Dichlorphosphato-Komplexe von Zinn,Titan und Molybdän Die Kristallstruktur von (AsPh4)2[MoOCl3(PO2Cl2)]2

Dichlorophosphato Complexes of Tin, Titanium, and Molybdenum. Crystal Structure of (AsPh₄)₂[MoOCl₃(PO₂Cl₂)]₂ The dichlorophosphate complexes (AsPh₄)₂[SnCl₄(PO₂Cl₂)]₂ ( I ), (AsPh₄)₂[TiCl₄(PO₂Cl₂)]₂ ( II ) and (AsPh₄)₂[MoOCl₃(PO₂Cl₂)]₂ ( III ) are prepared by the reactions of SnCl₄, TiCl₄, and MoCl₅, respectively, with AsPh₄[PO₂Cl₂] in dichlormethan solutions. According to their i.r. spectra, the complex anions form dimeric species via the oxygen atoms of the dichlorophosphate groups; the ¹¹⁹Sn Mössbauer spectra of I are reported in addition. The crystal structure of III is solved by X-ray diffraction methods and refined to R = 4.3%. (AsPh₄)₂[MoOCl₃(PO₂Cl₂)]₂ crystallizes in the triclinic space group P1 with one formula unit pro unit cell. The structure consists of tetraphenylarsonium cations and centrosymmetric anions [MoOCl₃(PO₂Cl₂)]₂^2?. The molybdenum atoms of the anions are linked via the O atoms of the dichlorophosphate groups forming nonplanar Mo₂O₄P₂ eight-membered rings.     

Über Thallium(I)-chlorooxomolybdate: Synthese und Kristallstrukturen von Tl[MoOCl4(NCCH3)], Tl[Mo2O2Cl7] und Tl2[Mo4O4Cl14] und die Struktur von Tl2[MoCl6]

On Thallium(I)-oxochloromolybdates: Synthesis and Crystal Structures of Tl[MoOCl₄(NCCH₃)], Tl[Mo₂O₂Cl₇], and Tl₂[Mo₄O₄Cl₁₄] and the Structure of Tl₂[MoCl₆] Black crystals of Tl₂[MoCl₆] are formed in the reaction of TlCl with MoOCl₃ in a sealed evacuated glass ampoule at 350 °C. The crystal structure analysis shows that Tl₂[MoCl₆] (cubic, Fm 3¯m, a = 986.35(7) pm) adopts the K₂[PtCl₆] structure with a Mo–Cl bond length of 236.6 pm. Tl[MoOCl₄(NCCH₃)] was obtained by the reaction of TlCl with MoOCl₃ in acetonitrile in form of yellow, moisture sensitive crystals. The structure (orthorhombic, Cmcm, a = 746.0(1), b = 1463.8(3), c = 857.3(2) pm) is built of Tl⁺ cations and octahedral [MoOCl₄(NCCH₃)]^– anions in which the acetonitrile ligand is bound in trans position to the oxygen. The reaction of TlCl and MoOCl₃ in dichloromethane yields Tl[Mo₂O₂Cl₇] and Tl₂[Mo₄O₄Cl₁₄] as green moisture sensitive crystals. The structure of Tl[Mo₂O₂Cl₇] (orthorhombic, Pmmn, a = 694.3(1), b = 951.9(2), c = 904.7(1) pm) consists of Tl⁺ cations and dinuclear [Mo₂O₂Cl₇]^– anions, with two equidistant chlorine bridges of 248.2 and one longer chlorine bridge of 265.7 pm. The oxygen atoms are located in the trans positions of the longer chloro bridge. The structure of Tl₂[Mo₄O₄Cl₁₄] (triclinic, P1¯, a = 692.8(1), b = 919.6(1), c = 998.9(1) pm, α = 104.94(1)°, β = 90.31(1)°, γ = 108.14(1)°) is build of Tl⁺ cations and [Mo₄O₄Cl₁₄]^2– anions which form tetramers of distorted octahedral, edgesharing (MoOCl₅) units with chlorine atoms in the bridging positions. The oxygen atoms are located in the trans positions of the longest chlorine bridges.     

