Bridging Chloride Research Articles

Coordination assemblies of rigid–flexible 1,3-bis(5-(pyridine-2-yl)-1,2,4-triazole-3-yl)propane ligands with MCl2 (M = Fe, Co, Cu or Zn): structural diversity and mass spectra

Reactions of the rigid–flexible N-heterocycle 1,3-bis(5-(pyridine-2-yl)-1,2,4-triazole-3-yl) propane (H2L) with MCl2 (M = Fe, Co, Cu or Zn) gave coordination complexes, {[Fe 2 III Cl4(H2L)2]·2Cl}·EtOH·H2O (1), {[Co3Cl5(HL)]·H2O} n (2), {[Co4Cl4(H2L)2(H2O)4]·[CoCl4]2}·H2O (3), [Cu2Cl3(HL)(H2O)]6·5H2O (4), [Cu 2 II CuICl4(HL)] n (5), {[Zn2Cl2(L)H2O]·H2O} n (6) and [Zn4Cl6(HL)2] (7), which have been characterized by single-crystal X-ray diffraction. Structural analysis reveals that the pyridine triazole ligand attains versatile coordination modes in these complexes. Complexes 1, 3, 4 and 7 consist of 0D clusters with binuclear or tetranuclear units; complex 2 presents a 2D network accompanied by HL− and chloride bridges; complexes 5 and 6 show 1D chains with [Cu3] and [Zn2] subunits. In addition, the electrospray ionization mass spectrometry properties of selected complexes were investigated, revealing the stabilities and structural states of these complexes in solution. These results indicate that H2L is an excellent multiconnection linker for the construction of diverse coordination complexes.

An unusual coordination of a 4-azopyrazol-5-one heterocyclic derivative with metals. Synthesis, X-ray studies, spectroscopic characteristics, and theoretical modeling

A series of novel transition and rare-earth metal complexes of (Z)-4-((1-(benzo[d]thiazol-2-yl)-3-methyl-5-oxo-4,5-dihydro-1H-pyrazol-4-yl)diazenyl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (HL) were isolated and identified by FT IR, EPR, 1H NMR, and UV–VIS spectroscopy. The crystallographic data for [Cu2Cl3(L)(H2O)]2·1.5H2O·CH2Cl2 were obtained. The compound exists in the form of a tetranuclear species with two different metal coordination modes. The coordination polyhedra of two cations can be described as somewhat distorted tetragonal pyramids as well as two other Cu atoms of the tetrameric molecule adopt the trigonal bipyramidal coordination. The bridging chloride ligands link differently coordinated metal cations. The quantum chemical calculations indicate the existence of a ferromagnetic exchange interaction in pairs. That is in agreement with the EPR spectrum of the substance. The complex formation constants in water-ethanol solutions were determined.

The dinuclear scandium(III) cyclooctatetraenyl chloride complex di-μ-chlorido-bis[(η8-cyclooctatetraene)(tetrahydrofuran-κO)scandium(III)

Only a few cyclooctatetraene dianion (COT) π-complexes of lanthanides have been crystallographically characterized. This first single-crystal X-ray diffraction characterization of a scandium(III) COT chloride complex, namely di-μ-chlorido-bis[(η8-cyclooctatetraene)(tetrahydrofuran-κO)scandium(III)], [Sc2(C8H8)2Cl2(C4H8O)2] or [Sc(COT)Cl(THF)]2 (THF is tetrahydrofuran), (1), reveals a dimeric molecular structure with symmetric chloride bridges [average Sc-Cl = 2.5972 (7) Å] and a η8-bound COT ligand. The COT ring is planar, with an average C-C bond length of 1.399 (3) Å. The Sc-C bond lengths range from 2.417 (2) to 2.438 (2) Å [average 2.427 (2) Å]. Direct comparison of (1) with the known lanthanide (Ln) analogues (La, Ce, Pr, Nd, and Sm) illustrates the effect of metal-ion (M) size on molecular structure. Overall, the M-Cl, M-O, and M-C bond lengths in (1) are the shortest in the series. In addition, only one THF molecule completes the coordination environment of the small ScIII ion, in contrast to the previously reported dinuclear Ln-COT-Cl complexes, which all have two bound THF molecules per metal atom.

