Dicyclopentadienyltitanium(IV) pyridine-2,6-dicarboxylate complexes. Synthesis and structural characterization as pentacoordinate titanocene derivatives

Reaction of (C₅H₅)₂Ti(CH₃)₂ or (CH₃)₄C₂(C₅H₄)₂Ti(CH₃)₂ with pyridine-2,6-dicarboxylic acid (dipicolinic acid) yields titanocene dipicolinate derivatives. The molecular structure of (C₅H₅)₂Ti dipicolinate is that of an axially symmetric, pentacoordinate titanocene derivative with two carboxyl oxygen atoms and the pyridine nitrogen atom as ligating atoms. Two identical chelate bite angles of only 71° make the dipicolinate ligand particularly suited to form a remarkably stable titanocene derivative with unprecedented pentacoordintae geometry.     

Calcium-mediated dearomatization, C-H bond activation, and allylation of alkylated and benzannulated pyridine derivatives

A facile and general synthetic pathway for the production of dearomatized, allylated, and C? H bond activated pyridine derivatives is presented. Reaction of the corresponding derivative with the previously reported reagent bis(allyl)calcium, [Ca(C₃H₅)₂] ( 1 ), cleanly affords the product in high yield. The range of N‐heterocyclic compounds studied comprised 2‐picoline ( 2 ), 4‐picoline ( 3 ), 2,6‐lutidine ( 4 ), 4‐tert‐butylpyridine ( 5 ), 2,2′‐bipyridine ( 6 ), acridine ( 7 ), quinoline ( 8 ), and isoquinoline ( 9 ). Depending on the substitution pattern of the pyridine derivative, either carbometalation or C? H bond activation products are obtained. In the absence of methyl groups ortho or para to the nitrogen atom, carbometalation leads to dearomatized products. C(sp³)? H bond activation occurs at ortho and para situated methyl groups. Steric shielding of the 4‐position in pyridine yields the ring‐metalated product through C(sp²)? H bond activation instead. The isolated compounds [Ca(2‐CH₂‐C₅H₄N)₂(THF)] ( 2 b ?(THF)), [Ca(4‐CH₂‐C₅H₄N)₂(THF)₂] ( 3 b ?(THF)₂), [Ca(2‐CH₂‐C₅H₃N‐6‐CH₃)₂(THF)_n] ( 4 b ?(THF)_n; n=0, 0.75), [Ca{2‐C₅H₃N‐4‐C(CH₃)₃}₂(THF)₂] ( 5 c ?(THF)₂), [Ca{4,4′‐(C₃H₅)₂‐(C₁₀H₈N₂)}(THF)] ( 6 a ?(THF)), [Ca(NC₁₃H₉‐9‐C₃H₅)₂(THF)] ( 7 a ?(THF)), [Ca(4‐C₃H₅‐C₉H₇N)₂(THF)] ( 8 b ?(THF)), and [Ca(1‐C₃H₅‐C₉H₇N)₂(THF)₃] ( 9 a ?(THF)₃) have been characterized by NMR spectroscopy and metal analysis. 9 a ?(THF)₄ and 4 b ?(THF)₃ were additionally characterized in the solid state by X‐ray diffraction experiments. 4 b ?(THF)₃ shows an aza‐allyl coordination mode in the solid state. Based on the results, mechanistic aspects are discussed in the context of previous findings.     

Generation of reactive cyclopentadienylcobalt(I) derivatives by reduction of dicyclopentadienyldicobalt tetraiodide

Reduction of [(C₅H₅)CoI₂]₂ by sodium amalgam in toluene in the presence of 1,3-butadiene, 1,3-cyclohexadiene or 1,5-cyclooctadiene affords the corresponding cyclopentadienylcobalt(I) diolefin complexes in high yields. Reduction of [(C₅H₅)CoI₂]₂ in the presence of 2-butyne yields the binuclear metallocyclic compound (C₅H₅)₂Co₂(C₄(CH₃)₄), previously characterized as a structurally fluxional catalyst for alkyne cyclotrimerisation, as the major product; a trinuclear dicarbyne compound, (C₅H₅)₃Co₃(C-CH₃)₂, is obtained as a minor product. With diphenylacetylene, the analogous phenylcarbyne derivative (C₅H₅)₃Co₃(C-C₆H₅)₂, previously obtained from thermal reaction with (C₅H₅)Co(CO)₂, is obtained along with the major product, the tetraphenylcyclobutadiene complex (C₅H₅)Co(C₄(C₆H₅)₄). Pathways and intermediates for these reactions are discussed.     

