A new polymeric chain in the dihydrogendecavanadate(V)–decavanadate(V) [NH2(CH2)4]5[V10O28H2]0.5[V10O28]0.5 obtained by in situ synthesis of the organic cation

A new polymeric compound, [NH₂(CH₂)₄]₅[V₁₀O₂₈H₂]_0.5[V₁₀O₂₈]_0.5, was obtained by in situ synthesis of the organic cation from an aqueous solution of V₂O₅–HCl–NH₂(CH₂)₄NH₂. The crystal structure was solved by single-crystal X-ray diffraction. [NH₂(CH₂)₄]₅[V₁₀O₂₈H₂]_0.5[V₁₀O₂₈]_0.5 consists of dihydrogendecavanadate(V), [H₂V₁₀O₂₈]^4?, and decavanadate(V), [V₁₀O₂₈]^6?, units assembled in one-dimensional arrays by interanionic hydrogen bonds O–H?O and cation-anion N–H?O interactions. The latter involve pyrrolidinium cations, which were obtained in the compound instead of the starting butane-1,4-diamine. Pyrrolidinium cations further connect the polymeric chains into a three-dimensional network. The presence of the two types of units, [H_nV₁₀O₂₈]^(6?n)? with n = 0 and n = 2, in one compound was not yet observed and is herein reported for the first time.     

Photochemical reductive elimination of [PtIV(NH3)4(NH2)Cl]2 +: Photogeneration of hydrazine

When [Pt^IV(NH₃)₅Cl]^3 + is deprotonated the complex [Pt^IV(NH₃)₄(NH₂)Cl]^2 + is formed. Upon NH₂⁻ → Pt^IV LMCT excitation (λ_irr > 250 nm) a reductive elimination takes place: [Pt^IV(NH₃)₄(NH₂)Cl]^2 + → [Pt^II(NH₃)₃Cl]⁺ + N₂H₄ + H⁺. Since Pt(II) ammine complexes can be reoxidized to Pt(IV) by H₂O₂ it is suggested that in a cyclic process the overall reaction could proceed according to the equation: 2 NH₃ + H₂O₂ → N₂H₄ + 2 H₂O.     

Binuclear cyano-bridged complex derived from [MnIII(salpn)] and [FeIII(CN)6]: Synthesis,structure and magnetic properties

The reaction of the neutral [Mn(salpn)C(CN)₃(H₂O)] (salpn^2 − = N,N^′-1,3-propylenebis(salicylideneiminato) dianion) with [Fe^III(CN)₆]^3 − in the presence of strong oxidizer (NH₄)₂S₂O₈ yields a binuclear anion complex [NH₃CH₂CH₂CH₂NH₃]^2 +{[Mn^III(salpn)(H₂O)][Fe^III(CN)₆]}^2 − (1). Its structure, DC and AC susceptibility have been studied. Frequency dependence of the AC susceptibility characteristic for single-molecule magnets has been found.     

Reversible nitro–nitrito inter-conversion in a simple mono-nuclear nickel(II) complex [NiII{C6H4(NH2)2}2(NO2)2] in the solid state

A simple mono-nuclear nickel(II) complex [Ni^II{C₆H₄(NH₂)₂}₂(NO₂)₂] (1) has been synthesized from an aqueous solution containing nickel chloride, sodium nitrite and ortho-phenylenediamine (opda). When crystals of compound 1 are heated in the temperature range of 110–120 °C for 5 min, their brown color changes to blue, that is accompanied by the conversion of nitro group (N-coordinated) in compound 1 into nitrito group (O-coordinated) in compound [Ni^II{C₆H₄(NH₂)₂}₂(ONO)₂] (2). On cooling, the nitrito compound 2 goes back to parent nitro-compound 1.     

