A radical mechanism of the reaction of molybdenum carbonyl complexes with bis(triethylgermyl)mercury

The reaction of [Cp(CO)₃Mo]₂ with (Et₃Ge)₂Hg occurs in toluene and THF by a radical mechanism. The interaction between [Cp(CO)₃Mo]₂Hg and (Et₃Ge)₂Hg has a radical character only in THF. The formation of Cp(CO)₃MoH at the first stage of these reactions substantially affects the further course of the process.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1648–1650, September, 1993.     

Metallkomplexe mit anionischen Liganden von Elementen der 4. Hauptgruppe. IX. Zum komplexchemischen Verhalten von Trichlorstannid-und Trichlorgermid-Ionen gegenüber Komplexen von Übergangsmetallen in niedrigen Oxydationsstufen

Metal Complexes with Anionic Ligands of the Main Group IV Elements. IX. Reactions of Trichlorostannide and Trichlorogermide Ions with Complexes of Transition Metals in Low Oxidation States Carhonyl trichlorostannido- and carbonyl trichlorogermido-metalate complexes have been synthesized both by photochemical and thermical substitution reactions of [ECl₃]^? ions (E = Sn, Ge) with M(CO)₆, (M = Cr, Mo, W), Fe(CO)₅ Fe₃(CO)₁₂, Co₂(CO)₈, as well as with the metalcarbonyl derivatives (π-arene)M(CO)₃, (M = Cr, Mo), (h⁵-C₅,H₅,)V(CO)₄, Mn(CO)₅,Cl, Co(NO)(CO)₃, and Fe(NO)₂,(CO)₂. Mainly the bonding properties of the [ECl₃]^? ligands are discussed by means of i.r. spectroscopic investigations. The progress of the reactions and the necessary reaction conditions show that the nucleophilic properties oft both anions [ECl₃]^? are unexpectedly small. The slightly weaker hasicity of [SnCl₃]^? compared with [GeC1₃]^? arreared, when both anions were reacted with Co₂,(CO)₈, forming the substitution product. [Co₂,(CO)₇,SnCl₃]^? and the products of a “base reaction” Cl₃GcCo(CO)₄, and [Co(CO)₄]^?.     

Isolation of a Diylide‐Stabilized Stannylene and Germylene: Enhanced Donor Strength through Coplanar Lone Pair Alignment

The preparation of the first stable diylide‐substituted stannylene and germylene ( Y₂E, with E=Ge, Sn and Y=[PPh₃‐C‐SO₂Tol]^?) is reported. The synthesis is easily accomplished in one step from the sulfonyl‐substituted metalated ylide YNa and the corresponding ECl₂ precursors. Y₂Ge and Y₂Sn exhibit unusual structures in the solid state and in solution, in which the three adjacent lone pairs in the C‐E‐C linkage are arranged coplanar to each other. As shown by DFT studies, this bonding situation is preferred over the typical π‐donation from the ligands into the empty p‐orbital at the metal due to the strong anion‐stabilizing ability of the sulfonyl groups in the ylide backbone and their additional coordination to the metal. The alignment of the three lone pairs leads to a remarkable boost of the HOMO energy and thus of the donor strengths of the tetrylenes. Hence, Y₂Ge and Y₂Sn become stronger donors than their diamino or diaryl congeners and comparable to cyclic alkyl(amino)carbenes. First reactivity studies confirm the high reactivity of Y₂Ge and Y₂Sn , which for example undergo an intramolecular C?H activation reaction via metal–ligand cooperation.     

9-Triptycenyl complexes of group 13 and 15 halides and hydrides

The reactions of 9-lithiotriptycene with AlCl₃, GaCl₃ and InBr₃ have been carried out and have yielded the complexes, [(tript)AlCl₂(OEt₂)], [(tript)GaCl₂(THF)] and [(tript)InBr(μ-Br)₂Li(OEt₂)₂], tript=9-triptycenyl. The latter two complexes have been structurally characterised. The corresponding reactions of 9-lithiotriptycene with ECl₃ (E=P, As, Sb or Bi) afforded the complexes, [(tript)ECl₂], of which all but the phosphorus compound have been crystallographically authenticated. In addition, the high yield syntheses of the thermally stable primary pnictanes [(tript)EH₂] (E=As, Sb) have been achieved by reaction of the relevant halide complex with LiAlH₄. The X-ray crystal structure of the antimony hydride complex is reported.     

