Hydroalumination and Hydrogallation Reactions with Tri(ethynyl)silanes – Generation of Compounds with up to Three Coordinatively Unsaturated Aluminium Atoms

Hydroalumination or hydrogallation of tri(ethynyl)silanes, RSi(C≡C‐Ar)₃ ( 1a , R = Ph, Ar = Ph; 1b , R = Me, Ar = Ph; 1c , R = Me, Ar = C₆H₄Me), with the element hydrides H‐EtBu₂ (E = Al, Ga) in stoichiometric ratios of 1:1 to 1:3 at ambient temperature yielded the addition products (PhC≡C)₂(R)Si[(tBu₂E)C=C(H)Ph] ( 2 , R = Ph, E = Ga; 3a , R = Me, E = Al; 3b , R = Me, E = Ga), (PhC≡C)(Me)Si[(tBu₂E)C=C(H)Ph]₂ ( 4a , E = Al, 4b , E = Ga) and (Me)Si[(tBu₂Al)C=C(H)Ar]₃ ( 5 , Ar = Ph; 6 , Ar = C₆H₄Me). Compounds 2 – 4 show a relatively close interaction between the coordinatively unsaturated aluminium or gallium atoms and one of the C_α(≡C) atoms of unreacted alkyne substituents [245 (E = Al) and 266 pm (E = Ga)] that stabilises the kinetically favoured cis addition products with E and hydrogen on the same side of the resulting C=C double bonds. In the absence of these stabilising effects the compounds were found to isomerise to the thermodynamically favoured trans isomers.     

Reactions of cationic vinylidene complexes [Fe{=C=C(R1)R2}(η-C5H5)(dppm)]+[dppm = bis(diphenylphosphino)methane] with nucleophiles: stereoselective synthesis and crystal structure of the alkenyl complex (E)-[Fe{C(H)=C(Me)Ph}(η-C5H5)(dppm)]

The reactivity of the cationic vinylidene complexes [Fe{CC(R¹)R²}(η-C₅H₅(dppm)]⁺ toward different nucleophiles has been investigated. Whereas the disubstituted complexes (R¹ = Me; R² = Ph or ^tBu) are unreactive with water and methanol, the addition of the anion hydride proceeds stereoselectively to give the alkenyl E isomers. The structure of (E)-[Fe{C(H)C(Me)Ph}(η-C₅H₅(dppm)] has been determined by an X-ray diffraction study. Nucleophilic additions to the unsubstituted complex (R¹ = R² = H) have also been examined.     

Reactions of Diazo Compounds with Alkenes Catalysed by [RuCl(cod)(Cp)]: Effect of the Substituents in the Formation of Cyclopropanation or Metathesis Products

The reaction of diazo compounds with alkenes catalysed by complex [RuCl(cod)(Cp)] (cod=1,5‐cyclooctadiene, Cp=cyclopentadienyl) has been studied. The catalytic cycle involves in the first step the decomposition of the diazo derivative to afford the reactive [RuCl(Cp){?C(R¹)R²}] intermediate and a mechanism is proposed for this step based on a kinetic study of the simple coupling reaction of ethyl diazoacetate. The evolution of the Ru–carbene intermediate in the presence of alkenes depends on the nature of the substituents at both the diazo N₂?C(R¹)R² (R¹, R²=Ph, H; Ph, CO₂Me; Ph, Ph; C(R¹)R²=fluorene) and the olefin substrates R³(H)C?C(H)R⁴ (R³, R⁴=CO₂Et, CO₂Et; Ph, Ph; Ph, Me; Ph, H; Me, Br; Me, CN; Ph, CN; H, CN; CN, CN). A remarkable reactivity of the complex was recorded, especially towards unstable aryldiazo compounds and electron‐poor olefins. The results obtained indicate that either cyclopropanation or metathesis products can be formed: the first products are favoured by the presence of a cyano substituent at the double bond and the second ones by a phenyl.     