Synthesis and crystal structures of two new inorganic–organic hybrid polyoxomolybdate complexes: [Himi]4[{Co(imi)2(H2O)2}Mo7O24] · 4H2O and [Zn(imi)4]2[(imi)2Mo8O26] · 6H2O

The two new inorganic–organic hybrid polyoxomolybdate complexes [Himi]₄[{Co(imi)₂(H₂O)₂}Mo₇O₂₄] · 4H₂O (1) and [Zn(imi)₄]₂[(imi)₂Mo₈O₂₆] · 6H₂O (2) (imi = imidazole) have been prepared by conventional aqueous solution synthesis. Compound 1 consists of heptamolybdate anions [Mo₇O₂₄]⁶⁻ covalently linked by [CoN₂O₄]²⁺ octahedra into one-dimensional zigzag-shaped chains. The zigzag-shaped chains are further linked together via the hydrogen-bonding interactions to form a 2D supramolecular framework. Compound 2 is build up of an imidazole-coordinated octamolybdate anion, two imidazole coordinating zinc cations and lattice water molecules to form a three-dimensional framework via complex hydrogen-bonding.     

A novel transition-metal-linked hexaniobate cluster with photocatalytic H2 evolution activity

A novel transition-metal (TM) complex based on Lindqvist polyoxoniobate K₁₀[(Nb₆O₁₉)Cr^III(H₂O)₂]₂·28H₂O (1) has been synthesized by a new two-pot synthesis strategy and structurally characterized by single crystal X-ray diffraction analysis, IR spectrum, UV–vis spectroscopy, XRPD and TG analysis. Compound 1 crystallizes in the C2/m space group with a = 32.143(19) Å, b = 10.030(6) Å, c = 12.878(8) Å, β = 110.611(9)°, and V = 3886(4) ų. X-ray structure analysis reveals that polyanion [(Nb₆O₁₉)Cr^III(H₂O)₂]₂^10 − (1a) represents the first example of two nuclear dimeric polyoxoniobate, in which two Lindqvist anions [Nb₆O₁₉]⁸ are sandwiched by two {Cr^III(H₂O)₂} groups. Further, 1 exhibits photocatalytic H₂ evolution activity.     

Tetra- and hexanuclear cage molecules based on diruthenium tetracarbonyl sawhorse units: Synthesis and molecular structure of [{Ru2(CO)4(PPh3)2}2(O2CCH2CO2)2] and [{Ru2(CO)4(PMe3)2}3(O2CC6H4CO2)3]

The thermal reaction of Ru₃(CO)₁₂ with malonic acid, followed by the addition of the corresponding ligand, yields the tetranuclear ruthenium complexes [{Ru₂(CO)₄L₂}₂(O₂CCH₂CO₂)₂] (L = PPh₃: 1, L = 3,5-Me₂NC₅H₃: 2), while the reaction of Ru₃(CO)₁₂ with terephthalic acid, followed by the addition of the corresponding ligand, gives rise to the formation of the hexanuclear ruthenium complexes [{Ru₂(CO)₄L₂}₃(O₂CC₆H₄CO₂)₃] (L = PMe₃: 3, L = 3,5-Me₂NC₅H₃: 4). The single-crystal X-ray structure analyses for 1 and 3, reveal both cages to consist of Ru₂(CO)₄ sawhorse units, 1 being a molecular loop, while 3 is a molecular triangle.     

Decavanadate with a novel coordination complex: Synthesis and characterization of (NH4)2[Ni(H2O)5(NH3)]2(V10O28)·4H2O

A new compound (NH₄)₂[Ni(H₂O)₅(NH₃)]₂[V₁₀O₂₈]·4H₂O (1) containing a {V₁₀O₂₈} ⁶⁻ anionic cluster and a novel complex cation, [Ni(H₂O)₅(NH₃)]^2 +, has been synthesized and fully characterized by single crystal X-ray crystallography, spectroscopy and thermogravimetric analysis. The presence of the ammonia ligand in the complex cation in 1 was established unambiguously by X-ray crystallography and variable temperature (200–400 °C) thermogravimetric analyses in combination with FTIR spectroscopic studies. The formation of the novel complex species {Ni(H₂O)₅(NH₃)}^2 + during the synthesis of 1 can be rationalized in terms of ligand substitution involving {Ni(H₂O)₆}^2 +.     

