate anions and water molecules linked by a complex hydrogen bonding. 1 and 2 are isomorphous with near isostructural [M2{C6(COO)6}(H2O)8] units in which the metal ion is coordinated by four water molecules and five oxygen atoms of the mellitate anions, and each mellitate group involves a tetrakis(bidentate) and bis(unidentate) coordination mode bridging six metal ions forming a three-dimensional framework. In 3 the ytterbium atom is bound with five water molecules and three oxygen atoms of the mellitate anion, and each mellitate moiety bridges four dodecahedral Yb(III) ions yielding a two-dimensional sheet structure. The magnetic susceptibility of 1 and 3 as a function of temperature (5.0–300 K) exhibits a sharp maximum at 6.0 K for both compounds.

Crystal structure and magnetic properties of manganese (II) mellitate, [Mn2{C6(COO)6}(H2O)6][Mn(H2O)6]·2H2O with two-dimensional layered structure and three-dimensional hydrogen bonding networks

Abstract The crystal and molecular structure of manganese (II) mellitate, [Mn2{C6(COO)6}(H2O)6][Mn(H2O)6]·2H2O, has been determined by X-ray structure analysis. The complex crystallizes in the monoclinic system, space group C2/c, with cell constants a = 23.298(3), b = 6.456(3), c = 17.072(2) A , β = 101.01(1)° and Z = 4 . The structure was solved and refined to R = 0.029 (Rw = 0.036). There are two types of manganese ions in the structure. Mn(1) is situated on a crystallographic center of symmetry and bound to six water molecules while Mn(2) is coordinated octahedrally by three water molecules and three carboxylate oxygen atoms. The major structure feature is that the polyanion formed by Mn(2) ions and the mellitate hexanions with composition of [Mn2{C6(COO)6}(H2O)6]n2n− possesses a two-dimensional layered structure which is linked through a complex three-dimensional hydrogen bonding associated with the Mn(1) cation [Mn(H2O)6]2+ and the water of crystallization. Analysis of variable-temperature magnetic susceptibility data (5.0–300 K) shows that the complex displays antiferromagnetic exchange.

SYNTHESIS AND STRUCTURE OF A THREE-DIMENSIONAL LANTHANUM(III) COORDINATION POLYMER WITH MELLITATE, {La2[C6(COO)6](H2O)9} · 2H2O

Abstract The crystal and molecular structure of a lanthanum(III) mellitate, La2C12H22O23, has been determined by X-ray structural analysis using a combination of direct and heavy atom methods. The complex crystallizes in the monoclinic space group P21/n with unit-cell dimensions of a = 6.723(4), b = 11.368(5), c = 29.813(4) A and β = 95.851(3)°. Block-diagonal least-squares refinement using automated diffractometer-collected data resulted in R = 2.5 and Rw = 3.4. The crystal structure consists of layers perpendicular to the a axis. Each layer is formed by an extended network of lanthanum ions coordinated with mellitate anions and water molecules, and linked through a complex three-dimensional hydrogen-bonding network. Among the six carboxylate groups of the mellitate anion, five form coordination bonds to six lanthanum atoms. The two independent lanthanum ions are both nine-coordinate and the configuration around lanthanum is a tricapped trigonal prism with the La-O bond distances ranging from 2.457 A to ...

Structure and 1H NMR study of copper(I) complex with ethylene and tetramethylethylenediamine

Abstract A ternary copper(I) complex with ethylene and tetramethylethylenediamine(tmen) has been prepared and the structure characterized by the single crystal X-ray method. The copper atom is coordinated to two nitrogen atoms of tmen and an ethylene molecule in a trigonal-planar arrangement. The CC bond distance of 1.36(1) A is slightly longer than that of the free ethylene (1.335 A). In the 1 H NMR study, chemical shifts of ethylene protons at 5.46 ppm move upfield (4.16 ppm) upon coordination to copper(I). This indicate that the π back donation from copper to the ethylene is rather weak compared with other metal-ethylene systems.

Syntheses, structures and properties of palladium (II) complexes with photochromic 4-methoxyazobenzene

Abstract Two palladium (II) complexes with the photochromic ligand 4-methoxyazobenzene (MeOazbH), [Pd(MeOazb) (PhCN) (H2O)] (ClO4) (1) and [Pd(MeOazbH)2Cl2] (2) were prepared and their molecular structures determined by X-ray crystallography. 1: triclinic, P 1 , a=9.684(3), b=11.833(2), c=9.731(3) A , α=102.41(1), s=94.54(3), γ=94.82(2)°, V=1079.7(4) A 3 , Z=2 . 2: triclinic, P 1 , a=9.497(3), b=9.719(4), c=8.226(3) A , α=96.43(4), s=109.24(3), γ=62.13(2)°, V=632.9(4) A 3 , Z=1 . The molecular structure of complex 1 shows a significantly distorted square planar coordination around the Pd atom and the MeOazb group forms a five-membered chelate ring with the metal ion by means a σ-bond at an ortho-carbon atom and the lone pair of the further nitrogen. In complex 2 the palladium atom lies on an inversion center, surrounded in an essentially square planar fashion by the symmetry related two MeOazbH ligands and two chloride ions. In contrast with the ortho-metalation reaction in 1, MeOazbH in 2 acts as a monodenate ligand to bind the metal center via a PdN σ-bond. Electronic spectroscopic studies of the two complexes together with the free ligand were carried out in solution at room temperature and upon irradiation of light; while rigidity imparted to the MeOazb linkage by palladation in 1 inhibits its photochromic reaction, the monodentate-coordinated MeOazbH in 2 shows a trans-cis photoisomerization.