Mercury(II) complexes of new bidentate phosphorus ylides: synthesis,spectra and crystal structures

The reaction of dppm (1,1-bis(diphenylphosphino)methane) with 2-bromo-4-phenylacetophenone and benzyl bromoacetate in chloroform produces new phosphonium salts, [Ph₂PCH₂PPh₂CH₂C(O) C₆H₄Ph]Br (I) and [Ph₂PCH₂PPh₂CH₂COOCH₂Ph]Br (II). By allowing the phosphonium salts to react with the appropriate base, the bidentate phosphorus ylides, Ph₂PCH₂PPh₂=C(H)C(O)C₆H₄Ph (III) and Ph₂PCH₂PPh₂=C(H)C(O)OCH₂Ph (IV), were obtained. The reaction of these ligands with mercury(II) halides in dry methanol led to the formation of the mononuclear complexes {HgX₂[(Ph₂PCH₂PPh₂C(H)C(O)C₆H₄Ph)]} (X = Cl (V); X = Br (VI); X = I (VII)) and {HgX₂[(Ph₂PCH₂PPh₂C(H)COOCH₂Ph)]} (X = Cl (VIII); X = Br (IX); X = I (X)). The FTIR and ¹H, ³¹P and ¹³C NMR spectra were studied. The structure of compound III was unequivocally determined by the single-crystal X-ray diffraction technique. Single-crystal X-ray analysis of the {HgBr₂[(Ph₂PCH₂PPh₂C(H)C(O)C₆H₄Me)]} complex (XI) revealed the presence of a mononuclear complex containing the Hg atom in a distorted tetrahedral environment. In all complexes, the ylides referred to above were coordinated through the ylidic carbon and the phosphine atom.     

Enol ethers and acetals: acylation with dichloroacetyl,acetyl and benzoyl chloride in ionic liquid medium

Synthesis of 4-alkoxy-1,1-dichloro-3-alken-2-ones [CHCl₂C(O)C(R²)C(R¹)-OR, where R, R¹, R² = Et, H, H; Me, Me, H; Et, H, Me; Me, –(CH₂)₂–; Me, –(CH₂)₃–; Et, Et, H; Et, Bu, H; Et, i-Pr, H; Et, i-Bu, H; Me, Ph, H; Me, thien-2-yl, H] from acylation of enol ethers and acetals with dichloroacetyl chloride, in ionic liquid ([BMIM][BF₄] or [BMIM][PF₆]) is reported. The synthesis of alkenones [R³–C(O)C(R²)C(R¹)-OR], where R/R¹/R²/R³ = Et/H/H/Ph, t-Bu/H/H/Ph, Me/-(CH₂)₄/Ph, Me/-(CH₂)₄/Me] from the reaction of enol ethers with benzoyl chloride or acetyl chloride, in ionic liquid [BMIM][BF₄], is also reported. Last products are described for the first time.     

Electrical conductivity of FeCl3-doped poly(alkynylsilane)s

The electrical conductivies of the poly(alkynylsilane)s [C-SiR¹R²-CC-Z]_n (R¹R²Si = Ph₂Si, ⁿOct(Me)Si, 2,3.4,5-tetraphenyl-1-sila-2,4-cyclopentene; Z = (hetero)aromatic group) doped with FeCl₃ are found to lie in the range 10⁻⁹ < α < 10⁻³ S cm⁻¹, whereas those of the undoped polymers are less than 10⁻¹⁰ S cm⁻¹. The presence of Ph groups on Si leads to incresed conductivity.     

Chemistry of Fischer-type rhenacyclobutadiene complexes. II. Reactions with alkynes and sulfonium ylides, and rearrangements induced by nitriles and pyridine

