Molybdenum Bisphosphonates with Cr(III) or Mn(III) Ions

The synthesis of Mo^VI bisphosphonates (BPs) complexes in the presence of a heterometallic element has been studied. Two different BPs have been used, the alendronate ligand, [O₃PC(C₃H₆NH₃)(O)PO₃]^4? (Ale) and a new BP derivative with a pyridine ring linked to the amino group, [O₃PC(C₃H₆NH₂CH₂C₅H₄N)(O)PO₃]^4? (AlePy). Three compounds have been isolated, a tetranuclear Mo^VI complex with Cr^III ions, (NH₄)₅[(Mo₂O₆)₂(O₃PC(C₃H₆NH₃)(O)PO₃)₂Cr]·11H₂O (Mo₄(Ale)₂Cr), its Mn^III analogue, (NH₄)_4.5Na_0.5[(Mo₂O₆)₂(O₃PC(C₃H₆NH₃)(O)PO₃)₂Mn]·9H₂O (Mo₄(Ale)₂Mn), and a cocrystal of two polyoxomolybdates, (NH₄)₁₀Na₃[(Mo₂O₆)₂(O₃PC(C₃H₆NH₂CH₂C₅H₄N)(O)PO₃)₂Cr]₂[CrMo₆(OH)₆O₁₈]·37H₂O ([Mo₄(AlePy)₂Cr]₂[CrMo₆]). In this latter compound an Anderson-type POM [CrMo₆(OH)₆O₁₈]^3? is sandwiched between two tetranuclear Mo^VI complexes with AlePy ligands. The protonated triply bridging oxygen atoms bound to the central Cr^III ion of the Anderson anion develop strong hydrogen bonding interactions with the oxygen atoms of the bisphosphonate complexes. The UV–Vis spectra confirm the coexistence in solution of both POMs. Cyclic voltammetry experiments have been performed, showing the reduction of the Mo centers. In strong contrast with the reported Mo^VI BP systems, the presence of trivalent cations in close proximity to the Mo^VI centers dramatically impact the potential solid-state photochromic properties of these compounds.     

Interaction of bivalent transition metal ions with iminodiacetato-(pentaammine/tetraammine)cobalt(III) ions. A kinetic and equilibrium study

Summary The kinetics of reversible complexation of Ni^II and Co^II with iminodiacetato(pentaammine)cobalt(III), [(NH₃)₅-Co(idaH₂)]³⁺ and Ni^II with iminodiacetato(tetraammine)-cobalt(III), [(NH₃)₄Co(idaH)]²⁺, have been investigated by the stopped-flow technique at 25 °C, pH = 5.7–6.9 and I = 0.3 mol dm ^–3. The reaction paths (NH₃)₅Co(idaH)²⁺+M²⁺(NH₃)₅Co(ida)M³⁺+H⁺ (NH₃)₅Co(ida)⁺+M²⁺(NH₃)₅Co(ida)M³⁺ (NH₃)₄Co(ida)⁺+Ni²⁺(NH₃)₄Co(ida)Ni³⁺ have been identified (idaH = N⁺H₂(CH₂CO₂)₂H, ida = NH(CH₂COO)^2–]. The rate parameters for the formation and dissociation of the binuclear species are reported. The data are essentially consistent with an I _d mechanism. The dissociation rate constants of the binuclear species indicate that Ni²⁺ and Co²⁺ are chelated by the coordinated iminodiacetate moiety.     

Hydrazinium Oxalatometallates of Rare Earths(III)

Oxalates of La(III), Ce(III), Pr(III), Nd(III) and Sm(III) with the hydrazinium cation with the general formulae (N₂H₅)₄Ln₂(C₂O₄)₅7H₂O (Ln=La³⁺, Ce³⁺, Pr³⁺) and N₂H₅Ln(C₂O₄)₂·3.5H₂O (Ln=Nd³⁺, Sm³⁺) were synthesized. The thermal decompositions of these compounds take place in three stages: thermal dehydration at 65–100°C, exothermic decomposition of the N₂H₄ at 230–260°C, and oxidation of the oxalate ion.This revised version was published online in November 2005 with corrections to the Cover Date.     