Porphyrin–BODIPY-based hybrid model compounds for artificial photosynthetic reaction centers

In this review, we report the synthesis and photophysical studies of porphyrin–4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) compounds linked either with different covalent bonds or with axial coordination to metalloporphyrin. BODIPY moiety significantly increases the light absorption capability of porphyrins by efficient BODIPY to porphyrin excitation energy transfer. The type of linkage between the two chromophores significantly affects the energy transfer efficiency. The most efficient energy transfer was proved for compounds linked via a cyanuric chloride bridge (∼99% quenching). Therefore, this type of bond seems to be more appropriate choice in constructing porphyrin–BODIPY assemblies for light harvesting applications. Moreover, the functionalization of the conjugates with fullerenes appears to be interesting electron transfer dynamics in the excited state. Divers systèmes ont été synthétisés afin d'imiter le processus de la photosynthèse naturelle. Ces molécules doivent être capables de produire des réactions de transfert rapide d'énergie et d'électrons et de ralentir la recombinaison de charge. Parmi les différents composés organiques, les porphyrines et les conjugués de BODIPY ont été intensivement utilisés en tant qu'imitateurs photosynthétiques artificiels. Dans cette revue, nous décrirons la synthèse et les études photophysiques des composés de porphyrine-BODIPY qui sont liés entre eux par différentes liaisons covalentes ou avec une coordination axiale a la métalloporphyrine. La partie BODIPY augmente de manière significative la capacité d'absorption de la lumière des porphyrines par un transfert d'énergie efficace, après excitation de BODIPY vers la porphyrine. De plus, le fonctionnalisation des conjugués avec des fullerènes apparaît intéressante du point de vue de la dynamique du transfert d'électrons dans l'état excité.

Copper(II) complexes of two TEMPO-functionalized polypyridyl ligands: structure and catalytic activity in alcohol oxidation

The reaction of copper(II) salts with Bpy-TEMPO and Tpy-TEMPO (Bpy-TEMPO = [2,2′]Bipyridinyl-5,5′-dicarboxylic acid bis-[(2,2,6,6-tetramethyl-1-oxy-piperidin-4-yl)-amide]; Tpy-TEMPO = 2,2,6,6-tetramethyl-4-(2,2′:6′,2″-terpyridin-4′-yloxy)piperidin-1-oxyl) gave dinuclear Bpy-TEMPO-Cu2 (1) and mononuclear Tpy-TEMPO-Cu (2), respectively. The Cu(II) complexes were characterized by single crystal X-ray analysis. In 1, Cu(II) has a distorted square pyramidal coordination geometry, with a bridging chloride as the axial ligand. The Cu(II) core in 2 also exhibited a distorted square pyramidal coordination geometry, with one chloride as an axial ligand. Weak interactions such as π-interactions and hydrogen bonds are observed in both complexes. When applied as catalysts for the oxidation of benzyl alcohol to benzaldehyde in air, 1 exhibited higher activity than 2 for reactions in o-xylene at 60°C with DBU as a base. High yield (67%) of benzaldehyde was observed when using 1 as a catalyst in a solution of o-xylene with DBU at 60°C.

A comparative study of magnetization dynamics in dinuclear dysprosium complexes featuring bridging chloride or trifluoromethanesulfonate ligands.