Mass spectra of 5-fluorouracil derivatives. N-1-substituted sulfonyl derivatives

The electron impact mass spectra of 1-sulfonyl substituted derivatives of 5-fluorouracil were investigated. The substituents were CH₃SO₂ (compound I), CH₃(CH₂)₃SO₂ (II), C₆H₅SO₂ (III) and p-CH₃C₆H₄SO₂ (IV).     

Toxicology and antitumour activity of ferrocenylamines and platinum derivatives

Toxicity, antitumour, platinum distribution, hepatotoxicity and histology data are presented for a series of ferrocenylamines: [(η‐C₅H₄(CH₂)_nNH₂)FeCp] (n = 0,1) ( 1 , 2 ); [(η‐C₅H₄CH₂NHPh)FeCp] ( 3 ); [(η‐C₅H₄CH₂NMe₂)FeCp] ( 4 ); {[η‐C₅H₄CH(Me)NMe₂]FeCp} ( 5 ); [η‐C₅H₄CH₂NMe₂)₂Fe] ( 6 ); {[1,2η‐C₅H₃(CHMeNMe₂)(PPh₂)]FeCp} ( 7 ); {[1,2η‐C₅H₃(CHMeNMe₂)(PPh₂)]Fe[η‐C₅H₄PPh₂]} ( 8 ); and their complexes cis‐PtCl₂L₂ ( 9 ); trans ‐ Pt(L)(dmso)X₂ ( 10 ); [σ ‐ (L)Pt(dmso)X] ( 11 , 12 ) {σ‐(L)[Pt(dmso)X]₂} ( 13 ); [σ‐(L)PtP(OPh)₃Cl] ( 14 ) (L = ferrocenylamine). The toxicity order is 1 – 3 ≫ 4 – 8 for the ferrocenylamines; the lower toxicity of tertiary amines may be due to protonation in vivo. Pt(II) complexes all show increased toxicity over the ligand. Liver, not kidney, damage is the norm from i.p. injection of 1 – 14 and detailed platinum distribution, blood serum and histology studies with 9 and 11 show that the platinum distribution does not correlate with liver dysfunction. Complexes 9 – 14 , but not 1 – 8 , were active against P‐388 mouse leukaemia tumour and cisplatin‐resistant sarcoma, but inactive against L‐1210 mouse leukaemia and B‐16 melanoma. Copyright © 1999 John Wiley & Sons, Ltd.     

Mass spectra of monohapto-cyclopentadienyl derivatives of group IVB elements

Dissociative ionisation of organometallic cyclopentadiene derivatives containing one, two or three M(CH₃)₃ groups (M  Si, Ge, Sn) has been studied.Among the monometallated compounds, C₅H₅Si(CH₃)₂Cl, C₅H₅Si(CH₃)₂OCH₃ and (C₅H₅)₄Sb have also been investigated. To verify fragmentation patterns, the spectra of deuterated compounds such as C₅D₅Si(CH₃)₃, C₅D₅Sn(CH₃)₃, C₅D₄Si₂(CH₃)₆ and C₅D₃Si₃)₉ have been measured. Dissociative ionisation of h¹-cyclopentadienyl derivatives has been shown to differ essentially from that of h⁵-compounds.     

Bis(cyclopentadienyl)methan-verbrückte Zweikernkomplexe: II. Synthese und Reaktionen ringverbrückter Cobalt-Zweikernkomplexe mit zwei nucleophilen Metallzentren

