Self-assembly luminescent complexes with [Ag2 (μ-dppm)2 (MeCN)2](SbF6)2 and tptz as components

[Ag₂(μ-dppm)₂(tptz)(MeCN)](SbF₆)₂·2H₂O·2MeCN (1), [Ag₂(μ-dppm)₂(tptz)₂](SbF₆)₂·1.75H₂O (2) and [Ag₂(μ-dppm)(tptz)₂](SbF₆)₂· 2MeCN (3) were synthesized by self-assembly with metal diphosphine [Ag₂(μ-dppm)₂ (MeCN)₂](SbF₆) ₂ and tptz as components in different molar ratios [(dppm = bis(diphenylphosphino)methane and tptz = 2,4,6-tris(2′-pyridyl)-1,3,5-triazine)] and characterized by IR spectra, elemental analysis, ¹H NMR spectra, ³¹P NMR spectra and Visible–Ultraviolet spectra. Structures of all the complexes were determined by X-ray analysis. π − π interactions were found in complex (3). Further studies show that all the complexes were of well luminescent properties both in solution and solid state.     

Laser photolysis of 1-(4-nitrophenyl)-3-methylpyrazole and 1-ethyl-3-(4-nitrophenyl)-5-chloropyrazole

The spectral kinetic characteristics of the triplet states of 1-(4-nitrophenyl)-3-methylpyrazole (1) and 1-ethyl-3-(4-nitrophenyl)-5-chloropyrazole (2) were studied by the laser nanosecond photolysis technique in different solvents. The triplet lifetimes (τ_T) of molecules 1 and 2 were found to depend strongly on the solvent nature. An increase in τ_T by approximately two orders of magnitude on going from nonpolar and polar aprotic solvents (τ_T ≤ 15 ns) to aqueous-acetonitrile solutions (τ_T = 1100 ns for a volume acetonitrile to water ratio of 1 : 3) was analyzed, taking into account the influence of the medium on the relative contribution of the n,π*- and π,π*-configurations to the lowest triplet state. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1115–1119, May, 2005.     

Copper complexes of 1-[(2-carboxyethyl)benzene]-3-[2-pyridine]triazene

The triazenide, 1-[(2-carboxyethyl)benzene]-3-[2-pyridine]triazene (HL), has been synthesized. In the presence of Et₃N, the reaction of HL with Cu(OAc)₂·H₂O or CuCl₂·2H₂O gives the tetranuclear copper(II) complexes {Cu₄(L)₂(μ₂-OH)₂(OAc)₄} 1 and {Cu₄L₄(μ₄-O)Cl₂} 2, respectively. The X-ray crystal structures of both complexes have been obtained. Magnetic studies indicate significant antiferromagnetic coupling between the copper(II) centers for both complexes, with coupling constants (J) of −493.4 cm⁻¹ for 1 and −165 cm⁻¹ for 2.     

Effect of the Counter Anion and Solvate on the Structure,Stability and Spectral Properties of a Ruthenium(II) Complex Containing Group 15 Donors and 2,2′ :6′,2′′-terpyridine

Ruthenium complexes [Ru(κ³−tpy)(AsPh₃)₂C1]PF₆ · 0.42H₂O (tpy =2,2′:6′,2′′-terpyridine) (1) and a new crystal form of [Ru(κ³−tpy)(AsPh₃)₂Cl]BF₄ (2), which crystallized without water solvate, and their comparative studies on spectral, structure and stability aspects are reported. The complexes have been characterized by elemental analyses, FAB-MS, i.r., ¹H n.m.r. and electronic spectral studies. In these complexes weak C—H···Fπ and face-to-face π–π interactions lead to a single helical motif while, C—H···FX (X=F, Cl) interactions result in linear chains. Various studies on the stability of the complexes suggested that the compound containing the counter anion PF₆^- is more stable than the other containing BF₄^- as the counterpart.     

Synthesis, crystal structures and properties of the novel mononuclear copper(II) and tetranuclear cobalt(II) complexes with 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine

A novel monomer copper(II) complex [Cu(L)₂(SCN)] · ClO₄ (1) and a tetranuclear cobalt(II) complex [Co₄(L)₄(N₃)₄](OH)₄ · 2H₂O (2)(L = 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine) have been synthesized and structurally characterized. Single crystal X-ray analyses show that the Cu(II) atom is in a distorted trigonal bipyramidal coordinated environment consisting of four N atoms of L and one N atom of SCN⁻ in complex (1), and the monomer is extended to a 1D chain by the weak intermolecular π...π stacking interactions. In the complex (2), four Co(II) atoms are linked by four bridging azido groups in μ-1,1-N₃ (end-on) coordination mode to form a tetranuclear configuration. The fungicidal activity of the title compounds have been studied, and the results show that there are certain activities against several bacteria for the complexes and the ligand. Furthermore, two complexes exhibit blue emission fluoresce in the solid state at room temperature.     

