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]⁺.     

Arene ruthenium complexes incorporating immine/azine hybrid-chelating N-N donor ligands: synthetic, spectral, structural aspects and DFT studies

New series of mono and binuclear arene ruthenium complexes [{(η⁶-arene)RuCl(L)}]⁺ and [{(η⁶-arene)RuCl}₂(μ-L)₂]²⁺ (arene=benzene, p-cymene or hexamethylbenzene), {L=pyridine-2-carbaldehyde azine (paa), p-phenylene-bis(picoline)-aldimine (pbp) and p-bi-phenylene-bis(picoline)-aldimine (bbp)} are reported. The complexes have been fully characterized and molecular structure of the representative mononuclear complex [(η⁶-C₆Me₆)RuCl(paa)]BF₄ (1), binuclear complexes [{(η⁶-C₁₀H₁₄)RuCl}₂(μ-paa)](BF₄)₂ (3) and [{(η⁶-C₁₀H₁₄)RuCl}₂(μ-pbp)](BF₄)₂ (6) have been determined by single crystal X-ray diffraction analyses. Single crystal X-ray structure determination revealed that in the binuclear complexes the [(η⁶-C₁₀H₁₄)RuCl]⁺ units are trans disposed. Further, the crystal packing in the complexes 1, 3 and 6 is stabilized by C-H?X type (X=Cl, F) inter, intramolecular hydrogen bonding and π-π stacking (3). To explore the ambiguous nature of the bonding between pyridine-2-carbaldehyde azine (paa) with ruthenium containing units [(η⁶-arene)RuCl]⁺, DFT/B3LYP calculations have been performed on the complexes [(η⁶-arene)RuCl(paa)]⁺ (arene=C₆H₆, I; C₆Me₆, II; C₁₀H₁₄, III).     

Synthesis, characterisation and theoretical studies on some piano-stool ruthenium and rhodium complexes containing substituted phenyl imidazole ligands

Reactions of the chloro-bridged arene ruthenium complexes [{(η⁶-arene)RuCl(μ-Cl}₂] (η⁶-arene = benzene, p-cymene) and structurally analogous rhodium complex [{(η⁵-C₅Me₅)RhCl(μ-Cl}₂] with imidazole based ligands viz., 1-(4-nitro-phenyl)-imidazole (NOPI), 1-(4-formylphenyl)-imidazole (FPI) and 1-(4-hydroxyphenyl)-imidazole (HPI) have been investigated. The resulting complexes have been characterised by elemental analyses, IR, ¹H and ¹³C NMR, electronic absorption and emission spectral studies. Crystal structure of the representative complex [(η⁵-C₅Me₅)RhCl₂(NOPI)] has been determined crystallographically. Geometrical optimisation on the complexes have been performed using exchange correlation functional B3LYP. Optimised bond lengths and angles of the complexes have been found to be in good agreement with our earlier reports and single crystal X-ray data of the complex [(η⁵-C₅Me₅)RhCl₂(NOPI)].     

Synthesis of [(μ2-η2-CHCHPh)(μ-S){Fe2(CO)6}2(μ4-S)]− and its reactions with electrophiles

The action of [(μ₂-η²-CHCHPh)(μ-CO)Fe₂(CO)₆]⁻ with (μ-S)₂Fe₂(CO)₆ gives the anionic complex [(μ₂-η²-CHCHPh)(μ-S){Fe₂(CO)₆}₂(μ₄-S)]⁻ (1). The anion 1 reacts with alkyl halides, acid chlorides and Cp(CO)₂FeI to yield neutral products (μ₂-η²-CHCHPh)(μ-RS)[Fe₂(CO)₆]₂(μ₄-S) (R=Me, 2a; Et, 2b; PhCH₂, 2c; PhC(O), 3a; PhCHCHC(O), 3b and Cp(CO)₂Fe, 4).     