Reactions of bis(trimethylsilyl)amine and -amide with MoOCl4

Oxo-Mo(VI) imido-chloride, [MoOCl₂(NH)(Et ₂O)] _n and nitrido-chloride, [Mo₂O₂Cl₂(N)₂(Et ₂O)] _n have been synthesized by equimolar reactions of MoOCl₄ with HN(SiMe ₃)₂ and LiN(SiMe ₃)₂, respectively. Higher molar reactions of HN(SiMe ₃)₂ lead to imido-silylamido derivatives, [Mo₂OCl₃(NH)₃(NHSiMe ₃)] _n , whereas those of LiN(SiMe ₃)₂ give silylimido bridged compounds, Mo₄O₄Cl₄(NSiMe ₃)₆ and Mo₄O₄(NSiMe ₃)₈. Elemental analyses, redox titration, magnetic moment, molecular weight, molar conductance, infrared,¹H-NMR and TG-DTG-DTA studies are reported.

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Reaktionen von Bis(trimethylsilyl)amin und -amid mit MoOCl₄

Zusammenfassung Durch equimolare Reaktionen von MoOCl₄ mit HN(SiMe ₃)₂ und LiN(SiMe ₃)₂ wurden die Oxo-Mo(VI) Imido-chloride [MoOCl₂(NH)(Et ₂O)] _n und die Nitrido-chloride [Mo₂O₂Cl₂(N)₂(Et ₂O)] _n dargestellt. Höhermolekulare Reaktionen von HN(SiMe ₃)₂ führen zu Imido-silylamido Derivaten [Mo₂OCl₃(NH)₃(NHSiMe ₃)] _n , währenddessen die von LiN(SiMe ₃)₂ silylimidoüberbrückte Verbindungen ergeben: Mo₄O₄Cl₄(NSiMe ₃)₆ und Mo₄O₄(NSiMe ₃)₈. Die Strukturen sind mit Elementaranalysen, Redoxtitrationen, Messung der magnetischen Momente, Molekulargewichten, molarer Leitfähigkeit, Infrarot,¹H-NMR und TG-DTG-DTA-Untersuchungen charakterisiert.

     

Synthesis,characterization, and fluorescence properties of dinuclear cadmium(II) complexes

Four dinuclear cadmium(II) complexes, [Cd₂(L¹)(μ₂-Cl)Cl₂] (1), [Cd₂(L²)(μ₂-Cl)Cl₂] (2), [Cd₂(L³)(μ₂-Cl)Cl₂] (3), and [Cd₂(L⁴)₃ClO₄] (4), where HL¹ = 4-methyl-2,6-bis(1-(2-piperidinoethyl)iminomethyl)-phenol, HL² = 4-methyl-2,6-bis(1-(2-pyrrolidinoethyl)iminomethyl)-phenol, HL³ = 4-methyl-2,6-bis(1-(2-morpholinoethyl)iminomethyl)-phenol and HL⁴ = 4-methyl-2,6-bis(cyclohexylmethyl)iminomethyl)-phenol, were synthesized. They were characterized by elemental analysis, FT-IR, UV–Vis, fluorescence and electronspray ionization mass spectroscopy. Complexes 1 and 4 were also characterized by single crystal X-ray analysis. The cadmiums atoms in 1 are linked by μ₂-chloride in a distorted square pyramidal geometry, whereas cadmium atom in 4 is in a distorted octahedral environment. The complexes show emission bands around 500 nm with excitation at 395 nm.     

Coordination of di- and triimine ligands at ruthenium(II) and ruthenium(III) centers: structural,electrochemical and radical scavenging studies

Herein, we explore the coordination of di- and triimine chelators at ruthenium(II) and ruthenium(III) centers. The reactions of 2,6-bis-((4-tetrahydropyranimino)methyl)pyridine (thppy), N¹,N²-bis((3-chromone)methylene)benzene-1,2-diamine (chb), and tris-((1H-pyrrol-2-ylmethylene)ethane)amine (H₃pym) with trans-[Ru^IICl₂(PPh₃)₃] afforded the diamagnetic ruthenium(II) complex cis-[RuCl₂(thppy)(PPh₃)] (1) and the paramagnetic complexes [mer-Ru₂(μ-chb)Cl₆(PPh₃)₂] (2), and [Ru(pym)] (3), respectively. The complexes were characterized by IR, NMR, and UV–vis spectroscopy and molar conductivity measurements. The structures were confirmed by single crystal X-ray diffraction studies. The redox properties of the metal complexes were probed via cyclic- and squarewave voltammetry. Finally, the radical scavenging capabilities of the metal complexes towards the NO and 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) radicals were investigated     

