Further Evidence for ‘Extended’ Cumulene Complexes: Derivatives from Reactions with Halide Anions and Water

Reactions of [Ru{C=C(H)-1,4-C₆H₄C≡CH}(PPh₃)₂Cp]BF₄ ([ 1 a ]BF₄) with hydrohalic acids, HX, results in the formation of [Ru{C≡C-1,4-C₆H₄-C(X)=CH₂}(PPh₃)₂Cp] [X=Cl ( 2 a-Cl ), Br ( 2 a-Br )], arising from facile Markovnikov addition of halide anions to the putative quinoidal cumulene cation [Ru(=C=C=C₆H₄=C=CH₂)(PPh₃)₂Cp]⁺. Similarly, [M{C=C(H)-1,4-C₆H₄-C≡CH}(LL)Cp ]BF₄ [M(LL)Cp’=Ru(PPh₃)₂Cp ([ 1 a ]BF₄); Ru(dppe)Cp* ([ 1 b ]BF₄); Fe(dppe)Cp ([ 1 c ]BF₄); Fe(dppe)Cp* ([ 1 d ]BF₄)] react with H⁺/H₂O to give the acyl-functionalised phenylacetylide complexes [M{C≡C-1,4-C₆H₄-C(=O)CH₃}(LL)Cp’] ( 3 a – d ) after workup. The Markovnikov addition of the nucleophile to the remote alkyne in the cations [ 1 a–d ]⁺ is difficult to rationalise from the vinylidene form of the precursor and is much more satisfactorily explained from initial isomerisation to the quinoidal cumulene complexes [M(=C=C=C₆H₄=C=CH₂)(LL)Cp’]⁺ prior to attack at the more exposed, remote quaternary carbon. Thus, whilst representative acetylide complexes [Ru(C≡C-1,4-C₆H₄-C≡CH)(PPh₃)₂Cp] ( 4 a ) and [Ru(C≡C-1,4-C₆H₄-C≡CH)(dppe)Cp*] ( 4 b ) reacted with the relatively small electrophiles [CN]⁺ and [C₇H₇]⁺ at the β-carbon to give the expected vinylidene complexes, the bulky trityl ([CPh₃]⁺) electrophile reacted with [M(C≡C-1,4-C₆H₄-C≡CH)(LL)Cp’] [M(LL)Cp’=Ru(PPh₃)₂Cp ( 4 a ); Ru(dppe)Cp* ( 4 b ); Fe(dppe)Cp ( 4 c ); Fe(dppe)Cp* ( 4 d )] at the more exposed remote end of the carbon-rich ligand to give the putative quinoidal cumulene complexes [M{C=C=C₆H₄=C=C(H)CPh₃}(LL)Cp’]⁺, which were isolated as the water adducts [M{C≡C-1,4-C₆H₄-C(=O)CH₂CPh₃}(LL)Cp’] ( 6 a–d ). Evincing the scope of the formation of such extended cumulenes from ethynyl-substituted arylvinylene precursors, the rather reactive half-sandwich (5-ethynyl-2-thienyl)vinylidene complexes [M{C=C(H)-2,5-^cC₄H₂S-C≡CH}(LL)Cp’]BF₄ ([ 7 a – d ]BF₄ add water readily to give [M{C≡C-2,5-^cC₄H₂S-C(=O)CH₃}(LL)Cp’] ( 8 a – d )].     

