Ni(2,2':6',2''-terpyridine): a high-spin octahedral formal Ni(0) complex.

We have synthesised and characterised the complex Ni(tpy) (tpy = 2,2':6',2''-terpyridine). This formally Ni(0) complex is paramagnetic both in the solid state and in solution ( = 2). The crystal structure shows an octahedral geometry, with molecules arranged in independent dimers involving π-stacking between pairs of complexes.

Bidirectional noninnocence of hinge-like deprotonated bis-lawsone on selective ruthenium platform: a function of varying ancillary ligands.

The present work aimed to obtain discrete heavier metal complexes of unperturbed deprotonated bis-lawsone (hinge-like HL = 2,2'-bis(3-hydroxy-1,4-napthoquinone). This is primarily due to its limited examples with lighter metal ions (Co, Zn, and Ga) and the fact that our earlier approach with the osmium ion facilitated its functionalisation. Herein, we demonstrated the successful synthesis and structural characterisation of L-derived diruthenium [(bpy)Ru(μ-L)Ru(bpy)](ClO) [1](ClO) ( = 0), (acac)Ru(μ-L)Ru(acac)2 ( = 1) and monoruthenium (pap)Ru(L) 3 ( = 0) derivatives (bpy = 2,2'-bipyridine, acac = acetylacetonate, and pap = 2-phenylazopyridine).

Heteronuclear Dirhodium-Gold Anionic Complexes: Polymeric Chains and Discrete Units.

In this article, we report on the synthesis and characterization of the tetracarboxylatodirhodium(II) complexes [Rh(μ-OCCHOMe)(THF)] () and [Rh(μ-OCCH--CMe)(OH)] () by metathesis reaction of [Rh(μ-OCMe)] with the corresponding ligand acting also as the reaction solvent. The reaction of the corresponding tetracarboxylato precursor, [Rh(μ-OCR)], with PPh[Au(CN)] at room temperature, yielded the one-dimensional polymers (PPh)[Rh(μ-OCR)Au(CN)] (R = Me (), CHOMe (), CHOEt ()) and the non-polymeric compounds (PPh){Rh(μ-OCR)[Au(CN)]} (R = CMe (), CH--CMe ()). The structural characterization of , , , , , and is also provided with a detailed description of their crystal structures and intermolecular interactions.

pH- and Time-Dependent Release of Phytohormones from Diruthenium Complexes.

The controlled release of functionally active compounds is important in a variety of applications. Here, we have synthesized, characterized, and studied the magnetic properties of three novel metal-metal-bonded tris(formamidinato) Ru complexes. We have used different auxin-related hormones, indole-3-acetate (IAA), 2,4-dichlorophenoxyacetate (2,4-D), and 1-naphthaleneacetate (NAA), to generate [RuCl(μ-DPhF)(μ-IAA)] (), [RuCl(μ-DPhF)(μ-2,4-D)] (), and [RuCl(μ-DPhF)(μ-NAA)] () (DPhF = ,'-diphenylformamidinate).

Three Bis-BODIPY Analogous Diruthenium Redox Series: Characterization and Electronic Structure Analysis.

The dianion derived from (2Z,6Z)-3,7-diphenyl-N2,N6-di(pyridin-2-yl)pyrrolo[2,3-f]indole-2,6(1H,5H)-diimine (H BL), a modified BODIPY ligand precursor, is shown to be capable of bridging two metal complex fragments RuL , L=2,4-pentanedionato (acac ), 2,2'-bipyridine (bpy) or 2-phenylazopyridine (pap) in [Ru(acac) Ru(μ-BL)Ru(acac) ] (1/2), [Ru(bpy) Ru(μ-BL)Ru(bpy) ](ClO ) ([3](ClO ) ) and [Ru(pap) Ru(μ-BL)Ru(pap) ](ClO ) ([4](ClO ) ). The compounds, including a diastereoisomeric pair 1 (meso) and 2 (rac) were spectroscopically and structurally characterized. Reversible electron transfers as revealed by cyclic and differential pulse voltammetry allowed for an EPR and UV-vis-NIR spectroelectrochemical investigation of several neighboring charge states.

Preparation of Dimeric Monopentamethylcyclopentadienyltitanium(III) Dihalides and Related Derivatives.

The synthesis, crystal structure, and reactivity of a series of half-sandwich titanium(III) dihalide complexes [Ti(η-CMe)X] (X = Cl, Br, I) and several of its Lewis base derivatives were investigated. The reaction of the trihalides [Ti(η-CMe)X] (X = Cl (), Br (), I ()) with LiAlH (≥1 equiv) in toluene at room temperature results in the formation of the halide-bridged dimers [{Ti(η-CMe)X(μ-X)}] (X = Cl (), Br (), I ()). The treatment of with [Li{N(SiMe)}] (≥2 equiv) at room temperature affords the precipitation of the amido titanium(III) complex [{Ti(η-CMe)(μ-Cl){N(SiMe)}}] (), but analogous reactions of with other lithium reagents [LiR] (R = Me, CHSiMe, NMe) lead to disproportionation into titanium(IV) [Ti(η-CMe)R] and presumably titanium(II) derivatives.