We utilized a rigid ligand platform PyCp22- (PyCp22- = [2,6-(CH2C5H3)2C5H3N]2-) to isolate dinuclear Dy3+ complexes [(PyCp2)Dy-(μ-O2SOCF3)]2 (1) and [(PyCp2)Dy-(μ-Cl)]2 (3) as well as the mononuclear complex (PyCp2)Dy(OSO2CF3)(thf) (2). Compounds 1 and 2 are the first examples of organometallic Dy3+ complexes featuring triflate binding. The isolation of compounds 1 and 3 allows us to comparatively evaluate the effects of the bridging anions on the magnetization dynamics of the dinuclear systems. Our investigations show that although the exchange coupling interactions differ for 1 and 3, the dynamic magnetic properties are dominated by relaxation via the first excited state Kramers doublet of the individual Dy sites. Compounds 1 and 3 exhibit barriers to magnetization reversal (Ueff = 49 cm-1) that can be favorably compared to those of the previously reported examples of [Cp2Dy(μ-Cl)]2 (Ueff = 26 cm-1) and [Cp2Dy(thf)(μ-Cl)]2 (Ueff = 34 cm-1).

Mer, fac, and Bidentate Coordination of an Alkyl-POP Ligand in the Chemistry of Nonclassical Osmium Hydrides.

Nonclassical and classical osmium polyhydrides containing the diphosphine 9,9-dimethyl-4,5-bis(diisopropylphosphino)xanthene (xant(PiPr2)2), coordinated in κ3-mer, κ3-fac, and κ2-P,P fashions, have been isolated during the cyclic formation of H2 by means of the sequential addition of H+ and H- or H- and H+ to the classical trihydride OsH3Cl{xant(PiPr2)2} (1). This complex adds H+ to form the compressed dihydride dihydrogen complex [OsCl(H···H)(η2-H2){xant(PiPr2)2}]+ (2). Under argon, cation 2 loses H2 and the resulting unsaturated fragment dimerizes to give [(Os(H···H){xant(PiPr2)2})2(μ-Cl)2]2+ (3). During the transformation the phosphine changes its coordination mode from mer to fac. The benzofuran counterpart of 1, OsH3Cl{dbf(PiPr2)2} (4; dbf(PiPr2)2 = 4,6-bis(diisopropylphosphino)dibenzofuran), also adds H+ to afford the benzofuran counterpart of 2, [OsCl(H···H)(η2-H2){xant(PiPr2)2}]+ (5), which in contrast to the latter is stable and does not dimerize. Acetonitrile breaks the chloride bridge of 3 to form the dihydrogen [OsCl(η2-H2)(CH3CN){xant(PiPr2)2}]+ (6), regenerating the mer coordination of the diphosphine. The hydride ion also breaks the chloride bridge of 3. The addition of KH to 3 leads to 1, closing a cycle for the formation of H2. Complex 1 reacts with a second hydride ion to give OsH4{xant(PiPr2)2} (7) as consequence of the displacement of the chloride. Similarly to the latter, the oxygen atom of the mer-coordinated diphosphine of 7 has a tendency to be displaced by the hydride ion. Thus, the addition of KH to 7 yields [OsH5{xant(PiPr2)2}]- (8), containing a κ2-P,P-diphosphine. Complex 8 is easily protonated to afford OsH6{xant(PiPr2)2} (9), which releases H2 to regenerate 7, closing a second cycle for the formation of molecular hydrogen.

Crystal structure of di-μ-chlorido-bis-[chlorido-bis-(1,2-dimethyl-5-nitro-1H-imidazole-κN3)copper(II)] acetonitrile disolvate.

1,2-Dimethyl-5-nitro-imidazole (dimetridazole, dimet) is a compound that belongs to a class of nitro-imidazole drugs that are effective at inhibiting the activity of certain parasites and bacteria. However, there are few reports that describe structures of compounds that feature metals complexed by dimet. Therefore, we report here that dimet reacts with CuCl2·H2O to yield a chloride-bridged copper(II) dimer, [Cu2Cl4(C5H7N3O2)4] or [Cu(μ-Cl)Cl(dimet)2]2. In this mol-ecule, the CuII ions are coordinated in an approximately trigonal-bipyramidal manner, and the mol-ecule lies across an inversion center. The dihedral angle between the imidazole rings in the asymmetric unit is 4.28 (7)°. Compared to metronidazole, dimetridazole lacks the hy-droxy-ethyl group, and thus cannot form inter-molecular O⋯H hydrogen-bonding inter-actions. Instead, [Cu(μ-Cl)Cl(dimet)2]2 exhibits weak inter-molecular inter-actions between the hydrogen atoms of C-H groups and (i) oxygen in the nitro groups, and (ii) the terminal and bridging chloride ligands. The unit cell contains four disordered aceto-nitrile mol-ecules. These were modeled as providing a diffuse contribution to the overall scattering by SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9-18], which identified two voids, each with a volume of 163 Å3 and a count of 46 electrons, indicative of a total of four aceto-nitrile mol-ecules. These aceto-nitrile mol-ecules are included in the chemical formula to give the expected calculated density and F(000).