Reactions of molybdenum(III) with macrocyclic polythiaethers

Reactions of MoCl₃(THF)₃ and MoCl₃(PrCN)₃ with the macrocyclic polythiaethers: 1,4,8,11-tetrathiacyclotetradecane (TTP) and 1,4,7,10,13,16-hexathiacyclooctadecane (HTO) were studied. The type of reaction and the complexes formed depend on reactant concentration and nature of the solvent. The complexes: [MoCl₃(HTO)], [(MoCl₃)₂(HTO)(THF)₃], [MoCl₃(TTP)(THF)] and [MoCl₃(TTP)] in which the macrocyclic polythiaethers are coordinated to the molybdenum through sulphur atoms were isolated. Some new mixed-valence complexes were formed in reactions where a partial change in the molybdenum oxidation state and a cleavage of the macrocyclic ring took place. The following complexes were isolated: [Mo₃Cl₉(PHT)₂(PrCN)]·CH₂Cl₂, [Mo₃Cl₉(PHT)₂(THF)] · CH₂Cl₂, [Mo₂Cl₆ (PHT)] · CH₂Cl₂, [Mo₃Cl₉(TTT)₂(THF)] · CH₂Cl₂, where PHT = 3,6,9,12,15-pentathiaheptadec- 16-ene-1-thiolato(1-) and TTT = 4,7,11-trithiatridec-12-ene-1-thiolato(1-). The complexes were characterized on the basis of elemental analyses, magnetic measurements, IR, ¹H NMR, ¹³C NMR and mass spectra.     

Synthesis and characterization of cobalt(II), nickel(II), copper(II) and zinc(II) complexes with acetylacetone bis-benzoylhydrazone and acetylacetone bis-isonicotinoylhydrazone

Summary Acetylacetone bis-benzoylhydrazone (PhCONHN=CMe)₂ CH₂(LH₂) and acetylacetone bis-isonicotinoylhydrazone (NC₅H₄CONHN=CMe)₂CH₂(LH₂) complexes of the types [ML] and [ML] (M = Co^II, Ni^II, Cu^II or Zn^II) have been prepared and characterized. All the complexes are non-electrolytes and the cobalt(II) complexes are lowspin, the nickel(II) complexes are diamagnetic and the copper(II) complexes are paramagnetic. The ligands chelate via two C=N groups and two deprotonated enolate groups. The e.s.r. spectra of the copper(II) complexes indicate a tetragonally distorted dimeric structure. The X-ray diffraction parameters for [CoL] and [NiL] correspond to a tetragonal crystal lattice.     

The Electron Transfer Series [MoIII(bpy)3]n (n=3+, 2+, 1+, 0, 1−), and the Dinuclear Species [{MoIIICl(Mebpy)2}2(μ2‐O)]Cl2 and [{MoIV(tpy.)2}2(μ2‐MoO4)](PF6)2⋅4 MeCN

The electronic structures of the five members of the electron transfer series [Mo(bpy)₃]ⁿ (n=3+, 2+, 1+, 0, 1?) are determined through a combination of techniques: electro‐ and magnetochemistry, UV/Vis and EPR spectroscopies, and X‐ray crystallography. The mono‐ and dication are prepared and isolated as PF₆ salts for the first time. It is shown that all species contain a central Mo^III ion (4d³). The successive one‐electron reductions/oxidations within the series are all ligand‐based, involving neutral (bpy⁰), the π‐radical anion (bpy^.)^1?, and the diamagnetic dianion (bpy^2?)^2?: [Mo^III(bpy⁰)₃]³⁺ (S=3/2), [Mo^III(bpy^.)(bpy⁰)₂]²⁺ (S=1), [Mo^III(bpy^.)₂(bpy⁰)]¹⁺ (S=1/2), [Mo^III(bpy^.)₃] (S=0), and [Mo^III(bpy^.)₂(bpy^2?)]^1? (S=1/2). The previously described diamagnetic dication “[Mo^II(bpy⁰)₃](BF₄)₂” is proposed to be a diamagnetic dinuclear species [{Mo(bpy)₃}₂(μ₂‐O)](BF₄)₄. Two new polynuclear complexes are prepared and structurally characterized: [{Mo^IIICl(^Mebpy⁰)₂}₂(μ₂‐O)]Cl₂ and [{Mo^IV(tpy^.)₂}₂(μ₂‐Mo^VIO₄)](PF₆)₂?4 MeCN.     