Über Reaktionen oxygenierter Kobalt(II)-Komplexe. IX. Oxydative Eigenschaften von Tetrakis(äthylendiamin)-μ-peroxo-μ-hydroxo-dikobalt(III)

Reactions of oxygenated cobalt(II) complexes. IX. Oxidative properties of tetrakis(ethylenediamine)-μ-peroxo-μ-hydroxo-dicobalt(III)

1 VIII s. [1].

[(en)₂Co(O₂, OH)Co(en)₂]³⁺ ( a ) reacts with I^? in acidic aqueous solution according to: Co^III(O₂, OH)Co^III + 21^? + 5H⁺ ? 2Co^III + 3H₂O + I₂. Using I^? in excess first order rate constants are obtained which, to a first approximation, are independent of [I^?]. Comparison with kinetic data of deoxygenation of [(en)₂Co(O₂, OH)Co(en)₂]³⁺ under analogous conditions suggests that both reactions have the same rate determining step. The singly bridged species [(en)₂(H₂O)CoO₂Co(H₂O) (en)₂]⁴⁺ is shown to be the reactive intermediate in the iodide oxidation (Schema 2).     

209Bi NQR study of bismuth(III) complexes

Potassium pentafluorobismuthate(III), nitrate-chloride Bi^III complexes MBiCl₃NO₃ (M=K, (NH₂)₂CNH₂), sulfate-chloride Bi^III complexes MBiCl₂SO₄ (M=K, Rb, NH₄, (NH₂(₂CNH₂), and Bi^III complexonates with the anions of ethylenediaminetetraacetic acid M[Bi(edta)]₂·nH₂O (M=Mg, Ca, Ni, Cd) and nitrilotriacetic acid Bi(nta)·2H₂O, and Bi(nta)·3thio·H₂O (thio is thiourea) were studied by²⁰⁹Bi NQR spectroscopy. A second-order phase transition was observed in K₂BiF₅ at 100 K. The compounds Bi(nta)·2H₂O, (NH₂)₂CNH₂BiCl₃NO₃, and MBiCl₂SO₄ (M=K, NH₄) are piezoelectrics. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2237–2240, November, 1998.     

Ruthenium(III) and iridium(III) complexes with nicotine

A new chloride-dimethylsulfoxide-ruthenium(III) complex with nicotine trans-[Ru^IIICl₄(DMSO)[H-(Nicotine)]] (1) and three related iridium(III) complexes; [H-(Nicotine)]trans-[Ir^IIICl₄(DMSO)₂] (2), trans-[Ir^IIICl₄(DMSO)[H-(Nicotine)]] (3) and mer-[Ir^IIICl₃(DMSO)(Nicotine)₂] (4) have been synthesized and characterized by spectroscopic techniques and by single crystal X-ray diffraction (1, 2, and 4). Protonated nicotine at pyrrolidine nitrogen is present in complexes 1 and 3 while two neutral nicotine ligands are observed in 4. In these three inner-sphere complexes coordination occurs through the pyridine nitrogen. Moreover, in the outer-sphere complex 2, an electrostatic interaction is observed between a cationic protonated nicotine at the pyrrolidine nitrogen and the anionic trans-[Ir^IIICl₄(DMSO)₂]^¯ complex.     

Complexation of cobalt(II) with histidinato(pentaammine)cobalt(III) in aqueous medium. A kinetic and mechanistic study

Summary The kinetics of formation and dissociation of the binuclear complex of Co^II with histidinato(pentaammine)Co^III have been studied at 10.0°Ct°C25°C and I = 0.3 mol dm^–3 (ClO _inf4 ^sup– ). The formation of the binuclear complex, [(NH₃)₅Co^IIILCo^II]⁴⁺ (L = histidinate), in the 5.7–6.8 pH range involves the reaction of Co(OH₂) _inf6 ^sup2+ with the deprotonated, (NH₃)₅CoL²⁺, and monoprotonated, (NH₃)₅CoLH₃₊, forms of the complex. The rate and activation parameters for the formation are consistent with an I _d mechanism. The binuclear species undergoes dissociation to yield the parent Co^III substrate and Co(OH₂) _inf6 ^sup2+ via spontaneous and acid-catalysed paths. Comparison of spontaneous dissociation rate of the binuclear complex with other related systems indicated the chelate nature of the binuclear species.     