Syntheses and Structures of trans-bis(Alkenylacetylide) Ruthenium Complexes

A series of ruthenium alkenylacetylide complexes trans-[Ru{C≡CC(=CH₂)R}Cl(dppe)₂] (R=Ph ( 1 a ), ^cC₄H₃S ( 1 b ), 4-MeS-C₆H₄ ( 1 c ), 3,3-dimethyl-2,3-dihydrobenzo[b]thiophene (DMBT) ( 1 d )) or trans-[Ru{C≡C-^cC₆H₉}Cl(dppe)₂] ( 1 e ) were allowed to react with the corresponding propargylic alcohol HC≡CC(Me)R(OH) (R=Ph ( A ), ^cC₄H₃S ( B ), 4-MeS-C₆H₄ ( C ), DMBT ( D ) or HC≡C-^cC₆H₁₀(OH) ( E ) in the presence of TlBF₄ and DBU to presumably give alkenylacetylide/allenylidene intermediates trans-[Ru{C≡CC(=CH₂)R}{C=C=C(Me)}(dppe)₂]PF₆ ([ 2 ]PF₆). These complexes were not isolated but deprotonated to give the isolable bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH₂)R}₂(dppe)₂] (R=Ph ( 3 a ), ^cC₄H₃S ( 3 b ), 4-MeS-C₆H₄ ( 3 c ), DMBT ( 3 d )) and trans-[Ru{C≡C-^cC₆H₉}₂(dppe)₂] ( 3 e ). Analogous reactions of trans-[Ru(CH₃)₂(dmpe)₂], featuring the more electron-donating 1,2-bis(dimethylphosphino)ethane (dmpe) ancillary ligands, with the propargylic alcohols A or C and NH₄PF₆ in methanol allowed isolation of the intermediate mixed alkenylacetylide/allenylidene complexes trans-[Ru{C≡CC(=CH₂)R}{C=C=C(Me)}(dmpe)₂]PF₆ (R=Ph ([ 4 a ]PF₆), 4-MeS-C₆H₄ ([ 4 c ]PF₆). Deprotonation of [ 4 a ]PF₆ or [ 4 c ]PF₆ gave the symmetric bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH₂)R}₂(dmpe)₂] (R=Ph ( 5 a ), 4-MeS-C₆H₄ ( 5 c )), the first of their kind containing the dmpe ancillary ligand sphere. Attempts to isolate bis(allenylidene) complexes [Ru{C=C=C(Me)R}₂(PP)₂]²⁺ (PP=dppe, dmpe) from treatment of the bis(alkenylacetylide) species 3 or 5 with HBF₄ ⋅ Et₂O were ultimately unsuccessful.     

Synthesis and spectral studies of new N2S2 and N2O2 Mannich base ligands and their metal complexes

New Mannich bases bis(thiosemicarbazide methyl) phosphinic acid H₃L¹ and bis(1-phenylsemicarbazide methyl) phosphinic acid H₃L² were synthesized from condensation of phosphinic acid and formaldehyde with thiosemicarbazide and 1-phenylsemicarbazide, respectively. Monomeric complexes of these ligands, of general formula K₂[Cr^III(L ⁿ )Cl₂], K₃[Fe^II(L¹)Cl₂], K₃[Mn^II(L²)Cl₂], and K[M(L ⁿ )] (M = Co(II), Ni(II), Cu(II), Zn(II) or Cd(II); n = 1, 2) are reported. The mode of bonding and overall geometry of the complexes were determined through IR, UV-Vis, NMR, and mass spectral studies, magnetic moment measurements, elemental analysis, metal content, and conductance. These studies revealed octahedral geometries for the Cr(III), Mn(II), and Fe(II) complexes, square planar for Co(II), Ni(II), and Cu(II) complexes and tetrahedral for the Zn(II) and Cd(II) complexes. Complex formation via molar ratio in DMF solution has been investigated and results were consistent to those found in the solid complexes with a ratio of (M : L) as (1 : 1).     

Mössbauer effect studies on alkali tris(maleato) ferrates(III)

Mössbauer spectra of alkali tris(maleato) ferrates(III), i.e., M₃[Fe(C₂H₂C₂O₄)₃]·nH₂O [M=Li, Na, K, Cs] at 300 K display a doublet. The Mössbauer parameters indicate these complexes to be high spin with octahedral symmetry. The isomer shift shows a decreasing trend with the increase in electronegativity/polarizing power of the substituent cation (Li⁺, Na⁺, K⁺, Cs⁺). A linear correlation between isomer shift values and the (Fe?O) stretching frequencies has also been observed.     

