Bis(4′-phenyl-2,2′:6′,2″-terpyridine)ruthenium(II): Holding the {Ru(tpy)2} embraces at bay

The solid state structure of [Ru(Phtpy)₂][PF₆]₂ · 4MeCN has been determined (Phtpy = 4′-phenyl-2,2′:6′,2″-terpyridine); [Ru(Phtpy)₂]²⁺ cations pack into sheets by virtue of {M(tpy)₂}₂ embraces, and the MeCN solvent molecules are involved in NH–C interactions which prevent the efficient packing of adjacent sheets. Comparisons with related structures lead to some generalizations about packing motifs in salts containing [M(Phtpy)₂]²⁺ or [M(pytpy)₂]²⁺ cations (pytpy = 4′-pyridyl-2,2′:6′,2″-terpyridine).     

Contribution of intermolecular interactions to constructing supramolecular architecture: Synthesis, structure and Hirshfeld surface analysis of a new hybrid of polyoxomolybdate and ((1H-tetrazole-5-yl) methyl)morpholine

A new soluble organic–inorganic hybrid based on polyoxomolybdate, [C₆H₁₂N₅O]₃[(PO₄)Mo₁₂O₃₆]·6H₂O (1), has been successfully synthesized and characterized by using elemental analysis, IR, UV spectroscopies, ¹H NMR technique, and single-crystal X-ray diffraction. According to the results of X-ray crystallography the anion [(PO₄)Mo₁₂O₃₆]³⁻ has a typical Keggin structure and the Mo–O distances of Mo–O–Mo bonds are alternately short and long in the polyoxoanion structure. Hirshfeld surface analyses, especially d_norm surface and fingerprint plots, are used for decoding intermolecular interactions in the crystal network and contribution of component units for the construction of the 3D architecture. The results indicate that in 1 the hydrogen bond interaction play a main role in the construction of the 3D architecture, especially the CHO interaction which overruns the classic NHO, NHO hydrogen bond interactions; van der Waals force between the peripheral atoms of component units cannot be ignored.     

Magnetic behavior within a new Ni(mnt)2-based molecular solid containing 1-(2′-fluorobenzyl)isoquinolinium

A novel molecular solid, [OFBzIQl][Ni(mnt)₂] (1), where [OFBzIQl]⁺ = 1-(2′-fluorobenzyl)isoquinolinium and mnt²⁻ = maleonitriledithiolate, forms 1D column of alternating between cations and anions via ππ stacking interaction between Ni(mnt)₂ plane and isoquinoline ring, and the Ni(mnt)₂ anions between the adjacent columns exist short CN interaction. The extensive hydrogen bonds between anions and cations in the crystal generate a 2D network structure. Magnetic susceptibility measurement for 1 in the temperature range 2.0–300 K shows that 1 exhibits a magnetic constant transition from ferromagnetic to antiferromagnetic around 35 K as the temperature is lowered.     

Synthesis and spectroscopic studies of new adducts of organotin(IV) chlorides with a polydentate N,S ligand

The reaction of a polydentate N,S ligand, 1′-amino-1′-cyclohexyl 2-cyclohexylideneamino-1-cyclohexene-1-dithiocarboxylate (ACCCD), with Ph₂SnCl_2, Ph₃SnCl and Me₂SnCl₂ was investigated. The new adducts have been characterized by UV–Vis, ¹H NMR, IR, mass spectroscopy and elemental analysis. These data are consistent with 1:1 adducts. The ligand behaves as a bidentate and shows both nitrogen and sulfur coordination. There is also evidence that the ligand ACCCD exhibits some interest in forming possible inter-/intra-molecular hydrogen bonds through ClH₂N interactions in Me₂SnCl₂ and Ph₂SnCl₂ adducts. The UV–Vis spectra indicate that the compounds partially dissociate in chloroform.     