Synthesis,molecular structures and PMR spectra of heteronuclear niobocene derivatives containing a niobium-tin bond

Treatment of niobocene carbonylhydride, Cp₂Nb(CO)H (I), with Ph_nSnCl_4?n and Et₂SnCl₂ in THF in the presence of Et₃N leads to the respective heteronuclear complexes Cp₂Nb(CO)SnR_nCl_3?n (R = Ph, n = 3 ÷ 1 (II–IV), R = Et, n = 2 (V)). Treatment of II with HCl in ether gives Cp₂Nb(CO)SnCl₃ (VI). Complex VI and its analog (MeC₅H₄)₂Nb(CO)SnCl₃ (VIII) were prepared by an alternative synthesis using direct reaction of I or (MeC₅H₄)₂Nb(CO)H with an equimolar quantity of SnCl₄ in THF in the presence of Et₃N. Complex VI is also generated by insertion of SnCl₂ into the NbCl bond in Cp₂Nb(CO)Cl (VII). X-Ray analysis of complexes II and VIII was performed: for II, space group P2₁/n, a = 10.1021(21), b = 17.4633(32), c= 14.2473(29) Å, β = 95.578(16)°, Z = 4; for VIII, space group. P2₁/n, a= 8.9369(15), b = 13.3589(12), c = 13.9292(20) Å, β = 99.490(14)°, Z = 4. The NbSn bond in VIII (2.764(9) Å) is shorter than that in II (2.825(2) Å). In both cases the NbSn bond is significantly shorter than the sum of Nb and Sn covalent radii (1.66 + 1.40 = 3.06 Å). It is probably partly multiple in character owing to an additional interaction of the lone electron pair of the Nb^III ion (d² configuration) with the antibonding Sn orbitals. The PMR spectra of II–VI exhibit two satellites of the singlet of C₅H₅ protons because of HSn¹¹⁷ and HSn¹¹⁹ spin-spin coupling (SSC). The SSC constant correlates with the number of electronegative chlorine atoms on the Sn atom.     

Carbonylniobium chemistry : III. Tricarbonyl-η-cyclopentadienylhydridoniobate(−I): Preparation and Nb NMR spectroscopic invesitgation of [Et4N][CpNb(H)(CO)3] and [Et4N][CpNb(D)(CO)3]

The complexes [Et₄N][CpNb(X)(CO)₃] (X = H, D) have been prepared by reduction of CpNb(CO)₄ in THF and subsequent treatment with CX₃CN/[Et₄N]Cl. There is IR-spectroscopic evidence for the formation of an intermediate [CpNb(CO)₃]²⁻. The isotope effect (¹H, ²H) on the ⁹³Nb shielding (6 ppm) and the temperature dependencies of δ(⁹³Nb) (0.25 ppm/deg) and the line widths are discussed.     

Facile synthesis of rhodium and iridium complexes bearing a [PEP]-type ligand (E = Ge or Sn) via E-C bond cleavage

Rhodium and iridium complexes bearing a tridentate [PEP] type ligand ([PEP] = {o-(Ph(2)P)C(6)H(4)}(2)E(Me); E = Ge or Sn) were synthesized through the phosphine exchange reaction accompanied by selective E-C bond cleavage. The ligand precursors {o-(Ph(2)P)C(6)H(4)}(2)EMe(2) (E = Ge or Sn) were readily obtained in excellent yields by treating {o-(Ph(2)P)C(6)H(4)}(2)Li with 0.5 equivalents of Me(2)ECl(2). Tris(triphenylphosphine)rhodium(i) carbonyl hydride M(H)(CO)(PPh(3))(3) (M = Rh, Ir) cleaved one of the E-Me bonds of {o-(Ph(2)P)C(6)H(4)}(2)EMe(2) exclusively to afford the trigonal bipyramidal (TBP) complexes, [PEP]M(CO)(PPh(3)). Square-planar rhodium complexes [PEP]Rh(PPh(3)) were also prepared from the reactions of tetrakis(triphenylphosphine)rhodium(i) hydride Rh(H)(PPh(3))(4) with {o-(Ph(2)P)C(6)H(4)}(2)EMe(2). Further, the trans influence of group 14 elements E (E = Si, Ge, Sn) in [PEP]Rh(PPh(3)) is discussed in terms of the (1)J(Rh-P) coupling constants, indicating that E exhibited a stronger trans labilizing effect in the order Sn < Ge < Si.     

