Terminal Chloride Ion Research Articles

A lanthanide–mercury compound: preparation and photophysical properties

A neodymium (Nd)–mercury (Hg) complex [Nd(IA)2(H2O)3(NO3)(HgCl2)] n ·2nH2O·nEtOH (1; IA is isonicotinic acid anion) was synthesised and characterised. Compound 1 is of monoclinic system, space group C2/c with a = 25.4224(12), b = 8.1410(3), c = 22.2963(9) Å, β = 90.788(4)°, V = 4614.1(3) Å3, C14H24Cl2HgN3NdO13, Z = 8, M r = 858.09, D c = 2.471 g/cm3, S = 1.120, μ(Mo Kα) = 9.174 mm−1, F(000) = 3256, R = 0.0530 and wR = 0.1288. The mercury (II) (Hg2+) ions are bound by two terminal chloride (Cl−) ions and two nitrogen (N) atoms, displaying a distorted tetrahedral geometry. The neodymium (III) (Nd3+) ion is coordinated with nine oxygen (O) atoms to form a monocapped square antiprismatic polyhedron. Every two neighbouring neodymium (III) ions are interlinked by two μ 3-bridging IA groups to form a one-dimensional (1D) infinite –Nd–IA2–Nd– chain. The 1D chains link to each other through HgCl2N2 tetrahedra and yield a two-dimensional layer. It emits cyan photoluminescence, which should be due to the 4 G 11/2 → 4 I 9/2 transition of the 4f electrons of the neodymium ions. It exhibits Commission Internationale de l’Éclairage chromaticity coordinates of (0.1274, 0.3525). A solid-state diffuse reflectance spectrum unveils that it has a 2.51 eV band gap.

Zinc complexes with 1-(1H-benzimidazol-1-ylmethyl)-1H-benzotriazole: the structure, quantum chemical calculations, and luminescence properties

An organic ligand 1-(1H-benzimidazol-1-ylmethyl)-1H-benzotriazole (bta) and two zinc complexes of the composition [Zn(bta)2Hal2] (Hal = Cl, Br) were synthesized. The crystal structure of the complex [Zn(bta)2Cl2] was determined and its features were discussed. According to X-ray diffraction data, the central atom has a tetrahedral environment composed of two nitrogen atoms from two ligand molecules coordinated in monodentate mode and two terminal chloride ions. Density functional theory (DFT) calculations of the ligand and complex [Zn(bta)2Cl2] were carried out. A study of the luminescence properties of the compounds synthesized suggests that excitation of the zinc complexes gives rise to a dual-band luminescence similar to that of the free ligand. Most probably, the emission originates from π—π* and π—π* intra-ligand transitions.

Two CuII complexes of 3,4,5-tri-methyl-1H-pyrazole.

The crystal structure of complexes of 3,4,5-tri-methyl-1H-pyrazole with CuCl2·2H2O and Cu(NO3)2·2.5H2O are presented, namely di-μ-chlorido-bis[chloridobis(3,4,5-trimethyl-1H-pyrazole-κN2)copper(II)], [Cu2Cl4(C6H10N2)4] (1) and aquatetrakis(3,4,5-trimethyl-1H-pyrazole-κN2)copper(II) dinitrate, [Cu(C6H10N2)4(H2O)](NO3)2 (2), and compared to the previously determined structures for 3-methyl-1H-pyrazole and 3,5-di-methyl-1H-pyrazole. CuCl2 forms a 2:1 ligand-to-metal chloride-bridged complex with 3,4,5-tri-methyl-1H-pyrazole, with a square-pyramidal coordination geometry about each copper(II) center. Similarly to the previously obtained 3,5-di-methyl-1H-pyrazole complex with CuCl2, the pyrazole ligands are cis to each other, with two chloride ions bridging the two copper(II) centers, and a terminal chloride ion occupying the axial position. Cu(NO3)2 forms a 4:1 ligand-to-metal complex with 3,4,5-tri-methyl-1H-pyrazole that is also arranged in a square-pyramidal geometry about CuII. The newly obtained copper(II) complex has the same coordination geometry as the 3,5-di-methyl-1H-pyrazole complex, including an axial water mol-ecule, two nitrate ions hydrogen-bonded to the water mol-ecule, and four pyrazole ligands in the equatorial plane, suggesting that similar steric forces are at play in the formation of these complexes.