UNIQUE TETRANUCLEAR COPPER(II) CLUSTER AND MONOMERIC IRON(II), (III) COMPLEXES WITH A TRIS(IMIDAZOLYL) CHELATING LIGAND

Copper(II) and iron(II, III) complexes of the tripodal ligand, tris(1-methyl-1 H -imidazol-2-yl)methanol (Htmim), have been synthesized and characterized by elemental analysis, 1 H NMR and IR spectroscopies, magnetic moment measurement and X-ray crystallography. The structure of the copper complex, [Cu 4 (tmim) 4 (CF 3 SO 3 ) 2 ](CF 3 SO 3 ) 2 ·2MeOH ( 1 ), can be regarded as a polyimidazole-linked tetranuclear cluster where each copper atom adopts a five-coordinate square-pyramidal geometry ligated by the tmim anion. The two iron complexes, [Fe II (Htmim) 2 ][Fe II Cl 4 ]·4MeOH ( 2 ) and [Fe III (Htmim) 2 ][Fe III Cl 4 ] 2 Cl ( 3 ), contain the isostructural [Fe(Htmim) 2 ] cation and tetrahedral [FeCl 4 ] − anion. While Htmim shows a normal tripodal tridentate mode in the iron complexes capping one face of an essentially octahedral coordination sphere, its deprotonated species exhibit an unusual non-tripodal tetradentate coordination with copper(II) ions. The observed magnetic moment at room temperature for 1 is 1.13 BM per Cu atom, consistent with antiferromagnetic coupling between the copper(II) atoms of the tetramer. Both 2 and 3 show magnetic properties consistent with low-spin electronic configurations of the cation and high-spin nature of the metal ion in the anion.

Synthesis and Structure of Polymeric Silver(I) Complex of Tetrakis(methylthio)-tetrathiafulvalene: The First Example of the Silver(I) Ion Coordinated Directly to TTF-Derivatives

Abstract Reaction of silver(I) trifluoromethanesulfonate with tetrakis(methylthio)tetrathiafulvalene (TMT-TTF) yielded polynuclear silver(I) complex [Ag(TMT-TTF)(O3SCF3)]. The compound crystallizes in the orthorhombic system, space group Pbam with cell constants a = 14.855(5), b = 22.510(3), c = 13.310(8) A, Z = 8. It is a neutral 1: 1 metal/ligand complex in which each Ag(I) ion is six-coordinated by four sulfur atoms from the bridging TMT-TTF and two oxygen atoms from the bidentate O3SCF3 anion, which results in a two interwoven polymeric chain structure. It represents the first example of the silver(I) ion coordinated directly to TTF-derivatives. The compound is an insulator at room temperature but behaves as a semiconductor when doped with iodine.

Syntheses, Characterization and X-Ray Crystal Structures of Tetrakis(Ethylthio)Tetrathiafulvalenium Hexachlorodicopper(II) and Hexabromodicopper(II)

Abstract Oxidation of tetrakis(ethylthio)tetrathiafulvalene (TTC2-TTF) with CuCl2 and CuBr2 in acetonitrile yielded the organic radical cation salts, (TTC2-TTF)2[Cu2Cl6] 1 and (TTC2-TTF)2[Cu2Br6] 2, whose structures have been determined by X-ray structure analysis. Both 1 and 2 crystallize in the triclinic system, space group P 1, with one molecule per unit cell. 1: a = 12.065(4), b = 12.644(3), c = 8.988(2) A, α = 103.54(2), β = 90.24(2), γ = 112.42(2)°. 2: a = 12.330(3), b = 12.647(2), c = 8.956(2) A, α = 101.72(2), β = 94.66(2), γ = 111.69(1)°. Both structures consist of two segregated stacks of TTC2-TTF+ donors and Cu2X6 2- acceptors associated via short S···X contacts. Consistent with the structural results, the two compounds exhibit low electrical conductivities with [sgrave]25°C being 4 × 10−8 and 8 × 10−8 S cm−1 for 1 and 2, respectively.

One-, two- and three-dimensional copper(I) and silver(I) complexes of 2,11-dithia[3.3]paracyclophane

Two copper(I) and one silver(I) complex of 2,11-dithia[3.3]paracyclophane (dtpcp), [Cu2Br2(dtpcp)(MeCN)2]1, [Cu2I2(dtpcp)2]·thf 2 and [Ag(dtpcp)(NO3)]3, have been synthesized and their molecular structures determined by X-ray crystallography. All three structures contain an infinite network comprising metal cations linked via ditha-bridged paracyclophane and the counter anions. Complexes 1 and 2 are not isostructural. The repeating dinuclear units [Cu2Br2(dtpcp)(MeCN)2] joined by dtpcp in 1 generate a one-dimensional polymeric chain running parallel to a diagonal axis of the triclinic cell. Complex 2 is a two-dimensional sheet structure in which a large ring containing six copper atoms includes a tetrahydrofuran molecule as guest inside the open cavity. The one-nitrate oxygen bridging two metal centres in complex 3 yields a unique three-dimensional channel framework of silver(I) ions. The iodine-doped black products of compounds 1–3 at room temperature exhibited conductivities of 10–5.9, 10–5.1 and 10–4.7 S cm–1, respectively.