An unprecedented mixed valence cobalt(III)/cobalt(II) ion-pair complex ([CoCO3(bipy)2]2[Co(DCA)2]⋅16H2O) with two novel water tapes

An unprecedented mixed valence cobalt(III)/cobalt(II) ion-pair complex, [CoCO₃(bipy)₂]₂[Co(DCA)₂]⋅16H₂O (1) [bipy = 2,2′-bipyridine, DCA = demethylcantharidate, exo-1,4-epoxy-cyclohexyl-2,3-dicarboxylate group, (C₈H₈O₅)^2 −], has been synthesized and characterized by elemental analysis, IR, UV–vis, Thermogravimetric analysis (TGA) and single crystal X-ray diffraction. The crystal structure of 1 consists of three independent molecular moieties: [CoCO₃(bipy)₂]⁺, [Co(DCA)₂]^2–, and water molecules of crystallization. Interestingly, two novel water tapes, one comprises of alternate cyclic water tetramer and octamer, the other is constructed by alternate cyclic water hexamer and carboxylate–water hybrid octamer [(H₂O)₂(COO)₂]^2 −, have been detected for the first time in the host framework of 1. The two novel water tapes are linked together by the DCA and carbonate ligands via hydrogen bonds into a 2D water layer, and then the water layers assemble complex ions ([CoCO₃(bipy)₂]⁺ and [Co(DCA)₂]^2 −) through hydrogen bonds, π–π interactions and electrostatic interactions to form the overall 3D metal–organic framework structure.     

A novel polyoxometalate-based metal-organic compound constructed from an unprecedented [Ag8(Hpyttz)4(H2pyttz)2] cluster and an in-situ [VW12O40]3 − anion

A novel polyoxometalate (POM)-based metal-organic compound constructed from a multinuclear Ag^I cluster and Keggin-type [VW₁₂O₄₀]^3 − anion, [Ag₄(Hpyttz)₂(H₂pyttz)][HVW₁₂O₄₀]·3H₂O (1) (H₂pyttz = 5′-(pyridin-4-yl)-1H,2′H-3,3′-bi(1,2,4-triazole), was hydrothermally synthesized and characterized by IR spectroscopy, TG analysis, powder and single-crystal X-ray diffraction. In compound 1, [VW₁₂O₄₀]^3 − (VW₁₂) was in-situ transformed from [SiW₁₂O₄₀]^4 − anion. Eight Ag^I ions were connected by six Hpyttz/H₂pyttz ligands with three coordination modes forming an unprecedented [Ag₈(Hpyttz)₄(H₂pyttz)₂] cluster, which connected with six VW₁₂ anions to construct a 2-D double-layer (3,6)-connected network with {4³}₂{4⁶.6⁶.8³} topology. Moreover, the photocatalytic activity of 1 has been investigated.     

pH-controlled the formation of 4-sulfocalix[4]arene-based 1D and 2D coordination polymers

Three manganese/4-sulfocalix[4]arene complexes, namely, {H[(C₂₈H₂₀O₁₆S₄)Mn(H₂O)₄Mn_0.5(H₂O)₂]}_n ·6nH₂O (1), {NH₄[(C₂₈H₂₀O₁₆S₄)Mn(H₂O)₄Mn_0.5(H₂O)₂]}_n · 5nH₂O (2), [(C₂₈H₂₀O₁₆S₄)Mn₂(H₂O)₈]_n · 6nH₂O (3), have been synthesized under different pH conditions. Complex 1, which exhibits a one-dimensional (1D) structure, is formed at [H⁺] = 2.0 mol L⁻¹. Reaction at pH 4 leads to another one-dimensional (1D) coordination polymer of 2. At pH 5, a two-dimensional (2D) coordination polymer of complex 3 is formed, showing clearly structural effects on pH response.     