Di-μ-chlorido-bis[(2,2′-bipyridine-κ2N,N′)chlorido(N,N-dimethylformamide-κO)nickel(II)

The title compound, [Ni2Cl2(μ-Cl)2(C10H8N2)2(C3H7NO)2], exists as a centrosymmetric dimer of two octahedral nickel centers. In the crystal, two chloride ions bridge the two nickel centers with one terminal chloride ion bound to each nickel atom. Coupled with a chelating bipyridine ligand and an O-boundN,N-dimethylformamide solvent molecule, each nickel center exhibits an slightly distorted octahedral coordination environment. The meridional chloride ions all sit in equatorial positions, with the bipyridine ligand occupying one equatorial and one axial position, and theN,N-dimethylformamide ligand occupying the final axial position. The 2,2′-bipyridine ligand binds to nickel in a near planar fashion, with the non-H atoms possessing a mean devation from planarity of 0.046 Å. No π–π interactions are observed in the crystal.

Crystal structure of bis-[μ-bis-(di-phenyl-phosphan-yl)methane-κ(2) P:P']-μ-chlorido-chlorido-1κCl-(1-phenyl-thio-urea-2κS)disilver aceto-nitrile hemisolvate.

In the dinuclear title complex, [Ag2Cl2(C7H8N2S)(C25H22P2)2]·0.5CH3CN, each AgI ion displays a distorted tetra­hedral coordination geometry with two P atoms from two bis­(di­phenyl­phosphan­yl)methane (dppm) ligands, one bridging chloride ion, one terminal chloride ion and one terminal S atom from the N,N′-phenyl­thio­urea (ptu) ligand. The dppm ligands and the bridging chloride ion force the two Ag atoms into close proximity, with a short Ag⋯Ag separation of 3.2064 (2) Å. In the crystal, complex mol­ecules are linked by N—H⋯Cl hydrogen bonds forming a dimer. The dimers are linked via weak C— H⋯Cl hydrogen bonds forming a two-dimensional supra­molecular architecture in the yz plane. In addition, an intra­molecular N—H⋯Cl hydrogen bond is observed.

Playing with different metalloligands [NiL] and Hg to [NiL] ratios to tune the nuclearity of Ni(II)–Hg(II) complexes: Formation of di-, tri-, hexa- and nona-nuclear Ni–Hg clusters

Five new hetero-metallic nickel(II)–mercury(II) complexes, [(NiL1)HgCl2] (1), [(NiL1)2HgCl2] (3), [(NiL1)2Hg(N3)2] (4), [{(NiL2)2Hg(N3)(μ1,1-N3)}2] (5) and [{(NiL2)2Hg(N3)(μ1,1-N3)HgCl2}2{Hg(N3)(μ1,1-N3)}] (6) have been synthesized by reacting metalloligands [NiL1] or [NiL2] (where H2L1 is N,N′-bis(salicylidene)-1,2-ethylenediamine and H2L2 is N,N′-bis(salicylidene)-1,3-propanediamine) with HgX2 (X−=Cl− or N3−) at different molar ratios. All five complexes have been characterised by X-ray single-crystal structural, elemental and spectroscopic analyses. In complex 1, the Hg(II) ion is coordinated to two phenoxido oxygen atoms of one [NiL1] moiety and two terminal chloride ions to form a NiHg dinuclear complex. In the trinuclear complexes 3 and 4, the central Hg(II) ion is coordinated by two terminal [NiL1] units through two phenoxido oxygens from each and two terminal chloride (in 3) or azide (in 4) ions. The centrosymmetric hexanuclear complex 5 consists of two trinuclear [(NiL2)2Hg(N3)(μ1,1-N3)] units, where the phenoxido bridges connect two terminal Ni(II) atoms of the trinuclear units. In these trinuclear units, one azido ligand adopts a μl,1-briding mode between Hg and Ni whereas the other one is terminal. In the nonanuclear complex 6, two tetranuclear [{(NiL2)2Hg(N3)(μ1,1-N3)}HgCl2] units are linked to a central Hg(II) positioned on a two fold axis, via chlorido, azido, and phenoxido bridges. The tetranuclear unit is formed by the addition of a HgCl2 molecule to a trinuclear [(NiL2)2 Hg(N3)(μ1,1-N3)] unit, similar to that present in 5. Complex 5 shows weak ferromagnetic interactions (J=+2.1cm−1) between the two octahedral Ni(II) ions through double phenoxido bridges with a Ni–O–Ni bond angle of 95.87(11)°.