Further investigations into the chemistry of the rhenacyclobutadiene complexes (CO)₄Re(η²-C(R)C(CO₂Me)C(X)) (1: R=Me, X=OEt (1a), O(CH₂)₃CCH (1b), NEt₂ (1c); R=CHEt₂, X=OEt (1d); R=Ph, X=OEt (1e)) are reported. Reactions of 1 with alkynes at reflux temperature of toluene and at ambient temperature either under photochemical conditions or in the presence of PdO yield ring-substituted η⁵-cyclopentadienylrhenium tricarbonyl complexes, 2. The symmetrical alkynes R^′CCR^′ (R^′=Ph, Me, CO₂Me) afford the pentasubstituted complexes (η⁵-C₅(Me)(CO₂Me)(OEt)(Ph)(Ph))Re(CO)₃ (2d), (η⁵-C₅(Me)(CO₂Me)(OEt)(Me)(Me))Re(CO)₃ (2e), (η⁵-C₅(Me)(CO₂Me)(OEt)(CO₂Me)(CO₂Me))Re(CO)₃ (2f), and (η⁵-C₅(Me)(CO₂Me)(NEt₂)(CO₂Me)(CO₂Me))Re(CO)₃ (2i) on reaction with the appropriate 1, whereas the unsymmetrical alkynes R^′CCR″ (R^′=Ph; R″=H, Me) give either only one, (η⁵-C₅(Me)(CO₂Me)(OEt)(Ph)H)Re(CO)₃ (2a)), or both, (η⁵-C₅(Me)(CO₂Me) (OEt)(Ph)(Me))Re(CO)₃ (2b) and (η⁵-C₅(Me)(CO₂Me)(OEt)(Me)(Ph))Re(CO)₃ (2c), (η⁵-C₅(Ph)(CO₂Me)(OEt)(Ph)H)Re(CO)₃ (2g) and (η⁵-C₅(Ph)(CO₂Me)(OEt)(H)(Ph))Re(CO)₃ (2h), of the possible products of [3 + 2] cycloaddition of alkyne to η²-C(R)C(CO₂Me)C(X). Thermolysis of (CO)₄Re(η²-C(Me)C(CO₂Me)C(O(CH₂)₃CCH)) (1b) containing a pendant alkynyl group proceeds to (η⁵-C₅(Me)(CO₂Me)(O(CH₂)₃)H)Re(CO)₃ (2j), a η⁵-cyclopentadienyl-dihydropyran fused-ring product. Competition experiments showed that each of PhCCH and MeO₂CCCCO₂Me reacts faster than PhCCPh with 1a. The results with unsymmetrical alkynes are rationalized by steric properties of substituents at the CC and ReC bonds and by a preference of ReC(Me) over ReC(OEt) to undergo alkyne insertion. A mechanism is proposed that involves substitution of a trans CO by alkyne in 1, insertion of alkyne into ReC bond to give a rhenabenzene intermediate, and collapse of the latter to 2. Complexes 1a and 1d undergo rearrangement in MeCN at reflux temperature to give rhenafuran-like products, (CO)₄Re(κ²-OC(OMe)C(CHCR₂)C(OEt)) (R=H (3a) or Et (3b)). The reaction of 1d also proceeds in EtCN, PhCN, and t-BuCN at comparable temperature, but is slower (especially in t-BuCN) than in MeCN. In pyridine at reflux temperature, 1a undergoes a similar rearrangement, with CO substitution, to give (CO)₃(py)Re(κ²-OC(OMe)C(CHCEt₂)C(OEt)) (4). A mechanism is proposed for these reactions. The sulfonium ylides Me₂SCHC(O)Ph and Me₂SC(CN)₂ (Me₂SCRR^′) react with 1a in acetonitrile at reflux temperature by nucleophilic addition of the ylide to the ReC(Me) carbon, loss of Me₂S, and rearrangement to a rhenafuran-type structure to yield (CO)₄Re(κ²-OC(OMe)C(C(Me)CRR^′)C(OEt)) (R=H, R^′=C(O)Ph (5a); R=R^′CN (5b)). All new compounds were characterized by a combination of elemental analysis, mass spectrometry, and IR and NMR spectroscopy.     

Diastereoselective addition of organomanganese compounds to α-alkoxysubstituted propanals

Reactions of organomanganese compounds R¹MnI (R¹ = Ph, 4-MeC₆H₄-, Me, Bu,n-C₇H₁₅, BuC=C, PhOC), prepared from R¹Li and Mnl₂ in Et₂O, with aldehydes MeCH(OR²)CHO (R² = CH₂Ph, CH₂OMe, CH₂OCH₂Ph) affordthreo-alcohols MeCH(OR²)CH(OH)R¹ with high diastereoselectivity. The interactions of phenylmanganese derivatives PhMnX (X = Cl, Br, I), Ph₂Mn, and Ph₃MnLi with 2-benzyloxypropanal were used as examples for studying the influence of reagent and solvent nature on addition diastereoselectivity.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 178–181, January, 1993.     

