A diphosphide adduct of ditungsten-hexaisopropoxide: X-ray crystal structure of W2(OPri)6(py)(μ-P2)

From the reaction between W₂(OPrⁱ)₆(py)₂ and CO₂(μ-P₂)(CO)₆ in hexane at room temperature a black crystalline product has been shown to be W₂(OPrⁱ)₆(py)(μ-P₂) by a single crystal X-ray determination. There is a central pseudo tetrahedral W₂P₂ moiety with WW = 2.695(1) Å, PP = 2.154(4) Å and WP = 2.45(2) Å (averaged) corresponding to essentially single bond distances. This new compound is an analogue of the ethyne adducts W₂(OR)₆(py)(μ-C₂H₂), where R = Bu^t and CH₂Bu^t, and these in turn are related to CO₂(CO)₆(μ-X) compounds (X = P₂, C₂R₂) by isolobal relationships.     

Aryl- and acetylene-nickel(I) complexes

Reduction of various pentafluorophenylnickel(II) complexes in the presence of phosphines gives unstable nickel(I) compounds but Ni(C₆F₅)(CO)₂(PPh₃)₂ is isolated in the presence of CO. Similar NiR(CO)₂(PPh₃)₂ (R = C₆F₅,C₆Cl₅, 2,3,5,6-C₆Cl₄H) are obtained by reaction of the halogenonickel(I) complex with MgRBr or LiR. Reduction of NiX₂L₂ in the presence of acetylenes gives [NiXL₂]₂(μ-PhCCR) (R = H, X = Cl and R = Ph, X = Cl, Br) when L = P-n-Bu₃ but only NiX(PPh₃)₃ are recovered when L = PPh₃. No reaction with the alkyne is observed for [NiX(PPh₃)₂]_n but [NiCl(PPh₃)]_n reacts with RCCR′ to give paramagnetic NiCl(PPh₃)(CRCR′) (R = Ph, R′= H, COOEt), diamagnetic [NiCl(PPh₃)]₂(μ-PhCCPh) and cyclotrimerization when R = R′ = COOMe. Chemical and structural behaviour of the new nickel(I) complexes is described.     

Anionic tolylmethylidyne(carbaborane)tungsten complexes: protonationa and reaction with trimethylphosphine

Protonation of the closely related salts [N(PPh₃)₂][W(CC₆H₄Me-4)(CO)₂(η-1,2-C₂B₉H₉R₂] (Ia, R = H; Ib, R = Me) affords structurally different products: [N(PPh₃)₂][W₂(μ-H){μ-C₂(C₆H₄Me-4)₂}(CO)₄(η-1,2-C₂B₉H₁₁)₂] (III) and [W(CC₆H₄Me-4)(CO)₂(η-1,2-C₂B₉H₁₀Me₂)] (V), respectively. Treatment of Ib, with PMe₃, gives the ketenyl complex [N(PPh₃)₂][W(CO)(PMe₃){η²-C(C₆H₄Me-4)C(O)}(η-1,2-C₂B₉H₉Me₂)] (VI). Protonation and methylation of the latter yields the alkyne-tungsten compounds [W(CO)(PMe₃){η-C₂(OR′)(C₆H₄Me-4)}(η-1,2-C₂B₉H₉Me₂)] (IXa, R′ = H; IXb, R′ = Me).     

Synthesis of the compounds [Re(CR)(CO)2(η5-C9H7)][BF4] (R = C6H4Me-4 or C6H3Me2-2,6) and the preparation of complexes with FeRe bonds

The salts [Re(CR)CO)₂(η⁵-C₉H₇)][BF₄] [R = C₆H₄Me-4 or C₆H₃Me-2,6; η⁵- C₉H₇ = indenyl] have been prepared and used to synthesize the dimetal compounds [FeRe(μ-CR)(μ-NO)(CO)₄(η⁵-C₉H₇)]. The iron-rhenium species containing a bridging p- tolylmethylidyne ligands react with [Fe₂(CO)₉] or with [Ru(CO)₄(η-C₂H₄)], respectively, to yield the trimetal compounds ([FeMRe(μ₃-CC₆H₄Me-4)(μ-CO)(μ-NO)(CO)₆(η ₅-C₉H₇)] (M = Fe or Ru).     

