The chemistry of niobium and tantalum halides,MX5, with haloacetic acids and their related anhydrides: Anhydride C–H bond activation promoted by MF5

Niobium and tantalum pentahalides, MX₅ (1), react with acetic acid and halo-substituted acetic acids, in 1:1 ratio, to give the dinuclear complexes [MX₄(μ-OOCMe)]₂ [M = Nb, X = Cl, 2a; M = Ta, X = Cl, 2b; Br, 2c] and [MCl₄(μ-OOCR)]₂ [M = Nb, R = CH₂Cl, 4a; CHCl₂, 4c; CCl₃, 4e; CF₃, 4g; CHBr₂, 4i; CH₂I, 4j; M = Ta, R = CH₂Cl, 4b; CHCl₂, 4d; CCl₃, 4f; CF₃, 4h]. The solid state structures of 2b and 4e have been ascertained by X-ray diffraction studies. The reactions of 1 with acetic anhydride and halo-substituted acetic anhydrides result in C–O bond activation and afford 2 and 4, respectively, with concomitant formation of acetyl halides. Moreover, the complexes MCl₅[OC(Cl)Me] [M = Nb, 3a; M = Ta, 3b] have been detected in significant amounts within the mixtures of the reactions of MCl₅ with acetic anhydride. TaI₅ is unreactive, at room temperature, towards both MeCOOH and (MeCO)₂O. MF₅ react with RCOOH (R = Me, CH₂Cl) in 1:1 molar ratio, to afford the ionic compounds [MF₄(RCOOH)₂][MF₆], 5a–d, in high yields. The additions of (RCO)₂O (R = Me, CH₂Cl) to MF₅ give 5, suggesting that anhydride C–H and C–O bonds activation is operative during the course of these reactions.     

Structural studies of phosphor-1,1-diselenoato Mn(I) and Re(I) complexes

Mononuclear complexes of the type, M(CO)₄[Se₂P(OR)₂] (M = Mn, R = ⁱPr, 1a; Et, 1b; M = Re, R = ⁱPr, 3a; Et, 3b) can be prepared from either [-Se(Se)P(OⁱPr)₂]₂ (A) or [Se{-Se(Se)P(OEt)₂}₂] (B) with M(CO)₅Br. O,O′-dialkyl diselenophosphate ([(RO)₂PSe₂]^-, abbreviated as dsep) ligands generated from A and B act as a chelating ligand in these complexes. Upon refluxing in acetonitrile, these mononuclear complexes yield dinuclear complexes with a general formula of [M₂(CO)₆{Se₂P(OR)₂}₂] (M = Mn, R = ⁱPr, 2a; Et, 2b; M = Re, R = ⁱPr, 4a; Et, 4b). Dsep ligands display a triconnective, bimetallic bonding mode in the dinuclear compounds and this kind of connective pattern has never been identified in any phosphor-1,1-diselenoato metal complexes. Compounds 2b, 3b, and 4 are structurally characterized. Compounds 2b and 3b display weak, secondary Se?Se interactions in their lattices.     

Diiron-aminocarbyne complexes with amine or imine ligands: C-N coupling between imine and aminocarbyne ligands promoted by tolylacetylide addition to [Fe2{μ-CN(Me)R}(μ-CO)(CO)(NHCPh2)(Cp)2][SO3CF3]

A terminally coordinated CO ligand in the complexes [Fe₂{μ-CN(Me)R}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃] (R = Me, 1a; R = Xyl, 1b; Xyl = 2,6-Me₂C₆H₃), is readily displaced by primary and secondary amines (L), in the presence of Me₃NO, affording the complexes [Fe₂{μ-CN(Me)R}(μ-CO)(CO)(L)(Cp)₂][SO₃CF₃] (R = Me, L = NH₂Et, 4a; R = Xyl, L = NH₂Et, 4b; R = Me, L = NH₂Prⁱ, 5a; R = Xyl, L = NH₂Prⁱ, 5b; R = Xyl, L = NH₂C₆H₁₁, 6; R = Xyl, L = NH₂Ph, 7; R = Xyl, L = NH₃, 8; R = Me, L = NHMe₂, 9a; R = Xyl, L = NHMe₂, 9b; R = Xyl, = NH(CH₂)₅, 10). In the absence of Me₃NO, NH₂Et gives addition at the CO ligand of 1b, yielding [Fe₂{μ-CN(Me)(Xyl)}(μ-CO)(CO){C(O)NHEt}(Cp)₂] (11). Carbonyl replacement is also observed in the reaction of 1a-b with pyridine and benzophenone imine, affording [Fe₂{μ-CN(Me)R}(μ-CO)(CO)(L)(Cp)₂][SO₃CF₃] (R = Me, L = Py, 12a; R = Xyl, L = Py, 12b; R = Me, L = HNCPh₂, 13a; R = Xyl, L = HNCPh₂, 13b). The imino complex 13b reacts with p-tolylacetylide leading to the formation of the μ-vinylidene-diaminocarbene compound [Fe₂{μ-η¹:η²- CC(Tol)C(Ph)₂N(H)CN(Me)(Xyl){(μ-CO)(CO)(Cp₂)] (15) which has been studied by X-ray diffraction.     