Chromotropism in halo-bridged dimers. Structural characterization of bis(μ-halo)bis(halo N-(pyridin-2-ylmethyl)cyclohexanamine copper(II))

Two dinuclear copper(II) complexes, [LCu(μ-Cl)Cl]2 (DMF) (1) and [LCu(μ-Br)Br]2 (2), with the bidentate ligand N-(pyridin-2-ylmethyl)cyclohexanamine, L, were synthesized and characterized by physicochemical and spectroscopic (IR, UV–vis) data. The crystal structural analysis of 1 shows that both copper(II) ions are in a distorted square pyramidal N2Cl3 environment with the apical position of the copper(II) being occupied by the bridging chloride anion which is equatorial to the other copper ion, forming a dimeric copper(II) complex. The chromotropic properties of both complexes, including solvato-, thermo-, and halochromism, were investigated. The complexes show reversible thermochromism in solution which is irreversible in the solid state. It was found that the solvatochromism is due to structural change followed by solvation of the vacant sites of the complexes. Their halochromic properties were studied in pH range of 1–11 by visible absorption spectroscopy. The color changes from blue to green and to colorless are due to deprotonation and protonation of the ligands.

Synthesis and structural characterization of two cationic dinuclear cymene-ruthenium(II) complexes with thiolato and chloro bridges

Treatment of [(p-cymene)RuCl2]2 with HSp-Tol or HSCH2Ph in the presence of K[PF6] gave the cationic dinuclear cymene–ruthenium(II) complexes [(p-cymene)2Ru2(μ-Cl)(μ-Sp-Tol)2][PF6] (1) and [(p-cymene)2Ru2(μ-Cl)(μ-SCH2Ph)2][PF6] (2), respectively, which have been characterized by IR, NMR spectroscopies and mass spectrometry along with microanalyses. Their crystal structures were determined by single-crystal X-ray diffraction analyses. The structures of the cationic complexes contain the unusual pseudo-trigonal-bipyramidal Ru2S2Cl framework without a ruthenium–ruthenium single bond. The two p-cymene–ruthenium units are held together by two bridging thiolates and one bridging chloride.

Yttrium complexes containing heteroscorpionate ligands [(3,5-But 2C3HN2)2CHC(Ph)2O]– and [o-Me2NC6H4CH2C(NCy)2