First X-ray structure of discrete anion [HgBr5]: Synthesis, characterization and single crystal X-ray structure determination of [Co(NH3)6][HgBr5]

A new cobalt(III) complex salt, [Co(NH₃)₆][HgBr₅](1) was crystallized from a solution of hexaamminecobalt(III)bromide and potassium tetrabromomercurate(II) in aqueous medium in 1:1 molar ratio. This complex salt has been characterized by elemental analyses, spectroscopic techniques (e.g. UV/Visible, IR), solubility product and conductance measurements. The complex salt crystallizes in Orthorhombic crystal system with space group Pnma. Single crystal X-ray structure determination revealed the presence of discrete ions: [Co(NH₃)₆]³⁺ cation and a new anion [HgBr₅]³⁻. This is the first structural report of a complex salt containing this new anion. The structure consists of stacks of cations and anions demonstrating supramolecular arrangements through N–HBr hydrogen-bond interactions. The crystal lattice is stabilized by these non-covalent interactions besides electrostatic interaction.     

A new NiCuCu Ni complex containing doubly end-on azido bridged dicopper(II) and macrocyclic nickel(II) complex ancillary ligands: Synthesis, structure and magnetism

[Cu₂(NiL)₂(N₃)₄] was synthesized by combining “complex as ligand” approach and “pure bridging ligand” approach (H₂L = dimethyl 5,6,7,8,15,16-hexahydro-15-methyl-6,7-dioxodibenzo[1,4,8,11]tetraazacyclotetradecine-13,18-dicarboxylate). The two Cu^II ions are bridged by two end-on azido ligands. ππ and oxamido–carbonyl interactions link the molecules into 1D supramolecular chains. Ferromagnetic interactions exist between the two Cu^II ions.     

3D supramolecular network constructed by intermolecular interactions in mixed ligand complex of zinc

New complex [Zn(quin-2-c)₂(Him)₂] (quin-2-c = quinoline-2-carboxylate ion, Him = imidazole) was synthesized by self assembly and its structure was determined by X-ray analysis. The compound crystallizes in P21/c space group. Four independent molecules of complex are present in the structure. Strong hydrogen bonds create three different 1D chains which are collected in two different layers. The alternately packed layers form the 3D supramolecular structure. The interchain and interlayer contacts are of the C–HO, ππ and C–Hπ type. The influence of strong hydrogen bond on the vibrational characteristics of the monodentately coordinated carboxylate group in zinc complexes with quin-2-c ion is discussed.     

Adsorption mechanism and property of novel composite material PMAA/SiO2 towards phenol

In this paper, functional macromolecule poly(methacrylic acid) (PMAA) was grafted on the surface of silica gel particles using 3-methacryloxypropyl trimethoxysilane (MPS) as intermedia, and the grafted particle PMAA/SiO₂ with strong adsorption ability for phenol was prepared. The adsorption mechanism and properties of PMAA/SiO₂ for phenol were researched by static and dynamic methods. The experimental results showed that PMAA/SiO₂ possesses strong adsorption ability for phenol with interaction of three kinds of hydrogen bonds including peculiar O–Hπ hydrogen bond (aromatic hydrogen bond) and O–HOC π hydrogen bond. The saturated adsorption amount could reach up to 162.88 mg g⁻¹. The empirical Freundlich isotherm was found to describe well the equilibrium adsorption data. pH and temperature were found to have great influence on the adsorption amount. Finally, PMAA/SiO₂ was observed to possess excellent reusability properties as well.     

A new type of supramolecular assembly consisting of crown ether complex cation and a polyoxometalate anion: Synthesis and crystal structure of [Na(C20H24O6)(CH3CN)2]2[Mo6O19] · 4CH3CN

A novel supramolecular assembly consisting of sodium-dibenzo-18-crown-6(DB18C6) complex cation [Na(C₂₀H₂₄O₆)(CH₃CN)₂]²⁺ and isopolyanion [Mo₆O₁₉]²⁻ has been demonstrated in the 3D structure of [Na(C₂₀H₂₄O₆)(CH₃CN)₂]₂[Mo₆O₁₉] · 4CH₃CN (1). Weak intermolecular forces (C–HO hydrogen bonds) between isopolyanion and crown ether play a significant role in the construction of supramolecular framework in the crystal structure of 1. Compound 1 has been characterized in the solid state by single crystal X-ray diffraction, IR, CHN analysis, and TGA.     