Die Reaktion von Ph3AsCl2 mit Acetonitril. Kristallstrukturen von [Ph3AsNC(Me)C(AsPh3)CN]+Cl– und des Palladium‐Molekülkomplexes [Ph3AsNC(Me)C(AsPh3)CN–PdCl3]

The Reaction of Ph₃AsCl₂ with Acetonitrile. Crystal Structures of [Ph₃AsNC(Me)C(AsPh₃)CN]⁺Cl^– and of the Palladium Molecular Complex [Ph₃AsNC(Me)C(AsPh₃)CN–PdCl₃] In the presence of potassium hydride the reaction of Ph₃AsCl₂ with acetonitrile leads to [Ph₃AsNC(Me) · C(AsPh₃)CN]⁺Cl^– ( 1 ), which is characterized by its infrared spectrum and by a crystal structure analysis. 1 can be explained as an insertion reaction of acetonitrile into an ylidic As–C bond of the primarily formed [(Ph₃As)₂CCN]Cl. 1 : Space group P1, Z = 2, lattice dimensions at –70 °C: a = 991.9(1), b = 1255.2(1), c = 1381.3(1) pm, α = 81.64(1)°, β = 80.12(1)°, γ = 78.17(1)°; R₁ = 0.051. 1 reacts with palladium(II) chloride to give the molecular complex [Ph₃AsNC(Me)C(AsPh₃)CN–PdCl₃] ( 2 ) with zwitterionic structure. The fragment {PdCl₃^–} is terminally bonded at the nitrogen atom of the CCN group of the cation of 1 in a linear arrangement CCNPd. 2 · CH₃CN: Space group P2₁, Z = 2, lattice dimensions at –90 °C: a = 1079.2(1), b = 1261.5(1), c = 1560.9(1) pm; β = 110.20(1)°; R₁ = 0.0283.     

Complexation and Versatile Reactivity of a Highly Lewis Acidic Cationic Mg Complex with Alkynes and Phosphines

[(BDI)Mg⁺][B(C₆F₅)₄⁻] ( 1 ; BDI=CH[C(CH₃)NDipp]₂; Dipp=2,6-diisopropylphenyl) was prepared by reaction of (BDI)MgnPr with [Ph₃C⁺][B(C₆F₅)₄⁻]. Addition of 3-hexyne gave [(BDI)Mg⁺ ⋅ (EtC≡CEt)][B(C₆F₅)₄⁻]. Single-crystal X-ray analysis, NMR investigations, Raman spectra, and DFT calculations indicate a significant Mg-alkyne interaction. Addition of the terminal alkynes PhC≡CH or Me₃SiC≡CH led to alkyne deprotonation by the BDI ligand to give [(BDI-H)Mg⁺(C≡CPh)]₂ ⋅ 2 [B(C₆F₅)₄⁻] ( 2 , 70 %) and [(BDI-H)Mg⁺(C≡CSiMe₃)]₂ ⋅ 2 [B(C₆F₅)₄⁻] ( 3 , 63 %). Addition of internal alkynes PhC≡CPh or PhC≡CMe led to [4+2] cycloadditions with the BDI ligand to give {Mg⁺C(Ph)=C(Ph)C[C(Me)=NDipp]₂}₂ ⋅ 2 [B(C₆F₅)₄⁻] ( 4 , 53 %) and {Mg⁺C(Ph)=C(Me)C[C(Me)=NDipp]₂}₂ ⋅ 2 [B(C₆F₅)₄⁻] ( 5 , 73 %), in which the Mg center is N,N,C-chelated. The (BDI)Mg⁺ cation can be viewed as an intramolecular frustrated Lewis pair (FLP) with a Lewis acidic site (Mg) and a Lewis (or Brønsted) basic site (BDI). Reaction of [(BDI)Mg⁺][B(C₆F₅)₄⁻] ( 1 ) with a range of phosphines varying in bulk and donor strength generated [(BDI)Mg⁺ ⋅ PPh₃][B(C₆F₅)₄⁻] ( 6 ), [(BDI)Mg⁺ ⋅ PCy₃][B(C₆F₅)₄⁻] ( 7 ), and [(BDI)Mg⁺ ⋅ PtBu₃][B(C₆F₅)₄⁻] ( 8 ). The bulkier phosphine PMes₃ (Mes=mesityl) did not show any interaction. Combinations of [(BDI)Mg⁺][B(C₆F₅)₄⁻] and phosphines did not result in addition to the triple bond in 3-hexyne, but during the screening process it was discovered that the cationic magnesium complex catalyzes the hydrophosphination of PhC≡CH with HPPh₂, for which an FLP-type mechanism is tentatively proposed.     