The dinuclear cobalt complex [CH₂(C₅H₄)₂][Co(PMe₃)₂]₂ (2), which is prepared from CoCl(PMe₃)₃ and [CH₂(C₅H₄)₂]Li₂, reacts with NH₄PF₆ and CH₃I to form the protonated and methylated dications {[CH₂(C₅H₄)₂][CoR(PMe₃)₂]₂}²⁺ (R = H, CH₃). Treatment of {[CH₂(C₅H₄)₂][CoCH₃(PMe₃)₂]₂}I₂ (4) with LiCH₃ affords the neutral compound [CH₂(C₅H₄)₂][Co(CH₃)₂(PMe₃)]₂ (5). Ligand substitution of [CH₂(C₅H₄)₂][Co(CO)₂]₂ (6) with P₂Me₄ and 1,2-C₂H₄(PMe₂)₂(dmpe) gives the doubly-bridged complexes [CH₂(C₅H₄)₂][Co₂(CO)₂(μ-P₂Me₄)] (7) and [CH₂(C₅H₄)₂][Co₂(CO)₂(μ-dmpe)] (8), respectively. Similarly, [CH₂(C₅H₄)₂][Co-(CO)(PMe₃)]₂ (9) is obtained from the reaction of 6 with PMe₃. Oxidation of 6 with iodine gives [CH₂(C₅H₄)₂][Co(CO)I₂]₂ (11) which is transformed via {[CH₂(C₅H₄)₂][Co(PMe₂H)₃]₂}I₄ (12) into the triply-bridged cobalt(II) complex [CH₂(C₅H₄)₂][CO₂(μ-PMe₂)₂] (13).     

Mass spectra of organometallic compounds—VII; Organonitrogen derivatives of metal carbonyls

The positive-ion mass spectra of the following organonitrogen derivatives of metal carbonyls are discussed: (i) The compounds NC₅H₄CH₂Fe(CO)₂C₅H₅, NC₅H₄CH₂COMo(CO)₂C₅H₅, NC₅H₄CH₂W(CO)₃C₅H₅, NC₅H₄CH₂COMn(CO)₄, C₅H₁₀NCH₂CH₂Fe(CO)₂C₅H₅, (CH₃)₂NCH₂CH₂COFeCOC₅H₅ and (CH₃)₂NCH₂CH₂COMn(CO)₄ obtained from metal carbonyl anions and haloalkylamines, (ii) The isocyanate derivative C₅H₅Mo(CO)₃CH₂NCO; (iii) The arylazomolybdenum derivatives RN₂Mo(CO)₂C₅H₅ (R ? phenyl, p-tolyl, or p-anisyl); (iv) The compound (C₆H₅N)₂COFe₂(CO)₆ obtained from Fe₃(CO)₁₂ and phenyl isocyanate; (v) The N,N,N′,N′-tetramethylethylenediamine complex (CH₃)₂NCH₂CH₂N(CH₃)₂W(CO)₄. Further examples of eliminations of hydrogen, CO, and C₂H₂ fragments were noted. In addition evidence for the following more unusual processes was obtained: (i) Elimination of HCN fragments from the ions [NC₅H₄CH₂MC₅H₅]⁺ to give the ions [(C₅H₅)₂M]⁺ (M ? Fe, Mo and W); (ii) Conversion of C₅H₅Mo(CO)₃CH₂NCO to C₅H₅Mo(CO)₂CH₂NCO within the mass spectrometer; (iii) Elimination of N₂ from [RN₂MoC₅H₅]⁺ to give [RMoC₅H₅]⁺; (iv) Novel eliminations of HNCO, FeNCO, and C₆H₅NC fragments in the mass spectrum of (C₆H₅N)₂COFe₂(CO)₆; (v) Facile dehydrogenation of the N,N,N′,-N′-tetramethylethylenediamine ligand in the complex (CH₃)₂NCH₂CH₂N(CH₃)₂W(CO)₄.     

Trinuclear π-cyclopentadienyl bridging sulphido derivatives of iron

The reaction of [Fe(π-C₅H₅)(CO)₂]₂ with the dialkyl disulphides R₂S₂ (R = CH₃, C₂H₅, t-C₄H₉ or CH₂C₆H₅) affords, as well as dinuclear derivatives of the type [Fe(π-C₅H₅)(CO)SR]₂, trinuclear species of formula [Fe₃(π-C₅H₅)₃(CO)₂(S)SR].     

Preparation and properties of methyl(cyclopentadienyl)thalium derivatives

The preparation of the compound CH₃(C₅H₅)TIX [where X = OCOCH₃, OCOC₂H₅, OCO-i-C₃H₇, tropolonate and 4-isopropyltropolonate] is described and their chemical behaviours as well as their PMR and IR spectra are discussed.     