Ring Contraction by NHC‐Induced Pnictogen Abstraction

The reaction of [Cp′′′Co(η⁴‐P₄)] ( 1 ) (Cp′′′=1,2,4‐tBu₃C₅H₂) with ^MeNHC (^MeNHC=1,3,4,5‐tetramethylimidazol‐2‐ylidene) leads through NHC‐induced phosphorus cation abstraction to the ring contraction product [(^MeNHC)₂P][Cp′′′Co(η³‐P₃)] ( 2 ), which represents the first example of an anionic CoP₃ complex. Such NHC‐induced ring contraction reactions are also applicable for triple‐decker sandwich complexes. The complexes [(Cp*Mo)₂(μ,η^6:6‐E₆)] ( 3 a , 3 b ) (Cp*=C₅Me₅; E=P, As) can be transformed to the complexes [(^MeNHC)₂E][(Cp*M)₂(μ,η^3:3‐E₃)(μ,η^2:2‐E₂)] ( 4 a , 4 b ), with 4 b representing the first structurally characterized example of an NHC‐substituted As^I cation. Further, the reaction of the vanadium complex [(Cp*V)₂(μ,η^6:6‐P₆)] ( 5 ) with ^MeNHC results in the formation of the unprecedented complexes [(^MeNHC)₂P][(Cp*V)₂(μ,η^6:6‐P₆)] ( 6 ), [(^MeNHC)₂P][(Cp*V)₂(μ,η^5:5‐P₅)] ( 7 ) and [(Cp*V)₂(μ,η^3:3‐P₃)(μ,η^1:1‐P{^MeNHC})] ( 8 ).     

Hydroxylation of azomethine carbon: isolation of complexes of η5 and η6-cyclic hydrocarbon platinum group metals with a new Schiff-base ligand

A new Schiff base, (pyridin-2-yl)-N-(3,5-di(pyridin-2-yl)-4H-1,2,4-triazol-4-yl)methanimine, (L), was synthesized. Reaction of [(η⁶-arene)Ru(µ-Cl)Cl]₂ and [Cp*M(µ-Cl)Cl]₂ (M = Rh and Ir) with one equivalent of L in the presence of NH₄PF₆ in methanol yielded dinuclear complexes, [(η⁶-arene)₂Ru₂(L-OH)Cl](PF₆)₂ {arene = C₆H₆ (1), p-ⁱPrC₆H₄Me (p-cymene) (2) and C₆Me₆ (3)}, and [Cp*₂M₂(L-OH)Cl](PF₆)₂ [M = Rh (4) and Ir (5)], respectively, leading to the formation of five new chiral complexes with –OH on the azomethine carbon. L is a pentadentate ligand where one of the metal centers is coordinated to two nitrogen atoms in a bidentate chelating fashion while the other metal is bonded tridentate to three nitrogen atoms. Although the ligand is neutral before coordination, after complexation it is anionic (uni-negative) with negative charge on the azo nitrogen {see the structures: N(5) in 2[PF₆]₂ and N(3) for 4[PF₆]₂}. The complexes have been characterized by various spectroscopic methods including infrared and ¹H NMR and the molecular structures of the representative complexes are established by single-crystal X-ray diffraction studies.     

Dppm-substituted ruthenium clusters with capping sulfido and selenido ligands derived from thiourea, tetramethylthiourea and elemental selenium