Electrochemical Approach to Copper‐Catalyzed Reversed Atom Transfer Radical Cyclization

Electrochemically mediated atom transfer radical cyclization (eATRC) has been developed as an easy and clean method allowing the synthesis of halogenated cyclic compounds. This method has been successfully applied to the copper‐catalyzed atom transfer radical cyclization of some N‐allyl‐α,α‐dichloroamides in acetonitrile (CH₃CN) using a copper complex with tris(2‐pyridylmethyl)amine (TPMA) with a metal loading of 1%. The catalyst is introduced as [Cu(II)TPMA]²⁺ and is activated and continuously regenerated to its active copper(I) form by reduction at a platinum (Pt) electrode. During the ATRC process a new copper(II) complex, namely, [ClCu(II)TPMA]⁺, whose reduction potential is ca. 0.350 V more negative than that of the starting [Cu(II)TPMA]²⁺, is formed. Therefore, the choice of the applied potential is critical and should be done taking care that all copper(II) species are reduced to copper(I). The compounds undergo very high conversions (79–100%) in a few hours of electrolysis, producing a cyclic γ‐lactam (yield 60–98%) as a mixture of two isomers, with a good cis‐diastereoselectivity [dr (cis/trans)=59/41–83/17]. [Cu(II)PMDETA]²⁺ (PMDETA=N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine), which is much cheaper, albeit less reactive than [Cu(II)TPMA]²⁺, was also investigated but the results were not satisfactory.

     

Synthesis and characterization of mono- and heterodinuclear complexes with dicompartmental macrocyclic ligand containing hexa- and pentadentate coordination sites

A novel macrobicyclic heterobinuclear Zn(II)–Ni(II) complex with a phenol based dicompartmental ligand possessing contiguous hexa- (N₄O₂) and pentadentate (N₃O₂) coordination sites was prepared by a stepwise method. The prepared mono- and bimetallic macrocyclic complexes were characterized by elemental analysis, IR, NMR spectroscopies, and molar conductance measurements. Characterization results confirms the expected C₂ symmetric geometry for mononuclear macrocyclic zinc complex. The ¹H NMR spectrum and X-ray crystal structure of the macrocyclic Zn(II)–Ni(II) complex demonstrated a C₁ symmetric geometry with a five-membered heterocycle ring attached to the diethylenetriamine link as a result of an intramolecular rearrangement. The explanation for these topological transformation and intramolecular rearrangement as well as electrochemical behavior of dinuclear complex are discussed.     

Novel Copper(II) Complexes of <Emphasis Type="Italic">N</Emphasis>-Phenylanthranilic Acid Containing Ethanol and Hydroxo Ligands

The complexes, tetra-μ-[2-(phenylamino)benzoato](O,O′)-bis[(ethanol)copper(II)] (1) and di-μ-[2-(phenylamino)benzoato](O,O′)-bis[(hydroxo)copper(II)] (2), were synthesized by the reaction of N-phenylanthranilic acid and CuCl₂·2H₂O in an ethanol water mixture. In complex 1, each Cu(II) atom, which is in a slightly distorted square pyramidal environment, is coordinated equatorially by four N-phenylanthranilate O-atoms and axially by the ethanol O-atoms. In complex 2, [Cu₂(C₆H₅NHC₆H₄COO)₂(OH)₂], each Cu(II) atom, which is in tetrahedral environment, is coordinated by two N-phenylanthranilate O-atoms and hydroxo ligands. The crystal structure (monoclinic, P21/c space group) of complex 1 comprises a dinuclear [Cu₂(C₆H₅NHC₆H₄COO)₄(CH₃CH₂OH)₂] species and the dimer is located on a crystallographic inversion centre. The Cu(II) ions, 2.591(2) Å apart, are bridged by the carboxylate groups of four N-phenylanthranilate ligands. The complex molecules show three-dimensional supramolecular networks by O–H···O, C–H···O and C–H···π interactions.     

Solvothermal in situ formation of a hexanuclear copper(I) complex with 2-thiolate-N,N′-dimethylnicotinamide

Solvothermal reaction of 2-mercaptonicotinic acid (HL¹) with copper(II) nitrate in DMF/methanol medium leads to the production of a novel hexanuclear complex [Cu(L²)]₆ · (H₂O)₂ (1), in which in situ formation of an anionic ligand 2-thiolate-N,N′-dimethylnicotinamide (L²) and reduction of copper(II) to copper(I) are observed. X-ray single-crystal structure of 1 reveals that each copper(I) center adopts a trigonal geometry provided by two thiolate and one pyridyl groups from three separated L² ligands. As a result, six copper(I) ions are interconnected by six μ₃–L² bridges to afford a hexanuclear cluster, in which the octahedral Cu₆ core is stabilized by significant cuprophilic interactions.     