Synthesis, structure, and properties of chromium(III) sulfates

Reactions between CrO₃ and 50- are studied at temperatures up to the boiling point of the acid. Depending on the H₂SO₄ concentration and synthesis temperature, Cr₂(SO₄)₃, CrH(SO₄)₂, (H₃O)[Cr(SO₄)₂], Cr₂(SO₄)₃·H₂SO₄·4H₂O (gross formula), and (H₅O₂)[Cr(H₂O)₂(SO₄)₂], are obtained as identified reaction products in addition to the incompletely characterized chromic-sulfuric acid. The Cr^III-based sulfates are characterized by X-ray powder diffraction, thermogravimetric, and magnetic susceptibility measurements. The nuclear and magnetic structures of Cr₂(SO₄)₃ at are determined, the structure type of (H₃O)[Cr(SO₄)₂] is established, and the crystal structure of (H₅O₂)[Cr(H₂O)₂(SO₄)₂] is firmly stipulated. Magnetic susceptibility data suggest that the samples of CrH(SO₄)₂ are in a micro-crystalline rather than in an amorphous state. All Cr^III-based sulfates synthesized in this study appear to undergo paramagnetic-to-antiferromagnetic transitions at around .     

Synthesen und Kristallstrukturen neuer Bromoferrate(III), Chloro‐ und Aquachloroferrate(III) mit tetraedrischer und oktaedrischer Eisenkoordination,darunter zwei Neutralkomplexe von Eisen(II) und ‐(III)

Halogeno Metallates of Transition Elements with Cations of Nitrogen‐containing Heterocyclic Bases. VIII Syntheses and Crystal Structures of Novel Bromoferrates(III), Chloro‐, and Aquachloroferrates(III) with Tetrahedral and Octahedral Iron Coordination, among them two Neutral Complexes of Iron(II) and (III) (dmpipzH₂)[Fe^IIIBr₄]₂ ( 1 ), (trienH₂)[Fe^IIIBr₄]Br ( 2 ), (dmpipzH₂)[Fe^IIICl₄]Cl ( 3 ), (dmpipzH₂)₂[Fe^III(H₂O)₂Cl₄][Fe^IIICl₄]Cl₂ ( 4 ), and (trienH₂)[Fe^III(H₂O)₃Cl₃]Cl₂ ( 5 ) crystallize from aqueous mineralic acid solutions of iron(II) halide and the organic bases (1,4‐dimethylpiperazine or triethylenediammine) in the presence of atmospheric oxygen whereas (dmpipzH₂)[FeCl₄(H₂O)₆]Cl₂ ( 6 ) was obtained under the exclusion of air. 1 , 2 , and 3 contain the known tetrahedral halogeno complexes, 4 contains a novel octahedral iron(III) complex, and in 6 a neutral binuclear iron(II) complex has been found which has not been described before. The crystal structures and the hydrogen bridging systems of the complexes are described.     

Organoantimony(III)‐Containing Tungstoarsenates(III): From Controlled Assembly to Biological Activity

A family of three sandwich‐type, phenylantimony(III)‐containing tungstoarsenates(III), [(PhSb^III){Na(H₂O)}As^III₂W₁₉O₆₇(H₂O)]^11? ( 1 ), [(PhSb^III)₂As^III₂W₁₉O₆₇(H₂O)]^10? ( 2 ), and [(PhSb^III)₃(B‐α‐As^IIIW₉O₃₃)₂]^12? ( 3 ), have been synthesized by one‐pot procedures and isolated as hydrated alkali metal salts, Cs₃K_3.5Na_4.5[(PhSb^III){Na(H₂O)}As^III₂W₁₉O₆₇(H₂O)]?41H₂O ( CsKNa ‐ 1 ), Cs_4.5K_5.5[(PhSb^III)₂As^III₂W₁₉O₆₇(H₂O)]?35H₂O ( CsK‐2 ), and Cs_4.5Na_7.5[(PhSb^III)₃(B‐α‐As^IIIW₉O₃₃)₂]?42H₂O ( CsNa ‐ 3 ). The number of incorporated {PhSb^III} units could be selectively tuned from one to three by careful control of the reaction parameters. The three compounds were characterized in the solid state by single‐crystal XRD, IR spectroscopy, and thermogravimetric analysis. The aqueous solution stability of sandwich polyanions 1 – 3 was also studied by multinuclear (¹H, ¹³C, ¹⁸³W) NMR spectroscopy. Effective inhibitory activity against six different kinds of bacteria was identified for all three polyanions, for which the activity increased with the number of incorporated {PhSb^III} groups.     