Treatment of [Ru₃(CO)₁₀(μ-dppm)] (4) [dppm = bis(diphenylphosphido)methane] with tetramethylthiourea at 66 °C gave the previously reported dihydrido triruthenium cluster [Ru₃(μ-H)₂(μ₃-S)(CO)₇(μ-dppm)] (5) and the new compounds [Ru₃(μ₃-S)₂(CO)₇(μ-dppm)] (6), [Ru₃(μ₃-S)(CO)₇(μ₃-CO)(μ-dppm)] (7) and [Ru₃(μ₃-S){η¹-C(NMe₂)₂}(CO)₆(μ₃-CO)(μ-dppm)] (8) in 6%, 10%, 32% and 9% yields, respectively. Treatment of 4 with thiourea at the same temperature gave 5 and 7 in 30% and 10% yields, respectively. Compound 7 reacts further with tetramethylthiourea at 66 °C to yield 6 (30%) and a new compound [Ru₃(μ₃-S)₂{η¹-C(NMe₂)₂}(CO)₆(μ-dppm)] (9) (8%). Thermolysis of 8 in refluxing THF yields 7 in 55% yield. The reaction of 4 with selenium at 66 °C yields the new compounds [Ru₃(μ₃-Se)(CO)₇(μ₃-CO)(μ-dppm)] (10) and [Ru₃(μ₃-Se)(μ₃-η³-PhPCH₂PPh(C₆H₄)}(CO)₆(μ-CO)] (11) and the known compounds [Ru₃(μ-H)₂(μ₃-Se)(CO)₇(μ-dppm)] (12) and [Ru₄(μ₃-Se)₄(CO)₁₀(μ-dppm)] (13) in 29%, 5%, 2% and 5% yields, respectively. Treatment of 10 with tetramethylthiourea at 66 °C gives the mixed sulfur-selenium compounds [Ru₃(μ₃-S)(μ₃-Se)(CO)₇(μ-dppm)] (14) and [Ru₃(μ₃-S)(μ₃-Se){η¹-C(NMe₂)₂}(CO)₆(μ-dppm)] (15) in 38% and 10% yields, respectively. The single-crystal XRD structures of 6, 7, 8, 10, 14 and 15 are reported.     

Reactivity studies of (η6-arene)ruthenium(II) dimers with arylazoimidazole ligands: molecular structure of [(η6-p-cymene)RuCl(Me-C6H4-Nequals;N-C3H2N2-1-CH3)]PF6

The complexes [{(η ⁶-arene)Ru(μ-Cl)Cl}₂] (arene?=?p-cymene (1), hexamethylbenzene reacts at low temperature with the arylazoimidazole (RaaiR′) ligands 2-(phenylazo)imidazole (Phai-H), 1-methyl-2-(phenylazo)imidazole (Phai-Me), 1-ethyl-2-(phenylazo)imidazole (Phai-Et), 2-(tolylazo)imidazole (Tai-H), 1-methyl-2-(tolylazo)imidazole (Tai-Me) and 1-ethyl-2-(tolylazo)imidazole (Tai-Et) to give complexes of the type [(η ⁶-arene)RuCl(RaaiR′)]⁺. The complexes were characterized by FTIR and ¹H NMR and ¹³C {¹H} NMR spectroscopy. The molecular structure of [(η ⁶-p-cymene)RuCl(Me-C₆H₄-N=N-C₃H₂N₂-1-CH₃)]PF₆ was established by single-crystal X-ray diffraction methods.     

Syntheses and structural studies of mononuclear arene ruthenium complexes with nitrogen-based chelating ligands

Dinuclear arene ruthenium complexes [(η⁶-arene)Ru(μ-Cl)Cl]₂ (arene?=?C₆H₆; p ⁱPrC₆H₄Me; C₆Me₆) and monomeric cyclopentadienyl complexes [(η⁵-Cp)Ru(PPh₃)₂Cl] (Cp?=?cyclopentadienyl) react with polypyridyl nitrogen ligands L¹ (3-(pyridin-2-yl)-1H-1,2,4-triazole) and L² (1,3-bis(di-2-pyridylaminomethyl)benzene) in methanol to afford cationic mononuclear compounds [(η⁶-arene)Ru(L¹)Cl]⁺ (arene?=?C₆H₆, 1; p ⁱPrC₆H₄Me, 2; C₆Me₆, 3), [(η⁶arene)Ru(L²)Cl]⁺ (arene?=?C₆H₆, 4; p ⁱPrC₆H₄Me, 5; C₆Me₆, 6), [(η⁵-Cp)Ru(L¹)(PPh₃)]⁺ (7), and [(η⁵Cp)Ru(L²)(PPh₃)]⁺ (8). All cationic mononuclear compounds were isolated as their hexafluorophosphate salts and characterized by elemental analyses, NMR, and IR spectroscopic methods and some representative complexes by UV-Vis spectroscopy. The solid state structures of two derivatives, [6]PF₆ and [7]PF₆, have been determined by the X-ray structure analysis.     