Synthesis,Characterization, Crystal Structure and Antimicrobial Evaluation of a Novel –M–X–M–X– Type Infinite Chain 1D Cu(II) Complex with Eflornithine Hydrochloride Hydrate as Ligand

A novel –M–X–M–X– type infinite chain 1D copper(II) complex of Eflornithine, Dichloro-[2-amino-5-ammonio-2-(difluoromethyl)pentanoate]copper(II) hydrate, [Cu(C₆H₁₂F₂N₂O₂)Cl₂]·H₂O 1 has been synthesized and characterized by elemental analysis, spectroscopic techniques (UV/Vis and FT-IR), TGA and X-ray diffraction. Single-crystal X-ray diffraction analysis of the complex 1 showed the structure to be monoclinic with space group Cc, a = 13.1295(15) Å, b = 12.1859(14) Å, c = 8.1927(9) Å, β = 118.359(3) Å, V = 1153.5(2) Å³, Z = 4. The complex exhibits a quadratic planar coordination of the Cu-atom. The Cu(II) centre is coordinated by two chloride atoms, an oxygen atom of the carboxyl- and a nitrogen atom of the amino-group, respectively, forming a quadratic planar geometry. The terminal amino group of the ligand is protonated to form NH₃ ⁺ while the carboxylic moiety is deprotonated to form Zwitterionic eflornithine ligand, with the coordination of the metal at the nitrogen atom of the second amino group. The compound has –M–X–M–X– infinite 1D chain polymeric structure. Two neigbouring Cu(EFL)Cl chain units are bridged by an Cl^? ion, forming a –Cu–Cl–Cu–Cl– linear chain structure along C-axis. The antibacterial activities of the complex on Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) were investigated and found to be active at higher concentration than the parent ligand.     

Crown ether bridged homo- and heterodinuclear copper(II) and nickel(II) cyclidene complexes: Interaction with anions

Homodinuclear (3CuCu, 3NiNi) and heterdionuclear (3CuNi) cyclidene complexes linked by two 1,10-diaza-18-crown-6 ethers were synthesized and their properties characterized. For the 3CuCu in the negative potential range the mixed-valence state Cu^I-Cu^II was observed and the comproportionation constants were determined. The redox potentials of M^II/III showed a good correlation with DN of the solvent. In acetonitrile solution containing 0.1 mol dm⁻³ Bu₄NPF₆ reversible M^II/III redox processes were observed. However, in the presence of stronger ion pairing anions (e.g. BF₄⁻ and ClO₄⁻) the “potential inversion” occurred. Redox potentials of dinuclear complexes were compared with mononuclear cyclidene complexes. The influence of selected anions (Cl⁻ and NO₃⁻) on the redox process M^II/III was studied. The effect of Cl⁻ anion was different for 3CuCu and 3NiNi. In 3CuCu coordination of two chloride anions took place after oxidation of copper centers. In the 3NiNi complex two Cl⁻ anions were coordinated to one of the nickel(II) centers facilitating oxidation, at different potentials, of both nickel(II) cations. The behaviour of heteronuclear complex with Cl⁻ anions was similar to 3NiNi. All dinuclear complexes interacted with NO₃⁻ anions and the observed potential shifts were larger for nickel(II) than for copper(II) cations.     

Synthesis and Structural Characterization of Two New Nano-Coordination Compounds Based on Mercury(II) NN Donor Schiff Base

Two new nano mercury(II) coordination compounds, [Hg₂(μ-L1)(μ-I)₂I₃]_n (1) and [Hg(L2)(I)₂] (2) {L1?=?(E)-N′-(pyridin-2-ylmethylene)isonicotinohydrazide and L2?=?(E)-N′-(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide} have been synthesized by a sonochemical method. The new nano-structures were characterized by scanning electron microscopy, X-ray powder diffraction, elemental analysis and IR spectroscopy. The compounds were also characterized by single crystal X-ray diffraction and the results indicate a 1D fishbone-like structure containing dinuclear units for 1 and a mononuclear structure for 2. In coordination polymer 1, the two Hg(II) centers are four coordinate into a chain-axis and also in the terminal linkages. In complex 2, the Hg(II) center is four coordinate. The chains of polymer 1 interact with each other through π–π stacking interactions which create a 3D framework.     