Synthesis and characterization of manganese(II), nickel(II), copper(II) and zinc(II) Schiff-base complexes derived from 1,10-phenanthroline-2,9-dicarboxaldehyde and 2-mercaptoethylamine

The synthesis of a new Schiff base containing 1,10-phenanthroline-2,9-dicarboxaldehyde and 2-mercaptoethylamine is described. The reaction of 1,10-phenanthroline-2,9-dicarboxaldehyde with 2-mercaptoethylamine leads to 2,9-bis(2-ethanthiazolinyl)-1,10-phenanthroline (I) which undergoes rearrangement when reacted with manganese, nickel, copper or zinc ions to produce complexes of the tautomeric Schiff base 2,9-bis[2-(2-mercaptoethyl)-2-azaethene]-1,10-phenanthroline (L). The [M(L)Cl₂] complexes [where M = Mn(II), Ni(II), Cu(II) and Zn(II) ions] were characterized by physical and spectroscopic measurements which indicated that the ligand is a tetradentate N₄ chelating agent.     

Metal Complexes with Macrocyclic Ligands. Part XXXIX. Mono- and binuclear copper(II) complexes of a bridging bis[1, 4, 7-triazacyclononane]

The new bis-macrocycle 1, 1′-[(1H-pyrazol-3], 5-diyl)bis(methylene)bis[1, 4, 7-triazacyclononane] ( 1 ) was synthesized and its complexation with Cu²⁺ studied. Potentiometric and spectrophotometric titrations indicate that, in addition to the mononuclear species [Cu(LH₂)]⁴⁺, [Cu(LH)]³⁺, [CuL]²⁺, and [Cu(LH_?1)]⁺, binuclear complexes such as [Cu₂L]⁴⁺, [Cu₂(LH_?1)]³⁺, and [Cu₂(LH_-2)]²⁺ are also formed in solution. The stability constants and spectral properties of these are reported. The binuclear species [Cu₂(LH_?1)]³⁺ specifically reacts with an azide ion to give a ternary complex [Cu₂(LH_?1)(N₃)]²⁺, the stability and structure of which were determined spectrophotometrically and by X-ray diffraction, respectively. The two Cu²⁺ ions are in a square-pyramidal coordination geometry. The axial ligand is one of the N-atoms of the 1, 4, 7-triazacyclononane ring, whereas at the base of the square pyramid, one finds the other two N-atoms of the macrocycle, one N-atom of the pyrazolide and one of the azide, both of which are bridging the two metal centres. In [Cu₂(LH_?1)(N₃)]²⁺, a strong antiferromagnetic coupling is present, thus resulting in a species with a low magnetic moment of 1.36 B.M. at room temperature.     

Voltammetry of oxorhenium(V) complexes containing the [O=Re−OR] core and substituted pyridine ligands

Compounds of the general formula [ORe(OR)Cl₂(PPh₃)₂] and [ORe(OEt)Cl₂(PPh₃)(py)], where R=alkyl or aryl and py=a substituted pyridine, were synthesized and their voltammetric behaviour investigated. For the former, the electron-transfer mechanism was observed to be dependent on solvent. In dry MeCN, a quasi-reversible oxidation and a reduction followed by a chemical reaction was observed. There were indications of nucleophilic attack on electrochemically generated [ORe(OEt)Cl₂(PPh₃)₂]⁺, forming an unstable species whose reduction potentials were strongly dependent on the identity of the nucleophile. Voltammetric and spectroscopic observations of the oxorhenium(V) alkoxypyridine complex indicate the pyridine to be labile in halogenated hydrocarbon solvents but not in Me₂CO, MeCN, or CCl₄. Electrochemical generation of [ORe(OEt)Cl₂(PPh₃)(Cl_xC_yH_z)]⁺ (x=1,2, or 3; y=1 or 2; z=2,3, or 4) appears to be followed by transfer of a hydrogen atom from the solvent to form [(HO)Re(OEt)Cl₂(PPh₃)]⁺. Various pyridine complexes of this type were preparedvia substitution reactions under mild conditions. Varying the reaction conditions allowed the synthesis oftrans-dioxotetrapyridyl complexes in excellent yield.     