Cyclopentadienyleisen-komplexe mit P(OR)3-liganden; Synthese und spektroskopische charakterisierung

Reactions of reactive cyclopentadienyliron complexes C₅H₅Fe(CO)₂I, [C₅H₅Fe(CO)₂THF]BF₄, [C₅H₅Fe(CO)((CH₃)₂S)₂]BF₄ and [C₅H₅Fe(p-(CH₃)₂C₆H₄)]PF₆ with P(OR)₃ as ligands (R = CH₃, C₂H₅, i-C₃H₇ and C₆H₅) lead to the formation of the complex compounds C₅H₅Fe(CO)_2?n(P(OR)₃)_nI and [C₅H₅Fe(CO)_3?n(P(OR)₃)_n]X (n = 1, 2 and n = 1–3, X = BF₄, PF₆). Spectroscopic investigations (IR, ¹H, ¹³C and ³¹P NMR) indicate an increase of electron density on the central metal with increasing substitution of CO groups by P(OR)₃ ligands. The stability of the compounds increase in the same way.     

Transition‐Metal Complexes Based on the 1,3,5‐Triethynyl Benzene Linking Unit

The synthesis of a unique series of heteromultinuclear transition metal compounds is reported. Complexes 1‐I‐3‐Br‐5‐(FcC≡C)‐C₆H₃ ( 4 ), 1‐Br‐3‐(bpy‐C≡C)‐5‐(FcC≡C)‐C₆H₃ ( 6 ), 1,3‐(bpy‐C≡C)₂‐5‐(FcC≡C)‐C₆H₃ ( 7 ), 1‐(XC≡C)‐3‐(bpy‐C≡C)‐5‐(FcC≡C)‐C₆H₃ ( 8 , X = SiMe₃; 9 , X = H), 1‐(HC≡C)‐3‐[(CO)₃ClRe(bpy‐C≡C)]‐5‐(FcC≡C)‐C₆H₃ ( 11 ), 1‐[(Ph₃P)AuC≡C]‐3‐[(CO)₃ClRe(bpy‐C≡C)]‐5‐(FcC≡C)‐C₆H₃ ( 13 ), 1‐[(Ph₃P)AuC≡C]‐3‐(bpy‐C≡C)‐5‐(FcC≡C)‐C₆H₃ ( 14 ), [1‐[(Ph₃PAuC≡C]‐3‐[{[Ti](C≡CSiMe₃)₂}Cu(bpy‐C≡C)]‐5‐(FcC≡C)‐C₆H₃]PF₆ ( 16 ), and [1,3‐[(tBu₂bpy)₂Ru(bpy‐C≡C)]₂‐5‐(FcC≡C)‐C₆H₃](PF₆)₄ ( 18 ) (Fc = (η⁵‐C₅H₄)(η⁵‐C₅H₅)Fe, bpy = 2,2′‐bipyridiyl‐5‐yl, [Ti] = (η⁵‐C₅H₄SiMe₃)₂Ti) were prepared by using consecutive synthesis methodologies including metathesis, desilylation, dehydrohalogenation, and carbon–carbon cross‐coupling reactions. In these complexes the corresponding metal atoms are connected by carbon‐rich bridging units comprising 1,3‐diethynyl‐, 1,3,5‐triethynylbenzene and bipyridyl units. They were characterized by elemental analysis, IR and NMR spectroscopy, and partly by ESI‐TOF mass spectrometry., The structures of 4 and 11 in the solid state are reported. Both molecules are characterized by the central benzene core bridging the individual transition metal complex fragments. The corresponding acetylide entities are, as typical, found in a linear arrangement with representative M–C, C–C_C≡C and C≡C bond lengths.     

Cooperative Effects in π-Ligand Bridged Dinuclear Complexes. XII [1]. Heterodinuclear Electron Poor μ-Cyclooctatetraene Complexes with CrFe-and CrCo-Combinations

The synfacial heterodinuclear μ-Cot complexes (Cot = cyclooctatetraene) [(CpCr) (CpM)]μ-Cot (Cp = cyclopentadienyl; M ? Fe, 3 ; M ? Co, 4 ) are formed in a thermal reaction of the mononuclear mixed sandwich compound CpCr(n⁶-Cot) and CpML_n [M ? Fe, L_n = benzene (Bz); M ? Co, L_n = (C₂H₄)₂]. 3 possesses two unpaired electrons whereas 4 has only one unpaired electron and is ESR active. From the molecular structure of 3 and from the ESR data of 4 it can be deduced that the unpaired electrons are localized at the Cr centers predominantly forcing a close electronical relation between the heterodinuclear compounds 3 and 4 and the mononuclear sandwich complexes chromocene and CpCrBz, respectively.     

