Hydrothermal syntheses and structures of vanadium oxyfluorides templated by organic and metal organic cations

The hydrothermal reactions of V₂O₅, HF and an organodiphosphonic acid, in the presence of appropriate templating organoammonium or metal-organic complex cations provided three new oxyfluorovanadate compounds. The V(IV) species [H₃N(CH₂)₂NH₂(CH₂)₂NH₂(CH₂)₂NH₃][V₃O₃F₂(H₂O){O₃PCH₂PO₃}₂]·2H₂O (1·2H₂O) exhibits a three-dimensional anionic framework constructed from {VO(O₃PCH₂PO₃)}_n²ⁿ⁻ chains and {VF₂O₄} octahedra. The molecular structure of [N(CH₂CH₂NH₃)₃]₂[NH₄][V₃O₂F₆(O₃PCH₂PO₃)₂]·2H₂O (2·2H₂O) is characterized by the presence of unique {V₃O₂F₆(O₃PCH₂PO₃)₂}⁷⁻ clusters. The bimetallic phase [{Cu(ophen)}VOF{HO₃P(CH₂)₅PO₃}] (3) is one-dimensional with {Cu₂V₂O₂F₂(HO₃PR)₂(O₃PR)₂} cluster building blocks.     

Studies on Polyoxins,Antifungal Antibiotics

Seven additional components, polyoxins C, D, E, F, G, H and I were isolated from polyoxin complex. They have molecular formulae corresponding to C₁₁H₁₅N₃O₈, C₁₇H₂₃N₅O₁₄, C₁₇H₂₃N₅O₁₃, C₂₃H₃₀N₆O₁₅, C₁₇H₂₅N₅O₁₂, C₂₃H₃₂N₆O₁₃ and C₁₉H₂₄N₄O₁₂, respectively. These polyoxins except inactive polyoxins C and I were highly active against various kinds of phytopathogenic fungi. The close structural similarity among them including polyoxins A and B is also discussed.     

A series of inorganic-organic hybrid compounds constructed from bis(undecatungstophosphate) lanthanates and copper-organic units

A series of inorganic-organic hybrid compounds built from bis(undecatungstophosphate) lanthanates and copper-complexes, namely, H₈[Cu(en)₂H₂O]₄[Cu(en)₂]{[Cu(en)₂][La(PW₁₁O₃₉)₂]}₂·18H₂O (1), H₆[Na₂(en)₂(H₂O)₅][Cu(en)₂H₂O]₄[Cu(en)₂]{[Cu(en)₂][Ce(PW₁₁O₃₉)₂]}₂·16H₂O (2), H₆[Na₂(en)₂(H₂O)₅][Cu(en)₂H₂O]₄[Cu(en)₂]{[Cu(en)₂][Pr(PW₁₁O₃₉)₂]}₂·18H₂O (3), H₆[Na₂(en)₂(H₂O)₄][Cu(en)₂H₂O]₄[Cu(en)₂]{[Cu(en)₂][Nd(PW₁₁O₃₉)₂]}₂·14H₂O (4), H₆[Na₂(en)₂(H₂O)₅][Cu(en)₂H₂O]₄[Cu(en)₂]{[Cu(en)₂][Sm(PW₁₁O₃₉)₂]}₂·20H₂O (5), and H₇[Cu(en)₂]₂[Sm(PW₁₁O₃₉)₂]·10H₂O (6) (where en = 1,2-ethylenediamine), have been prepared. In these compounds, two lacunary [PW₁₁O₃₉]⁷⁻ anions sandwich an eight-coordinated Ln(III) cation to yield [Ln(PW₁₁O₃₉)₂]¹¹⁻ anion in a twisted square anti-prismatic geometry, which is further bridged by [Cu(en)₂]²⁺ fragments to generate a 1D zigzag-like chain. In 1-6, the coordination bond interactions and weak interactions between adjacent 1D chains play an important role in the zigzagging distances and angles of different 1D chains. The magnetic studies indicate that antiferromagnetic interactions exist in compounds 1, 2 and 4.     