Vibrational energy transfer in ozone by infrared-ultraviolet double resonance

Absorption transients at 254 nm have been observed in O₃-O₂ mixtures following laser irradiation at 9.64 μm. From analysis of these transients, we are able to determine vibrational relaxation rate constants (O₃-O₂ λ₁^?1/[O₂] = (2560±370) Torr^?1 S^?1, λ₂^?1/[O₂] = (640±50) Torr^?1 S^?1, and also a v₁-v₃ equilibration rate constant (O₃-O₃) of (1.5±1.0) × 10⁶ Torr^?1 S^?1.     

Syntheses and structures of nickel(II) and copper(II) complexes with biacetyl bis(benzoylhydrazone): one-dimensional self-assembly via π–π interaction and hydrogen bonding

Reactions of Ni(O₂CCH₃)₂·4H₂O and Cu(O₂CCH₃)₂·H₂O with biacetyl bis(benzoylhydrazone) (H₂babh) in alcoholic media afford mononuclear nickel(II) and copper(II) complexes of general formula [M(babh)]. The complexes have been characterized by microanalysis (C, H, N), magnetic susceptibility, and various spectroscopic measurements. X-ray structures of both complexes have been determined. The metal centre in [Ni(babh)] is in square-planar N₂O₂ environment provided by the tetradentate babh²⁻. On the other hand, [Cu(babh)] crystallizes as distorted square-pyramidal [Cu(babh)(CH₃OH)] from methanol. Here the tetradentate babh²⁻ constitutes the N₂O₂ square-base and the O-coordinating methanol occupies the apical site. In the crystal lattice, the molecules of [Ni(babh)] form a one-dimensional π-stacked structure. The [Cu(babh)(CH₃OH)] molecules also form a one-dimensional structure with alternating long and short Cu···Cu distances via intermolecular O–H···N hydrogen bonding and π–π interaction.     

Ruthenium(II) phenylazopyridinearylazoimidazoles: Synthesis, spectral studies and redox properties

Tris-chelate complex [Ru(Pap)(RAaiR′)₂](ClO₄)₂ (I, II, III/a, b, c) (where RAaiR′ = 1-alkyl-(2-arylazo)imidazole, R = H, Me, Cl (a, b, c); R′ = Me, Et, CH₂Ph (I, II, III), and Pap = phenylazopyridine) was prepared by silver assisted synthetic route. IR spectra of the complexes support Ru-azo nitrogen π-bonding interaction. ¹H NMR spectra suggest that there are two types of streochemical orientation of RAaiR′ around ruthenium(II). Cyclic voltammetry of the complexes shows one metal oxidation Ru(II)/Ru(III) at 1.4–1.5 V and three successive ligand reduction couples at the negative side of the reference potential in the range from −0.5 to −0.56, −0.7 to −0.8, and from −1.25 to −1.40 V, respectively. The text was submitted by the author in English.     

1-(2′-Pyridylazo)-2-naphtholate complexes of ruthenium: Synthesis,characterization, and DNA binding properties

Reaction of 1-(2′-pyridylazo)-2-naphthol (Hpan) with [Ru(dmso)₄Cl₂] (dmso = dimethylsulfoxide), [Ru(trpy)Cl₃] (trpy = 2,2′,2″-terpyridine), [Ru(bpy)Cl₃] (bpy = 2,2′-bipyridine) and [Ru(PPh₃)₃Cl₂] in refluxing ethanol in the presence of a base (NEt₃) affords, respectively, the [Ru(pan)₂], [Ru(trpy)(pan)]⁺ (isolated as perchlorate salt), [Ru(bpy)(pan)Cl] and [Ru(PPh₃)₂(pan)Cl] complexes. Structures of these four complexes have been determined by X-ray crystallography. In each of these complexes, the pan ligand is coordinated to the metal center as a monoanionic tridentate N,N,O-donor. Reaction of the [Ru(bpy)(pan)Cl] complex with pyridine (py) and 4-picoline (pic) in the presence of silver ion has yielded the [Ru(bpy)(pan)(py)]⁺ and [Ru(bpy)(pan)(pic)]⁺ complexes (isolated as perchlorate salts), respectively. All the complexes are diamagnetic (low-spin d⁶, S = 0) and show characteristic ¹H NMR signals and intense MLCT transitions in the visible region. Cyclic voltammetry on all the complexes shows a Ru(II)–Ru(III) oxidation on the positive side of SCE. Except in the [Ru(pan)₂] complex, a second oxidative response has been observed in the other five complexes. Reductions of the coordinated ligands have also been observed on the negative side of SCE. The [Ru(trpy)(pan)]ClO₄, [Ru(bpy)(pan)(py)]ClO₄ and [Ru(bpy)(pan)(pic)]ClO₄ complexes have been observed to bind to DNA, but they have not been able to cleave super-coiled DNA on UV irradiation.     