Synthesis and Structural Characterization of Divalent Transition Metal Alkynylamidinate Complexes

A series of new alkynylamidinate complexes of selected first and second row transition metals has been synthesized and fully characterized. Treatment of MCl₂ precursors (M=Mn, Fe, Co) with 2 equiv. of the lithium alkynylamidinates Li[c-C₃H₅−C≡C−C(NR′)₂] ⋅ THF (R′=ⁱPr (2), Cy (cyclohexyl) ( 2 )) afforded a series of binuclear complexes of the type M₂[c-C₃H₅−C≡C−C(NR)₂-κN:κN′]₂[c-C₃H₅−C≡C−C(NR)₂-κ²N,N′]₂ ( 3 : M=Mn, R=Cy; 4 a : M=Fe, R=ⁱPr; 4 b : M=Fe, R=Cy; 5 : M=Co, R=ⁱPr) with no significant metal-metal bonding. In marked contrast, a similar reaction of CrCl₂ with 2 equiv. of 1 afforded the homoleptic dinuclear chromium(II) complex Cr₂[c-C₃H₅−C≡C−C(NⁱPr)₂-κN:κN′]₄ ( 6 ) which supposedly comprises a Cr−Cr quadruple bond. Complex 6 could also be prepared in a more rational way and in better yield (61 %) by using dichromium(II) tetraacetate, Cr₂(OAc)₄, as starting material. Related reactions employing dimolybdenum(II) tetraacetate, Mo₂(OAc)₄, and 2 or 3 equiv. of 1 afforded the mixed-ligand paddle wheel-type complexes trans-Mo₂(OAc-κO:κO′)₂([c-C₃H₅−C≡C−C(NⁱPr)₂-κN:κN′]₂ ( 7 ) and Mo₂(OAc-κO:κO′)([c-C₃H₅−C≡C−C(NⁱPr)₂-κN:κN′]₃ ( 8 ). All title compounds were structurally characterized through single-crystal X-ray diffraction and spectroscopic techniques (NMR, IR, Raman).     

Reactions of Ruthenium Complexes Containing Pentatetraenylidene Ligand

Two ruthenium acetylide complexes [Ru]?C≡C?C≡C?C(OR)(C₃H₅)₂ ( 2 , R=H and 2 a , R=CH₃; [Ru]=Cp(PPh₃)₂Ru) each with two cyclopropyl rings were synthesized from TMS?C≡C?C≡C?C(OH)(C₃H₅)₂ ( 1 ; TMS=trimethylsilyl). Treatments of 2 and 2 a with allyl halide in the presence of KPF₆ afforded the vinylidene complexes 3 and 3 a , respectively. When NH₄PF₆ was used, instead of KPF₆, additional ring‐opening reaction took place on one of the three‐membered ring. Treatment of [Ru]Cl with 1,3‐butadiyne ( 6 ), bearing an epoxide ring, afforded acetylide complex 7 with a furyl ring. Treatment of 2 a with Ph₃CPF₆ presumably afforded pentatetraenylidene complex {[Ru]=C=C=C=C=C(C₃H₅)₂}[PF₆] ( 10 ), which was not isolated. Additions of various alcohols in a solution of 10 generated a number of disubstituted allenylidene complexes {[Ru]=C=C=C(OR)?C=C(C₃H₅)₂}[PF₆] ( 11 ). Treatment of 11 with K₂CO₃ afforded the acetylide complex 12 bearing a carbonyl group, characterized by single X‐ray diffraction analysis. Addition of a primary amine to 10 caused cleavage of the farthermost C=C bond and several allenylidene complexes {[Ru]=C=C=C(Me)(NHR)}[PF₆] ( 18 ) were isolated.     