Synthesis and molecular and crystal structures of binuclear complexes of Sm(III), Eu(III), Gd(III), Tb(III), and Dy(III) nitrates with 4,4,10,10-tetramethyl-1,3,7,9-tetraazospiro[5.5]undecane-2,8-dione

Binuclear complexes of Sm(III), Eu(III), Gd(III), Tb(III), and Dy(III) nitrates with 4,4,10,10-tetramethyl-1,3,7,9-tetraazospiro[5.5]undecane-2,8-dione (C₁₁H₂₀N₄O₂, SC)—[Sm(NO₃)₃(SC)(H₂O)]₂(I), [Eu(NO₃)₃(SC)(H₂O)]₂ (II), [Gd(NO₃)₂(SC)(H₂O)₃)]₂(NO₃)₂ (III), [Tb(NO₃)₃(SC)(H₂O)]₂ (IV), [Dy(NO₃)₃(SC)(H₂O)]₂ (V), are synthesized, and their X-ray diffraction analyses are carried out. The crystals of complexes I–V are monoclinic: space group P2₁/n for III and P2₁/c for I, II, IV, and V. In centrosymmetric coordination complexes II, III, IV, and V, the Ln atoms are coordinated by two O(1) and O(2) atoms of two molecules of the SC ligands bound by a symmetry procedure (1 ? x, ?y, 1 ? z), three bidentate nitrate anions, and a water molecule. The coordination numbers of the metal atoms are equal to 9, and the coordination polyhedra are considerably distorted three-capped trigonal prisms, whose bases include the O(1), O(2), O(12) and O(3), O(7), O(9) atoms. The dihedral angle between the bases of the prism is 18°, and that between the mean planes of the side faces is 55°–71° for I, 17° and 55°–71° for II, 16° and 55°–70° for IV, and 16° and 55°–70° for V. The Sm...Sm distance in complex I is 9.44 Å, Eu...Eu in II is 9.42 Å, Tb...Tb in IV is 9.36Å, and Dy...Dy in V is 9.36Å. The gadolinium atom in complex III is coordinated by two oxygen atoms of two ligand molecules bound by a symmetry procedure (?x, ?y + 1, ?z + 1), two bidentate nitrate anions, and three water molecules. One of the nitro groups in compound III is localized in the external coordination sphere of the metal. The coordination number of gadolinium is 9, and the coordination polyhedron is a significantly distorted three-capped trigonal prism, whose base includes the O(1), O(2), O(7) and O(4), O(5), O(9) atoms. The dihedral angle between the bases of the prism is 22.8°, and that between the mean planes of the side faces is 53°–72°. The Gd...Gd distance in complex III is 9.17 Å.     

Cerium(III) Complexes with Lacunary Polyoxotungstates. Synthesis and Structural Characterization of a Novel Heteropolyoxotungstate Based on α-[SbW9O33]9− Units

Several cerium(III) complexes with lacunary polyoxotungstates -B-XW₉O^9– ₃₃ (X=As^III, Sb^III) and W₅O^6– ₁₈, have been synthesized and characterized by single-crystal X-ray analysis, elemental analysis and IR spectroscopy. The X-ray analysis of Na₂₅[Ce(H₂O)₅As₄W₄₀O₁₄₀]63H₂O (1) reveals the framework of the well-known [As₄W₄₀O₁₄₀]^28– anion with a {Ce(H₂O)₅}³⁺ unit in the central site S1. The anion in (NH₄)₁₉[(SbW₉O₃₃)₄{WO₂(H₂O)}₂Ce₃(H₂O)₈(Sb₄O₄)]48H₂O (2) consists of a tetrahedral assembly of four -B-Sb^IIIW₉O^9– ₃₃ units connected by two additional six-coordinate tungsten atoms, three nine-coordinate monocapped square-antiprismatic cerium atoms and a Sb₄O₄ cluster. The Ce^III center in the [Ce(W₅O₁₈)₂]^9– anion in Na₉[Ce(W₅O₁₈)]NaCl30H₂O (3) displays the square-antiprismatic environment observed in all complexes of the type [Ln(W₅O₁₈)₂] ^n–.     