Synthesis and characterization of triosmium and triruthenium pyrene clusters

The reaction between 1-pyrenecarboxaldehyde (C₁₆H₉CHO) and the labile triosmium cluster [Os₃(CO)₁₀(CH₃CN)₂] gives rise to the formation of two new compounds by competitive oxidative addition between the aldehydic group and an arene C-H bond, to afford the acyl complex [Os₃(CO)₁₀(μ-H)(μ-COC₁₆H₉)] (1) and the compound [Os₃(CO)₁₀(μ-H) (C₁₆H₈CHO)] (2), respectively. Thermolysis of [Os₃(CO)₁₀(μ-H)(μ-C₁₆H₉CO)] (1) in n-octane affords two new complexes in good yields, [Os₃(CO)₉(μ-H)₂(μ-COC₁₆H₈)] (3) and the pyryne complex [Os₃(CO)₉(μ-H)₂(μ₃-η¹:η¹:η²-C₁₆H₈)] (4).In contrast, when 1-pyrenecarboxaldehyde reacts with [Ru₃(CO)₁₂] only one product is obtained, [Ru₃(CO)₉(μ-H)₂(μ₃-η¹:η¹:η²-C₁₆H₈)] (5), a nonacarbonyl cluster bearing a pyrene ligand. All compounds were characterized by analytical and spectroscopic data, and crystal structures for 1, 2, 4 and 5 were obtained.     

Ruthenium cluster chemistry: Monodentate bis(diphenylphosphino)acetylene-ligated cluster modules in chain and dendrimer formation

Reaction of Ru₃(μ-dppm)(CO)₁₀ [dppm = bis(diphenylphosphino)methane] with one equivalent of dppa [dppa = bis(diphenylphosphino)acetylene] afforded Ru₃(μ-dppm)(CO)₉(η¹-dppa) which possesses a monodentate dppa ligand,an X-ray structural study revealing that all phosphorus donor atoms are arranged in equatorial coordination sites with respect to the triruthenium cluster plane.Reaction of Ru₃(CO)₉(NCMe)₃ with excess dppa afforded fair yields of Ru₃(CO)₉(η¹-dppa)₃,which possesses three monodentate dppa ligands.Reaction of three equivalents of Ru₃(μ-dppm)(CO)₉(η¹-dppa) with Ru₃(CO)₉(NCMe)₃ or reaction of Ru₃(CO)₉(η¹-dppa)₃ with excess Ru₃(μ-dppm)(CO)₁₀ afforded low yields of the dodecanuclear first-generation dendrimer Ru₃(CO)₉{PPh₂C₂PPh₂Ru₃(μ-dppm)(CO)₉}₃.Reaction of WIr₃(μ-CO)₃(CO)₈(η-C₅Me₅) with excess Ru₃(μ-dppm)(CO)₉(η¹-dppa) afforded fair yields of the decanuclear dppa-bridged tri-cluster WIr₃(CO)₉{PPh₂C₂PPh₂Ru₃(μ-dppm)(CO)₉}₂(η-C₅Me₅).     