Dithiolylium‐Chlorooxomolybdate(V): Synthese und Kristallstruktur von (C3Cl3S2)[MoOCl4] und (C3Cl3S2)[Mo2O2Cl7]

Dithiolylium Chlorooxomolybdates(V): Synthesis and Crystal Structure of (C₃Cl₃S₂)[MoOCl₄] and (C₃Cl₃S₂)[Mo₂O₂Cl₇] The reaction of 3, 4, 5‐Trichlor‐1, 2‐dithiolylium chloride with MoOCl₃ in dichlormethane under solvothermal conditions at 65 °C simultaneously yields the green tetrachlorooxomolybdate(V) (C₃Cl₃S₂)[MoOCl₄] and the yellow‐brown heptachlorodioxodimolybdate(V) (C₃Cl₃S₂)[Mo₂O₂Cl₇]. The crystal structures of both compounds contain nearly planar (C₃Cl₃S₂)⁺ ions with a S—S bond length of 203 pm. The discrete [MoOCl₄]^— ion in the structure of (C₃Cl₃S₂)[MoOCl₄] has the shape of a square pyramid with the oxygen atom at the apex. The molybdenum atom is displaced by 58 pm from the basal plane towards the oxygen atom. The [Mo₂O₂Cl₇]^— ion in the structure of (C₃Cl₃S₂)[Mo₂O₂Cl₇] has the form of a face‐sharing double octahedron. It is formally composed of a [MoOCl₄]^— ion and a MoOCl₃ molecule connected by one symmetrical and two unsymmetrical chloro bridges. The molybdenum atoms placed in the centers of such connected octahedra are 357 pm apart, indicating no Mo—Mo bond.     

Formation of polymeric chain assemblies of transition metal complexes with a multidentate Schiff-base

The new multidentate Schiff-base (E)-6,6′-((1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(methan-1-yl-ylidene))bis(4-methyl-2-((E)(pyridine-2-ylmethylimino)methyl)phenol) H₂L and its polymeric binuclear metal complexes with Cr(III), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) are reported. The reaction of 2,6-diformyl-4-methyl-phenol with ethylenediamine in mole ratios of 2:1 gave the precursor 3,3′-(1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1ylidene))bis(methan-1-yl-1-ylidene)bis(2-hydroxy-5-methylbenzaldehyde) W. Condensation of the precursor with 2-(amino-methyl)pyridine in mole ratios of 1:2 gave the new N₆O₂ multidentate Schiff-base ligand H₂L. Upon complex formation, the ligand behaves as a dibasic octadentate species with the involvement of the nitrogen atoms of the pyridine groups in coordination for all complexes. The mode of bonding and overall geometry of the complexes were determined through physico-chemical and spectroscopic methods. These studies revealed octahedral geometries for Cr(III), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Cd(II) and Hg(II) complexes of general formulae [Cr₂^III(L)Cl₂]Cl₂, [Ni₂^II(L)(H₂O)₂]Cl₂ and [M₂(L)Cl₂] and five co-ordinate Zn(II) complex of general formula [Zn₂^II(L)]Cl₂.     

Reactions of tungsten(VI) and molybdenum(V) chlorides,and tungsten(VI) and molybdenum(VI) oxychlorides,with azoxybenzene

Reactions of W^VI and Mo^V chlorides with azoxybenzene yield ionic species of W^VI and Mo^VI oxychlorides in which the cation is a protonated azobenzene. The reaction between MoCl₅ or MoOCl₄ and azoxybenzene gives, after extraction with methylene chloride—ethanol mixture, the complex [trans-MoOCl₄(OC₂H₅)]^? [C₁₂H₁₀N₂H]⁺. In contrast, WOCl₄ reacts with azoxybenzene to give a stable non-ionic adduct in which the organic moiety is coordinated through its oxygen atom trans to the WO bond. Several complexes of substituted azoxybenzene having similar structures are described.     