Tetracarbonatodiruthenium Fragments and Lanthanide(III) Ions as Building Blocks to Construct 2D Coordination Polymers.

Two-dimensional coordination polymers of [Pr(DMSO)₂(OH₂)₃][Ru₂(CO₃)₄(DMSO)(OH₂)]·5H₂O () and [Ln(OH₂)₅][Ru₂(CO₃)₄(DMSO)]·H₂O (Ln = Sm (), Gd ()) formulae have been obtained by reaction of the corresponding Ln(NO₃)₃·6H₂O dissolved in dimethyl sulphoxide (DMSO) and K₃[Ru₂(CO₃)₄]·4H₂O dissolved in water. Some DMSO molecules are coordinated to the metal atoms reducing the possibilities of connection between the [Ru₂(CO₃)₄] and Ln building blocks giving rise to the formation of two-dimensional networks. The size of the Ln ion and the synthetic method seem to have an important influence in the type of two-dimensional structure obtained.

Synthesis and Structural Characterization of a Series of One-Dimensional Heteronuclear Dirhodium-Silver Coordination Polymers.

Herein, we describe the preparation of heteronuclear dirhodium-silver complexes by reaction between molecular Rh(II)-Rh(II) compounds [Rh₂(μ-O₂CR)₄L₂] (R = Me, Ph (), CH₂OEt (); L = solvent molecules) with paddlewheel structure and PPh₄[Ag(CN)₂]. One-dimensional coordination polymers of (PPh₄)[Rh₂(μ-O₂CR)₄Ag(CN)₂] (R = Me (), Ph (), CH₂OEt ()) formula have been obtained by replacement of the two labile molecules in the axial positions of the paddlewheel structures by a [Ag(CN)₂] bridging unit. The crystal structures of ⁻ display a similar arrangement, having anionic chains with a wavy structure and bulky (PPh₄)⁺ cations placed between the chains.

Questions of Noninnocence and Ease of Azo Reduction in Diruthenium Frameworks with a 1,8-Bis(( E)-phenyldiazenyl)naphthalene-2,7-dioxido Bridge.

Ligands containing the azo group are often used in various metal complexes owing to their facile one-electron reduction, which in effect extends the means of degrading environmentally harmful azo dyes. In order to probe the idea of the generally accepted ease of reduction of azo-containing compounds, we present here three different diruthenium complexes [(acac)Ru(μ-L)Ru(acac)] (diastereomeric 1/2), [(bpy)Ru(μ-L)Ru(bpy)](ClO) ([3](ClO)), and [(pap)Ru(μ-L)Ru(pap)](ClO) ([4](ClO) ) with a bridging ligand (L = 1,8-bis(( E)-phenyldiazenyl)naphthalene-2,7-dioxido) that contains azo groups in addition to phenoxide-type donors. The Ru-Ru complexes (1/2) display interesting one-dimensional-chain effects, as revealed by temperature-dependent magnetic studies.

Unsymmetric (μ-oxido)/(μ-pyrazolato) and Symmetric (μ-pyrazolato)2 Bridged Diosmium Frameworks: Electronic Structure and Magnetic Properties.

The present article deals with the structurally characterized unsymmetric oxido/pyrazolato-bridged [(bpy)2Os(III)(μ-oxido)(μ-pz)Os(III)(bpy)2](ClO4)3 ([1](ClO4)3) and symmetric dipyrazolato-bridged [(bpy)2Os(II)(μ-pz)2Os(II)(bpy)2](ClO4)2 ([2](ClO4)2) (pz = pyrazolato, bpy = 2,2'-bipyridine) complexes with the Os···Os separations of 3.484 and 4.172 Å, respectively.

Metal-Induced Thiophene Ring Opening and C-C Bond Formation To Produce Unique Hexa-1,3,5-trienediyl-Coupled Non-Innocent Ligand Chelates.

Ring opening of thiophenes containing an azo function in 2-position and subsequent dimerization through C-C coupling were observed on reaction with [Ru(acac)2 (CH3 CN)2 ] (acac=acetylacetonate) to produce two 1,3,5-hexatriene-linked redox-active azothiocarbonyl chelate systems. Interaction of the non-innocent chelate ligands and of the metals at a nanoscale distance of 1.45 nm via the conjugated hexatriene bridge was studied by magnetic and electron spectroscopic measurements in conjunction with DFT calculations, revealing four-center magnetic interactions of this unique setting and weak intervalence coupling after reduction.

Novel tetranuclear Ni(II) Schiff base complex containing Ni4O4 cubane core: synthesis, X-ray structure, spectra and magnetic properties.