Syntheses, structures and electrochemical study of π-acetylene complexes of cobalt

The preparation and characterisation of the complexes [Co₂(CO)₄(PMe₃)₂][Co₂(CO)₆](Me₃SiC₂C₂SiMe₃) (4), [Co₂(CO)₄(dppm)][Co₂(CO)₆](Me₃SiC₂C₂H) (5), [Co₂(CO)₄(dppa)][Co₂(CO)₆](Me₃SiC₂C₂SiMe₃) (6), [Co₂(CO)₄(dppm)]₂[Co₂(CO)₆](Me₃SiC₂CCC₂C₂SiMe₃) (7) and [{SiMe₃(Co₂(CO)₄(dppm))C₂}₂(HCC)(1,3,5-C₆H₃)] (8) are described. An electrochemical study of the complexes 5-8 and of the related [Co₂(CO)₄(dppm)]₂(Me₃SiC₂(CC)₂C₂SiMe₃) (1), [Co₂(CO)₄(dppa)]₂(Me₃SiC₂C₂SiMe₃) (2) and [{SiMe₃(Co₂(CO)₄(dppm))C₂}(HCC)₂(1,3,5-C₆H₃)] (3) is presented by means of the cyclic and square-wave voltammetry techniques. Crystals of 8 suitable for single-crystal X-ray diffraction were grown and the molecular structure of this compound is discussed.     

Effect of copper-substitution on the structure and nuclearity of Cu(II)-pyrazolates: from trinuclear to tetra-, hexa- and polynuclear complexes

The influence of terminal ligands on the structure and nuclearity of copper(II)-pyrazolates has been investigated. Exchange of the chloride ligands of [Cu₃(μ₃-X)(μ-pz)₃Cl₃]ⁿ⁻ (X=O, OH; n=2, 1) or [Cu₃(μ₃-Cl)₂(μ-pz)₃Cl₃]²⁻ complexes for cyanate, acetate or bromide ligands maintains the integrity of the triangular species: PPN[Cu₃(μ₃-OH)(μ-pz)₃(NCO)₃], PPN[Cu₃(μ₃-OH)(μ-pz)₃(O₂CCH₃)₃(H₂O)] · H₂O, Bu₄N[Cu₃(μ₃-OH)(μ-pz)₃(O₂CCH₃)₃] · 3H₂O and (Bu₄N)₂[Cu₃(μ₃-Br)₂(μ-pz)₃Br₃] have been prepared and characterized by spectroscopic and X-ray diffraction techniques, respectively. In contrast, tetranuclear complexes (Bu₄N)₂[Cu₄(μ₃-OH)₂(μ-4-X-pz)₂(μ-O₂CPh)₂(O₂CPh)₄] (X=H, Cl, Br, NO₂) and the hexanuclear complex (Bu₄N)₂[Cu₆(μ₃-O)(μ₃-OH)(μ-4-NO₂-pz)₆(μ-O₂CPh)₃(O₂CPh)₂(H₂O)] · (CH₂Cl₂)_0.5 have been obtained on substitution for benzoate ligands. An attempt to partially substitute the chlorides for tert-butoxide ligands, also provided a tetranuclear complex, (Bu₄N)₂[Cu₄(μ-OH)₂(μ-pz)₄Cl₄], without incorporation of the incoming ligand. Similarly, removal of all chloride ions in the absence of an appropriate substituting ligand leads to higher nuclearity metallacycles [Cu(μ-OH)(μ-pz)]_n (n=6, 8, 9, 12, 14).     

Coordination chemistry of copper-molybdates with alkoxide ligands: The {Mo4O10(OMe)6} and [Mo2O4{RC(CH2O)3}2] clusters as building blocks

