Field desorption mass spectra of [M(CO)3(η-arene)]X (MMn,Re; XBF4, PF6) salts

Field desorption mass spectra are reported for a range of [M(CO)₃(η-arene)]X (MMn or Re, XBF₄ or PF₆) salts. In most cases the spectra are simple, being dominated by molecular, [M]^+·, [M + 1]⁺, and [MCO]⁺ ions for the cationic part of their structure. However, with the π-chloroarene complexes [Mn(CO)₃(η-ClC₆H₅)]PF₆ and [Mn(CO)₃(η-1-Cl, 4-MeC₆H₄)]PF₆, facile loss of the chloro substituent and further fragmentation leads to unusually complex spectra, which include strong peaks arising from recombination of fragment species. Cluster ions are also noted in several cases, allowing identification of the anion.     

Structure of (BEDT-TTF)-Based Organic Metals with Photochromic Nitroprusside Anion (BEDT-TTF)4M[FeNO(CN)5]2, where M = Na+, K+, NH+4, Tl+, Rb+, and Cs+

The crystal and molecular structures of a family of three-component radical cation salts bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF), (BEDT-TTF)₄M[NP]₂, where M = Na⁺, K⁺, NH⁺ ₄, Tl⁺, Rb⁺, and Cs⁺and NP is the nitroprusside anion [FeNO(CN)₅]^2–, are studied by X-ray structure analysis. These salts are isostructural and behave as stable metals down to helium temperatures. Their structures are characterized by radical cation layers of the "-type alternating with layers of complex anions [M⁺(NP^2–)₂]^3–. The conducting radical cation system and photochromic nitroprusside anion in the crystals were shown to affect each other. On the one hand, this changes the geometric parameters of the nitroprusside anion as compared to those of the Na₂[NP] · 2H₂O crystals in the ground state and, on the other hand, makes the geometries of the two crystallographically independent BEDT-TTF molecules with a different number of shortened contacts with the anion different. Based on the data of crystallochemical analysis of the (BEDT-TTF)₄M[FeNO(CN)₅]₂structures, we suggest their possible routes of chemical modification with the purpose of changing their physical properties.     

Synthesis,protonation and substitution behaviour of K3[ReO2(CN)4]

Summary The preparation and characterization of salts of the [ReO₂(CN)₄]^3–, [ReO(OH)(CN)₄]^2–, [ReO(H₂O)(CN)₄]^–, [Re₂O₃(CN)₈]^4– and [ReO(NCS)(CN)₄]^2– species are described. The nature of the protonation reactions of [ReO₂(CN)₄]^3– was established by the successful isolation of these salts.     

The silver(I)‐catalyzed exchange of coordinated cyanide in hexacyanoferrate(II) by phenylhydrazine in aqueous medium

The [Ag]⁺‐catalyzed exchange of coordinated cyanide in [Fe(CN)₆]^4? by phenylhydrazine (PhNHNH₂) has been studied spectrophotometrically at 488 nm by monitoring increase in the absorbance for the formation of cherry red colored complex [Fe(CN)₅PhNHNH₂]^3?. The other reaction conditions were pH 2.80±,0.02, temperature = 30.0 ± 0.1^°C, and ionic strength (I) = 0.02 M (KNO₃). The reaction was followed as a function of pH, ionic strength, temperature, [Fe(CN)^4?₆], [PhNHNH₂], [Ag⁺] by varying one variable at a time. The initial rates were evaluated for each variation using the plane mirror method. The initial rates evaluated as a function of [Fe(CN)^4?₆] clearly indicate that the initial rate increases with the increase in [Fe(CN)^4?₆] and finally reaches to a limiting value when [Fe(CN)^4?₆]/[AgNO₃] ? 1000. It indicates the formation of a strong adduct between [Fe(CN)₆]^4? and AgNO₃ prior to the abstraction of CN^?. The variation in initial rates with [PhNHNH₂] also showed limiting values at [Fe(CN)^4?₆]/[PhNHNH₂] ? 8.30. The complex behavior due to pH and [Ag⁺] variations on the rate has been explained in detail. The composition of the final reaction product [Fe(CN)₅PhNHNH₂] formed during the course of reaction has been found to be 1:1 using the mole ratio method. The evaluated values of activation parameters for the catalyzed reaction are E_a = 53.85 kJ mol^?1, Δ H^≠, = 51.33 kJ mol^?1, and Δ S^≠ = ?134.63 J K^?1 mol^?1, which suggest an interchange dissociative mechanism. A most plausible mechanistic scheme has been proposed based on the experimental observations. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 447–456, 2007     