Deoxygenation of nitro and nitrosoaromatics by photolysis with t-BuHgl/Kl. Regiochemistry of tert-Butyl radical addition to nitrosoaromatics [1]

Photolysis of nitroaromatics in the presence of t-BuHgI/KI in Me₂SO or DMF leads to products formed by t-Bu^• addition to the nitroso compounds. Similar products are formed in the dark in the presence of K₂S₂O₈. Nitroso or nitrobenzene is converted into N,O-di-tert-butylphenylhydroxylamine by a process involving N-tert-butylphenylhydroxylamine as an intermediate. In the presence of PTSA and KI, N-tert-butylphenylhydroxylamine predominates in Me₂SO, but in DMF, the phenylhydroxylamine is reduced to N-tert-butylaniline. In a similar fashion, o-nitrosotoluene is converted into o-MeC₆H₄N(Bu-t)OBu-t, o-MeC₆H₄N(Bu-t)OH, and o-MeC₆H₄NHBu-t. p-Nitroso-N,N-dimethylaniline forms the N,O-di-tert-butylated derivative in the absence of acid but in the presence of PTSA/KI yields p-Me₂NC₆H₄NHBu-t. Excellent yields of the N,O-di-tert-butylated arylhydroxylamines are formed in DMF from the nitroaromatics with para Me₂N, OH, I, Br, Cl, and ortho Ph or PhNH substituents. Nitrobenzenes with p-CHO, p-PhCO, or p-CN substituents are deoxygenated to the nitroso compounds which react with t-Bu^• to form the tert-butoxyamino radicals (ArṄOBu-t). In Me₂SO, the amino radicals react to form ArN(HgI)OBu-t compounds which condense with the nitroso compounds to yield the azoxy compounds. With the p-CN substituent, the azoxy compound is subsequently deoxygenated and tert-butylated to yield p-NCC₆H₄N(Bu-t)NHC₆H₄CN-p. In the presence of PTSA/KI, the amino radicals are reduced to p-Y-ArNHOBu-t (Y = PhCO, CN). The compounds Y-ArN(Bu-t)OBu-t undergo photochemical degradation to yield Y-ArNHBu-t with Y = p-PhCO or p-CN in a reaction that is inhibited by I⁻. With PTSA/H₂O/KI in Me₂SO, p-Me₂NC₆H₄N(t-Bu)OBu-t is converted into 4-(N-tert-butylimino)-2,5-cyclohexadien-1-one, p-Me₂NC₆H₄NHBu-t, and p-tert-butylamino-m-tert-butoxy-N,N-dimethylaniline. o-MeC₆H₄N(Bu-t)OH reacts with PTSA/KI to form o-MeC₆H₄N(Bu-t)H in DMF or a mixture of the aniline and 4-(N-tert-butylimino)-3-methyl-2,5-cyclohexadien-1-one in Me₂SO. In the absence of KI, only the cyclohexadienone is formed in Me₂SO.     

Pyridine-Stabilized Cationic Silanethione Tungsten Complexes: Synthesis,Structures, and Reactivity

Silanethione compounds, R₂Si=S, have been recognized as highly reactive species. One reliable way to stabilize silanethione is its coordination to transition metal fragments to convert silanethione-coordinated transition metal complexes. Herein, we report the synthesis, structure, and reactivity of a second cationic silanethione tungsten complex [Cp*(OC)₃W{S=SiR₂(py)}]TFPB (R=Me ( 5 a ), Ph ( 5 b ), Cp*: η⁵-C₅Me₅, py: pyridine, and TFPB⁻: [B{3,5-(CF₃)₂C₆H₃}₄]⁻). Complex 5 was obtained by H⁻ abstraction from the Si atom in the corresponding silylsulfanyl complex Cp*(OC)₃W(SSiR₂H) ( 4 ) with Ph₃CTFPB, followed by the addition of pyridine. The reaction of 5 with PhNCS and PMe₃ produced [Cp*(OC)₃W{SSiR₂N(Ph)C(PMe₃)₂}]TFPB (R=Me ( 6 a ), Ph ( 6 b )) via the elimination of pyridine and the addition of the 1,3-dipolar species PhNC(PMe₃)₂ ( A ) to the Si atom.     