The reactions of the Keplerate super cluster [Mo₁₃₂O₃₇₂(CH₃CO₂)₃₀(H₂O)₇₂]⁴²⁻ with a Cu(II) source and an organonitrogen donor in methanol/DMF solutions yielded a series of bimetallic organic-inorganic oxide hybrid materials, including the molecular species [Cu(phen)₂MoO₄] (1) and [{Cu(terpy)}₂(MoO₄)₂] (2) and a series of materials constructed from the tetranuclear building block {Mo₄O₁₀(OMe)₆}²⁻: the molecular [{Cu₂(phen)₂(O₂CCH₃)₂ (MeOH)}Mo₄O₁₀(OMe)₆] (3), [{Cu(terpy)(O₂CCH₃)}₂Mo₄O₁₀(OMe)₆] (4) and [{Cu(terpy)Cl}₂Mo₄O₁₀(OMe)₆] (5), the one-dimensional phases [{Cu(bpy)(HOMe)₂}Mo₄O₁₀(OMe)₆] (6), [{Cu(bpy)(DMF)₂}Mo₄O₁₀(OMe)₆] (7), [{Cu(bpa)(DMF)₂}Mo₄O₁₀(OMe)₆] (8), [{Cu(phen)(DMF)₂}Mo₄O₁₀(OMe)₆] (9) and [{CuCl(dpa)}₂Mo₄O₁₀(OMe)₆] (10), and the two-dimensional material [{Cu₂(DMF)₂(pdpa)}{Mo₄O₁₀(OMe)₆}₂] (11). When methanol is replaced by the tridentate alkoxide tris-methoxypropane (trisp), the {Mo₂O₄(trisp)₂}²⁻ cluster building block is observed for [Cu(phen)Mo₂O₄(trisp)₂] (12), [Cu(bpa)(DMF)Mo₂O₄(trisp)₂] (13) and [{Cu(bpy)(NO₃)}₂Mo₂O₄(trisp)₂] (14).     

Extending the coordination chemistry of cobalt with the metalloligand [Pt2(μ-S)2(PPh3)4]: Synthesis of the first cobalt(III) derivatives

The coordination chemistry of the metalloligand [Pt₂(μ-S)₂(PPh₃)₄] towards cobalt(II) and cobalt(III) centres has been explored using an electrospray ionisation mass spectrometry (ESI MS)-directed methodology. Reaction of [Pt₂(μ-S)₂(PPh₃)₄] with CoCl₂·6H₂O in methanol gave a green-yellow suspension of the known adduct [Pt₂(μ-S)₂(PPh₃)₄CoCl₂], and the CoBr₂ adduct could be similarly prepared. When in situ-generated [Pt₂(μ-S)₂(PPh₃)₄CoCl₂] is reacted with 8-hydroxyquinoline (HQ) and base, the initial product is the cobalt(II) adduct [Pt₂(μ-S)₂(PPh₃)₄CoQ]⁺, which is then converted in air to the cobalt(III) adduct [Pt₂(μ-S)₂(PPh₃)₄CoQ₂]⁺, isolated as its hexafluorophosphate salt. The corresponding picolinate (Pic) derivative [Pt₂(μ-S)₂(PPh₃)₄Co(Pic)₂]⁺ was similarly prepared, however reaction of [Pt₂(μ-S)₂(PPh₃)₄], CoCl₂·6H₂O and 8-(tosylamino)quinoline (HTQ) produced only the cobalt(II) adduct [Pt₂(μ-S)₂(PPh₃)₄CoTQ]⁺. Reactions of [Pt₂(μ-S)₂(PPh₃)₄], CoCl₂·6H₂O and dithiocarbamates gave cobalt(III) complexes [Pt₂(μ-S)₂(PPh₃)₄Co(S₂CNR₂)₂]⁺ [R = Et or R₂ = (CH₂)₄], and proceeded much more rapidly, consistent with the known ability of the dithiocarbamate ligand to stabilize cobalt in higher oxidation states. A study of the fragmentation of cobalt(III) adducts by positive-ion ESI mass spectrometry indicated that [Pt₂(μ-S)₂(PPh₃)₄CoQ₂]⁺ fragments to form the radical cation [Pt₂(μ-S)₂(PPh₃)₄]⁺, which could also be generated by ESI MS analysis of [Pt₂(μ-S)₂(PPh₃)₄] in methanol-NaOH solution. In contrast, the corresponding indium(III) derivative [Pt₂(μ-S)₂(PPh₃)₄InQ₂]⁺, and the cobalt(III) dithiocarbamate [Pt₂(μ-S)₂(PPh₃)₄Co(S₂CN(CH₂)₄)₂]⁺ are much more reluctant to fragment under analogous conditions, and the differences are discussed in terms of cobalt(III) redox chemistry.     