Behaviour of α-functional organotransition metals. Synthesis,characterisation and some reactions of 1-acetoxyalkyl derivatives of iron(II) and molybdenum(II)

Acetoxyalkyl metal derivatives M(C₅H₅)(CO)_n[CHROC(O)Me] [M = Fe, n = 2; M = Mo, n = 3; R = H, Me] are readily prepared by reaction of bromoalkylacetates with the appropriate cyclopentadienylcarbonylmetallate anion. The complexes are characterised by their NMR (¹H and ¹³C) and IR parameters and by mass spectrometry. The acetoxyethyl species are thermally labile via β-hydrogen transfer. Treatment of acetoxymethyl complexes with protic acids leads to carbon-oxygen cleavage and release of acetic acid; HCl affords chloromethyl complexes, carboxylic acids yield new carboxylatomethyl derivatives, HBF₄ leads to decomposition. The metalloesters are resistant to hydrolysis, transesterification and carboxylate displacement by nucleophiles (HO^?, MeO^?, H₂N^? Et₂N^?). Migratory insertion of CO could not be induced.     

The kinetics of the 15NO exchange with transition metal nitrosyls

The kinetics of the ¹⁵NO exchange with M(NO)₂IL [M = Fe or Co, L = P(C₆H₅)₃ or As(C₆H₅)₃] in toluene have been studied, and the activation parameters evaluated. The effects of the ligands, L, on the rate constants indicate that the nitrosyl group behaves in much the same way as the CO group of carbonylic complexes.     

Double complex salts [Pt(NH3)5Cl][M(C2O4)3] · n H2O (M = Fe, Co, Cr): Synthesis and study

Double complexes [Pt(NH₃)₅Cl][Fe(C₂O₄)₃] · 4H₂O, [Pt(NH₃)₅Cl][Co(C₂O₄)₃] · 2H₂O, and [Pt(NH₃)₅Cl][Cr(C₂O₄)₃] · 4H₂O were synthesized and studied by single-crystal X-ray diffraction, X-ray phase analysis, differential thermal analysis, elemental analysis, and IR spectroscopy. The crystal structures of the compounds were examined from the viewpoint of the close packing of coordination polyhedra. The thermal properties of the synthesized complexes and K₃[M(C₂O₄)₃] salts (M = Fe, Co, Cr) were compared. A procedure for the synthesis of the FePt, CoPt, and CrPt intermetallic compounds through the thermolysis of the obtained complexes was developed. Original Russian Text ? K.V. Yusenko, D.B. Vasil’chenko, A.V. Zadesenets, I.A. Baidina, Yu.V. Shubin, S.V. Korenev, 2007, published in Zhurnal Neorganicheskoi Khimii, 2007, Vol. 52, No. 10, pp. 1589–1593.     

On the Lanthanide Ferrocyanides KLnFe(II)(CN)6·xH2O (Ln=La-Lu): Characterization and Thermal Evolution

The properties of a series of lanthanide hexacyanoferrate(II) n-hydrates were studied by thermal analysis, IR spectroscopy and X-ray diffraction. Thermal analysis results show that there are three kinds of complexes in this series, KLn[Fe(CN)₆]·4 H₂O (Ln=La-Nd), KSm[Fe(CN)₆]·3H₂O and KLn[Fe (CN)₆]·3.5H₂O (Ln=Eu-Lu). On the basis of IR spectra, only two different types of complexes show obvious differences. Indeed for the tetrahydrates, there is one OH stretching band; on the other hand, for the samarium phase and the 3.5 hydrates a splitting of HOH stretching mode is observed. The splitting of the H₂O band is correlated to a symmetry modification. The crystal structures of the three complexes KLn[Fe(CN)₆]·3.5H₂O (Ln=Eu, Er and Lu) were determined; they belong to orthorhombic symmetry (space group Cmcm). Heat-treated powders have been investigated by X-ray analysis which show the formation of thin needles of LnFeO₃ at 600°C.     