Novel tetranuclear nickel(II) Schiff base complex having symmetric Ni4O4 cubane-core, [Ni4O2(OAc)2(L)2] (1) has been synthesized. Single crystal of the complex exhibits four nickel atoms in the alternate corner of the cubane and other four sites are occupied by phenolate-O and μ3-O(2-). Variable temperature magnetic moment data suggests the Ni centres are weakly antiferromagnetically coupled with J1=-4.

Sensitivity of the valence structure in diruthenium complexes as a function of terminal and bridging ligands.

The compounds [(acac)2Ru(III)(μ-H2L(2-))Ru(III)(acac)2] (rac, 1, and meso, 1') and [(bpy)2Ru(II)(μ-H2L(•-))Ru(II)(bpy)2](ClO4)3 (meso, [2](ClO4)3) have been structurally, magnetically, spectroelectrochemically, and computationally characterized (acac(-) = acetylacetonate, bpy = 2,2'-bipyridine, and H4L = 1,4-diamino-9,10-anthraquinone). The N,O;N',O'-coordinated μ-H2L(n-) forms two β-ketiminato-type chelate rings, and 1 or 1' are connected via NH···O hydrogen bridges in the crystals. 1 exhibits a complex magnetic behavior, while [2](ClO4)3 is a radical species with mixed ligand/metal-based spin.

Structural, magnetic and electrical properties of one-dimensional tetraamidatodiruthenium compounds.

The first bromo and iodo tetraamidatodiruthenium compounds of the type [Ru2X(μ-NHOCC6H4-R)4]n [X = Br, R = o-Me (1), m-Me (2), p-Me (3); X = I, R = o-Me (4), m-Me (5), p-Me (6)] have been prepared using solvothermal or microwave activation procedures. In these reactions ethanol or methanol as solvents have been used to make the synthesis procedures more environment-friendly. Solvothermal synthesis has allowed us to isolate single crystals of these extremely insoluble compounds and the crystal structures of all of them have been determined using single crystal X-ray diffraction.

Influence of ancillary ligands on the electronic structure and anion sensing features of ligand bridged diruthenium complexes.

The present article deals with a newer class of ligand bridged asymmetric complexes incorporating ancillary ligands (AL) with varying electronic characteristics: [(bpy)2Ru(II)(μ-HL(2-)) Ru(II)(bpy)2](ClO4)2·([1](ClO4)2); [(pap)2Ru(II)(μ-HL(2-))Ru(II)(pap)2](ClO4)2 ([2](ClO4)2); [(bpy)2Ru(II)(μ-HL(2-))Ru(II)(pap)2](ClO4)2 ([3](ClO4)2); [(acac)2Ru(III)(μ-HL(2-))Ru(III)(acac)2] (4) and [(bpy)2Ru(II)(μ-HL(2-))Ru(III)(acac)2]ClO4 ([5]ClO4) (H3L: 5-(1H-benzo[d]imidazol-2-yl)-1H-imidazole-4-carboxylic acid, bpy = moderately π-accepting 2,2'-bipyridine, pap = strongly π-accepting 2-phenylazopyridine, acac(-) = σ-donating acetylacetonate). The molecular identity of [1](ClO4)2 was established by its single crystal X-ray structure. A large shift in Ru(II)/Ru(III) potential of 0.

Comparative study of different methods for the preparation of tetraamidato- and tetracarboxylatodiruthenium compounds. Structural and magnetic characterization.

Solvothermal and microwave assisted synthesis were used as green and very useful alternative methods to obtain new chloridotetraamidatodiruthenium compounds, [Ru(2)Cl(μ-NHOCR)(4)](n) [R = Me-o-C(6)H(4) (1), Me-m-C(6)H(4) (2), Me-p-C(6)H(4) (3)]. The analogous tetracarboxylato complexes [Ru(2)Cl(μ-O(2)CR)(4)](n) [R = Me-o-C(6)H(4) (4), Me-m-C(6)H(4) (5), Me-p-C(6)H(4) (6)] have also been obtained. These synthetic methods allow the use of greener solvents like water or ethanol.

Time-dependence structures of coordination network wires in solution.

We present a mechanochemistry-based procedure to isolate individual chains on surfaces of a ruthenium MMX polymer. After sonication of solutions containing the two building blocks of the mentioned MMX polymer, time-depending structures are formed in the solution. The architecture of the different structures obtained in this process, as a function of the time, is monitored using atomic force microscopy.

A conducting coordination polymer based on assembled Cu9 cages.

We report on a novel highly semiconducting 1D coordination polymer architecture obtained by the reaction of a Cu(II) salt with 2,2'-dipyridyldisulfide under microwave solvothermal conditions. This reaction proceeds with an unusual C-S and S-S bond cleavage of the 2,2'-dipyridyldisulfide ligand. The unprecedented architecture of this coordination polymer consists of a 1D chain formed by the assembling of Cu9 cluster cages.

MMX polymer chains on surfaces.

Fibres of [Ru(2)Br(micro-O(2)CEt)4]n polymer have been isolated on different surfaces under specific conditions, and morphologically characterised by AFM and STM, showing an unexpected helical internal structure.