Thallium(III) complexes of the metalloligands [Pt2(μ-S)2(PPh3)4] and [Pt2(μ-Se)2(PPh3)4]

Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with the diarylthallium(III) bromides Ar₂TlBr [Ar = Ph and p-ClC₆H₄] in methanol gave good yields of the thallium(III) adducts [Pt₂(μ-S)₂(PPh₃)₄TlAr₂]⁺, isolated as their salts. The corresponding selenide complex [Pt₂(μ-Se)₂(PPh₃)₄TlPh₂]BPh₄ was similarly synthesised from [Pt₂(μ-Se)₂(PPh₃)₄], Ph₂TlBr and NaBPh₄. The reaction of [Pt₂(μ-S)₂(PPh₃)₄] with PhTlBr₂ gave [Pt₂(μ-S)₂(PPh₃)₄TlBrPh]⁺, while reaction with TlBr₃ gave the dibromothallium(III) adduct [Pt₂(μ-S)₂(PPh₃)₄TlBr₂]⁺[TlBr₄]⁻. The latter complex is a rare example of a thallium(III) dihalide complex stabilised solely by sulfur donor ligands. X-ray crystal structure determinations on the complexes [Pt₂(μ-S)₂(PPh₃)₄TlPh₂]BPh₄, [Pt₂(μ-S)₂(PPh₃)₄TlBrPh]BPh₄ and [Pt₂(μ-S)₂(PPh₃)₄TlBr₂][TlBr₄] reveal a greater interaction between the thallium(III) centre and the two sulfide ligands on stepwise replacement of Ph by Br, as indicated by shorter Tl-S and Pt?Tl distances, and an increasing S-Tl-S bond angle. Investigations of the ESI MS fragmentation behaviour of the thallium(III) complexes are reported.     

Synthesis, characterization and structure of some arylantimony ferrocenylacrylates

A series of arylantimony ferrocenylacrylates with the formula (C₅H₅FeC₅H₄CHCHCO₂)_nSbAr_(5−n) (n=1, 2; Ar C₆H₅, 4-CH₃C₆H₄, 3-CH₃C₆H₄, 2-CH₃C₆H₄, 4-FC₆H₄) have been synthesized and characterized by elemental analysis, IR, ¹H NMR and mass spectra. The crystal structures of C₅H₅FeC₅H₄CHCHCO₂Sb(C₆H₅)₄ (I₁) and (C₅H₅FeC₅H₄CHCHCO₂)₂Sb(C₆H₅)₃ (II₁) have been determined by X-ray diffraction.     

Influence of chain length on mono- versus di-alkylation in the reactivity of [Pt2(μ-S)2(PPh3)4] towards α,ω-dihalo-n-alkanes; a synthetic route to platinum(II) ω-haloalkylthiolate complexes