A reaction of benzophenone with bis(3,5-di-tert-butylpyrazolyl)methyllithium (3,5-But2C3HN2)2CHLi (obtained in situ by metallation of (3,5-But2C3HN2)2CH2 with n-butyllithium in THF at–70 °C) led to the synthesis of alkoxide lithium complex [(3,5-But2-C3HN2)2CHCPh2O]Li(THF) (1) containing a new monoanionic heteroscorpionate ligand [(3,5-But2C3HN2)2CHCPh2O]–. Hydrolysis of complex 1 gave 2,2-bis(3,5-di-tert-butylpyrazolyl)-1,1-diphenylethanol (2) in 90% yield. The structure of alcohol 2 was established by X-ray crystallography. A reaction of anhydrous YCl3 with two molar equivalents of lithium alkoxide 1 in THF furnished yttrium monochloride complex [(3,5-But2C3HN2)2CHCPh2(μ-O)]2-YCl(THF)[(μ-Cl)Li]2 (3). According to X-ray diffraction data, chloride 3 is a monomeric ate-complex with one terminal and two bridging chloride ligands. The nitrogen atoms of the pyrazole rings are not involved in the coordination of the ligand with the yttrium ion. The bisalkyl complex [(3,5-But2C3HN2)2CHCPh2O]Y(CH2SiMe3)2(THF)2 (4) obtained by the reaction of alcohol 2 with an equimolar amount of Y(CH2SiMe3)3(THF)2 turned out to be unstable and completely decomposed in solution in C6D6 at 25 °C within two hours. An exchange reaction of equimolar amounts of YCl3 and {[o-Me2NC6H4CH2C(NCy)2]Li(THF)2}2 (5) (Cy is the cyclohexyl) in THF led to the formation of a neutral monochloride complex [o-Me2NC6H4CH2C(NCy)2]2YCl(THF)2 (6). A reaction of complex 6 with an equimolar amount of o-Me2NC6H4CH2Li in toluene led to the synthesis of a new yttrium aminobenzyl complex [o-Me2NC6H4CH2C(NCy)2]2Y[CH2C6H4-o-NMe2] (7). X-ray diffraction studies showed that in complexes 6 and 7 the donor NMe2 groups of amidinate ligands are not involved in the metal—ligand interaction. Yttrium complexes 4 and 7 exhibited catalytic activity in polymerization of isoprene.

Cyanide-bridged manganese(II) and chloride-bridged copper(II) complexes with 2-pyridineethanol: synthesis, structural characterization and C-H⋯M interactions

[Mn(hepH)2Ni(μ-CN)2(CN)2]n (1) and [Cu2(μ-Cl)2(μ-hep)2]n (2) (2-pyridineethanol abbreviated to hepH) have been synthesized and characterized by FT-IR and Raman spectroscopies, elemental analyses, and single-crystal X-ray diffraction. X-ray single-crystal structure analysis reveals that the structures of 1 and 2 consist of 1-D infinite chains. The coordination environment of Mn(II) was identified as distorted octahedral, whereas Ni(II) has a square planar geometry in 1. Each Cu(II) in 2 adopts a distorted square pyramidal geometry in which the basal plane is constructed by oxygen and nitrogen atoms from hep and a bridging chloride ligand, respectively, and the apical position is occupied by the other chloride. The 1-D chains in 1 and 2 are extended into a 2-D supramolecular network by O−H⋯N and weak C−H⋯Cl hydrogen bonds, respectively. Adjacent 2-D layers are further connected by C−H⋯M interactions resulting in the formation of 3-D supramolecular networks. The most remarkable properties of complexes are the presence of close C–H⋯M interactions with distance values of 2.58 and 2.93 Å between H⋯Ni and H⋯Cu, respectively. The H⋯Ni interaction distance is shorter than the corresponding values of other tetracyanonickelate(II) complexes.

Synthesis and crystal structure of the dinuclear copper(II) Schiff base complex μ-hydroxido-μ-chlorido-bis{[bis(trans-2-nitrocinnamaldehyde)ethylenediamine]chloridocopper(II)} dichloromethane sesquisolvate.

Transition metal complexes of Schiff base ligands have been shown to have particular application in catalysis and magnetism. The chemistry of copper complexes is of interest owing to their importance in biological and industrial processes. The reaction of copper(I) chloride with the bidentate Schiff base N,N'-bis(trans-2-nitrocinnamaldehyde)ethylenediamine {Nca2en, systematic name: (1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]} in a 1:1 molar ratio in dichloromethane without exclusion of air or moisture resulted in the formation of the title complex μ-chlorido-μ-hydroxido-bis(chlorido{(1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]-κ(2)N,N'}copper(II)) dichloromethane sesquisolvate, [Cu2Cl3(OH)(C20H18N4O4)2]·1.5CH2Cl2. The dinuclear complex has a folded four-membered ring in an unsymmetrical Cu2OCl3 core in which the approximate trigonal bipyramidal coordination displays different angular distortions in the equatorial planes of the two Cu(II) atoms; the chloride bridge is asymmetric, but the hydroxide bridge is symmetric. The chelate rings of the two Nca2en ligands have different conformations, leading to a more marked bowing of one of the ligands compared with the other. This is the first reported dinuclear complex, and the first five-coordinate complex, of the Nca2en Schiff base ligand. Molecules of the dimer are associated in pairs by ring-stacking interactions supported by C-H...Cl interactions with solvent molecules; a further ring-stacking interaction exists between the two Schiff base ligands of each molecule.