Synthesis, Structure, Fluorescence, and Theoretical Studies of CuCl(2,2′-Bipyridine)2·3.5H2O

A cuprous compound CuCl(2,2′-bipyridine)2·3.5H2O (1) has been prepared through a hydrothermal reaction and structurally characterized by single crystal X-ray diffraction. The crystal structure analysis revealed that compound 1 is characterized by an isolated structure, based on CuCl(2,2′-bipyridine)2 moieties and lattice water molecules. The Cu+ ion coordinates to four nitrogen ions of two 2,2′-bipyridine molecules and one terminal chloride ion. Photoluminescent study displays that compound 1 has strong and broad emission bands, in combination with the molecular orbital (MO) calculation of 1, lead us to conclude that the emissions originate from ligand-to-ligand charge transfer (LLCT) transition.

Uncharged Selenium Rings as Terminal and Bridging Ligands in Selenium‐Rich Iridium Clusters

AbstractPurple air‐stable crystals of Ir8Se40Br10 were obtained by reacting Ir in an excess of Se and SeBr4 at 300 °C for two weeks. The monoclinic crystal structure [space group P21/c, a = 1371.9(1) pm, b = 1108.1(1) pm, c = 2058.2(1) pm, β = 106.897(2)° at 296(1) K] consists of uncharged clusters Ir8Se40Br10 = (Ir3+)8(Se22–)(Se42–)6(Se7)2(Br–)10. The iridium(III) cations are coordinated octahedrally by selenium and bromide ions. While the oligoselenide anions provide high intra‐cluster connectivity, μ6‐η2 in the case of Se22– and μ4‐η3 for Se42–, the terminal uncharged Se7 rings have boat conformation and are η1‐coordinating. About 10 % of the Se7 rings are substituted by Se6 rings with chair conformation. A similar reaction using SeCl4 yielded vermillion air‐stable crystals of Ir2Se9Cl6. X‐ray diffraction on a single‐crystal revealed a tetragonal lattice (space group I41/a) with a = 1229.8(1) pm and c = 2365.5(2) pm at 296(1) K. In the Se9(IrCl3)2 cluster, a crown‐shaped uncharged Se9 ring coordinates two iridium(III) cations as a bridging bis‐tridentate ligand. Three terminal chloride ions complete the distorted octahedral coordination of each transition metal atom.

Copper(II)–Mercury(II) Heterometallic Complexes Derived from a Salen-Type Ligand: A New Coordination Mode of the Old Schiff Base Ligand

Three heterometallic copper(II)–mercury(II) complexes, [(CuL-CH3)HgCl2] (1), [(CuL-CH3)2HgCl2] (2), and [(CuL-CH2-HgCl)2] (3), have been synthesized by reacting the “complex as ligand” [CuL-CH3] with HgCl2 by varying the reaction conditions and stoichiometry of the reactants, where H2L-CH3 = the di-Schiff base of 1,3-propanediamine and 2-hydroxyacetophenone. All three complexes have been characterized by X-ray single-crystal structure, elemental, and spectroscopic analyses. In complex 1, the Hg(II) ion is bonded by two phenoxido oxygen atoms of a [CuL-CH3] moiety and two terminal chloride ions to form a dinuclear species. In the trinuclear complex 2, the central Hg(II) ion is coordinated by two terminal [CuL-CH3] units through one phenoxido oxygen from each unit and two chloride ions. On the other hand, in the tetranuclear complex 3, the Hg(II) ion has a distorted-tetrahedral geometry, being bonded to one chloride, two phenoxido oxygen atoms of one [CuL–CH2]¯ unit, and a methyl carbon atom of another [CuL...