The reactions of [Pt₂(μ-S)₂(PPh₃)₄] with α,ω-dibromoalkanes Br(CH₂)_nBr (n = 4, 5, 6, 8, 12) gave mono-alkylated [Pt₂(μ-S){μ-S(CH₂)_nBr}(PPh₃)₄]⁺ and/or di-alkylated [Pt₂(μ-S(CH₂)_nS}(PPh₃)₄]²⁺ products, depending on the alkyl chain length and the reaction conditions. With longer chains (n = 8, 12), intramolecular di-alkylation does not proceed in refluxing methanol, with the mono-alkylated products [Pt₂(μ-S){μ-S(CH₂)_nBr}(PPh₃)₄]⁺ being the dominant products when excess alkylating agent is used. The bridged complex [{Pt₂(μ-S)₂(PPh₃)₄}₂{μ-(CH₂)₁₂}]²⁺ was accessible from the reaction of [Pt₂(μ-S)₂(PPh₃)₄] with 0.5 mol equivalents of Br(CH₂)₁₂Br. [Pt₂(μ-S){μ-S(CH₂)₄Br}(PPh₃)₄]⁺ can be cleanly isolated as its BPh₄⁻ salt, but undergoes facile intramolecular di-alkylation at −18 °C, giving the known species [Pt₂(μ-S(CH₂)₄S}(PPh₃)₄]²⁺. The reaction of I(CH₂)₆I with [Pt₂(μ-S)₂(PPh₃)₄] similarly gives [Pt₂(μ-S){μ-S(CH₂)₆I}(PPh₃)₄]⁺, which is fairly stable towards intramolecular di-alkylation once isolated. These reactions provide a facile route to ω-haloalkylthiolate complexes which are poorly defined in the literature. X-ray crystal structures of [Pt₂(μ-S){μ-S(CH₂)₅Br}(PPh₃)₄]BPh₄ and [Pt₂(μ-S(CH₂)₅S}(PPh₃)₄](BPh₄)₂ are reported, together with a study of these complexes by electrospray ionisation mass spectrometry. All complexes fragment by dissociation of PPh₃ ligands, and the bromoalkylthiolate complexes show additional fragment ions [Pt₂(μ-S){μ-S(CH₂)_n−2CHCH₂}(PPh₃)_m]⁺ (m = 2 or 3; m ≠ 4), most significant for n = 4, formed by elimination of HBr.     

Syntheses and structures of the heterometallic clusters [(Ph3PAu)3Re(CO)4], [(Ph3PAu)4Re(CO)4], [(Ph3PAu)6AuRe2(CO)8], and [(Ph3PAu)6Re(CO)3]

The reaction of [HRe₃(CO)₁₂]²⁻ with an excess of Ph₃PAuCl in CH₂Cl₂ yields [(Ph₃PAu)₄Re(CO)₄]⁺ as the main product, which crystallizes as [(Ph₃PAu)₄Re(CO)₄]PF₆ · CH₂Cl₂ (1 · CH₂Cl₂) after the addition of KPF₆.The crystal structure determination reveals a trigonal bipyramidal Au₄Re cluster with the Re atom in equatorial position.If [(Ph₃PAu)₄Re(CO)₄]⁺ is reacted with PPh₄Cl, a cation [Ph₃PAu]⁺ is eliminated as Ph₃PAuCl, and the neutral cluster [(Ph₃PAu)₃Re(CO)₄] (2) is formed.It combines with excess [(Ph₃PAu)₄Re(CO)₄]⁺ to afford the cluster cation, [(Ph₃PAu)₆AuRe₂(CO)₈]⁺. It crystallizes from CH₂Cl₂ as[(Ph₃PAu)₆AuRe₂(CO)₈]PF₆ · 4CH₂Cl₂ (3 · 4CH₂Cl₂). In [(Ph₃PAu)₃Re(CO)₄] the metal atoms are arranged in form of a lozenge while in [(Ph₃PAu)₆AuRe₂(CO)₈]⁺ two Au₄Re trigonal bipyramids are connected by a common axial Au atom.The treatment of [(Ph₃PAu)₄Re(CO)₄]⁺ with KOH and Ph₃PAuCl in methanol yields the cluster cation [(Ph₃PAu)₆Re(CO)₃]⁺, which crystallizes with from CH₂Cl₂ as [(Ph₃PAu)₆Re(CO)₃]PF₆ · CH₂Cl₂ (4 · CH₂Cl₂). The metal atoms in this cluster form a pentagonal bipyramid with the Re atom in the axial position.     

Formation of cyclo- and polystannanes by dehydrogenative stannane coupling catalyzed by platinum(II) complexes

Reaction of (PhMe₂P)₂PtMe₂ or [(κ²-P,N)-Ph₂PC₂H₄NMe₂]PtMe₂ with an excess of H₂SnBu₂ or H₂SnPh₂ resulted in the catalytic formation of cyclo-, oligo- and/or polystannanes. In the reaction of (PhMe₂P)₂PtMe₂ with H₂SnBu₂, linear oligomeric species H(SnBu₂)_nH were observed in the initial stage of the reaction, which eventually converted into cyclostannanes. Only polystannanes were observed in the reaction of [(κ²-P,N)-Ph₂PC₂H₄NMe₂]PtMe₂ with H₂SnBu₂. The reactions of H₂SnPh₂ were similar, but more difficult to analyze due to redistribution reactions and the formation of insoluble products. The mechanism of the reactions is clearly different to that previously observed for HSnR₃ because metal complexes indicative of oxidative addition/reductive elimination reactions were only observed as minor products.     