Characterization of Iron-Imido Species Relevant for N-Group Transfer Chemistry.

A sterically accessible tert-butyl-substituted dipyrrinato di-iron(II) complex [((tBu)L)FeCl]2 possessing two bridging chloride atoms was synthesized from the previously reported solvento adduct. Upon treatment with aryl azides, the formation of high-spin Fe(III) species was confirmed by (57)Fe Mössbauer spectroscopy. Crystallographic characterization revealed two possible oxidation products: (1) a terminal iron iminyl from aryl azides bearing ortho isopropyl substituents, ((tBu)L)FeCl((•)NC6H3-2,6-(i)Pr2); or (2) a bridging di-iron imido arising from reaction with 3,5-bis(trifluoromethyl)aryl azide, [((tBu)L)FeCl]2(μ-NC6H3-3,5-(CF3)2). Similar to the previously reported ((Ar)L)FeCl((•)NC6H4-4-(t)Bu), the monomeric iron imido is best described as a high-spin Fe(III) antiferromagnetically coupled to an iminyl radical, affording an S = 2 spin state as confirmed by SQUID magnetometry. The di-iron imido possesses an S = 0 ground state, arising from two high-spin Fe(III) centers weakly antiferromagnetically coupled through the bridging imido ligand. The terminal iron iminyl complex undergoes facile decomposition via intra- or intermolecular hydrogen-atom abstraction (HAA) from an imido aryl ortho isopropyl group, or from 1,4-cyclohexadiene, respectively. The bridging di-iron imido is a competent N-group transfer reagent to cyclic internal olefins as well as styrene. Although solid-state magnetometry indicates an antiferromagnetic interaction between the two iron centers (J = -108.7 cm(-1)) in [((tBu)L)FeCl]2(μ-NC6H3-3,5-(CF3)2), we demonstrate that in solution the bridging imido can facilitate HAA as well as dissociate into a terminal iminyl species, which then can promote HAA. In situ monitoring reveals the di-iron bridging imido is a catalytically competent intermediate, one of several iron complexes observed in the amination of C-H bond substrates or styrene aziridination.

Effect of reaction conditions on the assembly, structures and fluorescent sensing behaviors of Cd(II) metal-organic complexes

Three Cd(II) metal-organic complexes, namely [Cd(phen)2Cl2](1), [Cd(phen)Cl2](2) and [Cd(phen)(cam)]· H2O(3)(phen=1,10-phenanthroline, H2cam=camphoric acid), were hydrothermally synthesized using Cd2+, phen and H2cam as raw materials under different conditions of pH values, reaction temperatures or reactant ratios. The prepared complexes were structurally characterized by means of single-crystal X-ray diffraction, and the results show that complex 1 is a 2D supramolecular complex, which consists of [Cd(phen)2Cl2] mononuclear subunits, while complex 2 shows a 1D chain structure, in which Cd(II) ions are connected by chloride(Cl–) bridges, with phen hanging on both sides of the chain. No cam anions have been observed in the structures of complexes 1 and 2. In complex 3, cam connects Cd(II) ions to construct a 2D network, in which phen acts as terminal ligands. The adjacent 1D chains for complex 2 and the adjacent 2D layers for complex 3 are further linked by hydrogen bonding interactions or π-π intermolecular interactions to form 3D supramolecular networks, respectively. The effects of reaction conditions on the assembly and structures of the complexes have been discussed. The fluorescent and photocatalytic properties of complexes 1―3 and the fluorescent sensing behaviors of complexes 2 and 3 have also been investigated.