Ligand-centred coupling of the alkynyl radical cations [Mo(CCR)(Ph2PCH2CH2PPh2)(η-C7H7)]+ (R = Ph or Bun: crystal structure of the dimeric product [Mo2(Ph2PCH2CH2PPh2)2(η-C7H7)2(μ-C4R2)][PF6]2 (R = Ph)

The radical cations [Mo(CCR)(dppe)(η-C₇H₇)]⁺ (R = Ph or Buⁿ); dppe = Ph₂PCH₂CH₂PPh₂) undergo coupling at C_β of the alkynyl ligand to afford the divinylidene-bridged, dimeric products [Mo₂(dppe)₂(η-C₇H₇)₂(μ-C₄R₂)]²⁺, characterised crystallographically for R = Ph.     

Synthesis and characterization of heterobimetallic mixed-ligand complexes containing Zr(μ-OPri)2Al bridging units

Interesting varieties of heterobimetallic mixed-ligand complexes [Zr{M(OPrⁱ) _n }₂ (L)] (where M = Al, n = 4, L = OC₆H₄CH = NCH₂CH₂O (1); M = Nb, n = 6, L = OC₆H₄CH = NCH₂CH₂O (2); M = Al, n = 4, L = OC₁₀H₆CH = NCH₂CH₂O (3); M = Nb, n = 6, L = OC₁₀H₆CH = NCH₂CH₂O (4)), [Zr{Al(OPrⁱ)₄}₂Cl(OAr)] (where Ar = C₆H₃Me₂-2,5 (5); Ar = C₆H₂Me-4-Bu₂-2,6 (6), [Zr{Al(OPrⁱ)₄}₂(OAr)₂] (where Ar = C₆H₃Me₂-2,5 (7); Ar = C₆H₂Me-4-Bu₂-2,6 (8), [Zr{Al(OPrⁱ)₄}₃(OAr)] (where Ar = C₆H₃Me₂-2,5 (9); Ar = C₆H₃Me₂-2,6 (10), [ZrAl(OPrⁱ)_7-n (ON=CMe₂) _n ] (where n = 4 (11); n = 7 (12), [ZrAl₂(OPrⁱ)_10-n (ON=CMe₂) _n ] (where n = 4 (13); n = 6 (14); n = 10 (15) and [Zr{Al(OPrⁱ)₄}₂{ON=CMe(R)} _n Cl_2–n] [where n = 1, R = Me (16); n = 2, R = Me (17); n = 1, R = Et (18); n = 2, R = Et (19)] have been prepared either by the salt elimination method or by alkoxide-ligand exchange. All of these heterobimetallic complexes have been characterized by elemental analyses, molecular weight measurements, and spectroscopic (I.r., ¹H-, and ²⁷Al- n.m.r.) studies.     

Protonation of a series of diphosphazane- and diphosphine-bridged derivatives of iron and ruthenium: dependence of the nature of the hydride ligand on the metal and the bridging diphosphorus ligand

Protonation of the dinuclear compounds [M₂(μ-CO)(CO)₄(μ-R₂PYPR₂)₂] by HBF₄ or HPF₆ leads to the formation of crystalline cationic hydrido products [M₂H(CO)₅(μ-R₂PYPR₂)₂]X and [M₂(μ-H)(μ-CO)(CO)₄(μ-R₂PYPR₂)₂]X (X = BF₄ or PF₆) in which the hydride ligand is terminal for M = Ru, Y = N(Et) and R = OMe or OPrⁱ and bridging for M = Fe, Y = CH₂ and R = Me or Ph, for M = Fe, Y = N(Et) and R = OMe, OEt, OPrⁱ or OPh and for M = Ru, Y = CH₂ and R = Ph; the fluxional behaviour of [Ru₂H(CO)₅{μ-(RO)₂PN(Et)P(OR)₂}₂]⁺ (R = Me or Prⁱ) in solution is described.     