Synthesen im system {carbonylmetallat/ketenimin/säure}: XXX. Neue ferra- und rhenaazetidine

The metal carbonyl anions [Fe(η-C₅H₅(CO)₂]^? and [Re(CO)₅] undergo regio- and site-specific [2 + 2]-cycloadditions with the ketenimines Ph₂CCNR (R = Me, Ph) to give the (isolable) anionic complexes [L_n$\text{M{C(CPh}{}_2\text{)N(R)C}$(O)}]^? (L_nM = Fe(η-C₅H₅)CO, Re(CO)₄) which have been alkylated and acylated at the exocyclic oxygen atom of the carbonyl function. The result is stable neutral complexes having a metallaazetidine structure which is composed of an α-metallated enamine and an N,O carbene part. IR, ¹H, and ¹³C NMR data are presented.     

New homoleptic metal complexes of Schiff bases derived from 2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-one

New bidentate Schiff-base ligands 2-(2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-ylidene)hydrazinecarbothioamide HL¹ and 2-(2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-ylidene)hydrazinecarboxamide HL² were synthesized from the condensation of 2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-one with thiosemicarbazide and semicarbazide, respectively. Homoleptic complexes of these ligands, of general formula K[Cr(L ⁿ )₂Cl₂], K₂[Mn(L ⁿ )₂Cl₂], K₂[Fe(L¹)₂Cl₂] and [M(L ⁿ )₂] (where M = Co(II), Ni(II) Cu(II), Zn(II), Cd(II), and Hg(II) ions; n = 1 or 2) are reported. The mode of bonding and overall geometry of the complexes were determined through IR, UV-Vis, NMR and mass spectral studies, magnetic moment measurements, elemental analysis, metal content, and conductance. These studies revealed octahedral geometry for Cr(III), Mn(II), and Fe(II) complexes, square planar for Cu(II), Co(II), and Ni(II) complexes and tetrahedral for Zn(II), Cd(II), and Hg(II) complexes.     

Azametalla-closo-dodecaboranes

The azaborate K₂[nido-NB₁₀H₁₁] is gained from nido-NB₁₀H₁₃ and K[BHEt₃] in a 1:2 ratio. The anion [NB₁₀H₁₁]^2?, which is isoelectronic with [C₂B₉H₁₁]^2?, reacts with [{η⁶-(C₆R₆) · RuCl₂}₂] (R = H, Me), [{η⁵-(C₅Me₅)RhCl₂}₂], or [Ni(PPh₃)₂Cl₂] to give the azametalla-closo-dodecaboranes MNB₁₀H₁₁ with M = (C₆Me₆)Ru ( 2 ), (C₆H₆)Ru ( 3 ), (C₅Me₅)Rh ( 4 ), and (Ph₃P)₂Ni ( 5 ), respectively. The azametallaborane K[Co(NB₁₀H₁₁)₂] ( 6 ), which contains a sandwich-type coordinated Co atom, is formed from K₂[NB₁₀H₁₁] and CoCl₂. The structure of 2 · CH₂Cl₂ was determined by X-ray diffraction. The products 2 – 6 can be derived from the icosahedral anion [B₁₂H₁₂]^2? on replacing a BH^2? moiety by the isoelectronic nitrene NH and a BH moiety by the isolobal metal-complex fragment M. The N atom is six-coordinated in the cluster skeletons 2 – 6 .     

Bis(cyclopentadienyl)methan-verbrückte Zweikernkomplexe,V. Heteronukleare Co/Rh-, Co/Ir-, Rh/Ir- und Ti/Ir-Komplexe mit dem Bis(cyclopentadienyl)methan-Dianion als Brückenliganden