Synthesis,Structure and Voltammetric Studies of Copper(II) Polymer with DNA Interaction: The First 1-D Coordination Polymer Alternately Bridged by Oxalate and Oxamidate Ligands

A novel one-dimensional copper(II) complex formulated as [Cu₂(dmaeoxd)(ox)] _n ·nH₂O (dmaeoxd = N,N′-bis[2-(dimethylamino)ethyl]oxamide, ox = oxalate), which represents the first coordination polymer alternately bridged by oxalate and oxamidate ligands, has been synthesized and characterized by elemental analysis, conductivity measurement and IR spectra. The single-crystal X-ray analysis reveals that the [Cu₂(dmaeoxd)]²⁺ building blocks are bridged by oxalate groups to form a neutral 1-D coordination polymer, which involves hydrogen bonds with lattice water molecules and results in a three dimensional supermolecular structure. The voltammetric studies of the copper(II) polymer with DNA interaction are preliminarily investigated.     

The synthesis, structure, and magnetic properties of a novel copper(II) cluster with H-bonding directed 3D-structure comprised of interconnected double-stranded ladders

Reaction between 2,6-diformyl-4-methylphenol (DFMP) and tris(hydroxymethyl)aminomethane (THMAM) with copper(II) acetate and sodium azide formed the antiferromagnetically coupled, polymeric copper(II) coordination cluster {[(H₅L)Cu₂(μ-N₃)]₂[Cu(N₃)₄]·2CH₃OH}_n (1), with a novel double-stranded ladder like structure in which [Cu(N₃)₄]²⁻ anions link single-chains comprised of dinuclear subunits, forming a 3D-structure of interconnected ladders through H-bonding. The 3D-structure is the result of coordinatively driven and hydrogen-bonding directed self-assembly.     

Novel lanthanide salicylaldimine complexes with unusual coordination mode

The one-step metal promoted reaction between salicylaldehyde and 4-methyl-1,3-phenylenediamine in the presence of lanthanum(III) or gadolinium(III) nitrate yields new salicylaldimine complexes containing N,N′-bis(salicylidene)-4-methyl-1,3-phenylenediamine as a result of the [2 + 1] Schiff base condensation. The crystal structure of the gadolinium complex reveals a dinuclear species with four unionized ligands coordinating in the monodentate and bridging bidentate fashion, using exclusively the oxygens as donor atoms with the nitrogen atoms not being involved in coordination. The coordination number of nine is achieved by involving three bidentate nitrate counterions in the coordination sphere.     

Tautomerism of a compartmental Schiff base ligand and characterization of a new heterometallic CuII–DyIII complex — Synthesis,structure and magnetic properties

A crystal structure of a compartmental ligand N,N′-bis(2,3-dihydroxybenzylidene)-1,3-diaminopropane (H₄L = C₁₇H₁₈N₂O₄) (1) containing N₂O₂-inner and O₄-outer coordination sites and a characterization of its novel diphenoxo-bridged discrete dinuclear complex [CuDy(H₂L)(MeOH)(NO₃)₃]·2MeOH (2) are reported. The Schiff base ligand 1 crystallizes in the orthorhombic P2₁2₁2₁ space group with a molecule in a bent conformation. The compound at 100 and 293 K displays the keto-enol tautomerism with the equilibrium in both temperatures shifted with a different degree towards the zwitterionic keto-amino form. The quantum chemical calculations showed preferences for enol-imino form in a gas phase and for keto-amine in solutions. The keto-amino tautomer is stabilized by intermolecular interactions. The complex 2 crystallizes in the triclinic P-1 space group as a dinuclear compound with Cu^IIDy^III core. The Dy(III) ion is nine-coordinated whereas the coordination number of Cu(II) is five. The temperature dependence of the magnetic susceptibility and the field-dependent magnetization indicated that the interaction between Cu(II) and Dy(III) metal centers in 2 is ferromagnetic.