Conversion of allene into μ-dimethylcarbene at a diruthenium centre

Treatment of [Ru₂(CO)(μ-CO) {μ-C(O)C₂Ph₂} (η-C ₅H₅)₂] with allene in toluene at 100°C displaces diphenylacetylene and produces [Ru(CO)(η-C₅H₅)-{η³-C₃H₄Ru(CO)₂(η-C₅H₅)}]; upon protonation a 1-methylvinyl cation [Ru₂(CO)₂(μ-CO){μ-C(Me)CH₂}(η-C₅H₅)₂]⁺ is formed which undergoes nucleophillic attack by hydride to yield the μ-dimethylcarbene complex [Ru₂(CO)₂-(μ-CO)(μ-CMe₂)(η-C₅H₅)₂].     

Dithiolene transfer from nickel to a dimolybdenum centre: the first dithiolene alkyne complex

Transfer of dithiolene ligands from [Ni(S₂C₂Ph₂)₂] to the dimolybdenum complex [Mo₂(μ-C₂R₂)(CO)₄Cp₂] (R=CO₂Me, Cp=η-C₅H₅) affords the first example of a dithiolene alkyne complex, [Mo₂(μ-C₂R₂)(μ-S₂C₂Ph₂)₂Cp₂], together with [Mo₂(μ-SCRCR)(μ-SCPhCPh)Cp₂] in which sulfur transfer from dithiolene to alkyne has occurred.     

Molybdenum complexes containing substituted cyclopenta[l]phenanthrenyl ligand

The synthesis of new cyclopenta[l]phenanthrenyl complexes [(η⁵-C₁₇H₁₀Me)(η³-C₃H₅)Mo(CO)₂] and [(η⁵-C₁₇H₉(COOMe)N(CH₂)₄)(η³-C₃H₅)Mo(CO)₂] is described. Although these compounds are structural analogues their reactivity is different. Protonation of [(η⁵-C₁₇H₁₀Me)(η³-C₃H₅)Mo(CO)₂] gives a stable ionic compound [(η⁵-C₁₇H₁₀Me)Mo(CO)₂(NCMe)₂][BF₄] while its analogue containing both tertiary amino and carboxylic ester groups [(η⁵-C₁₇H₉(COOMe)N(CH₂)₄)(η³-C₃H₅)Mo(CO)₂] decomposes under the same conditions. [(η⁵-C₁₇H₁₀Me)Mo(CO)₂(NCMe)₂][BF₄] reacts with cyclopentadiene to give a stable η⁴-complex [(η⁴-C₅H₆)(η⁵-C₁₇H₁₀Me)Mo(CO)₂][BF₄] that was successfully oxidized to the Mo(IV) dicationic compound [(η⁵-C₅H₅)(η⁵-C₁₇H₁₀Me)Mo(CO)₂][Br][BF₄].     

Aqueous allylmolybdenum(II) chemistry

Dissolution of [MoCl(CO)₂(η³-C₃H₄R)(NCMe)₂] (R = H or Me) in methanol yields yellow conducting solutions containing the [Mo(CO)₂(η³-C₃H₄R)(HOMe)₃]⁺ cations. The same species are formed on dissolution of [Mo(CO)₂(η³-C₃H₄R)(NCMe)₃]BF₄ in methanol, and one of the cations (R = Me) has been isolated as its tetrafluoroborate salt. There is strong spectroscopic evidence that hydrated allyldicarbonylmolybdenum(II) cations [Mo(CO)₂(η³-C₃H₄R)(H₂O)_x]⁺ are present on dissolution of [MoCl(CO)₂(η³-C₃H₄R)(NCMe)₂] in deoxygenated water, and treatment of these solutions with bi- and tridentate ligands yields neutral complexes [MoCl(CO)₂(η³-C₃H₄R)L₂] (R = H or Me; L₂ = 2,2′-bipyridine (bipy) or 2,2′-bipyridylamine (bpa)), and cationic species [Mo(CO)₂(η³-C₃H₄R)L₃]⁺ (R = H or Me; L₃ = diethylenetriamine (dien) or bis(2-pyridylmethyl)amine (bpma)) respectively. The latter were isolated as their hexafluorophosphate salts. Addition of Ph₄AsCl to basic methanolic solutions of [MoCl(CO)₂(η³-C₃H₄R)(NCMe)₂] causes the precipitation of the anionic molybdenum derivatives Ph₄As[Mo₂(CO)₄(η³-C₃H₄R)₂(μ-OMe)₃] (R = H or Me).     