Synthesis of novel termetallic isopropoxides

Novel termetallic isopropoxides are reported which may be represented by the general formulae: [(PrⁱO)₃M(μ-OPrⁱ)₂Be(μ-OPrⁱ)₂Al(OPrⁱ)₂], [(PrⁱO)₂M(μ-OPrⁱ)₂Be(μ-OPrⁱ)₂Al(OPrⁱ)₂]₂ [where M = Ti(IV), Zr(IV) and Hf(IV)] and [(PrⁱO)₄M(μ-OPrⁱ)₂Be(μ-OPrⁱ)₂Al(OPrⁱ)₂] [where M = Nb(V) and Ta(V)]. Attempts to synthesize derivatives with the general formula, [(PrⁱO)₇M₂(μ-OPrⁱ)₂Be(μ-OPrⁱ)₂Al(OPrⁱ)₂] [where M = Ti(IV), Zr(IV) or Hf(IV)], were unsuccessful and in all such cases a mixture of M(OPrⁱ)₄ and [(PrⁱO)₃M(μ-OPrⁱ)₂Be(μ-OPrⁱ)₂Al(OPrⁱ)₂] was obtained. All these derivatives are soluble in common organic solvents and with the exception of titanium(IV) derivatives, they can be volatilised without noticeable disproportionation. These products have been characterized by elemental analyses, molecular weights, IR, ¹H NMR and (in representative cases) mass spectral studies also.     

Übergangsmetall-Carbin-Komplexe: CIII. Aktivierung von Ethylisocyanid an elektronenreichen Metallzentren; Synthese von einkernigen Wolfram-Aminocarbin-Komplexen des Typs Tp′(CO)2 WCN(R)Et (R  Me,Et)

A large-scale, high-yield synthesis of the aminocarbyne complexes Tp′(CO)₂WCN(R)Et (5: R  Me; 6: R  Et) [Tp′ = hydridotris(3,5-dimethylpyrazol-1-yl)borate] is reported, starting from Tp′W(CO)₃I (2). The first step of the synthetic procedure involves thermal decarbonylation of 2 with EtNC to give cis-Tp′W(CO)₂(CNEt)I (3). Complex 3 is then reduced with Na/Hg to give the metallate Na[Tp′W(CO)₂(CNEt)] (4). Finally, complex 4 is alkylated with RI (R  Me, Et) exclusively at the isocyanide nitrogen to give the aminocarbyne complexes 5 and 6. In contrast, the metallates Na[(η⁵-C₅R′₅)W(CO)₂(CNEt)] (R′  H, Me) undergo alkylation with RI at the metal centre to afford the W^II alkyl complexes cis/trans-(η-C₅R′₅)W(CO)₂(CNEt)R. This difference in reactivity is ascribed to the steric demands of the Tp′ ligand, which shields the metal centre from the incoming electrophile.     

Metallorganische verbindungen des 1,2-diethinylbenzols vom typ o-C6H4(CCMR3)2 (M = Si,Ge, Pb)

The preparation of the compounds o-C₆H₄(CCMR₃)₂ (M = Si, Ge, Pb; R = CH₃; M = Pb; R = C₆H₅) is described. Their properties are compared with those of o-C₆H₄(CCSnR₃)₂ (R = CH₃, C₆H₅) and those of their p-isomers. The structures and bonding conditions proposed for these molecules are supported by dipole measurements, mass spectroscopy, IR, Raman, ¹H NMR and ¹³C NMR data.     