Kinetics and mechanism of oxidation of chromium(III)-tetraoxalylurea complex by periodate

A novel chromium(III) complex of tetraoxalylurea was prepared. In aqueous solutions, [Cr^III(H₂L)(H₂O)]⁺ (H₂L = diprotonated tetraoxalylurea) is oxidized by IO ₄ ^– according to the rate law

Mössbauer study on solid state photolysis of alkali tris(malonato)ferrates(III)

Solid state photolysis of alkali tris(malonato)ferrates(III), i.e., M₃[Fe(CH₂C₂O₄)₃]xH₂O (M=Li, Na, K, NH₄) has been studied employing Mössbauer, infrared and reflectance spectroscopic techniques. The complexes were irradiated for 300 hours using a medium pressure mercury vapour lamp of 250 W, Photodecomposition led to the formation of an iron(II) intermediate, M₂[Fe^II(CH₂C₂O₄)₂(H₂O)₂] (M=Li, Na, K) which on prolonged standing in air oxidized to M[Fe^III(CH₂C₂O₄)₂(H₂O)₂]. However, in case of ammonium complex, Fe^IICH₂C₂O₄·2H₂O once formed remained stable. The extent of photoreduction showed the sequence: NH₄, K>Li>Na. The results have been compared with those of alkali tris (oxalato) ferrates(III).     

Copper(II), iron(III) and cobalt(III) complexes of the pendent-arm cyclam derivative 6,6,13-trimethyl-13-amino-1,4,8,11-tetraazacyclotetradecane

The interaction of Cu(II), Fe(III) and Co(III) with 6,6,13-trimethyl-13-amino-1,4,8,11-tetraazacyclotetradecane (L ³ ) incorporating a pendent amine group has led to isolation of the new octahedral complexes [Cu(HL ³ )(ClO₄)₂]Cl·H₂O (1), [Fe(L ³ )Cl](S₂O₆)·H₂O (2), [Co(L ³ )Cl](ClO₄)_1.5Cl_0.5·0.25H₂O (3), [Co(HL ³ )Cl₂](ClO₄)₂·H₂O (4) and [Co(L ³ )Cl]₂(S₂O₄)(ClO₄)₂ (5). In (1) the copper ion occupies the macrocyclic cavity of protonated (–NH₃ ⁺) L ³ which is present in its trans-III configuration; weakly bound ClO₄ ^? ligands occupy the axial positions. The X-ray structure of (2) showed that Fe(III) occupies the N₄-macrocyclic cavity of L ³ in a trans-III configuration, with the pendent amine group binding in an axial position. The remaining axial position is occupied by a Cl^? ligand. Chromatography of the product obtained from the reaction of Na₃[Co(CO₃)₃] with L ³ yielded three fractions. Fraction 1 yielded crystals (3) composed of three crystallographically independent species incorporating cations of type [Co(L ³ )Cl]²⁺ with very similar structures; in each case the macrocyclic ring nitrogens of L ³ are bound to the Co(III) in an asymmetric cis-fashion. Fraction 2 yielded the trans-III octahedral cationic complex (4) incorporating L ³ in its protonated form. The Co(III) complex (5) from fraction 3 shows a different coordination arrangement to the products from fractions 1 or 2. The macrocyclic ring coordinates in its trans-III form, but the axial sites in this case are occupied by the pendent-NH₂ group and a Cl^? ligand.     