Synthesis and characterization of trans-[Ru(NO)Cl(L)4](PF6)2 (L = isonicotinamide; 4-acetylpyridine) and related species

The trans-[RuCl₂(L)₄], trans-[Ru(NO)Cl (L)₄](PF₆)₂ (L = isonicotinamide and 4-acetylpyridine) and trans-[Ru(NO)(OH)(py)₄]Cl₂ (py = pyridine) complexes have been prepared and characterized by elemental analysis, UV–visible, infrared, and ¹H NMR spectroscopies, and cyclic voltammetry. The MLCT band energies of trans-[RuCl₂(L)₄] increase in the order 4-acpy < isn < py. The reduction potentials of trans-[RuCl₂(L)₄] and trans-[Ru(NO)Cl(L)₄]²⁺ increase in the order py < isn < 4-acpy. The stretching band frequency, ν_NO, of the nitrosyl complexes ranges from 1913 to 1852 cm^?1 indicating a nitrosonium character for the NO ligand. Due to the large π-acceptor ability of the equatorial ligands, the coordinated water is much more acidic in the water soluble trans-[Ru(NO)(H₂O)(py)₄]³⁺ than in trans-[Ru(NO)(H₂O)(NH₃)₄]³⁺.     

[Ag2(aca)2]n and [Ag4(aca)4(NH3)2] (acaH = 9-anthracenecarboxylic acid): Synthesis,X-ray crystal structures,antimicrobial and anti-cancer activities

[Ag₂(9-aca)₂]_n and [Ag₄(9-aca)₄(NH₃)₂] (9-acaH = 9-anthracenecarboxylic acid) have been prepared and structurally characterized. [Ag₂(9-aca)₂]_n consists of polymeric ribbons of linked disilver(I) syn–syn bridged dicarboxylate units. [Ag₄(9-aca)₄(NH₃)₂] is tetrameric and centrosymmetric, with two syn–syn bridging carboxylates linked to the bimetallic Ag–Ag core and a further two syn–anti bridged carboxylate ligands in the equatorial plane, being coordinated to one Ag in the bimetallic core and to a second Ag, with the latter also bonded to an NH₃ ligand. In vitro studies show that both complexes are extremely cytotoxic against selected human fungal and bacterial pathogens, and each complex also greatly inhibits the growth of two mammalian cancer cell lines.     

Ionothermal synthesis and crystal structure of a new layered nickel(II) diphosphate,DRM-1

A new layered ammonium nickel(II) diphosphate, (NH₄)₂[Ni₃(P₂O₇)₂(H₂O)₂], has been synthesized ionothermally in the ionic liquid 1-butyl-3-methyl imidazolium bromide and characterized by powder X-ray diffraction, elemental analysis, scaning electron microscopy, thermogravimetry etc. The results of the characterization show that the crystal adopts the monoclinic space group P2₁/a with the lattice constants a = 9.23529(2) Å, b = 7.98489(2) Å, c = 9.40772(2) Å, β = 100.2608(2)° and Z = 2. Its structure consists of chains of cis- and trans-edge-sharing [NiO₆]-octahedra linked via [P₂O₇] units to form layers of [Ni₃(P₂O₇)₂(H₂O)₂]^2? in the ab plane. Adjacent layers are separated in the c-direction by ammonium ions.     

A MnII5 tetragonal pyramid stabilized by p-tert-butylcalix[8]arene: Synthesis,structure and magnetic property

A compound, [Mn₅(H₄C8A)(OH)₂(C₃H₆NO₂)(DMF)₅(CH₃O)_1.5(HCO₂) (C₂H₃O₂)_0.5]·2DMF·CH₃OH (1) (H₈C8A = p-tert-butylcalix[8]arene, DMF = N,N′-dimethylformamide), was synthesized by the solvothermal method in the mixed CH₃OH/DMF (1:1) solvent. Compound 1 is featured with a tetragonal pyramid-like Mn^II₅ cluster encircled within a calix[8]arene molecule with a ‘pleated loop’ conformation. Magnetic study indicates that the Mn^II centers exhibit antiferromagnetic interactions.     