Die Tetracyanoborate M[B(CN)4], M = [Bu4N]+, Ag+, K+

The Tetracyanoborates M[B(CN)₄], M = [Bu₄N]⁺, Ag⁺, K⁺ The tetracyanoborate anion is prepared for the first time as the tetrabutylammonium salt by the reaction of [NBu₄]BX and BX₃ (X = Br, Cl) in toluene with KCN. After purification and recrystallization of the product from CHCl₃ colorless and needle size single crystals of [Bu₄N][B(CN)₄] are formed. After metathesis with AgNO₃ the silver salt and subsequently with KBr the potassium salt is prepared. The three salts are characterized by single crystal X‐ray diffraction (Ag[B(CN)₄] P 43m, a = 5.732(1) Å, V = 188.3 ų, Z = 1, R₁ = 0.75%; K[B(CN)₄] I4₁/a, a = 6.976(1), c = 14.210(3) Å, V = 691.5 ų, Z = 4, R₁ = 1.90%; [Bu₄N][B(CN)₄] Pnna, a = 17.765(3), b = 11.650(2), c = 11.454(2) Å, V = 2370.5 ų, Z = 4, R₁ = 6.09%) and by NMR‐, IR‐, Raman‐ as well by UV‐spectroscopy.     

Cyanidosilicates—Synthesis and Structure

Starting from fluoridosilicate precursors in neat cyanotrimethylsilane, Me₃Si?CN, a series of different ammonium salts [R₃NMe]⁺ (R=Et, ⁿPr, ⁿBu) with the novel [SiF(CN)₅]^2? and [Si(CN)₆]^2? dianions was synthesized in facile, temperature controlled F^?/CN^? exchange reactions. Utilizing decomposable, non‐innocent cations, such as [R₃NH]⁺, it was possible to generate metal salts of the type M₂[Si(CN)₆] (M⁺=Li⁺, K⁺) via neutralization reactions with the corresponding metal hydroxides. The ionic liquid [BMIm]₂[Si(CN)₆] (m.p.=72 °C, BMIm=1‐butyl‐3‐methylimidazolium) was obtained by a salt metathesis reaction. All the synthesized salts could be isolated in good yields and were fully characterized.     

Improved Access to Organo‐Soluble Di‐ and Tetrafluoridochlorate(I)/(III) Salts

A facile one‐pot gram‐scale synthesis of tetraalkylammonium tetrafluoridochlorate(III) [cat][ClF₄] ([cat]=[NEt₃Me]⁺, [NEt₄]⁺) is described. An acetonitrile solution of the corresponding alkylammonium chloride salt is fluorinated with diluted fluorine at low temperatures. The reaction proceeds via the [ClF₂]^? anion which is structurally characterized for the first time. The potential application of [ClF₄]^? salts as fluorinating agents is evaluated by the reaction with diphenyl disulfide, Ph₂S₂, to pentafluorosulfanyl benzene, PhSF₅. The CN moieties in acetonitrile and [B(CN)₄]^? are transferred in CF₃ groups. Exposure of carbon monoxide, CO, leads to the formation of carbonyl fluoride, COF₂, and elemental gold is dissolved under the formation of tetrafluoridoaurate [AuF₄]^?.     