An unusual organoyttrium alkyl complex containing a [C5HMe3(η(3)-CH2)-C5H4N-κ]- ligand and an elusive cyclopentadienide-based scandium tuck-over zwitterion obtained by C-H bond activation

The acid–base reaction between Y(CH₂SiMe₃)₃(thf)₂ and the pyridyl‐functionalized cyclopentadienyl (Cp) ligand C₅Me₄H? C₅H₄N (1 equiv) at 0 °C afforded a mixture of two products: (η⁵:κ‐C₅Me₄? C₅H₄N)Y(CH₂SiMe₃)₂(thf) ( 1 a ) and (η⁵:κ‐C₅Me₄? C₅H₄N)₂YCH₂SiMe₃ ( 1 b ), in a 5:2 ratio. Addition of the same ligand (2 equiv) to Y(CH₂SiMe₃)₃(thf)₂, however, generated 1 b together with the novel complex 1 c , the first well defined yttrium mono(alkyl) complex (η⁵:κ‐C₅Me₄? C₅H₄N)[C₅HMe₃(η³‐CH₂)‐C₅H₄N‐κ]Y(CH₂SiMe₃) containing a rare κ/η³‐allylic coordination mode in which the C? H bond activation occurs unexpectedly with the allylic methyl group rather than conventionally on Cp ring. If the central metal was changed to lutetium, the equimolar reaction between Lu(CH₂SiMe₃)₃(thf)₂ and C₅Me₄H? C₅H₄N exclusively afforded the bis(alkyl) product (η⁵:κ‐C₅Me₄? C₅H₄N)Lu(CH₂SiMe₃)₂(thf) ( 2 a ). Similarly, the reaction between the ligand (2 equiv) and Lu(CH₂SiMe₃)₃(thf)₂ gave the mono(alkyl) complex (η⁵:κ‐C₅Me₄? C₅H₄N)₂LuCH₂SiMe₃ ( 2 b ), in which no ligand redistribution was observed. Strikingly, treatment of Sc(CH₂SiMe₃)₃(thf)₂ with C₅Me₄H? C₅H₄N in either 1:1 or 1:2 ratio at 0 °C generated the first cyclopentadienide‐based scandium zwitterionic “tuck‐over” complex 3 , (η⁵:κ‐C₅Me₄? C₅H₄N)Sc(thf)[μ‐η⁵:η¹:κ‐C₅Me₃(CH₂)‐C₅H₄N]Sc(CH₂SiMe₃)₃. In the zwitterion, the dianionic ligand [C₅Me₃(CH₂)‐C₅H₄N]^2? binds both to Sc1³⁺ and to Sc2³⁺, in η⁵ and η¹/κ modes. In addition, the reaction chemistry, the molecular structures, and the mechanism are also discussed in detail.     

A novel synthesis of carbene complexes of manganese and molybdenum containing the trichlorogermyl group

A number of carbene complexes of formulas Cl₃GeMn(CO)₄C(OR′)R and C₅H₅Mo(CO)₂(GeCl₃)C(OR′)CH₃ (R = CH₃, C₆H₅; R′ = CH₃, C₂H₅) have been prepared by the reaction of [N(C₂H₅)₄]GeCl₃ with CH₃Mn(CO)₅, C₆H₅Mn(CO)₅, or C₅H₅Mo(CO)₃CH₃ followed by alkylation of the resulting trichlorogermylacylcarbonylmetallate ion. The compound C₅H₅Mo(CO)₂(GeCl₃)$\text{COCH}{}_2\text{CH}{}_2\text{C}$H₂ has been prepared directly by the reaction of [N(C₂H₅)₄]GeCl₃ with C₅H₅Mo(CO)₃(CH₂)₃Br.     