Chlorido[1-(2-ethoxyphenyl)3-(4-nitrophenyl)triazenido]mercury(II)

In the title compound, [Hg(C14H13N4O3)Cl], the HgII atom is four-coordinated by one O atom and two N atoms from a tridentate 1-(2-eth­oxy­phen­yl)-3-(4-nitro­phen­yl)triazenide ligand and one terminal chloride ion in a distorted square-planar geometry. In the crystal structure, the mononuclear complexes are linked into pairs through C—H⋯O and C—H⋯Cl hydrogen bonds as well as π–π and C—H⋯π stacking inter­actions. In addition, weak Hg–μ6-arene π-inter­actions [mean distance of 3.667 (2) Å] are present between these dimers. The π–π stacking inter­actions are between aromatic rings with a centroid–centroid distance of 3.884 (2) Å. Moreover, edge-to-face inter­actions are present between eth­oxy CH groups and aromatic rings with H⋯π distances of 2.81 Å.

Di-μ-chlorido-bis{chlorido[(R)/(S)-1,5-diphenyl-3-(2-pyridyl-κN)-2-pyrazoline-κN2]zinc(II)}

In the centrosymmetric binuclear title compound, [Zn2Cl4(C20H17N3)2], the coordination geometry of the ZnII ion can be described as a distorted ZnN2Cl3 trigonal bipyramid (τ = 0.89), arising from the N,N′-bidentate ligand, a terminal chloride ion and two bridging chloride ions. The N atoms occupy one axial and one equatorial site and the terminal chloride ion occupies an equatorial site. The dihedral angle between the pyridine and pyrazole rings is 12.8 (2)°. In the crystal, aromatic π–π stacking [centroid–centroid separations = 3.812 (3) and 3.848 (3) Å] and C—H⋯Cl and C—H⋯π inter­actions help to establish the packing.

A Neutral Four-Coordinate Mononuclear Cobalt(II) Complex with Biphenyl Appended N-Bidendate Ligand: Synthesis, Structure and Spectral Properties

A mononuclear cobalt(II) complex [Co(BP)(Cl2)], 1 with a new N,N-bidentate ligand, BP ([N,N-(1,1′-biphenyl-2,2′-dimethylene)]-2-aminomethyl) pyridine) was synthesized and characterized by elemental analysis, UV–Vis, paramagnetic NMR, magnetic moment and single crystal XRD. The air and moisture stable Co(II) title complex is a 15 electron species which crystallizes in the monoclinic space group P21/n with cell dimensions a = 10.406(3), b = 12.873(4), c = 13.859(7) A, β = 96.30(3)˚ and Z = 4. The cobalt atom has distorted tetrahedral (td) geometry with coordination provided by an amine and pyridyl nitrogen donors of BP and two terminal chloride ions. The packing is stabilized through C–H···π and van der Waals interactions. A neutral four coordinate cobalt(II) complex with a new N,N-bidentate ligand capped by a biphenyl appendage was characterized by spectroscopic and single crystal X-ray diffraction technique. The title complex is a 15 e− molecule whose crystal structure is the first report of a neutral tetrahedral Co(II) complex with biphenyl appended bidentate ligand with amino-methyl pyridine.

Catena-Poly[bis(trimethylphenylammonium) [hexa-μ-chlorido-dichloridotricuprate(II)]]: an alternating zigzag chain of CuCl4and Cu2Cl6complexes

The title compound, {(C(9)H(14)N)(2)[Cu(3)Cl(8)]}(n), consists of parallel chains of alternating quasiplanar Cu(2)Cl(6) and planar CuCl(4) complexes separated by trimethylphenylammonium cations. Both inorganic complexes possess inversion symmetry. Pairs of neighboring chloride ions of the CuCl(4) complex each form a symmetric bridge and an asymmetric bridge to Cu(2)Cl(6) complexes on either side. The Cu(2)Cl(6) complex contains two symmetric chloride bridges between the copper cations with a terminal chloride bound to each five-coordinated Cu(II) ion. The CuCl(4) complex completes its coordination environment by forming two long semicoordinate contacts to the bridging chloride ions of neighboring Cu(2)Cl(6) complexes. The use of the bridging rather than the terminal chloride ions to form semicoordinate contacts generates a new zigzag chain structure that differs from the straight chain structures found for other A(2)Cu(3)Cl(8) compounds. The zigzag chain structure is adopted so as to conform to the shorter repeat distance dictated by stacking of the organic cations.