Die Reaktionen von M[BF4] (M = Li,K) und (C2H5)2O·BF3 mit (CH3)3SiCN. Bildung von M[BFx>(CN)4—x] (M = Li,K; x = 1, 2) und (CH3)3SiNCBFx(CN)3—x, (x = 0, 1)

The Reactions of M[BF₄] (M = Li, K) and (C₂H₅)₂O·BF₃ with (CH₃)₃SiCN. Formation of M[BF_x(CN)_4—x] (M = Li, K; x = 1, 2) and (CH₃)₃SiNCBF_x(CN)_3—x, (x = 0, 1) The reaction of M[BF₄] (M = Li, K) with (CH₃)₃SiCN leads selectively, depending on the reaction time and temperature, to the mixed cyanofluoroborates M[BF_x(CN)_4—x] (x = 1, 2; M = Li, K). By using (C₂H₅)₂O·BF₃ the synthesis yields the compounds (CH₃)₃SiNCBF_x(CN)_3—x x = 0, 1. The products are characterized by vibrational and NMR‐spectroscopy, as well as by X‐ray diffraction of single‐crystals: Li[BF₂(CN)₂]·2Me₃SiCN Cmc2₁, a = 24.0851(5), b = 12.8829(3), c = 18.9139(5) Å V = 5868.7(2) ų, Z = 12, R₁ = 4.7%; K[BF₂(CN)₂] P4₁2₁2, a = 13.1596(3), c = 38.4183(8) Å, V = 6653.1(3) ų, Z = 48, R₁ = 2.5%; K[BF(CN)₃] P1¯, a = 6.519(1), b = 7.319(1), c = 7.633(2) Å, α = 68.02(3), β = 74.70(3), γ = 89.09(3)°, V = 324.3(1) ų, Z = 2, R₁ = 3.6%; Me₃SiNCBF(CN)₂ Pbca, a = 9.1838(6), b = 13.3094(8), c = 16.840(1) Å, V = 2058.4(2) ų, Z = 8, R₁ = 4.4%     

Preparation and Structural Characterization of [CpRu(1,10-phenanthroline)(CH3CN)][X] and Precursor Complexes (X=PF6, BArF,TRISPHAT-N)

Cationic [Ru(η⁵-C₅H₅)(CH₃CN)₃]⁺ complex, tris(acetonitrile)(cyclopentadienyl)ruthenium(II), gives rise to a very rich organometallic chemistry. Combined with diimine ligands, and 1,10-phenanthroline in particular, this system efficiently catalyzes diazo decomposition processes to generate metal-carbenes which undergo a series of original transformations in the presence of Lewis basic substrates. Herein, syntheses and characterizations of [CpRu(Phen)(L)] complexes with (large) lipophilic non-coordinating (PF₆⁻ and BAr_F⁻) and coordinating TRISPHAT-N⁻ anions are reported. Complex [CpRu(η⁶-naphthalene)][BAr_F] ( [1][BAr_F] ) is readily accessible, in high yield, by direct counterion exchange between [1][PF₆] and sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBAr_F) salts. Ligand exchange of [1][BAr_F] in acetonitrile generated stable [Ru(η⁵-C₅H₅)(CH₃CN)₃][BAr_F] ( [2][BAr_F] ) complex in high yield. Then, the desired [CpRu(Phen)(CH₃CN)] ( [3] ) complexes were obtained from either the [1] or [2] complex in the presence of the 1,10-phenanthroline as ligand. For characterization and comparison purposes, the anionic hemilabile ligand TRISPHAT−N (TTN) was introduced on the ruthenium center, from the complex [3][PF₆] , to quantitatively generate the desired complex [CpRu(Phen)(TTN)] ( [4] ) by displacement of the remaining acetonitrile ligand and of the PF₆⁻ anion. Solid state structures of complexes [1][BAr_F] , [2][BAr_F] , [3][BAr_F] , [3][PF₆] and [4] were determined by X-ray diffraction studies and are discussed herein.     