Transformation of C2 units on a bimetallic tetranuclear cluster.: Reactivity of [Ru3Mo(μ3-η-CC)(μ-CO)3(CO)2(η-C5H4R)3(η-C5H5)] (R = H, Me)

The reactivity of [Ru₃Mo(μ₄-η²-CC)(μ-CO)₃(CO)₂(η-C₅H₄R)₃(η-C₅H₅)] (R = H; Me) have been investigated, initially to elucidate the nature of the starting material, and, latterly, to define the reactivity of an interesting ethane-1,2-bis(ylidyne) species. While the mixed RuMo clusters were unreactive towards simple electrophiles and carbonyl substitution by phosphine ligands they did react with atmospheric oxygen or carbon monoxide to give substantially different products. In all instances oxygen was incorporated either at the metal centre or at the C₂ fragment. High-pressure carbonylations yielded [Ru₃(μ-CO)₃(η-C₅H₅)₃(μ₃-C-C(O)O{Ru(CO)₂(η-C₅H₅)})] and [{Ru₂(μ-CO)(CO)₂(η-C₅H₄Me)₂}(μ₄-η²-CC){Ru(CO)(η-C₅H₄Me)Mo(η-C₅H₅)(=O)(μ-O)}], an ethane-1,2-bis(ylidene) complex, this exemplifying a relatively rare raft geometry which further reacted with Cl₂CCCl₂ to give [Mo₃(μ₄-C₂(Ru(CO)₂(η-C₅H₄Me))(CO)(μ-CO)(η-C₅H₅)₃(Cl)₂] having a similar geometry and undergone halogenation. In order to extend the extant examples of these raft clusters we explored the reaction of [{Ru(CO)₂(η-C₅H₄R)₂}₂(μ-C₂)] with [{Ru(CO)₂(η-C₅H₅)₂}₂] to provide a rational synthetic pathway leading to very reactive [Ru(μ₄-η²-CC)(μ₂-CO)₂(CO)₄(η-C₅H₄Me)₂(η-C₅H₄R)₂] rafts.     

Heterometallische Clusterkomplexe der Typen Re2(μ-PR2)(CO)8(HgY) und ReMo(μ-PR2)(η5-C5H5)(CO)6(HgY) (R = Ph,Cy; Y = Cl,W(η5-C5H5)(CO)3)

Heterometallic Cluster Complexes of the Types Re₂(μ-PR₂)(CO)₈(HgY) and ReMo(μ-PR₂)(η⁵-C₅H₅)(CO)₆(HgY) (R = Ph, Cy; Y = Cl, W(η⁵-C₅H₅)(CO)₃) Dinuclear complexes Re₂(μ-H)(μ-PR₂)(CO)₈ and ReMo(μ-H)(μ-PR₂)(η⁵-C₅H₅)(CO)₆ (R = phenyl, cyclohexyl) were deprotonated and reacted as anions with HgCl₂ to compounds of the both types Re₂(μ-PR₂)(CO)₈HgCl) and ReMo(μ-PR₂)(η⁵-C₅H₅)(CO)₆(HgCl). The heterometallic three-membered cluster complexes correspond to an isolobal exchange of a proton against a cationic HgCl⁺ group. For one of the products ReMo(μ-PCy₂)(η⁵-C₅H₅)(CO)₆(HgCl) has been shown its conversion with NaW(η⁵-C₅H₅)(CO)₃ to ReMo(μ-PCy₂)(η⁵-C₅H₅)(HgW(η⁵-C₅H₅)(CO)₃) under substitution of the chloro ligand, par example. The newly prepared compounds were characterized by means of IR, UV/VIS and ³¹P NMR data. A complete determination of the molecular structure by single crystal analyses was done in the case of Re₂(μ-PCy₂)(CO)₈(HgCl) and of ReMo(μ-PCy₂)(η⁵-C₅H₅)(CO)₆(HgCl) which both are dimer because of the presence of an asymmetric dichloro bridge, and of ReMo(μ-PCy₂)(η⁵-C₅H₅)(CO)₆(HgW(η⁵-C₅H₅)(CO)₃). The structural study illustrates through comparison the influence of various metal types on an interaction between centric and edge-bridged frontier orbitals in three-membered metal rings.     