The synthesis of some (pentafluorophenyl)germanium compounds

Tris(pentafluorophenyl)germanium bromide reacts with lithium aluminium hydride or triethylgermane to give tris(pentafluorophenyl)germane. On reaction with HgR₂ [where R = Et, Et₃Ge and (Me₃Si)₂N] or reaction with diethylcadmium, the latter gave the hitherto unknown [(C₆F₅)₃Ge]₂Hg or [(C₆F₅)₃Ge]₂Cd. The germylmercurial compound could also be prepared by reaction of metallic mercury with [(C₆F₅)₃Ge]₂Cd and by exchange of bis(triethylgermyl)mercury with (C₆F₅)₃GeBr. Some reactions of bis[tris(pentafluorophenyl)germyl]mercury are discussed.     

H-Ge bond activation by tungsten carbonyls: An experimental and theoretical study

The activation of the Ge-H bond and the formation of several hydride complexes, characterized by high-field resonances, have been detected during the ¹H NMR spectroscopy monitoring of the photochemical reaction of Et₃GeH and Et₂GeH₂ with W(CO)₆ and the norbornadiene complex [W(CO)₄(η⁴-nbd)]. The activation of the Ge-H bond of triethylgermane in the photochemical reactions of tungsten(0) complexes has been applied in the hydrogermylation of norbornadiene (nbd), which leads to the formation of endo-triethylgermylnorbornene as the major product. The complex [{W(μ-η²-H-GeEt₂)(CO)₄}₂] has been fully characterized by NMR spectroscopy and by a single-crystal X-ray diffraction study. Evidence for the hydride ligand of the W(μ-η²-H-GeEt₂) group has been provided by ¹H NMR spectroscopy (δ = −9.02, ¹J_H-W = 31 Hz) and by DFT calculations. A DFT study of the structural properties and ¹H NMR chemical shifts of several possible intermediate σ and hydride complexes formed during the photochemical reaction of W(CO)₆ and Et₂GeH₂ has been performed.     

New heteroorganic betaines containing the (+)E15—C—E14—X(–) and (+)E15—C—E14(–) structural fragments (E15 = P,As; E14 = Si,Ge, Sn; X = C,S, O,NR)

The review surveys the data on the reactions of phosphorus and arsenic ylides with compounds containing E=X bonds (E = C, Si, Ge, or Sn; X = C or S), cyclic oligomers (R₂ES)_n (n = 2 or 3), and heavier analogs of carbenes. These reactions give rise to two new classes of heteroorganic betaines containing the ⁽⁺⁾E¹⁵—C—E¹⁴—X^(–) (I) and ⁽⁺⁾E¹⁵—C—E^14(–) (II) (E¹⁵ = P or As; E¹⁴ = Si, Ge, or Sn; X = C or S) structural fragments. Procedures for the synthesis of these compounds, their reactivities, the X-ray diffraction structures, and the electronic structures established by high-level quantum-chemical calculations are considered in detail. The carbon analogs of betaines of type I, viz., compounds bearing the ⁽⁺⁾P—C—C—X^(–) fragment (III), are also discussed. The latter were long considered as possible intermediates in the reactions of compounds containing the polar C=X bond (X = C, O, S, NR, etc.) with phosphorus ylides (classical Wittig and Corey—Chaykovsky reactions and related processes).     

Synthesis and Crystal Structure Analysis of Tetraphosphanylsilane and Identification of Tetraphosphanylgermane

Inversion-symmetric pairs, each with two weak P–H⋅⋅⋅P interactions, form molecules of Si(PH₂)₄ in the crystal (see drawing). The title compounds are formed from ECl₄ (E=Si,Ge) on reaction with [LiAl(PH₂)₄] and could serve as single-source CVD precursors for phosphides.     