Synthesis,structural characterization and substituent effects of two copper(II) complexes with benzaldehyde ortho-oxime ligands

Two new Cu(II) complexes, [Cu(L¹)₂] (1) and [Cu(L²)₂] (2) (HL¹ = (E)-3-bromo-5-chloro-2-hydroxy benzaldehyde O-methyl oxime; HL² = (E)-3-bromo-5-chloro-2-hydroxy benzaldehyde O-ethyl oxime), have been synthesized and characterized by physicochemical and spectroscopic methods. X-ray crystallographic analyses show that complexes 1 and 2 have similar structures, consisting of one Cu(II) atom and two L⁻ units. In both complexes, the Cu(II) atom, lying on an inversion center, is four-coordinated in a trans-CuN₂O₂ square-planar geometry by two phenolate O and two oxime N atoms from two symmetry-related N,O-bidentate oxime ligands. Moreover, both complexes form an infinite three-dimensional supramolecular structure involving intermolecular C–H···Br hydrogen bonds and π···π stacking interactions between the metal chelate rings and aromatic rings. Substituent effects in the two complexes are discussed.     

Kinetics and mechanism of the reactions of hexaaqua rhodium (III) with sulphur (IV) in aqueous medium

An O-bonded sulphito complex, Rh(OH₂)₅(OSO₂H)²⁺, is reversibly formed in the stoppedflow time scale when Rh(OH₂) ₆ ³⁺ and SO₂/HSO ₃ ⁻ buffer (1 <pH< 3) are allowed to react. For Rh(OH₂)₅OH₂₊+ SO₂ □ Rh(OH₂)₅(OSO₂H)²⁺ (k₁/k_-1), k₁ = (2.2 ±0.2) × 10³ dm³ mol⁻¹ s⁻¹, k₋1 = 0.58 ±0.16 s⁻¹ (25°C,I = 0.5 mol dm⁻³). The protonated O-sulphito complex is a moderate acid (K _d = 3 × 10⁻⁴ mol dm⁻³, 25°C, I= 0.5 mol dm⁻³). This complex undergoes (O, O) chelation by the bound bisulphite withk= 1.4 × 10⁻³ s⁻¹ (31°C) to Rh(OH₂)₄(O₂SO)⁺ and the chelated sulphito complex takes up another HSO ₃ ⁻ in a fast equilibrium step to yield Rh(OH₂)₃(O₂SO)(OSO₂H) which further undergoes intramolecular ligand isomerisation to the S-bonded sulphito complex: Rh(OH₂)₃(O₂SO)(OSO₂)^- → Rh(OH₂)₃(O₂SO)(SO₃)⁻ (k _iso = 3 × 10⁻⁴ s⁻¹, 31°C). A dinuclear (μ-O, O) sulphite-bridged complex, Na₄[Rh₂(μ-OH)₂(OH)₂(μ-OS(O)O)(O₂SO)(SO₃) (OH₂)]5H₂O with (O, O) chelated and S-bonded sulphites has been isolated and characterized. This complex is sparingly soluble in water and most organic solvents and very stable to acid-catalysed decomposition     

[Bis(trispivalatodimolybdenum (II))-μ-bis(4′-carboxylato-2,2′:6′,2″-terpyridine) Ruthenium (II)] (2+) Tetrafluoroborate. Preparation,Electronic Structure and Physical Properties

The homoleptic compound Ru(II)(L)₂ where L = 4′-carboxylato-2,2′:6′,2″-terpyridine was employed as a bridge to link two [Mo₂(O₂CBu ^t )₃]⁺ units in the formation of the title complex: [Mo₂(O₂CBu ^t )₃]₂-μ-Ru(II)L₂] (2+) [BF₄⁻]₂, which has been characterized by ¹H-NMR, UV–vis and emission spectroscopy, MALDI-TOF-MS and cyclic voltammetry. The electronic structure of the complex has been investigated by density functional theory employing Turbomole on the model complex cation [Mo₂(O₂CH)₃]₂-μ-(Ru(II)L₂)²⁺. The intense blue color of the cation arises from M₂ δ to bridge/terpyridine charge transfer. This paper is dedicated to Prof. F. A. Cotton in memoriam.     