Unusual tetra- and penta-ruthenium complexes from linking of ethylidyne and vinylidene ligands

The complexes [Ru₂(CO)₂(μ-CO)(μ-CMe)(η-C₅H₅)₂]^? and [Ru₂CO₂(μ-CO)(μ-CCH₂)(η-C₅H₅)₂] react together to give [{Ru₂CO)₃(η-C₅H₅)₂}₂(μ-CMeCHCH)]⁺ and [{Ru₃(CO)₃(η-C₅H₅)₃}(μ-CCH₂CHC){Ru₂(CO)₃(η-C₅H₅)₂}], each characterised by X-ray diffraction. The former results from ethylidyne-vinylidene linking followed by an alkylidyne to vinyl rearrangement.     

Isonitrilsynthesen am komplex: V. Desulfurierung von isothiocyanaten in carbonylmetallat-additions-verbindungen

The isocyanide complexes [Fe(η-C₅H₅)(CO)₂CNR][PF₆] and Cr(CO)₅CNR (R = CH₃, C₆H₁₁, C₆H₅) are conveniently prepared at ?50°C from carbonyl metallates, isothiocyanates, and phosgene. At room temperature Na[Fe(η-C₅H₅)(CO)₂] reacts with isothiocyanates ($\text{1}\text{1}$) to give the isocyanide bridged complexes [Fe₂(η-C₅H₅)₂(μ-CO)(μ-CNR)(CO)₂].     

Übergangsmetall-substituierte Acylphosphane und Phosphaalkene. 17 [1] Synthese und Struktur der μ-Isophosphaalkin-Komplexe [(η5-C5H5)2(CO)2Fe2(μ-CO)(μ-CPC6H2R3-2,4,6)] (R = Me,iPr, tBu)

Transition Metal Substituted Acylphosphanes and Phosphaalkenes. 17. Synthesis and Structure of the μ-Isophosphaalkyne Complexes [(η⁵-C₅H₅)₂(CO)₂Fe₂(μ-CO)(μ-C?PC₆H₂R₃)] (R = Me, iPr, tBu) . Condensation of (η⁵-C₅H₅)₂(CO)₂Fe₂(μ-CO)(μ-CSMe)}⁺SO₃CF₃^? ( 6 ) with 2,4,6-R₃C₆H₂PH(SiMe₃) ( 7 ) ( a : R = Me, b : R = iPr, c : R = tBu) affords the complexes (η⁵-C₅H₅)₂(CO)₂Fe₂(μ-CO)(η-C?PC₆H₂R₃-2,4,6) ( 9 a–c ) with edge-bridging isophosphaalkyne ligands as confirmed by the x-ray structure analysis of 9 a .     

Syntheses and Reactions of Dimolybdenum Alkyne Compounds Containing Functionally Substituted Ligands. The Crystal Structure of [Co2Mo2(μ4-CHCH)(μ-CO)4(CO)4-(η5-C5H4C(O)Me)2]

Abstract

Three dimolybdenum alkyne complexes containing functionally substituted ligands [Mo₂(μ-CHCH)(CO)₄(η⁵?C₅H₄C(O)R)₂] [R ? OEt, (1a); R ? Me, (1b); R ? Ph, (1c)] were synthesized by reactions of acetylene with in situ generated metal-metal triply bonded complexes [Mo(CO)₂(η⁵?C₅H₄C(O)R)]₂ (R ? OEt, Me, Ph). Further reaction of (1a), (1b) or (1c) with Co₂(CO)₈ in refluxing toluene gave another three new butterfly compounds [Co₂Mo₂-(μ₄-CHCH)(μ-CO)₄(CO)₄(η⁵-C₅H₄C(O)R)₂] [R ? OEt, (2a); R ? Me, (2b); R ? Ph, (2c)]. The resulting compounds were characterized by elemental analyses, IR, ¹H NMR and MS. The crystal structure of (2b) was determined by single-crystal X-ray analysis. The results indicate that the existence of functional groups on the cyclopentadienyl ring has an influence on the reactivity of this type of complex.     