Asymmetric acetylenic thioethers in ruthenium cluster chemistry

The compounds [Ru₃(CO)₉(μ,η²-SCCR)(μ₃,η²-CCR^′)] (R=SiMe₃, R^′=SiⁱPr₃ (1); R=SiⁱPr₃, R^′=SiMe₃ (2); R=SiⁱPr₃, R^′=H (3); R=H, R^′=SiⁱPr₃ (4)) have been obtained by cleavage of one S-C bond of the thioethers ⁱPr₃SiCCSCCR (R=H, SiMe₃) in the presence of Ru₃(CO)₁₂. Thermal treatment of [Ru₃(CO)₉(μ,η²-SCCSiⁱPr₃)(μ₃,η²-CCH)] yields to the cluster [Ru₄(CO)₉(μ-CO)₂(μ₄-S)(μ₄-η²-C(H)C)(CCSiⁱPr₃)] (5) which contains a bridging sulfur atom and a polycarbon chain as a consequence of the rupture of the S-C bond and a C-C coupling reaction. All derivatives have been characterized by spectroscopic data. An X-ray diffraction study was carried out on the species [Ru₃(CO)₉(μ,η²-SCCSiⁱPr₃)(μ₃,η²-CCSiMe₃)] and of [Ru₃(CO)₉(μ,η²-SCCSiⁱPr₃)(μ₃,η²-CCH)].     

Ringkontraktion durch NHC‐induzierte Pnictogen‐Abstraktion

Die Reaktion von [Cp′′′Co(η⁴‐P₄)] ( 1 ) (Cp′′′=1,2,4‐tBu₃C₅H₂) mit ^MeNHC (^MeNHC=1,3,4,5‐tetramethylimidazol‐2‐ylidene) führt über eine NHC‐induzierte Phosphorkationen‐Abstraktion zum Ringkontraktionsprodukt [(^MeNHC)₂P][Cp′′′Co(η³‐P₃)] ( 2 ), welches das erste Beispiel eines anionischen CoP₃‐Komplexes repräsentiert. Solche von NHCs induzierten Ringkontraktionsreaktionen lassen sich ebenfalls auf Tripeldecker‐Sandwich‐Komplexe anwenden. So werden die Komplexe [(Cp*Mo)₂(μ,η^6:6‐E₆)] ( 3 a , 3 b ) (Cp*=C₅Me₅; E=P, As) zu den Komplexen [(^MeNHC)₂E][(Cp*M)₂(μ,η^3:3‐E₃)(μ,η^2:2‐E₂)] ( 4 a , 4 b ) transformiert, wobei 4 b das erste strukturell charakterisierte Beispiel eines NHC‐substituierten As^I‐Kations darstellt. Darüber hinaus führt die Reaktion des Vanadium‐Komplexes [(Cp*V)₂(μ,η^6:6‐P₆)] ( 5 ) mit ^MeNHC zur Bildung der neuartigen Komplexe [(^MeNHC)₂P][(Cp*V)₂(μ,η^6:6‐P₆)] ( 6 ), [(^MeNHC)₂P][(Cp*V)₂(μ,η^5:5‐P₅)] ( 7 ) bzw. [(Cp*V)₂(μ,η^3:3‐P₃)(μ,η^1:1‐P{^MeNHC})] ( 8 ).     

Metal carbonyl clusters linked to cyanoiron units

In search of organometallic Prussian Blue analogs with cluster constituents the cyanoiron complexes Cp(CO)₂Fe-CN and Cp(dppe)Fe-CN were used as ligands to replace CO in the clusters Fe₃(CO)₁₂, Ru₃(CO)₁₂, RuCo,(CO)₁₁, Co₄(CO)₁₂, Fe₃(CO)₉(µ₃-P¹Bu)₂, Fe₃(CO)₉(µ₃-PPh)₂, and Co₃(CO)₉ (µ₃-CMe). 11 new complexes of the type L _n Fe-CN-Cluster were obtained. Their constitution was ascertained crystallographically for Cp(CO)₂Fe-CN-RU₃(CO)₁₁ and Cp(CO)₂Fe-CN-RuCo₂(CO)₁₀ showing that unlike phosphine ligands the cyanoiron ligands occupy axial positions on the cluster. Cyclic voltammetry has shown that unlike the parent clusters these derivatives are more easily oxidized than reduced.     