Extraction of f-elements from nitric acid solutions with phosphoryl ketones

The extraction ability and selectivity of a series of phosphoryl ketones Ph₂P(O)CH₂C(O)Me, and Ph₂P(O)CRR’CH₂C(O)Me (R = H, Me; R’ = H, Me, n-C₅H₁₁, Ph, 2-thienyl, 2-furyl) towards trivalent lanthanides (La^III, Nd^III, Ho^III, Yb^III) and actinides (U^VI, Th^IV) were studied. The efficiency and selectivity of the new ligands in the extraction of f-elements from nitric acid solutions into chloroform were compared to those of model phosphine oxide Ph₂P(O)Bu and known extractants: tributyl phosphate (BuO)₃P(O), trioctylphosphine oxide (C₈H₁₇)₃P(O), and carbamoylmethyl phosphine oxide Ph₂P(O)CH₂C(O)NBu₂.     

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.     

Bis(trimethylsilyl)diazene revisited. Density functional theory (DFT) calculations of nitrogen NMR parameters of some azo‐compounds

Calculations of nitrogen NMR parameters [chemical shifts δN and indirect nuclear spin–spin coupling constants J(N,N), J(N,¹³C), J(²⁹Si,N)] of noncyclic azo‐compounds R¹ NN R² (R¹, R² = H, Me, Ph, SiH₃, SiMe₃) and cyclic azo‐compounds [NNCH₂, NN(CH₂)₃ NN(CH₂)₂SiH₂, and NN(SiH₂CH₂SiH₂)] by density functional theory (DFT) methods [B3LYP/6‐311+G(d,p) level of theory] provide data in reasonable agreement with experimental values. The influence of cis‐ and trans‐geometry is reflected by the calculations, and amino‐nitrenes are also included for comparison. The spin–spin coupling constants are analyzed with respect to contact (Fermi contact term, FC) and non‐ contact contributions (paramagnetic and diamagnetic spin‐orbital terms, PSO and DSO, and spin‐dipole term, SD). Bis(trimethylsilyl)diazene 6a can be generated by an alternative method, using the reaction of bis(trimethylsilyl)sulfur diimide with bis‐ (trimethylsilyl)amino‐trimethylsilylimino‐phosphane. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:84–91, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20075     

Introduction of a phosphorus ylide moiety into [η-(ω-hydroxy)alkenyl]chromium(0) carbene complexes with Ph3PCCO and consecutive Wittig alkenations with 2-alkynals. Part 12: the chemistry of metallacyclic alkenylcarbene complexes

Ketenylidenetriphenylphosphorane, Ph₃PCCO (2), reacts selectively with the ω-hydroxy group of the alkene-carbene complexes (OC)₄CrC(η²-NMeCH₂CHCHCH₂OH)R¹ (1) (R¹=Me: (1a); Ph: (1b)) to give the acyl ylide terminated complexes (OC)₄CrC[(4,5-η²)-NMeCH₂CHCHCH₂O(O)C-CHPPh₃]R¹ (3) (R¹=Me: (3a); Ph: (3b)). Complexes 3 undergo Wittig alkenation reactions with aldehydes such as 2-alkynals, R²-CC-CHO (R²=H, SiMe₃, Ph), to give the corresponding 4Z, 9E-dien-11-ynes (OC)₄CrC[(4,5-η²)-NMeCH₂CHCHCH₂O(O)C-CHCH-CC-R²]R¹ (4-6) (R¹=Me, R²=H, SiMe₃, Ph: (4a-6a); R¹=Ph, R²=H, SiMe₃, Ph: (4b-6b)). All complexes were characterized in solution by one- and two-dimensional NMR spectroscopy (¹H, ¹³C, ²⁹Si, ³¹P, ¹H/¹H COSY, ¹³C/¹H HETCOR, ³¹P/³¹P EXSY).     