Solvent induced ionisation of η-allydicarbonylmolybdenum(II) complexes

[MoCl(η-C₃H₅)(CO)₂(MeCN)₂] dissolved in aprotic solvents is extensively ionised to [Mo(η-C₃H₅)(CO)₂(MeCN)₃]⁺[Mo₂Cl₃(η-C₃H₅)₂(CO)₄]^- with the liberation of free acetonitrile. The corresponding bromo- complex shows similar but less pronounced ionisation in (CD₃)₂CO, whereas the iodo-complex retains its molecular structure.     

Chalcogen–acetylide interaction and unusual reactivity of coordinated acetylide with water: synthesis and characterisation of [(η5-C5R5)Fe3(CO)6(μ3-E)(μ3-ECCH2RI)] (R=H,Me; RI=Ph,Fc; E=S,Se) and [(η5-C5R5)MoFe2(CO)6(μ3-S)(μ-SCCH2Ph)] (R=H,Me)

Photolysis of a benzene solution containing [Fe₃(CO)₉(μ₃-E)₂] (E=S, Se), [(η⁵-C₅R₅)Fe(CO)₂(CCR^I)] (R=H, Me; R^I=Ph, Fc), H₂O and Et₃N results in formation of new metal clusters [(η⁵-C₅R₅)Fe₃(CO)₆(μ₃-E)(μ₃-ECCH₂R^I)] (R=H, R^I=Ph, E=S 1 or Se 2; R=Me, R^I=Ph, E=S 3 or Se 4; R=H, R^I=Fc, E=S 5; R=Me, R^I=Fc, E=S 6 or Se 7). Reaction of [Fe₃(CO)₉(μ₃-S)₂]with [(η⁵-C₅R₅)Mo(CO)₃(CCPh)] (R=H, Me), under same conditions, produces mixed-metal clusters [(η⁵-C₅R₅)MoFe₂(CO)₆(μ₃-S)(μ-SCCH₂Ph)] (R=H 8; R=Me 9). Compounds 1–9 have been characterised by IR and ¹H and ¹³C-NMR spectroscopy. Structures of 1, 5 and 9 have been established crystallographically. A common feature in all these products is the formation of new C-chalcogen bond to give rise to a (ECCH₂R^I) ligand.     

Synthesis and characterization of the cluster complexes containing tetrahedral FeCrCo(μ3-S) cluster cores generated by isolobal displacement reactions. Crystal structures of (η-RC5H4)FeCrCo(μ3-S)(CO)8 (R=H, CO2Et) and FeCo2(μ3-S)2(CO)9