Organic acid effect on the structures of Cd(II) metal-organic complexes based on 2-(3-pyridyl)imidazo[4,5-<Emphasis Type="Italic">f</Emphasis>]-1,10-phenanthroline

Three new Cd(II) complexes consisting of phenanthroline derivative and organic acid ligands, formulated as [Cd₃(3-PIP)₂(L¹)₆] (I), [Cd(3-PIP)(L²)] · H₂O (II), and [Cd(3-PIP)(L³)] (III) (3-PIP = 2-(3-pyridyl)imidazo[4,5-f]-1,10-phenanthroline, HL¹ = 3,5-dinitrobenzoic acid, H₂L² = oxalic acid, H₂L³ = benzene-1,3-dicarboxylic acid), have been synthesized via the hydrothermal reaction and characterized by single-crystal X-ray diffraction, elemental analyses and FT-IR spectra. Complex I is a trinuclear structure. Complex II features a 1D zigzag chain. Complex III shows a twisted double chain of binuclear units sustained by double carboxylate bridges. Three complexes are further extended into 3D supramolecular frameworks by hydrogen bonding and π-π-stacking interactions. The structural differences among I–III show that the organic carboxylates have important effects on the structures. Furthermore, the supramolecular interactions are the critical factors in determining the final structures of the complexes. In addition, the thermal stabilities and luminescent properties of complexes I and II are also investigated.     

Comparative study on the photophysical properties between carbene-based Fe (II) and Ru (II) complexes

The comparative study on the photophysical properties between cheap metal Fe (II) complexes and noble metal Ru (II) complexes with identical ligand coordination is performed by the combination of density functional theory (DFT) and time-dependent density functional theory (TDDFT) to evaluate the potential alternative applications of Fe (II) complexes. RuBIP (BIP = 2,6-bis (imidazol-2- ylidene)pyridine) is theoretically established that the radiative lifetime of the second lowest triplet state is more consistence with experimental value. However, FeBIP retains nonluminous because of low-lying ³MC originated from weak d orbital splitting. FeBIPC (FeBIP with carboxylic acid groups) has twice longer lifetime than its parent complex FeBIP due to the great decrease of the energy gap between ³MLCT and ³MC. What's more, the lifetimes of Fe (II) complexes detected in the experiments are more accessible to nonradiative decay lifetimes of ³MC. The carboxylic acid groups are beneficial for the improvement of luminescent possibility and controllability of Fe (II) complexes, while there is still a huge challenge for effective material replacement comparing with Ru (II) complexes.     

Syntheses and crystal structures of two novel Cu(II) and Co(II) complexes with 3-methyl-4-(p-bromophenyl)-5-(2-pyridyl)-1,2,4-triazole

A new ligand, 3-methyl-4-(p-bromophenyl)-5-(2-pyridyl)-1,2,4-triazole (L) and its complexes, trans-[CuL₂(ClO₄)₂] (1) and cis-[CoL₂(H₂O)₂](ClO₄)₂·H₂O·CH₃OH (2), have been synthesized and characterized by UV, IR, electrospray ionization mass spectrum, elemental analyses, and single-crystal X-ray diffraction methods. In the structure, two L ligands are stabilized by intermolecular π···π interactions between the triazole rings. In the complexes, each L ligand adopts a chelating bidentate mode through N atom of pyridyl group and one N atom of the triazole. Both complexes have a similar distorted octahedral [MN₄O₂] core (M = Cu²⁺ and Co²⁺) with two ClO₄ ⁻ ions in the trans position in 1 but two H₂O molecules in the cis arrangement in 2.     

Two manganese(II) complexes based on anthracene-9-carboxylate: Syntheses,crystal structures,and magnetic properties