Synthesis and properties of pentamethylmetallocene derivatives Cp*MCp (M = Ru, Fe). Crystal structure of the salt [CpRuC5Me4CH2+OC6H2(NO2)3-]

Photolysis of a solution of Cp*RuCp (1) in CF₃CO₂H generates salt [CpRu(C₅Me₄CH₂)]-(O₂CCF₃)(2 • O₂CCF₃). The reaction of compound 1 with oleum at 20 °C through the intermediate dication [η⁵-(CH₂C₅Me₄)Ru(μ:η⁵,ν⁵-C₅H₄C₅H₅)Ru(C₅Me₄CH₂)-η⁶]²⁺ leads to the triply charged cation η⁷CH₂)₂C₅Me₃Ru(μη⁵,η⁵-C₅H₄C₅H₄)Ru(C₅Me₄CH₂)-η⁶]³⁺. Synthesis of pentamethylmetallocene derivatives CpMC₅Me₄X (M = Ru, Fe; X = CHO, CH₂OH, CH₂An) has been accomplished. The reactions of 1-hydroxymethyl-2,3,4,5-tetramethylruthenocene with acids CF₃CO₂H, HBF₄, CF₃CO₂H/NaB[C₆H₃(CF₃)₂]₄, and picric acid C₆H₂(NO₂)₃OH afforded salts 2•X (X = CF₃CO₂, BF₄, B[C₆H₃(CF₃)₂]₄), and (2,3,4,5-tetram ethylruthenocenyl)methyl picrate [CpRu(C₅Me₄CH₂)-η⁶][(C₆H₂(NO₂)₃O] (2•C₆H₂(NO₂)₃O). Structure of the latter was characterized by single crystal X-ray diffraction.     

Reactions of metal carbonyl derivatives : XI. Tertiary phosphine,phosphite and stibine and ditertiaryphosphine and arsine derivatives of bis(μ-phenyl- sulphidotricarbonyliron)

The ditertiary phosphines (C₆H₅)₂P(CH₂)_nP(C₆H₅)₂ (n = 1 and 2), cis(C₆H₅)₂PC₂H₂P(C₆H₅)₂ and (C₆H₅)₂PN(C₂H₅)P(C₆H₅₂ and the ditertiary arsines (C₆H₅)₂As(CH₂)_nAs(C₆H₅)2 (_n = 1 and 2) react with [Fe(CO)₃SC₆H₅]₂ to give a wide range of products, the nature of which depends on the reaction conditions and the ligand involved. Examples of the different types of comp isolated include, (i) Fe₂(CO)₅[(C₆H₅)₂PCH₂P(C₆H₅)₂](SC₆H₅)₂, in which the ligand acts as a monodentate, (ii) {[Fe(CO)₂SC₆H₅]₂[(C₆H₅)₂PC₂H₄P(C₆H₅)₂]}₂, in which two [Fe(CO)₂SC₆H₅]₂ moieties are bridged by two diphosphine ligands, (iii) [Fe(CO)₂SC₆H₅]₂[(C₆H₅)₂PN(C₂H₅)P(C₆H₅)₂], in which the ligand bridges the two iron atoms, and (iv) Fe(CO)₃(SC₆H₅)₂Fe(CO)[(C₆H₅)₂PC₂H₂P(C₆H₅)₂], which contains the ligand chelated to a single iron atom. The tertiary phosphines PR₃ (R=C₂H₅ and C₆H₅), phosphites P(OR′)₃(R′ = CH₃, C₂H₅, i-C₃H₇ and C₆H₅) and the stibine Sb(C₆H₅)₃ bring about mono-, bis- or tris-substitution in [Fe(CO)₃SC₆H₅]₂ depending on the reaction conditions and the ligand involved. Whereas in solution [Fe(CO)₂L(SC₆H₅)]₂ [L = PR₃ (R = C₂H₅ and C₆H₅), P(OC₆H₅)₃ and Sb(C₆H₅)₃] exist as a single isomer, [Fe(CO)₂L′(SC₆H₅)]₂ [L′=P(OR′)₃ (R'=CH₃, C₂H₅ and i-C₃H₇)] occur as a mixture of isomers.     