The monoanions (η⁵-RC₅H₄)(CO)₃Cr⁻ (1, R=H; 2, R=Me; 3, R=CO₂Et) reacted with tetrahedral cluster FeCo₂(μ₃-S)(CO)₉ to give single isolobal displacement products (η⁵-RC₅H₄)FeCrCo(μ₃-S)(CO)₈ (4, R=H; 5, R=Me; 6, R=CO₂Et) in 86-89% yields, whereas monoanion (η⁵-RC₅H₄)(CO)₃Cr⁻ (7, R=C(O)Me) reacted with FeCo₂(μ₃-S)(CO)₉ to afford the expected single isolobal displacement product (η⁵-RC₅H₄)FeCrCo(μ₃-S)(CO)₈ (8, R=C(O)Me) in 5% yield and an unexpected square pyramidal cluster FeCo₂(μ₃-S)₂(CO)₉ (9) in 45% yield. Similarly, the dianions [η⁵-C₅H₄CH₂(CH₂OCH₂)_nCH₂C₅H₄-η⁵][(CO)₃Cr⁻]₂ (10, n=1; 11, n=2; 12, n=3) reacted with two molecules of FeCo₂(μ₃-S)(CO)₉ to produce double isolobal displacement products [η⁵-C₅H₄CH₂(CH₂OCH₂)_nCH₂C₅H₄-η⁵][FeCrCo(μ₃-S)(CO)₈]₂ (13, n=1; 14, n=2; 15, n=3) in 32-36% yields, while treatment of dianion [η⁵-C₅H₄C(O)CH₂]₂[(CO)₃Cr⁻]₂ (16) with two molecules of FeCo₂(μ₃-S)(CO)₉ gave the unexpected square pyramidal cluster FeCo₂(μ₃-S)₂(CO)₉ (9) in 42% yield and the corresponding double isolobal displacement product [η⁵-C₅H₄C(O)CH₂]₂[FeCrCo(μ₃-S)(CO)₈]₂ (17) in 8% yield. Products 4-6, 8, 9, 13-15 and 17 were characterized by elemental analyses, IR and ¹H NMR spectroscopy, as well as for 4, 6 and 9 by X-ray diffraction techniques.     

Synthesis and molecular structure of [Re2(μ:η-C24H18N4)(CO)6] containing the rtct-tetrakis(2-pyridyl)cyclobutandiyl ligand, derived from the reaction of [Re2(CO)8(MeCN)2] and 1,2-bis(2-pyridyl)ethene

The reaction of the labile compound [Re₂(CO)₈(CH₃CN)₂] with trans-1,2-bis(2-pyridyl)ethene (C₁₂H₁₀N₂) at room temperature in tetrahydrofuran affords the compounds [Re₂(μ:η³-C₁₂H₁₀N₂)(CO)₈] (1) and the oxidative addition product [Re₂(μ-H)(μ:η³-C₁₂H₉N₂)(CO)₇] (2). When the reaction is carried out at temperatures of refluxing tetrahydrofuran, besides compounds 1 and 2, the oxidative addition product [Re₂(μ-H)(μ:η⁴-C₁₂H₉N₂)(CO)₆] (3), the insertion product [Re₂(μ:η⁴-C₁₂H₁₀N₂)(CO)₈] (4) and [Re₂(μ:η⁶-C₂₄H₁₈N₄)(CO)₆] (5) are obtained. Compound 5 contains the organic ligand rtct-tetrakis(2-pyridyl)cyclobutandiyl which is derived from a [2 + 2] cycloaddition of 1,2-bis(2-pyridyl)ethene mediated by its coordination to the bimetallic framework. The molecular structures of 1, 2, 4 and 5 were confirmed by X-ray crystallographic studies.     