Reactivity of Cyanide and Thiocyanate Towards the Nitrosyl Carbonyl [Co(CO)3(NO)]

The reaction of equimolar amounts of [Co(CO)₃(NO)] and [PPN]CN, PPN⁺ = (PPh₃)₂N⁺, in THF at room temperature resulted in ligand substitution of a carbonyl towards the cyanido ligand presumably affording the complex salt PPN[Co(CO)₂(NO)(CN)] as a reactive intermediate species which could not be isolated. Applying the synthetic protocol using the nitrosyl carbonyl in excess, the title reaction afforded unexpectedly the novel complex salt PPN[Co₂(μ-CN)(CO)₄(NO)₂] ( 1 ) in high yield. Because of many disorder phenomena in crystals of 1 the corresponding NBu₄⁺ salt of 1 has been prepared and the molecular structure of the dinuclear metal core in NnBu₄[Co₂(μ-CN)(CO)₄(NO)₂] ( 2 ) was determined by X-ray crystal diffraction in a more satisfactory manner. In contrast to the former result, the reaction of [PPN]SCN with [Co(CO)₃(NO)] yielded the mononuclear complex salt PPN[Co(CO)₂(NO)(SCN-κN)] ( 3 ) in good yield whose molecular structure in the solid was even determined and its composition additionally confirmed by spectroscopic means.     

Syntheses,crystal structures and magnetic properties of two cyano-bridged two-dimensional assemblies [Fe(salpn)]2 [Fe(CN)5NO] and [Fe(salpn)]2[Ni(CN)4]

Two cyano-bridged assemblies, [Fe^III(salpn)]₂[Fe^II(CN)₅NO] (1) and [Fe^III (salpn)]₂[Ni^II(CN)₄] (2) [salpn = N, N-1,2-propylenebis(salicylideneiminato)dianion], have been prepared and structurally and magnetically characterized. In each complex, [Fe(CN)₅NO]^2– or [Ni(CN)₄]^2– coordinates with four [Fe(salpn)]⁺ cations using four co-planar CN^– ligands, whereas each [Fe(salpn)]⁺ links two [Fe(CN)₅NO]^2– or [Ni(CN)₄]^2– ions in the trans form, which results in a two-dimensional (2D) network consisting of pillow-like octanuclear [—M^II—CN—Fe^III—NC—]₄ units (M = Fe or Ni). In complex (1), the NO group of [Fe(CN)₅NO]^2– remains monodentate and the bond angle of Fe^II—N—O is 180.0°. The variable temperature magnetic susceptibilities, measured in the 5–300 K range, show weak intralayer antiferromagnetic interactions in both complexes with the intramolecular iron(III)iron(III) exchange integrals of –0.017 cm^–1 for (1) and –0.020 cm^–1 for (2), respectively.     

Chemie der Isoblausäure. VIII. Protonierung eines ‚mobilen’︁ Cyanoliganden: cis-[(μ-CNH2)Fe2Cp2(CO)3]X (X = Cl,BF4, PF6, I)

Chemistry of Hydrogen Isocyanide. VIII. Protonation of a ‘Mobile’ Cyano Ligand: cis-[μ-CNH₂)Fe₂Cp₂(CO)₃]X (X = Cl, BF₄, PF₆, I) . Protonation of the terminal cyano ligand in the complex cis-Na[Fe₂(CN)Cp₂(CO)₃] affords the N-diprotonated produkt [Fe₂Cp₂(CO)₃(μ-CNH₂)]⁺ X^? (X = Cl, BF₄, PF₆, I) exclusively; the structure of the chloride has been determined by X-ray analysis.     

Convenient Access to α‐Fluorinated Alkylammonium Salts

A series of novel α‐fluoroalkyl ammonium salts was obtained from the corresponding cyano compounds or nitriles by reaction with anhydrous HF. Room‐temperature stable trifluoromethyl ammonium salts were obtained in quantitative yield in a one‐step reaction at ambient temperature from the commercially available starting materials BrCN or ClCN. The novel cations [CF₃CF₂NH₃]⁺, [HCF₂CF₂NH₃]⁺, and [(NH₃CF₂)₂]²⁺ were obtained from CF₃CN, HCF₂CN, and (CN)₂, respectively, and anhydrous HF. The aforementioned fluorinated ammonium cations were isolated as room temperature stable [AsF₆]^? and/or [SbF₆]^? salts, and characterized by multi‐nuclear NMR and vibrational spectroscopy. The salts [HCF₂NH₃][AsF₆] and [CF₃NH₃][Sb₂F₁₁] were characterized by their X‐ray crystal structure.     