Synthesis,DNA-binding and cleavage studies of macrocyclic copper(II) complexes

Two macrocyclic copper(II) complexes, [CuL¹](ClO₄)₂ (L¹ = 2,6,9,13-tetraparacyclophane, a Schiff base) and [CuL²]Cl₂ [L² = 3,10-bis(2-benzyl)-1,3,5,8,10,13-hexaazacyclotetradecane] have been prepared and characterized by elemental analysis, u.v.–vis., i.r. and mass spectra. Absorption, fluorescence, circular dichroic spectra and viscosity experiments have been carried out on the interaction of the two complexes with calf thymus CT DNA. The results suggest that both complexes can bind to CT DNA by intercalation via the aromatic moiety ring in the macrocycle into the base pairs of DNA. [CuL¹](ClO₄)₂ binds to CT DNA more strongly than [CuL²]Cl₂. The position of the aromatic ring in the macrocycle plays an important role in deciding the extent of binding of the complexes to DNA. Significantly, the complexes have been found to be single-strand DNA cleavers in the presence of H₂O₂ or/and 2-mercaptoethanol.     

Darstellung,Strukturen und EPR-Spektren der Rhenium(II)-Nitrosylkomplexe [Re(NO)Cl2(PPh3)(OPPh3)(OReO3)], [Re(NO)Cl2(OPPh3)2(OReO3)] und [Re(NO)Cl2(OPPh3)3](ReO4)

Synthesis, Structures, and EPR-Spectra of the Rhenium(II) Nitrosyl Complexes [Re(NO)Cl₂(PPh₃)(OPPh₃)(OReO₃)], [Re(NO)Cl₂(OPPh₃)₂(OReO₃)], and [Re(NO)Cl₂(OPPh₃)₃](ReO₄) The paramagnetic rhenium(II) nitrosyl complexes [Re(NO)Cl₂(PPh₃)(OPPh₃)(OReO₃)], [Re(NO)Cl₂(OPPh₃)₂ · (OReO₃)], and [Re(NO)Cl₂(OPPh₃)₃](ReO₄) are formed during the reaction of [ReOCl₃(PPh₃)₂] with NO gas in CH₂Cl₂/EtOH. These and two other Re^II complexes with 5 d⁵ ”︁low-spin”︁”︁-configuration can be observed during the reaction EPR spectroscopically. Crystal structure analysis shows linear coordinated NO ligands (Re–N–O-angles between 171.9 and 177.3°). Three OPPh₃ ligands are meridionally coordinated in the final product of the reaction, [Re(NO)Cl₂(OPPh₃)₃][ReO₄] (monoclinic, P2₁/c, a = 13.47(1), b = 17.56(1), c = 24.69(2) Å, β = 95.12(4)°, Z = 4). [Re(NO)Cl₂(PPh₃)(OPPh₃)(OReO₃)] (triclinic P 1, a = 10.561(6), b = 11.770(4), c = 18.483(8) Å, α = 77.29(3), β = 73.53(3), γ = 64.70(4)°, Z = 2) and [Re(NO)Cl₂ (OPPh₃)₂(OReO₃)] (monoclinic P2₁/c, a = 10.652(1), b = 31.638(4), c = 11.886(1) Å, β = 115.59(1)°), Z = 4) can be isolated at shorter reaction times besides the complexes [Re(NO)Cl₃(Ph₃P)₂], [Re(NO)Cl₃(Ph₃P) · (Ph₃PO)], and [ReCl₄(Ph₃P)₂].     

Ruthenium(II) ligated to tetradentate diaminodithioethers: synthesis,characterisation and electrochemistry

Ruthenium(II) complexes containing two tetradentate ligands, 1,2-bis(o-aminophenylthio)ethane (L¹) and 1,2-(oaminophenylthio)xylene (L²), have been prepared. The complexes, which are of the type Ru(L)Cl₂ [L = L¹ (1);/L² (2)], [Ru(L)(PPh₃)Cl]Cl [L = L¹ (3); L² (4)] and [Ru(L)(bpy)](PF₆)₂ [L = L¹ (5);/L² (6)], were characterised by elemental analysis, i.r., u.v.-vis. and n.m.r. spectroscopy and their electrochemical behaviour has been examined by cyclic voltammetry using a glassy carbon working electrode and an Ag/AgCl electrode as the reference electrode. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synthesis and Characterization of Novel Trans-Mixed Diamine Platinum(II) and Platinum(IV) Complexes

A series of novel trans-mixed diamine platinum(II) and platinum(IV) complexes of type trans-[Pt^II(R-NH₂)(R'-NH₂)Cl₂] and trans -[Pt^IV(R-NH₂)(R'-NH₂)Cl₄] (where R-NH₂ = ethylamine or butylamine and R'-NH₂ = methylamine, propylamine, isopropylamine, pentylamine, or hexylamine) was synthesized and characterized using elemental analysis and infrared and ¹⁹⁵Pt nuclear magnetic resonance spectroscopic techniques.     