Polymer chlorobismuthate complex catena-{((Me,Me)Bpe)[BiCl5]} n : Synthesis and crystal structure

The reaction of BiCl3 and N,N-dimethyl-1,2-bis(pyridyl)ethane chloride (Me,Me-Bpe) in 2 M HCl affords a polymer chlorobismuthate complex {((Me,Me)Bpe)[BiCl5]}n (I). The structure of complex I is determined by X-ray diffraction analysis (CIF file CCDC 1058842). The anionic moiety of the complex is presented by a 1D coordination polymer ([BiCl5]2n–)n consisting of octahedral blocks {Cl6} linked by µ2- bridging chloride ligands into infinite zigzag chains.

Synthesis, structure and spectroscopic properties of bis(triphenylphosphane)iminium (chlorido)(cyanido)argentates(I)

Four new compounds containing the (chlorido)(2−x)(cyanido)xargentate(I) anion (x=2, 1.63, 1 and 0.5) are reported. Their solid-state structures with the monocation PPN, bis(triphenylphosphane)iminium, are described; in a few cases the products also contain solvent molecules. The compounds have the formula (PPN)2[Ag2Cl3(CN)], (PPN)[Ag(CN)Cl](CH2Cl2) and (PPN)[Ag(CN)1.63Cl0.37](hexane)0.5 and (PPN)[Ag(CN)2](CH2Cl2). Apart from the molecular structures and the synthetic process, also the solid-state luminescence has been studied.In the case of (PPN)2[Ag2Cl3(CN)], the silver ions are pseudo-trigonally coordinated, with 2 chloride bridges between the Ag+ ions. The terminal Cl− and terminal CN− ligands are disordered over two positions, but only a single 13C NMR signal is observed for the cyanide ligands of this compound. The compound (PPN)[Ag(CN)2] serves as a reference compound and contains the linear [Ag(CN)2] unit.The compound with CN/Cl=1.0 shows disorder of the [AgCl(CN)] unit, and also in the compounds with other CN/Cl ratios, disorder among the Cl− and CN− ligands is seen. The Ag+ ion is linearly coordinated by two ligands in these two cases, and for cyanides normal Ag–C bond lengths are observed in both cases (1.97–1.99Å). The [Ag(CN)2] anion is linear and uneventful. The PPN cation has normal bond lengths in all 4 compounds and no short contacts with other atoms in the lattice are observed. The luminescence properties of the new compounds were explored as solid powders. Only one of the compounds (compound 2, with x=1) shows luminescence under excitation. The other three compounds do not show emission when irradiated at 320nm, 350nm or 380nm.

Two different one-dimensional Cd(II) halide coordination polymers constructed through bridging carboxylate ligands.

Two cadmium halide complexes, catena-poly[[chloridocadmium(II)]-di-μ-chlorido-[chloridocadmium(II)]-bis[μ2-4-(dimethylamino)pyridin-1-ium-1-acetate]-κ(3)O:O,O';κ(3)O,O':O], [CdCl2(C9H12N2O2)]n, (I), and catena-poly[1-cyanomethyl-1,4-diazoniabicyclo[2.2.2]octane [[dichloridocadmium(II)]-μ-oxalato-κ(4)O(1),O(2):O(1'),O(2')] monohydrate], {(C8H15N3)[CdCl2(C2O4)]·H2O}n, (II), were synthesized in aqueous solution. In (I), the Cd(II) cation is octahedrally coordinated by three O atoms from two carboxylate groups and by one terminal and two bridging chloride ligands. Neighbouring Cd(II) cations are linked together by chloride anions and bridging O atoms to form a one-dimensional zigzag chain. Hydrogen-bond interactions are involved in the formation of the two-dimensional network. In (II), each Cd(II) cation is octahedrally coordinated by four O atoms from two oxalic acid ligands and two terminal Cl(-) ligands. Neighbouring Cd(II) cations are linked together by oxalate groups to form a one-dimensional anionic chain, and the water molecules and organic cations are connected to this one-dimensional zigzag chain through hydrogen-bond interactions.