Reactions of silicon-, germanium- and tin-containing carbene complexes of tungsten Ph3E-CW(OBu)3 (E=Si, Ge, Sn) with hydrogen chloride: crystal structures of carbene complexes Ph3E-CHWCl2(OBu)2 (E=Si, Ge)

The novel organosilicon, -germanium and -tin-containing carbene complexes of tungsten of the type Ph₃E-CHWCl₂(OBu^t)₂ (E=Si, Ge, Sn) have been prepared by the reaction of heteroelement-containing carbene complexes of tungsten Ph₃E-CW(OBu^t)₃ (E=Si, Ge, Sn) with hydrogen chloride. The tin-containing carbene complex was identified in solution by ¹H NMR spectroscopy. Silicon- and germanium-containing carbene complexes were isolated in high yields as crystalline solids and characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR and ²⁹Si NMR spectroscopy and X-ray diffraction studies. The geometry of the W atoms in the compounds can be described as a distorted square pyramid.     

Rhenium complexes with π-acetylenic ligands that contain silicon,germanium, and tin

Conclusions A study was made of the reaction of CpRe(CO)₂·THF with acetylenes of type Ph₃MCCPh, where M=Si, Ge, Sn. The previously unknown acetylenic complexes of rhenium CpRe(CO)₂(-Ph₃MCCPh), where M=Si and Ge, were isolated and studied, and it was shown that these complexes can undergo partial rearrangement to compounds with phenylvinylidene ligands.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1124–1126, May, 1979.     

Phosphine-Stabilized Pnictinidenes

The reaction of the intramolecular germylene-phosphine Lewis pair (o-PPh₂)C₆H₄GeAr* ( 1 ) with Group 15 element trichlorides ECl₃ (E=P, As, Sb) was investigated. After oxidative addition, the resulting compounds (o-PPh₂)C₆H₄(Ar*)Ge(Cl)ECl₂ ( 2 : E=P, 3 : E=As, 4 : E=Sb) were reduced by using sodium metal or LiHBEt₃. The molecular structures of the phosphine-stabilized phosphinidene (o-PPh₂)C₆H₄(Ar*)Ge(Cl)P ( 5 ), arsinidene (o-PPh₂)C₆H₄(Ar*)Ge(Cl)As ( 6 ) and stibinidene (o-PPh₂)C₆H₄(Ar*)Ge(Cl)Sb ( 7 ) are presented; they feature a two-coordinate low-valent Group 15 element. After chloride abstraction, a cyclic germaphosphene [(o-PPh₂)C₆H₄(Ar*)GeP] [B(C₆H₃(CF₃)₂)₄] ( 8 ) was isolated. The ³¹P NMR data of the germaphosphene were compared with literature examples and analyzed by quantum chemical calculations. The phosphinidene was treated with [iBu₂AlH]₂, and the product of an Al−H addition to the low-valent phosphorus atom (o-PPh₂)C₆H₄(Ar*)Ge(H)P(H)Al(C₄H₉)₂ ( 9 ) was characterized.     

Regioselectivity of reactions of vinyl- and isopropenylcyclopentadienide anions with electrophilic agents. Synthesis and crystal structures of complexes [C5H4C(Me)=CH2]ZrCl3 · 2THF and [C5Me4CH=CH2]ZrCl3 · 2THF

Regioselectivity of the reactions of lithium vinyl- and isopropenylcyclopentadienides C₅H₄C(R)=CH₂ ^-Li⁺(R = H, Me) and lithium tetramethylvinylcyclopentadienide C₅Me₄CH=CH₂ ^-Li⁺ with various electrophilic agents (Me₃SiCl, Me₃SnCl, Et₂PCl, 2-chloro-1, 3-dioxaphospholane, and MeI) was studied. Two new monocyclopentadienyl zirconium complexes, [C₅H₄C(Me) = CH₂]ZrCl₃ · 2THF and [C₅Me₄CH=CH₂]ZrCl₃ · 2THF, were synthesized. Their crystal structures were established by X-ray diffraction. The results of quantum chemical calculations for the C₅H₄C(R) = CH₂ ^- (R = H, Me) and C₅Me₄CH=CH₂ ^- anions by the DFT method (RMPW1PW91) with the 6-311+G(d, p) split valence basis set are in good agreement with experimental data on the regioselectivity of their reactions with electrophilic agents.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 390–399, February, 2005.     