Vibrational,NQR and thermogravimetric study of complexes between triphenyl group VB compounds and mercuric halides

The synthesis, identification, vibrational (IR—FIR), NQR and thermal (TGA) study of a series of donor-acceptor complexes (Ph₃E^VB)_n(HgX₂)_m (E^VB = As, Sb, Bi;Ph = phenyl; X = Cl, Br, I; n/m = 2/2, 2/1) is reported. Elemental analysis proved that the aimed stoichiometry is only obtained for the (Ph₃Sb)_n(HgI₂)_m and (Ph₃As)_n(HgX₂)_m complexes, (Ph₃As)₂(HgI₂)₂ excepted. In all other cases a much lower Ph₃E^VB content is found. Assignments for the skeletal vibrational frequencies are based upon a “tetrahedral” C_2v and a “bridge-like” C_2h symmetry for (Ph₃E^VB)₂HgX₂ and (Ph₃E^VB)₂(HgX₂)₂ complexes, respectively. Changes in the electron distribution of the Hg—X bond dominate the halogen NQR frequency. TG curves are characterized by a single step mass loss and the absence of any residue suggests volatilization rather than decomposition.     

Phenyllead(IV) diorganophosphinodithioates,PhnPb(S2PR2)4−n. Synthesis,spectroscopic characterization,and NMR study of the redistribution/decomposition of diphenyllead(IV) derivatives

Tri- and diphenyllead(IV) diorganophosphinodithioates, Ph_nPb(S₂PR₂)_4−n (n = 2 and 3; R = Me, Et, Ph) were prepared by reacting the corresponding organolead(IV) chloride with the sodium or ammonium salt of the phosphinodithioic acid. The title compounds were investigated by infrared, ¹H and ³¹P NMR, and mass spectroscopy, and possible structures were proposed. The diphenyllead(IV) phosphinodithioates, Ph₂Pb(S₂PR₂)₂, undergo decomposition on standing or on moderate heating, the least stable being the ethyl derivative. The process was monitored by using ¹H and ³¹P NMR spectroscopy, and a reaction pathway leading to Ph₃PbS₂PR₂, Pb(S₂PR₂)₂, and R₂P(S)SPh was established.     

REACTIONS OF A PHOSPHORANIMINE ANION WITH SOME ORGANIC ELECTROPHILES

Abstract

The reactions of a variety of electrophiles with the N-silyl-P-trifluoroethoxyphosphoranimine anion Me₃Sin°P(Me)(OCH₂CF₃)CH^? ₂ (1a), prepared by the deprotonation of the dimethyl precursor Me₃SiN[dbnd]P(OCH₂CF₃)Me₂ (1) with n-BuLi in Et₂O at-78°C, were studied. Thus, treatment of 1a with alkyl halides, ethyl chloroformate, or bromine afforded the new N-silylphosphoranimine derivatives Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂R [2: R = Me, 3: R = CH₂Ph, 4: R = CH[sbnd]CH₂, 5: R = C(O)OEt, and 6: R = Br]. In another series, when 1a was allowed to react with various carbonyl compounds, 1,2-addition of the anion to the carbonyl group was observed. Quenching with Me₃SiCl gave the O-silylated products Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂°C(OSiMe₃)R¹R² [7: R ¹ = R ² = Me; 8: R ¹ = Me, R ² = Ph; 9: R¹ = Me, R ² = CH[sbnd]CH₂; and 10: R ¹ = H, R ² = Ph]. Compounds 2–10 were obtained as distillable, thermally stable liquids and were characterized by NMR spectroscopy (¹H, ¹³C, and ³¹P) and elemental analysis.     

Interaction between cobaltocenium and decamethylcobaltocenium salts and Ph3ELi (E = Si,Ge, Sn)

Reactions of cobaltocenium salts [(C₅R₅)₂Co]PF₆ (R = H, Me) with Ph3ELi (E = Si, Ge, Sn) and with Ph₂SbLi mainly follow two pathways (nucleophilic addition and one-electron reduction), yielding cobalt cyclopentadiene-cyclope ntadienyl complexes (⁴-Ph₃EC₅R₅)(⁵-C₅R₅)Co (R = H, E = Si, Ge, Sn; R = Me, E = Si) and cobaltocenes (C₅R₅)₂Co (R = H, Me), respectively. The contribution of nucleophilic addition of Ph₃ELi decreases in the order of elements Si > Ge > Sn and when hydrogen atoms are replaced by methyl groups in the initial cobaltocenium salt. Thermal decomposition of cobalt cyclopentadiene-cyclopentadienyl complexes results in substituted cobaltocenes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 10, pp. 2557–2560, October, 1996.