Formation of mixed-metal alkoxides mediated by the reactivity of coordinated pinacol: Synthesis and molecular structures of Ce2Ti2(μ3-O)2(μ,η2-OCMe2CMe2O)4(OPri)4(PriOH)2 and of Ce2Nb2(μ3-O)2(μ,η2-OCMe2CMe2O)4(OPri)6

The addition of pinacol to mixtures of titanium and cerium isopropoxides as well as the use of insoluble titanium and cerium pinacolate synthons was investigated as a route to M-Ce (M=Ti, Nb) species. Pinacol was able to promote the formation of mixed-metal species and the first Ce-Ti and Ce-Nb species namely Ce_2Ti(pin)₂(OPrⁱ)₈ and [M₂Ce₂(μ₃-O)₂(μ,η²pin)₄(OPrⁱ)₆H_x] [M=Ti, x=2; M=Nb, x=0; pin=OCMe₂-COMe₂] were isolated and characterized by FT-IR and ¹H NMR. The latter were also characterized by X-Ray diffraction. Their structures are based on a rhombus compressed along the M⋯M direction with 6-coordinated metals. The pinacolate moieties act as bridging-chelating ligands. The metal–oxygen bond lengths vary according to M–O(pin)<M-μ₃–O<Mμ–O(pin)<Ce–OPrⁱ<Ce–μ₃O.     

Säureinduzierte carbin-acylumwandlung

The reaction of dicarbonyl- and carbonyl(trimethylphosphine)(cyclopentadienyl)-carbyne complexes of molybdenum and tungsten η⁵-C₅H₅(CO)_2−n(PMe₃)_nMCR (n = 0, 1; M = Mo, W; R = CH₃, C₆H₅, C₆H₄CH₃, C₃H₅) with protic nucleophiles HX (X = Cl, CF₃COO, CCl₃COO) leads, through a combined protonation/carbon-carbon coupling reaction, to η²-acyl complexes η⁵-C₅H₅(CO)_1−nX₂(PMe₃)_n-M(η²-COCH₂R). The reaction conditions, the results of the spectroscopic measurements and the X-ray structure of η⁵-C₅H₅(CO)(Cl₂)W(η²-COCH₂CH₃) are reported.     

Synthesis and characterisation of a new mixed [Si(IV), Al(III)] μ-oxo-isopropoxide and its acid complexes

Reaction of dimethyldiacetoxysilane with aluminium isopropoxide was carried out in 1 : 2 molar ratio in refluxing cyclohexane and a mixed [Si(IV), Al(III)] μ-oxo-isopropoxide of the composition Me₂SiO₂Al₂(OPrⁱ)₄ was isolated. This compound was characterised by elemental analysis and IR and NMR spectral studies. The tertiary butanol derivative, Me₂SiO₂Al₂(OBu^t)₄, was prepared by alcoholysis. Reactions of this mixed [Si(IV), Al(III)] μ-oxo-isopropoxide with monobasic bidentate carboxylic acids, such as trans-cinnamic acid (HCA) and dihydrocinnamic acid (HDCA) and with dibasic tridentate carboxylic acids such as salicylic acid (H₂SA) and benzilic acid (H₂BA) were also studied. Products of the type Me₂SiO₂Al₂(OPrⁱ)_4-n(L)_n [where HL = trans-cinnamic acid (HCA), dihydrocinnamic acid (HDCA) and n = 1,2,3 or 4] and Me₂SiO₂Al₂(OPrⁱ)_4-2n(L)_n [where H₂L = salicylic acid (H₂SA), benzilic acid (H₂BA) and n = 1 or 2] were isolated and characterised by elemental and spectral studies.     

Reaktivität der M-M-mehrfachbindung in metallcarbonyl-derivaten: VII. Aktivierung von carbodiimiden durch [η-C5H5(CO)2Mo]2 als μ(η1:η2) ligand unter erhalt der Mo—Mo-Dreifachbindung

The reaction of Cp(CO)₂MoMo(CO)₂Cp (Cp = η-C₅H₅) with an excess of carbodiimides RN=C=NR′ results in the substitution of two carbonyl groups to give the new asymmetrically bridged complexes Cp₂(CO)₂Mo₂μ(η¹:η²-RN=C=NR′) with Cp₂(CO)₄Mo₂μ(η¹:η²-CNR) complexes as by products.     