Tuning the sulfur-heterometal interaction in organolead(IV) complexes of [Pt2(μ-S)2(PPh3)4]

Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with Ph₃PbCl, Ph₂PbI₂, Ph₂PbBr₂ and Me₃PbOAc result in the formation of bright yellow to orange solutions containing the cations [Pt₂(μ-S)₂(PPh₃)₄PbR₃]⁺ (R₃ = Ph₃, Ph₂I, Ph₂Br, Me₃) isolated as PF₆⁻ or BPh₄⁻ salts. In the case of the Me₃Pb and Et₃Pb systems, a prolonged reaction time results in formation of the alkylated species [Pt₂(μ-S)(μ-SR)(PPh₃)₄]⁺ (R = Me, Et). X-ray structure determinations on [Pt₂(μ-S)₂(PPh₃)₄PbMe₃]PF₆ and [Pt₂(μ-S)₂(PPh₃)₄PbPh₂I]PF₆ have been carried out, revealing different coordination modes. In the Me₃Pb complex, the (four-coordinate) lead atom binds to a single sulfur atom, while in the Ph₂PbI adduct coordination of both sulfurs results in a five-coordinate lead centre. These differences are related to the electron density on the lead centre, and indicate that the interaction of the heterometal centre with the {Pt₂S₂} metalloligand core can be tuned by variation of the heteroatom substituents. The species [Pt₂(μ-S)₂(PPh₃)₄PbR₃]⁺ display differing fragmentation pathways in their ESI mass spectra, following initial loss of PPh₃ in all cases; for R = Ph, loss of PbPh₂ occurs, yielding [Pt₂(μ-S)₂(PPh₃)₃Ph]⁺, while for R = Me, reductive elimination of ethane gives [Pt₂(μ-S)₂(PPh₃)₃PbMe]⁺, which is followed by loss of CH₄.     

Two novel bis­(2,9‐dimeth­yl‐1,10‐phenanthroline)copper(I) complexes: [Cu(dmp)2]2(PF6)2·0.5(bpmh)·CH3CN and [Cu(dmp)2][N(CN)2]

Two new salts of the cation [Cu^I(dmp)₂]⁺ (dmp is 2,9‐dimeth­yl‐1,10‐phenanthroline, C₁₄H₁₂N₂), namely bis­[bis­(2,9‐dimeth­yl‐1,10‐phenanthroline‐κ²N,N′)copper(I)] bis­(hexa­fluorophos­phate) hemi[bis­(4‐pyridylmethyl­idene)hydrazine] acetonitrile solvate, [Cu(C₁₄H₁₂N₂)₂]₂(PF₆)₂·0.5C₁₂H₁₀N₄·C₂H₃N or [Cu(dmp)₂]₂(PF₆)₂·0.5(bpmh)·CH₃CN [bpmh is bis­(4‐pyridylmethyl­idene)hydrazine, C₁₂H₁₀N₄], (I), and bis­(2,9‐dimeth­yl‐1,10‐phenanthroline‐κ²N,N′)copper(I) dicyanamide, [Cu(C₁₄H₁₂N₂)₂](C₂N₃) or [Cu(dmp)₂][N(CN)₂], (II), are reported. The Cu—N bond lengths and the distortion from idealized tetra­hedral geometry of the dmp ligands are discussed and compared with related compounds. The bpmh molecule in (I) is π–π stacked with a dmp ligand at a distance of 3.4 Å, rather than coordinated to the metal atom. The molecule lies across an inversion center in the crystal. In (II), the normally coordinated dicyanamide mol­ecule is present as an uncoordinated counter‐ion.     