Synthesis,characterization, and reactivity of self-assembled tetranuclear arene ruthenium metalla-rectangles

Self-assembly of 4,4′-bipyridine (bpy) with arene-ruthenium building blocks and 2,2′-bisbenzimidazole (H₂BiBzIm) in the presence of AgOTf (OTf = OSO₂CF₃) afforded tetranuclear cations of the type [Ru₄(η⁶-arene)₄(bpy)₂(BiBzIm)₂]⁴⁺ (arene = p-ⁱPrC₆H₄Me 1, C₆Me₆ 2), while similar reactions by use of [(η⁶-C₆Me₆)Ru(μ-Cl)Cl]₂ and excess AgOTf led to isolation of a cationic coordination network {[Ru₄(η⁶-C₆Me₆)₄(bpy)₂(BiBzIm)₂·Ag₂(OTf)₄]²⁺}_n (3), which could also be obtained by treatment of [2][OTf]₄ with AgOTf in methanol. Complex 3 is constructed by π coordination of BiBzIm(η²-carcon) with Ag(I). The coordination geometry around the silver(I) ion is pseudo-tetrahedral (taking the C=C group as one ligand). Self-assembly of only two components: [(η⁶-C₆Me₆)Ru(μ-Cl)Cl]₂ reacted with the 3-pyridyl-bian (mPy-bian) linker in the presence of limited AgOTf to give a chloro-bridged metalla-rectangle [Ru₄(η⁶-C₆Me₆)₄(μ-Cl)₄(mPy-bian)₂Ag]⁵⁺ (4), which enclosed a silver in the center. The coordination geometry around silver(I) in 4 is unusual square planar. The molecular structures of 1–4 were confirmed by X-ray crystallography along with other spectroscopic properties.     

The reaction of [H4Ru4(CO)12] with 1-penten-3-yne: dimerization and trimerization through the triple bonds

The clusters [Ru₄(μ-CO)(CO)₁₀(μ₄-η¹:η²:η¹:η²-C₅H₆)₂] (1), [Ru₄(CO)₈(μ₄-η⁴:η¹:η¹:η¹:η³-C₁₀H₁₂)(μ₃-η³:η²:η¹-C₅H₆)] (2) and [Ru₄(CO)₁₀(μ₄-η⁴:η¹:η¹:η³:η¹-C₁₅H₁₆)] (3) have been prepared from the reaction of [H₄Ru₄(CO)₁₂] with 1-penten-3-yne. This reaction is observed to proceed with dimerization and trimerization through the triple bonds. The products were characterized spectroscopically by ¹H- and ¹³C-NMR. X-ray crystal structures of compounds 1 and 2 are also described.     

Gold-ruthenium compounds containing bridging phosphide or thiolate groups: Crystal structures of the intermediate species [Ru3(CO)8L(μ3-η,η,η-{Me3SiCC(C2Fc)SC(Fc)CSCCSiMe3})] (L = NMe3 or PPh2H)

New tetranuclear complexes have been prepared using bridging phosphide or thiolate groups between phosphine gold fragments and the compound [Ru₃(CO)₉(μ₃-η²,η⁴,η³-{Me₃SiCC(C₂Fc)SC(Fc)CSCCSiMe₃})]. The crystal structures of the intermediates [Ru₃(CO)₈(NMe₃)(μ₃-η²,η⁴,η³-{Me₃SiCC(C₂Fc)SC(Fc)CSCCSiMe₃})] and [Ru₃(CO)₈(PPh₂H)(μ₃-η²,η⁴,η³-{Me₃SiCC(C₂Fc)SC(Fc)CSCCSiMe₃})] have been solved.     