1,3-Bis(2-ethoxyphenyl)triazenido]chloridomercury(II)

In the title compound, [Hg(C16H18N3O2)Cl], the HgII atom is four-coordinated in a tetra­hedral geometry by two N atoms from the 1,3-chelating and one O atom of a 1,3-bis­(2-ethoxy­phen­yl)triazenido ligand and one terminal chloride ion. The dihedral angle between the aromatic rings is 1.72 (14)°. In the crystal C—H⋯π stacking inter­actions occur.

Di-μ-chlorido-bis{aquachlorido[3-ethyl-4-phenyl-5-(2-pyridyl)-4H-1,2,4-triazole-κ2N1,N5]manganese(II)}

In the centrosymmetric dinuclear title compound, [Mn2Cl4(C15H14N4)2(H2O)2], the MnII atom is coordinated by an N,N′-bidentate ligand, a water mol­ecule, a terminal chloride ion and two bridging chloride ions in a distorted MnN2OCl3 octa­hedral geometry. The Mn⋯Mn separation is 3.6563 (9) Å. In the crystal structure, O—H⋯N and O—H⋯Cl hydrogen bonds help to establish the packing.

Di-μ-chlorido-bis[chlorido(1,4,6-trimethyl-6-nitro-1,4-diazepine)copper(II)

The title neutral copper complex, [Cu2Cl4(C8H17N3O2)2], shows a binuclear center with a Cu—(μ-Cl)2—Cu core, in which each copper ion is coordinated by the N,N,O donor atoms of the tridentate ligand 1,4,6-trimethyl-6-nitro-1,4-diazepine (meaaz-NO2) and three chloride exogenous ligands. Each metal ion is facially coordinated by meaaz-NO2 through N,N,O donor atoms, whereas two bridging and one terminal chloride ions occupy the other face of the highly Jahn–Teller-distorted octa­hedron. Two N atoms from tertiary amine groups of the meaaz-NO2 ligand and two exogenous Cl atoms with short Cu—N and Cu—Cl distances define the equatorial plane. The coordination around each CuII ion is completed by another Cl atom and an O atom from the NO2 group, in the axial positions. The binuclear complex exhibits a centrosymmetric structure with point symmetry .

Solvent effects on the reactions of copper chlorides with OP(NH-t-Bu)3 — Formation of the novel [Cu5Cl10]5– anion via in situ templation

X-ray structural investigations have shown that the products of the reaction of CuCl2·2H2O and OP[NH-t-Bu]3 are markedly dependent on solvent and temperature. The polymeric ionic complex [(t-BuNH3)2(Cu3(OH)(H2O)Cl7)]∞ (1), containing a trinuclear anionic repeating unit, is obtained from toluene at 80 °C, whereas the 2:1 adduct Cu(t-BuNH2)2Cl2 (4) is formed at 150 °C. By contrast, a neutral tetranuclear cluster Cu4[PO(NH-t-Bu)3]4(µ4-O)Cl6 (2) or the one-dimensional chain [Cu(Py)2Cl2]∞ (3) is produced when the reaction is carried out in hexane or pyridine, respectively, at 80 °C. The reaction of a mixture of CuCl and CuCl2·2H2O (2:1 molar ratio) with OP[NH-t-Bu]3 at 80 °C in toluene produces [t-BuNH3]5[Cu5Cl10] (5), in which the anion is a pentanuclear cluster with both terminal and bridging chloride ions. The removal of the chloride ions from the reaction mixture by the addition of AgNO3 yields the 2:1 adduct Cu[OP(NH-t-Bu)3]2(NO3)2 (6).Key words: copper halides, templation, P–N compounds, cluster complexes, one-dimensional framework

Investigation of Group 12 Metal Complexes with a Tridentate SNS Ligand by X-ray Crystallography and 1H NMR Spectroscopy