The formation of an antitubercular complex [Fe(CN)5(INH)]3− through mercury(II)‐catalyzed ligand substitution reaction: A kinetic and mechanistic study

The kinetics and mechanism of the formation of an antitubercular complex [Fe(CN)₅(INH)]^3? based on the substitution reaction between K₄[Fe(CN)₆] and isoniazid (INH), i.e., isonicotinohydrazide, catalyzed by Hg²⁺ in aqueous medium was studied spectrophotometrically at 435 nm (the λ_max of the golden‐yellow‐colored complex [Fe(CN)₅(INH)]^3?) as a function of pH, ionic strength, temperature, and the concentration of the reactants and the catalyst. The replacement of coordinated CN^? in [Fe(CN)₆]^4? was facilitated by incoming ligand INH under the optimized reaction conditions: pH 3.5 ± 0.02, temperature = 30.0 ± 0.1°C, and ionic strength I = 0.05 M (KNO₃). The stoichiometry of the reaction and the stability constant of the complex ([Fe(CN)₅(INH)]^3?) have been established as 1:1 and 2.10 × 10³ M, respectively. The rate of catalyzed reaction was found to be slow at low pH values, to increase with increasing pH, to attain a maximum value at 3.50 ± 0.02, and finally to decrease after pH > 3.5 due to less availability of H⁺ ions needed to regenerate the catalytic species. The initial rates were evaluated for each variation from the absorbance versus time curves. The reaction was found to be pseudo‐first order with respect to [INH] and first order with respect to [Fe(CN)₆^4?] at lower concentration, whereas it was found to be fractional order at higher [INH] and [Fe(CN)₆^4?]. The ionic strength dependence study showed a negative salt effect on the rate of the reaction. Based on experimental results, a mechanism for the studied reaction is proposed. The rate equation derived from this mechanism explains all the experimental observations. The evaluated values of activation parameters for the catalyzed reaction suggest an interchange dissociative (I_d) mechanism. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 398–406, 2012     

Coordination chemistry of the [Pt2(μ-S)2(PPh3)4] metalloligand with π-hydrocarbon derivatives of d ruthenium(II), osmium(II), rhodium(III) and iridium(III)

The reactivity of [Pt₂(μ-S)₂(PPh₃)₄] towards [RuCl₂(η⁶-arene)]₂ (arene=C₆H₆, C₆Me₆, p-MeC₆H₄Prⁱ=p-cymene), [OsCl₂(η⁶-p-cymene)]₂ and [MCl₂(η⁵-C₅Me₅)]₂ (M=Rh, Ir) have been probed using electrospray ionisation mass spectrometry. In all cases, dicationic products of the type [Pt₂(μ-S)₂(PPh₃)₄ML]²⁺ (L=π-hydrocarbon ligand) are observed, and a number of complexes have been prepared on the synthetic scale, isolated as their BPh₄⁻ or PF₆⁻ salts, and fully characterised. A single-crystal X-ray structure determination on the Ru p-cymene derivative confirms the presence of a pseudo-five-coordinate Ru centre. This resists addition of small donor ligands such as CO and pyridine. The reaction of [Pt₂(μ-S)₂(PPh₃)₄] with RuClCp(PPh₃)₂ (Cp=η⁵-C₅H₅) gives [Pt₂(μ-S)₂(PPh₃)₄RuCp]⁺. In addition, the reaction of [Pt₂(μ-S)₂(PPh₃)₄] with the related carbonyl complex [RuCl₂(CO)₃]₂, monitored by electrospray mass spectrometry, gives [Pt₂(μ-S)₂(PPh₃)₄Ru(CO)₃Cl]⁺.     

Synthesen und Schwingungsspektren der homoleptischen Acetonitrilkomplex-Kationen [Au(NCCH3)2]+, [Pd(NCCH3)4]2+, [Pt(NCCH3)4]2+ und des Adduktes CH3CN · SbF5. Kristallstrukturen der Salze [M(NCCH3)4][SbF6]2 · CH3CN,M = Pd,Pt