Synthesis of clusters Fe2(CO)6(μ-XCH2CH=CH2)(μ3-X)Fe(CO)2Cp (X = Se, S; Cp = η5-C5H5)

The clusters Fe₂(CO)₆(μ-XCH₂CH=CH₂)(μ₃-X)Fe(CO)₂Cp (X = S, Se) were prepared by the successive treatment of the bi- and trimetallic complexes Fe₂(CO)₆(μ-Se₂) and Fe₃(CO)₉(μ₃-X) with allylmagnesium chloride and CpFe(CO)₂I. The clusters obtained contain a noncoordinated C=C bond. The structure of the Se-containing cluster was suggested on the basis of comparison of its spectral data (IR,¹H NMR, and Mössbauer spectra) with the spectra of the analogous S-containing complex, which was previously characterized by X-ray diffraction analysis.     

A General Pathway to Heterobimetallic Triple-Decker Complexes

A systematic study on the reactivity of the triple-decker complex [(Cp’’’Co)₂(μ,η⁴:η⁴-C₇H₈)] ( A ) (Cp’’’=1,2,4-tritertbutyl-cyclopentadienyl) towards sandwich complexes containing cyclo-P₃, cyclo-P₄, and cyclo-P₅ ligands under mild conditions is presented. The heterobimetallic triple-decker sandwich complexes [(Cp*Fe)(Cp’’’Co)(μ,η⁵:η⁴-P₅)] ( 1 ) and [(Cp’’’Co)(Cp’’’Ni)(μ,η³:η³-P₃)] ( 3 ) (Cp*=1,2,3,4,5-pentamethylcyclopentadienyl) were synthesized and fully characterized. In solution, these complexes exhibit a unique fluxional behavior, which was investigated by variable temperature NMR spectroscopy. The dynamic processes can be blocked by coordination to {W(CO)₅} fragments, leading to the complexes [(Cp*Fe)(Cp’’’Co)(μ₃,η⁵:η⁴:η¹-P₅){W(CO)₅}] ( 2 a ), [(Cp*Fe)(Cp’’’Co)(μ₄,η⁵:η⁴:η¹:η¹-P₅){(W(CO)₅)₂}] ( 2 b ), and [(Cp’’’Co)(Cp’’’Ni)(μ₃,η³:η²:η¹-P₃){W(CO)₅}] ( 4 ), respectively. The thermolysis of 3 leads to the tetrahedrane complex [(Cp’’’Ni)₂(μ,η²:η²-P₂)] ( 5 ). All compounds were fully characterized using single-crystal X-ray structure analysis, NMR spectroscopy, mass spectrometry, and elemental analysis.     

Synthesis and reactions of some triple alkoxo- and thioato-bridged areneruthenium(II) complexes. X-ray structure determination of [Ru2(η-C6H6)2(OMe)3][BPh4]

Reaction of [{Ru(η-arene)Cl₂}₂] (arene = C₆H₆, 1,4-MeC₆H₄CHMe₂) with NaNH₂ in CH₃CN gives a dark oil which upon treatment with ROH/NaBPh₄ (R = Me, Et) gives the triple bridged complexes [Ru₂(η-arene)₂(OR)₃] [BPh₄]. The structure of the benzene complex (R = Me) has been verified by X-ray analysis. The crystals are monoclinic, space group P2₁/n with a 11.725(4), b 15.573(5), c 18.739(2) Å; β 103.29(2)°. These complexes undergo reactions with tertiary phosphines and hydrogen halides. There is also spectroscopic evidence for intermolecular exchange of the bridging alkoxo ligands on mixing pure solutions of the [M₂(arene)₂(OR)₃]⁺ cations (M = Ru, Os). Reaction of [{Ru(η-arene)Cl₂}₂] with Pb(SEt)₂ in CH₃CN gives the analogous [Ru₂(arene)₂(SEt)₃]⁺ cations.