Raman and infrared spectroscopic and theoretical studies of dinuclear rhenium and osmium complexes, M2(O2CCH3)4X2 (M = Re, Os; X = Cl, Br)

Infrared, far-infrared and Raman spectra of Re₂(O₂CCH₃)₄X₂ (X = Cl, Br) and Re₂(O₂CCD₃)₄Cl₂ have been recorded. Assignments of the vibrational spectra of Os₂(O₂CCH₃)₄Cl₂ and its deuterated derivative have been completed together with the Re complexes on the basis of normal-coordinate analysis. Force constant calculation was made for the acetate ion as well as for a four-atomic unit (with the CH₃ and CD₃ groups considered as point masses) using optimized masses of 16.7, 17.8, 20.5 and 21.6 for ¹²CH₃, ¹³CH₃, ¹²CD₃ and ¹³CD₃ groups, respectively. The force constants of the acetate ion have been adopted to the starting force field of the M₂(O₂CCH₃)₄X₂ type complexes. The metal-halide (0.889, 0.997 and 1.286 N cm⁻¹) and metal-metal stretching (3.32, 3.34 and 3.57 N cm⁻¹) force constants were obtained for Re₂(O₂CCH₃)₄Cl₂Re₂(O₂CCH₃)₄Br₂ and Os₂(O₂CCH₃)₄Cl₂ complexes, respectively. It was shown that the so-called diatomic approximation in most cases overestimates the M-M stretching force constants by 30-40%. Much better correlation has been obtained to fit these force constants, which produced values very close to those obtained by full normal-coordinate calculations. The Re-Re stretching force constants showed a reasonable correlation with the Re-Re bond distances for 18 rhenium complexes.     

Selective synthesis of triangular cluster oxido-sulfidocomplexes of Mo and W: High yield preparations of [Mo3O2S2(H2O)9], [W3O2S2(H2O)9], [W2MoO2S2(H2O)9] and their derivatization

Reaction of [Mo₂O₂(μ-S)₂(H₂O)₆]²⁺ with Mo(CO)₆ or metallic Mo under hydrothermal conditions (140 °C, 4 M HCl) gives oxido-sulfido cluster aqua complex [Mo₃(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (1). Similarly, [W₃(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (2) is obtained from [W₂O₂(μ-S)₂(H₂O)₆]²⁺ and W(CO)₆. While reaction of [Mo₂O₂(μ-S)₂(H₂O)₆]²⁺ with W(CO)₆ mainly proceeds as simple reduction to give 1, [W₂O₂(μ-S)₂(H₂O)₆]²⁺ with Mo(CO)₆ produces new mixed-metal cluster [W₂Mo(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (3) as main product. From solutions of 1 in HCl supramolecular adduct with cucurbit[6]uril (CB[6]) {[Mo₃O₂S₂(H₂O)₆Cl₃]₂CB[6]}Cl₂⋅18H₂O (4) was isolated and structurally characterized. The aqua complexes were converted into acetylacetonates [M₃O₂S₂(acac)₃(py)₃]PF₆ (M₃ = Mo₃, W₃, W₂Mo; 5a-c), which were characterized by X-ray single crystal analysis, electrospray ionization mass spectrometry and ¹H NMR spectroscopy. Crystal structure of (H₅O₂)(Me₄N)₄[W₃(μ₃-S)(μ₂-S)(μ₂-O)₂(NCS)₉] (6), obtained from 2, is also reported.     