Acetylenic derivatives of metal carbonyls of the triad Fe,Ru, Os—XI Mass spectra of some binuclear complexes

The mass spectra of the following acetylenic derivatives of iron, ruthenium and osmium carbonyls are reported: the iron compounds Fe₂(CO)₆[C₂(C₆H₅)s₂]₂, Fe₂(CO)₆[C₂(CH₃)₂]₂ and Fe₂(CO)₆[C₂(C₂H₅)₂]₂, the ruthenium compounds Ru₂(CO)₆[C₂(C₆H₅)₂]₂, and Ru₂(CO)₆[C₂(CH₃)₂]₂ and the osmium compounds Os₂(CO)₆[C₂(C₆H₅)₂]₂, Os₂(CO)₆[C₂HC₆H₅]₂ and Os₂(CO)₆[C₂(CH₃)₂]₂. Iron compounds exhibit breakdown schemes where binuclear, mononuclear and hydrocarbon ions are present. On the other hand, ruthenium and osmium compounds fragment in a similar way and give rise to singly and doubly charged binuclear ions. Phenylic derivatives of ruthenium and osmium also give weak triply charged ions. The results are discussed in terms of relative strengths of the metal-metal and metal-carbon bonds.     

Reactions of metal carbonyl derivatives X. The synthesis and reactivity of some dinuclear derivatives of iron containing both bridging carbonyls and bridging phosphido or sulphido groups

The tertiary phosphine π-C₅H₅Fe(CO)₂P(C₆H₅)₂ reacts with a suspension of Fe₂(CO)₉ in benzene to give the dinuclear complex π-C₅H₅Fe₂P(C₆H₅)₂(CO)₆. This compound is also obtained by nucleophilic attack of [π-C₅H₅Fe(CO)₂]⁻ on Fe(CO)₄-[P(C₆H₅)₂Cl] in tetrahydrofuran. Irradiation of a benzene solution of π-C₅H₅Fe₂-P(C₆H₅)₂(CO)₆ with ultraviolet light affords π-C₅H₅Fe₂P(C₆H₅)₂(CO)₅ which contains both a bridging carbonyl and a bridging phosphido group. The unstable bridged sulphido derivatives π-C₅H₅Fe₂SR(CO)₆ (R = CH₃ and C₆H₅) and π-C₅H₅Fe₂(t-C₄H₉S)(CO)₅ are similarly obtained employing π-C₅H₅Fe(CO)₂SR as ligand. The reactions of π-C₅H₅Fe₂P(C₆H₅)₂(CO)₅ with tertiary phosphines and phosphites yield three types of products depending on the reaction conditions and the ligand involved. Examples include π-C₅H₅Fe₂P(C₆H₅)₂(CO)₄P(C₆H₅)₃, a mono-substituted derivative of π-C₅H₅Fe₂P(C₆H₅)₂(CO)₅, and π-C₅H₅Fe₂P(C₆H₅)₂(CO)₅P(C₂H₅)₃ and π-C₅H₅Fe₂P(C₆H₅)₂(CO)₄[P(OCH)₃)₃]₂, mono- and bis-substituted derivatives of π-C₅H₅Fe₂P(C₆H₅)₂(CO)₆, respectively. The reaction of π-C₅H₅Fe₂P(C₆H₅₂(CO)₅ with (C₆H₅)₂PCH₂P(C₆H₅)₂ in benzene under reflux affords [π-C₅H₅Fe₂P(C₆H₅)₂(CO)₄](C₆H₅)₂PCH₂P(C₆H₅)₂ in which the ditertiary phosphine bridges two iron atoms.     

Derivate des borabenzols: XVI. (Borinato)(cyclobutadien)cobalt-komplexe mit tetramethyl- und tetraphenylcyclobutadien-liganden. Synthese,elektrophile aromatische substitution und ringgliedsubstitution am borinato-liganden

The preparation of (borinato)(cyclobutadiene)cobalt complexes from the reactions of Co(C₅H₅BR)(1,5-C₈H₁₂) with acetylenes C₂R′₂ and of [C₄(CH₃)₄]Co(CO)₂I with Tl(C₅H₅BR) (R,R′ = CH₃, C₆H₅) is described.In electrophilic substitution reactions Co(C₅H₅BCH₃)[C₄(CH₃)₄] (IVa) is more reactive than ferrocene. CF₃CO₂D effects H/D-exchange in the α-position of the borabenzene ring within a few minutes at ambient temperature and in the γ-position within less than four hours Friedel-Crafts acetylation with CH₃COCl/AsCl₃ in CH₂Cl₂ affords the 2-acetyl and the 2,6-diacetyl derivative of IVa. With the more active catalyst AlCl₃, ring-member substitution is effected to give cations [Co(arene)C₄(CH₃)₄]⁺ (arene = C₆H₅CH₃, 2-CH₃C₆H₄COCH₃). Vilsmeier formylation gives the 2-formyl derivative of IVa. The acyl derivatives Co(2-R¹CO-6-R²C₅H₃BCH₃)[C₄(CH₃)₄] (R¹ = CH₃, R² = H, CH₃CO and R¹ = R² = H) transform to the corresponding cations [Co(ortho-R¹R²C₆H₄)C₄(CH₃)₄]⁺ in superacidic media. The mechanistic relationship between acylation and ring-member substitution is discussed in detail.     