Some reactions of Ni-Mo and Ni-W propargylic cations with nucleophiles

Preliminary reactions of the metal stabilized carbocationic species [(η-C₅H₅)Ni(μ-η²(Ni),η³(Mo)-HC₂CMe₂)Mo(CO)₂(η-C₅H₄Me)]⁺ BF₄⁻ (Ni-Mo) with nucleophiles are reported. The Ni-Mo cationic propargylic complex undergoes nucleophilic attack by sodium methoxide to regenerate the neutral μ-alkyne complex [(η-C₅H₅)Ni{μ-η²,η²-HC₂CMe₂(OMe)}Mo(CO)₂(η-C₅H₄Me)] (Ni-Mo), from which the stabilized carbocation was originally derived by protonation. The new complexes [(η-C₅H₅)Ni{μ-η²,η²-HC₂CMe₂(C₅H₅)}Mo(CO)₂(η-C₅H₄Me)] (Ni-Mo), which exist as an inseparable mixture of 1(c)-1,3- and 2(c)-1,3-cyclopentadienyl isomers, were also obtained. When the Ni-Mo cations were treated with potassium t-butoxide, the alkyne isomers with pendant 1(c)-1,3- and 2(c)-1,3-cyclopentadienyl groups are also formed. The μ-hydroxyalkyne complex [(η-C₅H₅)Ni{μ-η²,η²-HC₂CMe₂(OH)}-Mo(CO)(η-C₅H₄Me)] (Ni-Mo) was also isolated concurrently, and presumably arises from nucleophilic attack of fortuitously present hydroxide ions in the BuO⁻ reagent on the Ni-Mo cation. When NaBH₄ was added to the Ni-Mo propargylic, nucleophilic attack by hydride resulted and the μ-ⁱPrC₂H heterobimetallic complex [(η-C₅H₅)Ni{μ-η²,η²-HC₂Prⁱ}Mo(CO)₂(η-C₅H₄Me)] (Ni-Mo) was recovered in good yield. Small quantities of other side-products were isolated and characterized spectroscopically. Some tantalizing differences in reactivity were observed when the corresponding Ni-W stabilized carbocation was reacted with methoxide ions. When the not fully characterized solid formed by protonating [(η-C₅H₅)Ni(μ-η²,η²-{HC₂CMe₂)(OMe)}W(CO)₂(η-C₅H₄Me)] (Ni-W) was treated with methoxide ions, regioisomers (1(c)-1,3- and 2(c)-1,3-cyclopentadienyl species) of composition [(η-C₅H₅)Ni{μ-η²,η²-HC₂CMe₂(C₅H₅)}W(CO)₂(η-C₅H₄Me)] (Ni-W) were formed. Direct reaction of the pure cation [(η-C₅H₅Niμ-η²,η³-HC₂CMe₂)W(CO)₂(η-C₅H₄Me)]⁺ (Ni-W) with methoxide also generated the same 1(c)-1,3- and 2(c)-1,3-cyclopentadiene-substituted alkyne complexes. Unlike the case with the Ni-Mo complexes, the initial μ-HC₂CMe₂(OMe) species was not regenerated.     

Photochemical reactions of allyl and crotyl halides with cyclopentadienyl-chromium, -molybdenum and -tungsten complexes

[MoCl(CO)₃(η⁵-C₅H₅)] on photolysis with allyl or crotyl halides C₅H₄RX gives Mo^IV complexes [MoX₂(CO)(η³-C₃H₄R)(η⁵-C₅H₅)] (R = H, X = Cl, Br, I; R = Me, X = Cl, Br). [WCl(CO)₃(η⁵-C₅H₅)] under similar conditions gives trihalides [WX₃(CO)₂(η⁵-C₅H₅)] (X = Cl, Br) on reaction with C₃H₅Cl and C₃H₅Br while [WCl(CO)₃(η⁵-C₅H₄SiMe₃)] and [CrI(CO)₃(η⁵-C₅H₅)] react with allyl chloride to give [WCl₃(CO)₂(η⁵-C₅H₄SiMe₃)] and [CrCl₂(η⁵-C₅H₅)] respectively.     

Unexpected reactions of (Me2C)(Me2Si)[(η-C5H3)Mo(CO)3]2 with diazoalkane and carbon disulfide: Activation and cleavage of the NN bond and disproportionation of carbon disulfide

The N-N bond cleavage of diazoalkane Ar₂CN₂ following a orthometalation of the aryl occurred in the thermal reactions with (Me₂C)(Me₂Si)[(η⁵-C₅H₃)Mo(CO)₃]₂ (1), which led to (Me₂C)(Me₂Si)[(η⁵-C₅H₃)₂Mo₂(CO)₂(O){μ-η¹:η²-NC(RC₆H₃)(RC₆H₄)}] [R = H (2), p-Me (3)]. Two products (Me₂C)(Me₂Si)[(η⁵-C₅H₃)₂Mo₂(CO)₄(μ-η¹:η²-CS)] (4) and (Me₂C)(Me₂Si)[(η⁵-C₅H₃)₂Mo₂(CO)₄(μ-η²:η²-CS₃)] (5) were isolated in the reaction of complex 1 with CS₂ with the disproportionation of carbon disulfide. The molecular structures of 2-5 have been determined by X-ray diffraction analysis. The proposed mechanism was discussed.     