Synthesis, spectroscopic and structural characterization of Cu(II) derivatives of tris(pyrazol-1-yl)methanes

The reaction between CuX₂ (X=ClO₄, NO₃, Cl, Br and CH₃COO) and excess of tris(pyrazol-1-yl)methane ligands L (L=CH(pz)₃, CH(4-Mepz)₃, CH(3,5-Me₂pz)₃, CH(3,4,5-Me₃pz)₃ or CH(3-Mepz)₂(5-Mepz)) yields [CuX₂(L)], [{CuX₂}₃(L₂)₂] or [Cu(L₂)]X₂-type complexes. The ligand to metal ratio is dependent on the number and disposition of the Me substituents on the azole-type ligand and mainly on the nature of the counter-ion X. All complexes have been characterized in the solid state as well as in solution (IR and UV spectra, and conductivity determinations). The solid-state structures of [Cu{(3,5-Me₂pz)₃CH}₂](NO₃)₂, [Cu{(3,5-Me₂pz)₃CH}₂](ClO₄)₂·0.5H₂O, [Cu{(3,4,5-Me₃pz)₃CH}₂](NO₃)₂·H₂O, [Cu{(4-Mepz)₃CH}₂]Br₂·3H₂O have been determined by single crystal X-ray studies.     

Synthesis, crystal structure and vibrational spectroscopy of a novel mixed ligands Ni(II) pentaborate: [Ni(C4H10N2)(C2H8N2)2][B5O6(OH)4]2

A novel organic-inorganic hybrid pentaborate [Ni(C₄H₁₀N₂)(C₂H₈N₂)₂][B₅O₆(OH)₄]₂ has been synthesized by hydrothermal reaction and characterized by FT-IR, Raman spectroscopy, elemental analyses and DTA-TGA. Its crystal structure was determined from single crystal X-ray diffraction. The structure consists of isolated polyborate anion [B₅O₆(OH)₄]⁻ and nickel complex cation of [Ni(C₄H₁₀N₂)(C₂H₈N₂)₂]²⁺, in which the two kinds of ligands come from the decomposition of triethylenetriamine material. The [B₅O₆(OH)₄]⁻ units are connected to one another through hydrogen bonds, forming a three-dimensional framework with large channel along the a and c axes, in which the templating [Ni(C₄H₁₀N₂)(C₂H₈N₂)₂]²⁺ cations are located. The assignments of the record FT-IR absorption frequencies and Raman shifts were given.     

Heterobimetallic platinum-bismuth aggregates derived from [Pt2(μ-S)2(PPh3)4]

The metalloligand [Pt₂(μ-S)₂(PPh₃)₄] reacts with Bi(S₂CNEt₂)₃ or Bi(S₂COEt)₃ in methanol to produce the orange cationic adducts [Pt₂(μ-S)₂(PPh₃)₄Bi(S₂CNEt₂)₂]⁺ and [Pt₂(μ-S)₂(PPh₃)₄Bi(S₂COEt)₂]⁺, respectively, isolated as their hexafluorophosphate salts. An X-ray structure determination on [Pt₂(μ-S)₂(PPh₃)₄Bi(S₂CNEt₂)₂]PF₆ reveals the presence of a six-coordinated bismuth centre with an approximately nido-pentagonal bipyramidal coordination geometry. Fragmentation pathways for both complexes have been probed using electrospray ionisation mass spectrometry; ions [Pt₂(μ-S)₂(PPh₃)₂Bi(S₂CXEt_n)₂]⁺ (X = O, n = 1, X = N, n = 2) are formed by selective loss of two PPh₃ ligands, and at higher cone voltages the species [(Ph₃P)PtS₂Bi]⁺ is observed. Ions formed by loss of CS₂ are also observed for the xanthate but not the dithiocarbamate ions.     