Crystal structure of catena-poly[hemi[1,3-bis-(2,6-diisoprop-ylphenyl)imidazolium] [[μ3-acetato-κ(3) O:O:O'-tri-μ2-acetato-κ(6) O:O'-dicopper(II)(Cu-Cu)]-μ-chlorido] di-chloro-methane sesqui-solvate

The title copper(II) complex, {(C27H37N2)[Cu4(CH3COO)8Cl]·3CH2Cl2}n, is a one-dimensional coordination polymer. The asymmetric unit is composed of a copper(II) tetra­acetate paddle-wheel complex, a Cl− anion situated on a twofold rotation axis, half a 1,3-bis­(2,6-diisoprop­ylphenyl)imidazolium cation (the whole mol­ecule being generated by twofold rotation symmetry) and one and a half of a di­chloro­methane solvent mol­ecule (one being located about a twofold rotation axis). The central metal-organic framework comprises of a tetra­nuclear copper(II) acetate ‘paddle-wheel’ complex which arises from the dimerization of the copper(II) tetra­acetate core comprising of three μ2-bidentate acetate and one μ3-tridentate acetate ligands per binuclear paddle-wheel complex. Both CuII atoms of the binuclear component adopt a distorted square-pyramidal coordination geometry (τ = 0.04), with a Cu⋯Cu separation of 2.6016 (2) Å. The apical coordination site of one CuII atom is occupied by an O atom of a neighbouring acetate bridge [Cu—O = 2.200 (2) Å], while that of the second CuII atom is occupied by a bridging chloride ligand [Cu⋯Cl = 2.4364 (4) Å]. The chloride bridge is slightly bent with respect to the Cu⋯Cu inter­nuclear axis [Cu—Cl—Cu = 167.06 (6)°] and the tetra­nuclear units are located about a twofold rotation axis, forming the one-dimensional polymer that propagates along [101]. Charge neutrality is maintained by the inclusion of the 1,3-bis­(2,6-diisoprop­ylphenyl)imidazolium cation within the crystal lattice. In the crystal, the cation and di­chloro­methane solvent mol­ecules are linked to the coordin­ation polymer by various C—H⋯O and C—H⋯Cl hydrogen bonds. There are no other significant inter­molecular inter­actions present.

Versatile Coordination Mode of a New Pyridine-Based Ditopic Ligand with Transition Metals: From Regular Pyridine to Alkyne and Alkenyl Bindings and Indolizinium Formation

The new BPMPB ligand, namely, bis[1-bis(2-pyridylmethyl),1 (pyridyl)]butyne, can be very easily obtained as a side product in the known reaction of picolyl chloride and sodium acetylide (which major product is the known terminal alkyne-substituted tripod). This symmetrical ligand contains two identical coordination sites with two methylenepyridines and one pyridyl group on each side, linked by an alkyne function providing a semirigid segment. Together with the molecular structure of the ligand which is reported, we describe the preparation of complexes with Fe(II)Cl2, Co(II)Cl2, Ni(II)Cl2, Cu(I)Cl, and Zn(II)Cl2 salts. All complexes have been characterized by X-ray diffraction studies as well as by standard spectroscopic techniques. The striking point in this work is the diversity of the structures that are obtained. Co(II) and Zn(II) provide isostructural dinuclear complexes in which both coordination sites are occupied within a tetrahedral symmetry. The Cu(I) complex is also a dinuclear compound, but in that case, the copper atom is coordinated to the alkyne moiety, two pyridines, and a bridging chloride. The (13)C NMR spectrum of the copper complex confirms that the metal center is coordinated to the alkyne in solution. The coordination of Ni(II) results in the formation of a mononuclear complex in which a pyridine has fused with the alkyne moiety to generate an indolizinium group; the structure of the corresponding alkenyl complex is reported. Finally, the addition of FeCl2 to the ligand results in the formation of a mononuclear complex with a free, noncoordinated indolizinium. The sequence developed in the present work illustrates the possibility for the metal centers to adopt various coordination modes which may be relevant to the conversion of an alkyne and a pyridyl unit into indolizinium.