Facile synthesis and reactivity of CO-free monocyclopentadienylvanadium(I) alkyne complexes

Reactive CO-free monocyclopentadienylvanadium(I) complexes CpV(η²-RCCR′)(PMe₃)₂ (R,R′ = Ph,Ph; Ph,Me; Et,Et) can be synthesized by Mg reduction of CpVCl₂(PMe₃)₂ in the presence of free alkyne. Reaction with a second alkyne, or use of diynes in the reduction, produces metallacycles with the metallacyclopentatriene structure.     

Homometallic glycolates containing hydroxyl functionality for anchoring another metal: synthesis and characterization of heterometallic alkoxide–glycolates of Ti and Zr incorporating Al and Nb

Reaction of Ti(OPrⁱ)₄ with 2-methyl-2,4-pentanediol [HOGOH, where G = CMe₂CH₂CH(Me)] in 1?:?3 M ratio under reflux afforded the monomeric [Ti(OGO)(OGOH)₂] (1), which on further reactions with [Al(OPrⁱ)₃] or [Nb(OPrⁱ)₅] in 1?:?1 and 1?:?2 M ratios afforded heterometallic derivatives, [Ti(OGO)₃{M(OPrⁱ)_n?2}] and [Ti(OGO)₃{M(OPrⁱ)_n?1}₂] [where M = Al (n = 3), Nb (n = 5)], respectively. Similar reactions of Zr(OPrⁱ)₄?PrⁱOH with a number of glycols [HOGOH, where G = CH(Me)CH(Me), CMe₂CMe₂, CMe₂CH₂CH(Me)] yielded dimeric [Zr₂(OGO)₂(OGOH)₄]. [Zr₂(OGO)₆{M(OPrⁱ)_n?2}₂] and [Zr₂(OGO)₄(OGOH)₂M(OPrⁱ)_n?2] [M = Al (n = 3), Ti (n = 4), Nb (n = 5)] were prepared by 1?:?2 and 1?:?1 reactions, respectively, of [Zr₂(OGO)₂(OGOH)₄] with Al(OPrⁱ)₃, Ti(OPrⁱ)₄, or Nb(OPrⁱ)₅. Surprisingly, a 1?:?2 reaction of [VO(OPrⁱ)₃] with 2,2-diethyl-1,3-propanediol in benzene followed a different reaction and produced a neutral tetranuclear derivative [V₄(O)₄(μ-OCH₂CEt₂CH₂O)₂(OCH₂CEt₂CH₂O)₄] (18). All of these derivatives were characterized by elemental analysis, molecular weight measurements, FT-IR, and ¹H NMR (and wherever possible, by ²⁷Al or ⁵¹V NMR) spectroscopic studies. The derivatives [Zr₂(OCMe₂CH₂CH(Me)O)₂(OCMe₂CH₂CH(Me)OH)₄] (9 and 18) were additionally characterized by single-crystal X-ray structure analysis.     