Abstract  To explore the influence of the anthracene ring skeleton, with a large conjugated π-system, on the structures and properties of its complexes, two Mn^II complexes with anthracene-9-carboxylate ligand were synthesized and structurally characterized: {[Mn(L)₂(H₂O)₂](H₂O)}_∞ (1) and [Mn₂(L)₄(phen)₂(μ-H₂O)](CH₃OH) (2) (L = anthracene-9-carboxylate and phen = 1,10-phenanthroline). Complex (1) has a one-dimensional (1D) chain structure that is further assembled to form a two-dimensional (2D) sheet, and then an overall three-dimensional (3D) network by π···π stacking and/or C–H···π interactions. Complex (2) makes a dinuclear structure by incorporating the chelating phen ligand, which is further interlinked via inter-molecular π···π stacking and C–H···π interactions to generate a higher-dimensional supramolecular network along the different crystallographic directions. The results reveal that the bulky anthracene ring skeleton in L, by virtue of intra- and/or inter-molecular π···π stacking and C–H···π interactions, plays an important role in the formation of complexes (1) and (2). The magnetic properties of (1) and (2) were further investigated. As expected, the very long inter-metallic separations result in weak magnetic coupling, with the corresponding coupling constant values of J = −10 cm⁻¹ for (1) and J = −2.46 cm⁻¹ for (2). Graphical abstract  The constructions of two new Mn^II complexes comprising 1D chain (1) and dinuclear subunit (2) structures have been successfully achieved by using a bulky anthracene-9-carboxylic acid (HL), together with incorporating the chelating 1,10-phenanthroline as a co-ligand for (2). The result reveals that the bulky anthracene ring skeleton of HL, by virtue of intra- and/or inter-molecular π···π stacking and C–H···π interactions, plays an important role in the formation of the supramolecular architectures of (1) and (2). Moreover, magnetic properties of the complexes have been investigated.      

Some donor-acceptor complexes of silicon phthalocyanine dianions

Studying the reaction of PcSiX₂ (X = Cl, OH) with KOH in DMSO we first discovered red D-A complexes [(Pc²⁻)·PcSiX²] and [(Pc²⁻)·O²] in which silicon phthalocyanine dianion Pc²⁻ is a donor, and the parent phthalocyanine silicon or oxygen are acceptors of electron density. The complexes were characterized by electron absorption, NMR, and ESR spectra. In the reactions with Me₃SiCl, H₂O, or CH₃COOH the complexes regenerate phthalocyanine and O₂. In O₂ atmosphere the [(Pc²⁻)·O₂] complex gradually degrades affording a product of unknown nature.     

Syntheses,Structures of Two Rare Earth-Vanadyl Complexes and Highly Selective Fluorescence Detection of Zn<Superscript>2+</Superscript>

Two rare earth vanadyl complexes incorporating N-(p-benzoic acid methylene)imino dimethylene phosphonic acid, {[Ce(H₂O)₇]₂[V₁₀O₂₈]}·11H₂O (1) and {[Gd(H₂O)₇]₂[V₁₀O₂₈]}·11H₂O (2) were synthesized and characterized by IR spectra, UV-Vis spectra, Fluorescence spectra and single crystal X-ray analysis. In complexes 1 and 2, they are isomorphism, triclinic, space group P-1, V⁵⁺ ion for the hexa-coordinate with oxygen constitute [V₁₀O₂₈] ⁶⁻ cluster, in which oxygen were taken μ1, μ2, μ3, μ6 method of allocation. Ce³⁺ ion is nine-coordinate. Complex 1 has a very strong selective of Zn²⁺ from the fluorescence spectra, and can as highly selective probes for Zn²⁺.     

Resonance capture of electrons by cyclopentadienyltricarbonylmanganese and -rhenium derivatives

Negative ion mass spectra of cyclopentadienyltricarbonylmanganese and-rhenium derivatives RC₅H₄M(CO)₃ (R=H, CN, COOH, COMe, COOMe, CH₂OH, CHO; M=Mn, Re) were studied. The subsequent detachment of carbonyl groups is the main process of the fragmentation of these compounds under the conditions of the resonance capture of electrons. On going fron the rhenium complexes to manganese derivatives, the maxima of the yields of the ions [M-nCO]⁻ (n=1–3) shift to the lower energy region indicating that the stability of the Re−CO bond is higher than that of Mn−CO. The average lifetimes of the molecular negative ions relative to the autodetachment of an electron (τ_a) and to dissociation (τ_d) were measured. It was found that electron-accepting substituents increase the τ_a value and decrease τ_d. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1161–1164, June, 1997.     

Synthesis, DNA-binding and photocleavage studies of ruthenium(Ⅱ) complexes [Ru(btz)_3]~(2+) and [Ru(btz)(dppz)_2]~(2+)

Two new ruthenium(Ⅱ) complexes, [Ru(btz)3](ClO4)2 (1) and [Ru(btz)(dppz)2](ClO4)2 (2) (btz = 4,4′-bithi-azole, dppz = dipyrido[3,2-a:2′,3′-c]phenazine), have been synthesized and characterized by elemental analysis, 1H NMR, ES-MS and X-ray crystallography. The DNA binding behaviors of two complexes have been studied by spectroscopic and viscosity measurements. The results suggest that complex 1 binds to CT-DNA via an electrostatic mode, while complex 2 via an intercalative mode. Under irradiation at 365 nm,...