Synthesis of cis-(Me3Sn)2Fe(CO)4 by reaction of (Me3Sn)3Sb with Fe2(CO)9. Formation of (Me3E)3SbFe(CO)4 (E = Si,Ge)

(Me₃Sn)₃Sb and Fe₂(CO)₉ reacted to form (Me₃Sn)₂Fe(CO)₄ in 79% yield. From (Me₃E)₃Sb(E = Si or Ge) and Fe₂(CO)₉ the complexes (Me₃E)₃SbFe(CO)₄ were obtained     

Photoinitiated reactions of allyltriorgano-silanes and -germanes with polyhaloidalkanes. Study of the mechanisms of the reactions by means of the 1H CIDNP method

The radical stages in the photolysis reactions of various allyltriorgano-silanes and -germanes (R₃MCH₂CHCH₂; M = Si, Ge) with polyhaloidalkanes have been studied using the ¹H CIDNP method. It has been shown that the mechanism of the photochemical reaction for M = Sn, Ge is different from the case when M = Sn. Some rather stable R₃MCH₂CH(Hal)CH₂R′ (M = Si, Ge) derivatives were isolated and characterized.     

Alkali-Phosphorverbindungen und ihr reaktives Verhalten. 81. 2-Organoelement-1,3-benzodiphospholene

Alkali Metal Phosphorus Compounds and their Reactivity. 81.2-Organoelement-1,3-benzodiphospholenes 2-Organoelement-1,3-benzodiphospholenes of the general formula (E = C, Si, Ge, Sn, P; R,R′ = alkyl, aryl), are formed by interactions of bissubstituted 1,2-diphosphinobenzenes and organoelement halides, R′₂ECl₂ and R′ECl₂, respectively. Other possibilities of the synthesis of these compounds as well as further representatives in this way are shown. The barriers of P-in- version of the title compounds (E = C, Si, Ge, Sn) are relative low in comparison with 1,3-diphospholanes (cis/trans-conversion ΔG_Tc* ≤ 84 KJ/mol. Also ³¹P-nmr spectra of the other prepared compounds are discussed.     

Synthesis and structures of silicon-, germanium-, and tin-containing imido-alkyl molybdenum complexes (ArN)2Mo(CH2EMe3)2 (E = Si, Ge, Sn)

New silicon-, germanium-, and tin-containing imido-alkyl molybdenum complexes (ArN)₂Mo(CH₂EMe₃)₂ (Ar is 2,6-diisopropylphenyl; E = Si (1), Ge (2), Sn (3)) were prepared in the crystalline state in 58–66% yields by the reactions of the (ArN)₂MoCl₂(DME) complex with alkyllithium derivatives Me₃ECH₂Li (E = Si or Ge) or the Grignard reagents Me₃ECH₂MgCl (E = Ge or Sn). The structures of complexes 1–3 and the known analog (ArN)₂Mo(CH₂Bu^t)₂ (4) were established by X-ray diffraction analysis. Complexes 1–3 were found to be isostructural. The coordination environment about the Mo atom can be described as a distorted tetrahedron. Complex 4 has a similar structure. The Mo-C distance tends to decrease with increasing electron donating ability of the EMe₃ group.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 597–600, March, 2005.     

Perfluormethyl-Element-Liganden. XL. Chrom- und Wolframpentacarbonylkomplexe von Bis(trifluormethyl)phosphanen des Typs (F3C)2PX′ (X′ = H,F, Cl,Br, I,NEt2)

Perfluormethyl-Element-Ligands. XL. Chromium and Tungsten Pentacarbonyl Complexes of Bis(trifluoromethyl)phosphanes of the Type (F₃C)₂PX′ (X′ = H, F, Cl, Br, I, NEt₂) The complexes M(CO)₅P(CF₃)₂X′ (M = Cr, W; X′ = H, F, Cl, Br, I) are obtained in preparative amounts (yields between 15 and 42%) by reacting the ligands (F₃C)₂PX′ with the adducts “M(CO)₅CH₂Cl₂”, photochemically generated from M(CO)₆ in methylene chloride. The corresponding derivatives of the aminophosphane Et₂NP(CF₃)₂ can be produced in good yields (60–75%) using the THF complexes M(CO)₅THF as precursors. The spectroscopic data (MS, IR, NMR) of the new compounds are reported. The CO valence frequencies v(CO) and the coordination shifts Δδ prove the high π-acidity of the ligands (F₃C)₂PX′.