The First Butyltin(IV) Homo- and Heterobimetallic Diethanolaminates

Equimolar reactions of BuSn(OPrⁱ)₃ with diethanolamines, RN(CH₂CH₂ OH) ₂ (abbreviated as RdeaH₂, where R = H or Me), afford dimeric isopropoxo-bridged six-coordinate butyltin(IV) complexes [{Bu(η³-Rdea)Sn(μ-OPrⁱ)}₂] (R = H ( 1 ), Me ( 2 )). Interactions between BuSn(OPrⁱ)₃ and diethanolamines (RdeaH₂) in a 1:2 molar ratio yield monomeric derivatives of the type [BuSn(Rdea)(RdeaH)] (R = H ( 3 ), R = Me ( 4 )). These homometallic complexes on 1:1 reactions with an appropriate metal alkoxide form monomeric heterobimetallic complexes of the type [BuSn (Rdea)₂ {M(OR′)_n}] (R = H, M = Al, R′ = Prⁱ, n = 2 ( 5 ); R = H, M = Ti, R = Prⁱ, n = 3 ( 6 ); R = H, M = Zr, R′ = Prⁱ, n = 3 ( 7 ); R = Me, M = Al, R′ = Prⁱ, n = 2 ( 8 ); R = Me, M = Ti, R′ = Prⁱ, n = 3 ( 9 ); R = Me, M = Ge, R′ = Et, n = 3 ( 10 )). The driving force behind this work was (i) to explore the utility of homometal complexes ( 1 ) –( 4 ) in assembling a metal alkoxide fragment via a condensation reaction and (ii) to gain insights into the structures of new compounds by NMR spectral data. All of these derivatives have been characterized by elemental analysis, spectroscopic (IR, NMR; ¹H, ²⁷Al, and ¹¹⁹Sn) studies, and molecular weight measurements. ¹¹⁹Sn NMR spectral studies indicate that both the homometallic ( 3 ) and ( 4 ) and heterobimetallic ( 5 ) – ( 9 ) complexes exist in a solution in an equilibrium of six- and five-coordinated tin(IV) species.     

Synthesis of mononuclear and oligomeric ruthenium(II) acetylides

The complexes trans-[Ru(PMe₃)₄(CCPh)₂] and trans-[Ru(PMe₃)₄(CCC₆H₄C₆H₄CCSnMe₃)₂] have been prepared from the reaction between trans-[Ru(PMe₃)₄Cl₂] and an excess of either Me₃SnCCPh or Me₃SnCCRCCSnMe₃ (R = p-C₆H₄C₆H₄), respectively. However, if only one equivalent of the latter reagent is used the rod-like polymeric species trans-[-Ru(PMe₃)₄CCRCC-]_n can be isolated.     

Synthesis and characterization of some novel triphenylarsenic(V) derivatives of monofunctional bidentate 2,2‐disubstituted benzothiazoline ligands

A series of triphenylarsenic(V) derivatives Ph₃As(OPrⁱ)[SC₆H₄N:C(R)CH₂C(O)R′] have been synthesized by the reactions of triphenylarsenic(V)‐ isoproproxide, Ph₃As(OPrⁱ)₂ with the corresponding 2,2‐disubstituted benzothiazolines of the type (where R = CH₃, R′ = CH₃( 1 ); R = CH₃, R′ = C₆H₅( 2 ); R = CH₃, R′ = 4‐CH₃C₆H₄( 3 ); R = CH₃, R′ = 4‐ClC₆H₄( 4 ); and R = CF₃, R′ = C₆H₅( 5 )) in equimolar ratio in refluxing benzene solution. Molecular weight measurements of these complexes show their monomeric nature in solution. Characterization of these compounds using elemental analyses, molecular weight measurements, and spectral studies (IR as well as NMR (¹H and ¹³C)) shows the monofunctional bidentate nature of the ligands and a hexacoordination around the central arsenic atom in these organoarsenic(V) derivatives. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:76–80, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20233     

Reactivity of unsaturated clusters. Phosphoruscarbon bond activation,hydrogen migration and acetylene interconversion in the reactions of 46-electron (H)Ru3(CO)9(μ-PPh2) with Ph2PCCR (R = Ph,But, Pri). X-ray structure of Ru3(CO)9(μ-PPh2)2(μ3-η2-HCCPh): a new type of 5-vertex, 7-skeletal pair cluster

Novel examples of PC bond activation under mild conditions are reported. The reactions of phosphinoalkynes Ph₂PCCR (R = Ph, Bu^t, Prⁱ) with the formally 46-electron cluster HRu₃(CO)₉(μ-PPh₂) result in PC bond cleavage, transfer of a phosphido group onto the cluster, and transfer of hydride to the acetylide. The new species Ru₃(CO)₇(μ-PPh₂)₂(μ₃-η²-HCCR), of which the derivative with R = Ph has been studied by X-ray diffraction, are representatives of a new class of μ₂-η²-| acetylene cluster with NIDO 5-vertex structures.