Two series of zinc triad complexes containing the ligand 2,6-bis(methylthiomethyl)pyridine (L1) were synthesized and characterized by X-ray crystallography and solution-state 1H NMR spectroscopy. The distorted meridional octahedral M(L1)2(ClO4)2 series includes the first structurally characterized Zn(II) and Cd(II) complexes with N2(SR2)4 coordination spheres. Coordination of HgCl2 and ZnCl2 with 1 equiv of ligand afforded mononuclear, five-coordinate species Hg(L1)Cl2 and Zn(L1)Cl2, respectively, with distorted square-pyramidal and trigonal-bipyramidal geometries. With CdCl2, the dimeric [Cd(L1)Cl(mu-Cl)]2 complex was obtained. The distorted octahedral coordination geometry of each Cd(II) center in this complex is formed by one tridentate ligand, two bridging chloride ions, and one terminal chloride ion. NMR spectra indicate that the intermolecular ligand-exchange rate of [M(L1)2](2+) decreased in the order Cd(II) > Zn(II) > Hg(II). Slow intermolecular ligand-exchange conditions on the chemical-shift time scale were found for 1:2 metal-to-ligand complexes of L(1) with Hg(II) and Zn(II) but not Cd(II). Slow intermolecular ligand-exchange conditions in acetonitrile-d(3) solutions permitting detection of (3-5)J(199Hg1H) were found for 1:1 and 1:2 Hg(ClO4)2/L1 complexes, but not for the related Cd(ClO4)2) complexes. The magnitudes of J(199Hg1H) for equivalent protons were smaller in [Hg(L1)2](2+) than in [Hg(L1)(NCCH3)x](2+). The relative intermolecular ligand-exchange rates of the zinc triad complexes investigated here suggest that the toxicity of Hg(II) is accentuated by the relative difficulty of displacing it from the coordination sites encountered.

Structural and magnetic characterization of copper(II) halide complexes with 2-(dimethylaminomethyl)-3-hydroxypyridine

Dimeric complexes, bis[dihalo(2-dimethylaminomethyl-3-hydroxypyridine)-copper(II)], [Cu(dmamhp)X 2] 2, were prepared from the reaction of copper(II) halide (Cl, Br) with 2-dimethylaminomethyl-3-hydroxypyridine (dmamhp) in methanol, and their single crystal structures were determined. The chloro compound was crystallized as green needles in space group P 1 ¯ of the triclinic system with Z = 1 and unit cell dimensions a = 7.3420(12), b = 9.196(3), c = 9.817(2) Å, α = 115.16(3)°, β = 92.433(16)° and γ = 111.59(2)°. The corresponding values for the bromo complex are a = 7.5652(15), b = 9.191(3), c = 9.7926(13) Å, α = 113.912(14)°, β = 92.396(14)° and γ = 111.24(2)°. The chloro compound consists of a dimeric molecule [Cu(dmamhp)Cl 2] 2, in which copper(II) ions are bridged by chloride ligands. The geometry at the copper is distorted trigonal bipyramidal with the pyridine nitrogen [N9], terminal chloride [Cl1] and the bridging chloride [Cl2 i] in the equatorial site; and with the amine nitrogen [N9] and the remaining bridging chloride [Cl2] in the axial site. The dimer units are held through the hydrogen bonding between the hydroxy group in a pyridine ring and the terminal chloride ion. The bromo compound shows a similar structure. The magnetic susceptibility data of both compounds were followed by the Bleaney–Bowers dimer equation with J = −11.17 and −21.11 cm −1 for the chloro and bromo complexes respectively, indicating that there are antiferromagnetic interactions between the copper(II) ions in the solid state.

Au(III) interaction with Methionine- and Histidine-containing peptides

Mononuclear Au(III) complexes of the peptides H-His-Met-OH (D) and H-Gly-Gly-Met-OH (T) and their N-protected forms Ac-His-Met-OH (Ac-D) and Ac-Gly-Gly-Met-OH (Ac-T) were structurally characterized by means of IR, MS and NMR. In the complexes with dipeptides [AuLCl2]Cl (L = D or Ac-D), Au(III) is coordinated through S and imidazole N atoms from methionine and histidine fragments of the ligands forming macrochelate rings at mol ratio Au : L = 1 : 1. Additionally, Au(III) is coordinated by two terminal chloride ions in a square-planar arrangement. In complexes with the tripeptides [AuL′Cl] (L′ = T or Ac-T), however, the metal ion is coordinated in a tridentate fashion, through S and two N atoms, also at mol ratio M : L = 1 : 1. The fourth position of Au(III) is occupied by a Cl− ligand.