Cobalt(III) complexes with biguanide derivatives: Synthesis,structures, and antiviral activity

Three Co(III) complexes with biguanide derivatives [Co(NH₂C(=NH)NHC(=NH)NR¹R²)₃]Cl₃ (R¹R² = Me₂ (I), Et₂ (II), and H^sBu (III)) were obtained and characterized by elemental analysis, IR spectroscopy, and electronic absorption spectroscopy. Structure III was confirmed by X-ray diffraction (CIF file CCDC no. 1401783). Complexes I–III and [M(SC(NH₂)₂)₄]Cl₂ (M = Pd, Pt, and [Co(En)₃]Cl₃) were tested for in vitro antiviral activity against the A/California/07/09 (H1N1pdm09) influenza virus. The best results were achieved with complex III and both thiourea complexes.     

Crystal chemical analysis of structures of the unsaturated tetraazamacrocyclic gold(III) complexes

The detailed comparative study is carried out for crystal structure packings of the following gold(III) complexes with unsaturated ligands: [Au(C₁₄H₂₂N₄)]Br (I), [Au(C₁₄H₂₃N₄)](ClO₄)₂ (II), [Au(C₁₄H₂₄N₄)](H₃O)(ClO₄)₄ (III). The determining role in the topological pattern of packings I–III belongs to the compositions and structures of the cations along with the ability of the ions of the complexes to act as donors and acceptors of hydrogen bonds. The 3D packings of complexes I and II containing iminate six-membered rings are determined and stabilized by a wide network of weak hydrogen bonds (C–H…π, C–H…Au, and C–H…Br(O)) and short contacts Au(N)…O (in structure II). The structure of imine complex III is characterized by one-dimensional piles formed due to hydrogen bonds O(w)–H…O and contacts Au…O of the О(2) atom of anion Сl(1)О ₄ ^- with cations (H₃O)⁺ and [Au(C₁₄H₂₄N₄)]³⁺ (CIF files CCDC 251258 (I), 276132 (II), and 287784 (III)).     

Polyol-Metall-Komplexe. 27. Bis-diolato-antimonate(III) mit Guanosin als Diol

Polyol Metal Complexes. 27. Bis-Diolato Antimonates(III ) with Guanosine as the Diol The complex anions of K₃[Sb^III(Guo1,2′,3′H_?3)₂] · 10 H₂O ( 1 ) and [Co(NH₃)₆][Sb^III(Guo1,2′,3′H_?3)₂] · 9 H₂O ( 2 ) are four-coordinate homoleptic bis(diolato)antimonate(III ) species. The guanosine trianions act as carbohydrate ligands through their cis-furanoidic ribosyl moiety, thus forming no nucleobase–metal bonds.     

Electron transfer. 153. Internal electron transfer to bound cobalt(III) induced by hydroxyl radical

Hydroxyl radicals, generated in aqueous solution from Fe²⁺ and H₂O₂, react with the formato, glycolato, lactato and mandelato complexes of (NH₃)₅Co^III, extracting H·, releasing CO₂ and inducing the internal reduction of Co^III to Co²⁺; decomposition of peroxynitrous acid (O=N—OOH) in the presence of these complexes also yields Co²⁺, indicating partial utilization (15% at 22°C and pH 1) of a path involving OH·.     

Zur Kenntnis der Sulfito-kobalt(III)-Ammine. I. Sulfitopentammin- und Sulfitoaquotetramminkobalt(III)-Salze

Sulphito Cobalt (III) Ammines. I. Sulphitopentaamminecobalt (III) and Sulphitoaquotetraamminecobalt(III) Salts Because of the trans effect of the sulphito group salts containing the cation [CoSO₃(NH₃)₅]⁺ react with H₂O forming [CoSO₃H₂O(NH₃)₄]⁺. In acid medium the conversion is complete. Therefore, sulphitopentaamminecobalt(III) salts have to be prepared and purified in solutions containing free ammonia. Earlier preparation methods not regarding this circumstance lead to tetraammine compounds or to mixture of pentaammine and tetraammine complexes. The preparation and the properties of a number of sulphitopentaammine and sulphito-aquotetraamminecobalt(III) salts are described (see “Inhaltsübersicht”). The light absorption and the IR spectra of the complexes [CoSO₃(NH₃)₅]⁺ and [CoSO₃H₂O(NH₃)₄]⁺ are reported and discussed.