Characterization of heterobimetallic and mixed-valence complexes of molybdenum(V) derived from bis(2-hydroxy-1-naphthaldehyde) malonoyldihydrazone

Heterobimetallic complexes [UO₂Mo^V(CH₂L)(hzd)(H₂O)₂] _n , [ZnMo^V(CH₂L)(hzd)(H₂O)₂] _n and mixedvalence complexes [Mo^VIO₂Mo^V(CH₂L)(hzd)(H₂O)₂] _n (where hzdH₃ = inhH₃, n = 1; slhH₃, n = 2) are synthesized from bis(2-hydroxy-1-naphthaldehyde)malonoyldihydrazone (CH₂LH₄) and monometallic precursor complexes [Mo(CH₂LH₂)(hzd)]·nH₂O (n = 0, 1) in ethanol. The composition of the complexes is established based on the data obtained from the elemental analysis. The structure of the complexes is discussed in the light of data obtained from molar conductance, magnetic moment, electronic, EPR, and IR spectroscopic studies. All complexes have ??B values in the range 1.59?C1.64 B.M., slightly lower than that required for one unpaired electron. The heterobimetallic complexes show two bands, while mixed-valence complexes show only one band in the visible region assigned to the d-d transition. The g-values decrease in going from uranyl-to-molybdenyl-to-zinc complexes containing the isonicotinoyldiazenido (inh) group, however, no such regular trend is observed in the case of complexes containing the salicyloyldiazenido (slh) group in the coordination sphere. In all complexes, the principal dihydrazone ligand is present in the enol form as a bridging hexadentate ligand in the anti-cis configuration where hydrazide ligands are coordinated to the metal centre as a trinegative bidentate ligand in the diazenido form.     

Heterobinuclear and Heterotrinuclear complexes of Oxorhenium(V) with Cu(II), Ni(II), Fe(III), UO2(VI) and Th(IV) in the solid state

New heteronuclear complexes containing oxorhenium(V), Cu(II), Ni(II), Fe(III), UO₂(VI) and Th(IV) ions were prepared by the reaction of the complex ligand, [ReO(H₄L)Cl]Cl₂, where H₄L = 8,17-dimethyl-6,15-dioxo-5,7,14,16-tetrahydrodibenzo[a,h][14]annulene-2,11-dicarboxylic acid, with the previous transition and actinide salts. Three heteronuclear Cu(II) complexes were isolated depending on the ratio of [ReO(H₄L)Cl]Cl₂?:?Cu(II) ion. When the ratios were 1?:?0.5, 1?:?1 and 1?:?2, the heteronuclear complexes {[ReO(H₃L)Cl]₂CuCl₂(OH₂)₂}SO₄ · H₂O (I), [ReO(H₃L)Cl₂Cu(OH₂)₂(SO₄)] (II) and {ReO(H₂L)Cl[Cu(OH₂)₃ SO₄]₂} (III) were obtained, respectively. Heteronuclear complexes of the other metal cations were obtained by mixing [ReO(H₄L)Cl]Cl₂ with the metal salt in the ratio 1?:?1 to obtain the heteronuclear complexes [ReO(H₃L)Cl₂Ni(OH₂)₂](NO₃)₂ (IV), [ReO(H₃L)Cl₃Fe(OH₂)₃](NO₃)₂ (V), [ReO(H₃L)ClUO₂(NO₃)₂ (OH₂)]Cl (VI) and [ReO(H₃L)Cl₃Th(NO₃)₂(OH₂)]NO₃ · 2H₂O (VII). The complex ligand coordinates with the heterometal ion via the carboxylate group, and the infrared bands ν_as COO and ν_s COO indicate that the carboxylate acts as a unidentate ligand to the heterometal cations. Cu(II) and Fe(III) cations in the heteronuclear complexes have octahedral geometry, while Ni(II) is square planar. Thermal studies explored the possibility of obtaining new heteronuclear complexes pyrolytically in the solid state from the corresponding mother complexes. The structures of the complexes were elucidated by conductance, IR and electronic spectra, magnetic moments, ¹H NMR and TG-DSC measurements as well as by mass spectroscopy.