Reactions of pyridyl side chain functionalized cyclopentadiene with ruthenium carbonyl

Abstract  

Reactions of the pyridyl side-chain-functionalized cyclopentadiene [C₅H₅CR₂(CH₂C₅H₄N)] [R ₂ = Et₂ (1), (CH₂)₄ (2)] with Ru₃(CO)₁₂ in refluxing xylene gave the new intramolecular C–H activated trinuclear product [μ-(C₅H₃N)CH₂C(C₂H₅)₂(C₅H₄)Ru(CO)]₂Ru(CO)₂ (3) and the normal dinuclear metal complex [(C₅H₄N)CH₂C(CH₂)₄(C₅H₄)Ru(CO)]₂(μ-CO)₂ (4). The structures of the trinuclear complex 3 and dinuclear complex 4 were characterized by elemental analysis, IR spectra, ¹H-NMR and X-ray diffraction.     

Synthesis of hetero-binuclear derivatives of the tetrathiolato complexes [Mo(η-C5H5CH2SR)2)], R = Prn and Ph,with platinum,palladium, and rhodium

The compound Mo(η-C₅H₄(CH₂)₂SPrⁿ)₂(SPrⁿ)₂ acts as a bidentate ligand giving the heteronuclear bi-metallic compounds [Mo(η-C₅H₄CH₂CH₂SPrⁿ)₂-(SPrⁿ)₂(PtCl₂)],[Mo(η-C₅H₄CH₂CH₂SPrⁿ)₂(SPrⁿ)₂(PdCl₂)₂], [Mo(η-C₅C₄CH₂CH₂SPrⁿ)₂(SPrⁿ)₂(RhCl₃)₂], [Mo(η-C₅H₄CH₂CH2SPrⁿ)₂(μ-SPrⁿ)₂Rh(dppe)]BF₄, [Mo(η-C₅H₄CH₂CH₂SPrⁿ)₂(μ-SPrⁿ)₂(COD)Rh]Cl, [Mo(η-C₅H₄CH₂CH₂SPrⁿ)₂-(μ-SPrⁿ)₂Pt(PPh₃)₂](PF₆)₂, and the compound [Mo(η-C₅H₄(CH₂)₂-μ-SPh)₂Cl₂Rh(COD)]Cl bonds via the ring-sulphur substituents giving [Mo(η-C₅H₄(CH₂)₂-μ-SPh)₂-Cl₂Rh(COD)]Cl.     

Ethylene polymerization with novel bridged tri- and tetranuclear titanocene/MAO systems

Two benzene centered tri- and tetracyclopentadienyl ligands C₆H₃(CH₂C₅H₅)₃-1,3,5 (1) and C₆H₂(CH₂C₅H₅)₄-1,2,4,5 (2) and their titanium complexes C₆H₃[CH₂C₅H₄Ti(C₅H₅)Cl₂]₃-1,3,5 (3), C₆H₃[CH₂C₅H₄Ti(C₅H₄CH₃)Cl₂]₃-1,3,5 (4), as well as C₆H₂[CH₂C₅H₄Ti(C₅H₅)Cl₂]₄-1,2,4,5 (5) were synthesized and characterized by mass and ¹H NMR spectra. In the presence of methylaluminoxane (MAO), 3, 4 and 5 are efficient catalysts for ethylene polymerization in toluene. The influence of the polymerization conditions such as catalyst concentration, MAO/Ti molar ratio, polymerization time and temperature were investigated in detail. 3, 4 and 5 produce linear polyethylene (PE) with broad molecular weight distributions (MWD) and a little lower molecular weight.