Synthesis and characterization of mono- and dinuclear nickel complexes with dichalcogenolate o-carboranyl ligands

Three mono- and dinuclear nickel complexes with dichalcogenolate o-carboranyl ligands were synthesized and characterized by X-ray crystallography. The reactions of Ni(COD)₂(COD=1,5-octadiene) with [(THF)₃LiE₂C₂B₁₀H₁₀Li(THF)]₂ (E=S, Se) in THF in the presence of air in different ratios afforded the mono- and dinuclear nickel complexes of formulae Li(THF)₄]₂[Ni(E₂C₂B₁₀H₁₀)₂] (E=S, 1a; E=Se, 1b) and [Li(THF)₄]₂[Ni₂(E₂C₂B₁₀H₁₀)₃] (E=S, 2a; E=Se, 2b). In 2a, two nickel atoms are connected by one chalcogen (η¹,η²-S₂C₂B₁₀H₁₀) bridging ligand with strong metal-metal interaction. Complex of formula (PPh₃)₂Ni(S₂C₂B₁₀H₁₀) · 0.5THF (3a) was also obtained from the reaction of (PPh₃)₂NiCl₂ and [(THF)₃LiS₂C₂B₁₀H₁₀Li(THF)]₂.     

Reactivity of [PdCl(μ-med)]2 with monodentate or bidentate ligands. Structure of the dinuclear complexes [Pd(μ-med)(PPh3)]2(BF4)2 and [Pd(μ-med)(bpy)]2(BF4)2. [Hmed=N-(2-mercaptoethyl)-3,5-dimethylpyrazole]

Treatment of the ligand N-(2-mercaptoethyl)-3,5-dimethylpyrazole with [Pd(CH₃COO)₂]₃ and reaction of [PdCl(μ-med)]₂ with pyridine (py) or triphenylphosphine (PPh₃) in the presence of AgBF₄ produced the following complexes: [Pd(CH₃COO)(μ-med)]₂, [Pd(μ-med)(py)]₂(BF₄)₂ and [Pd(μ-med)(PPh₃)]₂(BF₄)₂. Similar reactions carried out with 2,2^′-bipyridine (bpy) or 1,3-bis(diphenylphosphino)propane (dppp) produced [Pd(μ-med)(bpy)]_x(BF₄)_x (x=1 or 2) and [Pd(μ-med)(dppp)]_x(BF₄)_x (x=1 or 2). Treatment of [Pd(μ-med)(bpy)]_x(BF₄)_x with [PdCl₂(CH₃CN)₂] produced [Pd₃Cl₂(μ-med)₂(bpy)₂](BF₄)₂. Treatment of [Pd(μ-med)(dppp)]_x(BF₄)_x with [PdCl₂(CH₃CN)₂] produced a mixture of [Pd(μ-Cl)(dppp)]₂(BF₄)₂ and [Pd(μ-med)₂(dppp)]²⁺. X-ray crystal structures of [Pd(μ-med)(PPh₃)]₂(BF₄)₂ · 2CH₃CN and [Pd(μ-med)(bpy)]₂(BF₄)₂ · 0.5CH₃OH are presented.     

EPR study of the oxidation reaction of nickel(0) phosphine complexes with Lewis and Brønsted acids

The oxidation of Ni(PPh₃)₄ with BF₃ · OEt₂, H₃CCOOH, and F₃CCOOH, and that of (PPh₃)₂Ni(C₂H₄) with BF₃ · OEt₂ is studied by EPR spectroscopy. The reaction of the Ni(0) complexes with BF₃ · OEt₂ gives Ni(II) complexes with which they react to form Ni(I) compounds with covalent Ni-F and Ni-B bonds that transform with excess BF₃ · OEt₂ into cationic paramagnetic Ni(I) complexes. Acetic acid also adds oxidatively to Ni(PPh₃)₄ to form a Ni(II) complex that reacts further to give Ni(I) hydride and carboxylate complexes. The Ni(I) hydride is transformed by the acid into the Ni(I) carboxylate with release of hydrogen, the amount of which depends on the rate of acid addition. The following Ni(I) complexes are identified in the reaction medium: [Ni(PPh₃)₃]BF₄, [(PPh₃)₂Ni(OEt₂)]BF₄, [(PPh₃)Ni(OEt₂)_n]BF₄, (PPh₃)₂NiBF₂, (PPh₃)₃NiOOCCH₃, and [(PPh₃)₂Ni(OEt₂)P(OEt)₃]BF₄. Oxidation schemes of Ni(0) complexes by Lewis and Brønsted acids are given.