The Syntheses and Vibrational Spectra of the Homoleptic Metal Acetonitrile Cations [Au(NCCH₃)₂]⁺, [Pd(NCCH₃)₄]²⁺, [Pt(NCCH₃)₄]²⁺, and the Adduct CH₃CN · SbF₅. The Crystal and Molecular Structures of [M(NCCH₃)₄][SbF₆]₂ · CH₃CN, M = Pd or Pt Solvolyses of the homoleptic metal carbonyl salts [M(CO)₄][Sb₂F₁₁]₂, M = Pd or Pt, in acetonitrile leads at 50 °C both to complete ligand exchange for the cations as well as to a conversion of the di-octahedral anion [Sb₂F₁₁]^– into [SbF₆]^– and the molecular adduct CH₃CN · SbF₅ according to: [M(CO)₄][Sb₂F₁₁]₂ + 7 CH₃CN → [M(NCCH₃)₄][SbF₆]₂ · CH₃CN + 2 CH₃CN · SbF₅ + 4 CO M = Pd, Pt The monosolvated [M(NCCH₃)₄][SbF₆]₂ · CH₃CN are obtained as single crystals from solution and are structurally characterized by single crystal x-ray diffraction. Both salts are isostructural. The cations are square planar but the N–C–C-sceletial groups of the ligands depart slightly from linearity. The new acetonitrile complexes as well as [Au(NCCH₃)₂][SbF₆] and the adduct CH₃CN · SbF₅ are completely characterized by vibrational spectroscopy.     

Thermal and photochemical interaction of octacyanometallates(IV), [M(CN)8]4− (M = Mo or W) in the presence of pyrazine

The interactions between [M(CN)₈]^4– (M = Mo or W) and pyrazine (pz) in the solid state and in aqueous solutions have been analysed. In strongly acidic solutions {pzH⁺, [M(CN)₈]^4–} ion pair formation is observed; the pyrazinium salts (pzH)₂(H₃O)₂[Mo(CN)₈]·0.5pz·3H₂O and (pzH)₂K(H₃O)[W(CN)₈]·H₂O have been isolated. The X-ray crystal structure of the latter, and the spectroscopic properties of both, are described. The [W(CN)₈]^4– anion is approximately square antiprismatic (D_4d), with different H-bond environments around the N atoms. The ligand-field photolysis of [M(CN)₈]^4– in the presence of pyrazine in neutral and alkaline solution results in the formation of tetracyanooxometallates(IV) in equilibrium with pentacyanooxometallates(IV) through the [M(CN)₇(pz)]^3– anions as intermediates. The formation of the [M(CN)₆(pz)₂]^2– ion, postulated in the literature to be the final product of the alkaline photolysis, has definitively been excluded.     

Reactivity Studies of η5‐ Indenyl and η5‐Cp* Ruthenium(II) Complexes towards some Polypyridyl Ligands

The reaction of [(η⁵‐L³)Ru(PPh₃)₂Cl], where; L³ = C₉H₇ ( 1 ), C₅Me₅ (Cp*) ( 2 ) with acetonitrile in the presence of [NH₄][PF₆] yielded cationic complexes [(η⁵‐L³)Ru(PPh₃)₂(CH₃CN)][PF₆]; L³= C₉H₇ ([3]PF₆) and L³ = C₅Me₅ ([4]PF₆), respectively. Complexes [3]PF₆ and [4]PF₆ reacts with some polypyridyl ligands viz, 2,3‐bis (α‐pyridyl) pyrazine (bpp), 2,3‐bis (α‐pyridyl) quinoxaline (bpq) yielding the complexes of the formulation [(η⁵‐L³)Ru(PPh₃)(L²)]PF₆ where; L³ = C₉H₇, L² = bpp, ([5]PF₆), L³ = C₉H₇, L² = bpq, ([6]PF₆); L³ = C₅Me₅, L² = bpp, ([7]PF₆) and bpq, ([8]PF₆), respectively. However reaction of [(η⁵‐C₉H₇)Ru(PPh₃)₂(CH₃CN)][PF₆] ([3]PF₆) with the sterically demanding polypyridyl ligands, viz. 2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine (tptz) or tetra‐2‐pyridyl‐1,4‐pyrazine (tppz) leads to the formation of unexpected complexes [Ru(PPh₃)₂(L²)(CH₃CN)][PF₆]₂; L² = tppz ([9](PF₆)₂), tptz ([11](PF₆)₂) and [Ru(PPh₃)₂(L²)Cl][PF₆]; L² = tppz ([10]PF₆), tptz ([12]PF₆). The complexes were isolated as their hexafluorophosphate salts. They have been characterized on the basis of micro analytical and spectroscopic data. The crystal structures of the representative complexes were established by X‐ray crystallography.