A novel supramolecular adduct formed by CB[6]-based pseudo-rotaxane and hydrated Zn(II) ion

A novel supramolecular adduct of [C6N2(CB[6])]₃ · [Zn(H₂O)₆]Cl₂ · 14H₂O (1) is reported, where C6N2 = N,N′-bis(2-pyridylmethyl)-1,6-diaminohexane, CB[6] = Cucurbit[6]uril. It consists of a CB[6]-based pseudo-rotaxane and a six-hydrated Zn(II) ion, and forms an infinite 2D network and 3D spatial structure by hydrogen bonding interactions.     

Organometallic boxes built from 5,10,15,20-tetra(4-pyridyl)porphyrin panels and hydroxyquinonato-bridged diruthenium clips

Self-assembly of 5,10,15,20-tetra(4-pyridyl)porphyrin (tpp-H₂) tetradentate panels with dinuclear arene ruthenium clips [Ru₂(η⁶-arene)₂(dhbq)Cl₂] (arene = C₆H₅Me, p-PrⁱC₆H₄Me, C₆Me₆; dhbq = 2,5-dihydroxy-1,4-benzoquinonato) affords the cationic organometallic boxes [Ru₈(η⁶-C₆H₅Me)₈(tpp-H₂)₂(dhbq)₄]⁸⁺ ([1]⁸⁺), [Ru₈(η⁶-p-PrⁱC₆H₄Me)₈(tpp-H₂)₂(dhbq)₄]⁸⁺ ([2]⁸⁺) and [Ru₈(η⁶-C₆Me₆)₈(tpp-H₂)₂(dhbq)₄]⁸⁺ ([3]⁸⁺). These octanuclear cations have been isolated as their triflate salts and characterised by mass spectrometry, NMR and IR spectroscopy. The molecular structure of these systems was deduced by one-dimensional and two-dimensional NMR experiments (ROESY, COSY, HSQC).     

Synthesis,structure and stability of fac-[FeII(CO)3X3]1− (X = Br,I)

fac-[Fe^II(CO)₃X₃]^1? (X = Br, I) are synthesized and their structures have been determined. They are the first crystallographically characterized iron tricarbonyl trihalide complexes. fac-[Fe^II(CO)₃X₃]^1? (X = Br, I) are fairly thermally stable and therefore lead themselves as excellent starting materials for the preparation of various iron carbonyl complexes since both the halide and carbonyl ligands are substitutionally labile.     

[Zn(H2O)4][B6O10]: An open-framework borate with acentric structure

An open-framework borate [Zn(H₂O)₄][B₆O₁₀] with acentric structure, has been successfully obtained for the first time under solvothermal conditions. It has been characterized by powder and single crystal X-ray diffraction, IR spectroscopy, diffuse-reflectance spectroscopy and thermogravimetric (TG) analyses, respectively. It crystallizes in the orthorhombic system, space group Pna2₁, a = 11.3140(6) Å, b = 11.8995(7) Å, c = 8.6140(5) Å and Z = 4. In the structure, the alternative connections between [B₃O₇] units give rise to an unprecedented 3D borate framework with 11- and 10-MR channels, in which the [Zn(H₂O)₄]²⁺ complexes are located. It has a cut-off edge below 200 nm and exhibits second harmonic generation (SHG) efficiency approximately 0.4 times that of KH₂PO₄ (KDP).     

MLCT interaction in [Rh(II)2(CO3)4]4 −( x L)

Complexes of the type [Rh^II₂(CO₃)₄(H₂O)L]^n − with L = N-methylpyrazinium⁺ and 1-heptyl-4-(4-pyridinyl)pyridinium⁺ cations display intense long-wavelength (Rh(II) to L) MLCT absorptions. With L = H₂O, MLCT absorptions are not identified, but the photoreactivity of the complex in aqueous solution supports the assumption that (Rh(II) to CO₃^2 −) MLCT excited states are accessible. Upon irradiation with white light, Rh(II) is photooxidized while carbonate is reduced to CO. The efficiency of this photolysis is very low. However, the occurrence of this photoredox reaction is, nevertheless, of general interest with regard to the photochemical reduction of CO₂.