Sequential conversion of ethyne into μ-vinylidene, μ-methylcarbyne and μ-methylcarbene at a di-ruthenium centre: X-ray structures of [Ru2(CO)2(μ-CO) (μ-CCH2) (η-C5H5)2] and [Ru2(CO)2(μ-CO) (μ-CCH3) (η-C5H5)2] [BF4]

The ethyne-derived demetallocycle [Ru₂(CO) (μ-CO){μ-C(O)C₂H₂}(η-C₅H₅)₂ isomerises in boiling toluene to yield the μ-vinylidene complex [Ru₂(CO)₂(μ-CO)(μ-CCH₂) (η-C₅H₅)₂], which on protonation with dry HBF₄ provides the μ-carbyne complex [Ru₂(CO)₂(μ-CO)(μ-CCH₃)(η-C₅H₅)₂][BF₄]; the structure of each product has been determined by X-ray diffraction. The μ-carbyne cation is attacked by hydride to produce the μ-methylcarbene complex [Ru₂(CO)₂(μ-CO)(μ-CHCH₃)(η-C₅H₅)₂].     

Dithiocarbamate complexes of cyclopentadienylcobalt(III), [Co(η-C5H5)(L)(S2CNR2)] (L = ligand)

The reactions of [Co(η-C₅H₅)(L)I₂] with Na[S₂CNR₂] (R = alkyl or phenyl) give [Co(η-C₅H₅)(I)(S₂CNR₂)] (I) when L = CO and [Co(η-C₅H₅)(L)(S₂CNR₂)]I (II) when L is a tertiary phosphine, phosphite or stibine, or organo-isocyanide ligand. In similar reactions [Co(η-C₅H₅)(CO)(C₃F₇)I] gives [Co(η-C₅H₅)(C₃F₇)(S₂CNMe₂)] and [Mn(η-MeC₅H₄)(CO)₂(NO)]PF₆ forms [Mn(η-MeC₅H₄)(NO)(S₂CNR₂)]. The iodide ligands in I may be displaced by L, to give II, or by other ligands such as [CN]^?, [NCS]^?, H₂O or pyridine whilst SnCl₂ converts it to SnCl₂I. The iodide counter-anion in II may be replaced by others to give [BPh₄]^?, [Co(CO)₄]^? or [NO₃]^? salts. However [CN]^? acts differently and displaces (PhO)₃P from [Co(η-C₅H₅){P(OPh)₃}(S₂CNMe)]I to give [Co(η-C₅H₅)(CN)(S₂CNMe₂)] which may be alkylated reversibly by MeI and irreversibly by MeSO₃F to [Co(η-C₅H₅)(CNMe)(S₂CNMe₂)]⁺ salts. Conductivity measurements suggest that solutions of I in donor solvents are partially ionized with the formation of [Co(η-C₅H₅)(solvent)(S₂CNR₂)]⁺ I^? species. The IR and ¹H NMR spectra of the various complexes are reported. They are consistent with pseudo-octahedral “pianostool” molecular structures in which the bidentate dithiocarbamate ligands are coordinated to the metal atoms through both sulphur atoms.     

Electrophilic additions to unsaturated systems : By P.B.D. De la Mare and R. Bolton,Elsevier Scientific Publ. Co., Amsterdam and New York, 2nd Edition, 1982, xiii + 377 pages,U.S. $91.50, Dutch Fl. 215.00

The metalmetal double-bonded μ-alkyne complex [Ru₂(μ-CO)(μ-C₂Ph₂) (η-C₅H₅)₂] (1) reacts with diazomethane at 0°C to yield Ru₂(CO)(η-CH₂) {μ-C(Ph)C(Ph)CH₂} (η-C₅H₅)₂] (2) incorporating two methylene units, one bridging the metal atoms and one linked with the alkyne. Upon heating, a second carboncarbon bond formation occurs to link the methylene groups and give [Ru₂(CO)(μ-CO) {μ-C(Ph)C(Ph)C(H)Me} (η-C₅H₅)₂ (3); the structures of 1 and 2 were established by X-Ray diffraction.