Bis(cyclopentadienyl)methane-bridged Dinuclear Complexes, V^[1]. – Heteronuclear Co/Rh-, Co/Ir-, Rh/Ir-, and Ti/Ir Complexes with the Bis(cyclopentadienyl)methane Dianion as Bridging Ligand^* The lithium and sodium salts of the [C₅H₅CH₂C₅H₄]^- anion, 1 and 2 , react with [Co(CO)₄I], [Rh(CO)₂Cl]₂, and [Ir(CO)₃Cl]n to give predominantly the mononuclear complexes [(C₅H₅-CH₂C₅H₄)M(CO)₂] ( 3, 5, 7 ) together with small amounts of the dinuclear compounds [CH₂(C₅H₄)₂][M(CO)₂]₂ ( 4, 6, 8 ). The ¹H- and ¹³C-NMR spectra of 3, 5 , and 7 prove that the CH₂C₅H₅ substituent is linked to the π-bonded ring in two isomeric forms. Metalation of 5 and 7 with nBuLi affords the lithiated derivatives 9 and 10 from which on reaction with [Co(CO)₄I], [Rh(CO)₂Cl]₂, and [C₅H₅TiCl₃] the heteronuclear complexes [CH₂(C₅H₄)₂][M(CO)₂][M′(CO)₂] ( 11–13 ) and [CH₂(C₅H₄)₂]-[Ir(CO)₂][C₅H₅TiCl₂] ( 17 ) are obtained. Photolysis of 11 and 12 leads almost quantitatively to the formation of the CO-bridged compounds [CH₂(C₅H₄)₂][M(CO)(μ-CO)M′(CO)] ( 14, 15 ). According to an X-ray crystal structure analysis the Co/Rh complex 14 is isostructural to [CH₂(C₅H₄)₂][Rh₂(CO)₂(μ-CO)] ( 16 ).     

Alkinylphosphinhaltige substitutionsprodukte von chrom- und wolfram-hexacarbonyl

The photochemical preparation of [M(CO)₅(P(CCC₆H₅)_n(C₆H₅)_3-n], cis-[M(CO)₄(PCCC₆H₅)_n(C₆H₅)_3-n] (M = Cr, W; n = 1,2,3) and fac-[Cr(CO)₃(P(CCC₆H₅)(C₆H₅)₃] by the corresponding substitution reactions of the hexacarbonyls is described. The IR and Raman spectra of the complexes in the region of the ν(CO) and ν(CC) vibrations and the ³¹P NMR spectra are discussed.     

Synthesis and structural characterization of new multiferrocenyl diyne ligands and their cobalt carbonyl complexes

New multiferrocenyl diyne ligands FcC(CH₃)₂Fc′–C≡C–C≡C–Fc [L ₁ ; Fc?=?C₅H₅FeC₅H₄; Fc′?=?C₅H₅Fe(1,3-disubstituted)C₅H₃], FcC(CH₃)₂Fc′–C≡C–C≡C–Fc′C(CH₃)₂Fc (L ₂ ) and their complexes [FcC(CH₃)₂Fc′–C≡C–C≡C–Fc][Co₂(CO)₆] _n [n?=?1, (1); n?=?2, (2)], [FcC(CH₃)₂Fc′–C≡C–C≡C–Fc′C(CH₃)₂Fc][Co₂(CO)₆] _n [n?=?1, (3); n?=?2, (4)] have been synthesized by the coupling reaction of terminal ferrocenylacetylene and the reaction of ligands L₁ and L₂ with Co₂(CO)₈. The composition and molecular structure of the ligands L₁ , L₂ and their cobalt complexes were characterized by element analysis, IR, ¹H(¹³C)NMR and MS. The electrochemical properties of compounds L₁ , L₂ , 1, 2, 3, 4 were studied by cyclic voltammetry(CV). The results of the electrochemical research reveal that all three ferrocenyl groups in L₁ become redox active centers, but there are only two (not four) ferrocenyl redox active centers in L₂ .     

Inelastic neutron scattering study of low frequency motions in [Co(C5H5)2+] and [Cr(C6 H62+] intercalated in the MnPS3 layered compound

The incoherent inelastic neutron scattering (INS) spectra of Mn_0.84PS₃[Co(C₅H₅)₂] _0.32 and Mn_0.86 PS₃[Cr(C₆H₆)₂]_0.28 compounds at 10 K have been investigated within the frequency ranges 0–80 cm^?1 (E₀ = 12.5 meV) and 0–360 cm^?1 (E₀ = 50 meV). Also, infrared and Raman spectra (0–400 cm^?1 of Cr(C₆H₆)₂I at various temperatures have been obtained for the first time. From a comparison of far infrared, low frequency Raman and INS results, we propose an assignment for the internal torsion and for the librational motions in the intercalated organometallic cations. An estimate of the potential barrier height against the torsion and the R′_z whole-body rotation is derived; these values are compared with those calculated for the corresponding iodide salts. We conclude that a significant decrease of the intermolecular forces acting on the rings is taking place within the interlamellar space.