Iron(0) and ruthenium(0) complexes with tridentate phosphonite ligands and their potential for ketene formation from methyl iodide, CO and a base

An efficient route to the novel tridentate phosphine ligands RP[CH₂CH₂CH₂P(OR′)₂]₂ (I: R = Ph; R′ = i-Pr; II: R = Cy; R′ = i-Pr; III: R = Ph; R′ = Me and IV: R = Cy; R′ = Me) has been developed. The corresponding ruthenium and iron dicarbonyl complexes M(triphos)(CO)₂ (1: M = Ru; triphos = I; 2: M = Ru; triphos = II; 3: M = Ru; triphos = III; 4: M = Ru; triphos = IV; 5: M = Fe; triphos = I; 6: M = Fe; triphos = II; 7: M = Fe; triphos = III and 8: M = Fe; triphos = IV) have been prepared and fully characterized. The structures of 1, 3 and 5 have been established by X-ray diffraction studies. The oxidative addition of MeI to 1-8 produces a mixture of the corresponding isomeric octahedral cationic complexes mer,trans-(13a-20a) and mer,cis-[M(Me)(triphos)(CO)₂]I (13b-20b) (M = Ru, Fe; triphos = I-IV). The structures of 13a and 20a (as the tetraphenylborate salt (21)) have been verified by X-ray diffraction studies. The oxidative addition of other alkyl iodides (EtI, i-PrI and n-PrI) to 1-8 did not afford the corresponding alkyl metal complexes and rather the cationic octahedral iodo complexes mer,cis-[M(I)(triphos)(CO)₂]I (22-29) (M = Ru, Fe; triphos = I-IV) were produced. Complexes 22-29 could also be obtained by the addition of a stoichiometric amount of I₂ to 1-8. The structure of 22 has been verified by an X-ray diffraction study. Reaction of 13a/b-20a/b with CO afforded the acetyl complexes mer,trans-[M(COMe)(triphos)(CO)₂]I, 30-37, respectively (M = Ru, Fe; triphos = I-IV). The ruthenium acetyl complexes 30-33 reacted slowly with 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP) even in boiling acetonitrile. Under the same conditions, the deprotonation reactions of the iron acetyl complexes 34-37 were completed within 24-40 h to afford the corresponding zero valent complexes 5-8. It was not possible to observe the intermediate ketene complexes. Tracing of the released ketene was attempted by deprotonation studies on the labelled species mer,trans-[Fe(COCD₃)(triphos)(CO)₂]I (38) and mer,trans-[Fe(¹³COMe)(triphos)(CO)₂]I (39).     

Synthesis, characterization and luminescence study of dialkyl[1-arylmethyleneimino-2-naphthonato]gallium complexes: Crystal structure of dimethyl[1-(2-pridyl) methyleneimino-2-naphthonato]gallium

Eight dialkylgallium complexes of type R₂GaL [(M = Me, L = 1-(2-pyridyl)methyleneimino-2-naphthonato (1), M = Et, L = 1-(2-pyridyl)methyleneimino-2-naphthonato (2), M = Me, L = 1-phenylmethyleneimino-2-naphthonato (3), M = Et, L = 1-phenylmethyleneimino-2-naphthonato (4), M = Me, L = 1-(p-methoxylphenyl)methyleneimino-2-naphthonato (5), M = Me, L = 1-(3,4-dimethoxylphenyl)methyleneimino-2-naphthonato (6), M = Me, L = 1-naphthylmethyleneimino-2-naphthonato (7), M = Me, L = 1-naphthylmethyleneimino-2-naphthonato (8)) have been synthesized by reaction of trialkylgallium with appropriate 1-arylmethyleneimino-2-naphthols. The complexes have been characterized by elemental analysis, ¹H NMR, IR and mass spectrometry. Structure of dimethyl[1-(2-pyridyl)methyleneimino-2-naphthonato]gallium (1) has been determined by X-ray single crystal analysis. Ga atom is five coordinate in the structure. Photoluminescent properties have been measured. The maximum emission wavelengths are in the range of 358 and 412 nm with the intensity of 13-325 a.u. The electroluminescent properties of 3, 5, 7 and 8 have been measured. The maximum emission wavelengths are in the range of 450 and 480 nm.     

Reactivities governed by a single metal atom M in mixed-metal highnuclearity clusters having [Ru5M(C)] core (M = Co, Rh, Pd): Site-nonselective, site-selective, and chemo-selective variations in the SO2-trapping reactions

The SO₂ substitution for a CO ligand of the hexa-nuclear carbonyl complexes having Ru₅M(C) type carbido-metal core, [PPN][Ru₅Co(C)(CO)₁₆] (2), [PPN][Ru₅Rh(C)(CO)₁₆] (3), and Ru₅Pd(C)(CO)₁₆ (4), is dramatically affected by the kind of metal atom M: 2 (M = Co) is reactive but not site-selective, 3 (M = Rh) is reactive and site-selective, whereas 4 (M = Pd) is not reactive at all even though 4 can easily react with PPh₃ to give the substitution products.     

Syntheses, structures and electrochemistry of some 1-(η-allylamino)-1-ferrocenylcarbene complexes of chromium(0), molybdenum(0) and tungsten(0) : Part 13: The chemistry of metallacyclic alkenylcarbene complexes

The metallacyclic complexes (OC)₄MC(η²-NHCH₂CHCHX)Fc (4; X = H) and (5; X = CH₂OH) [M = Cr: a; Mo: b; W: c; Fc = ferrocenyl = CpFe(C₅H₄)] were obtained in good yields upon photo-decarbonylation of the bimetallic allylaminocarbene complexes (OC)₅MC(NHCH₂CHCHX)Fc (2; X = H)/(3; X = CH₂OH). At room temperature complexes 2/3 exist as mixtures of E- and predominantly Z-isomers with regard to the C-N bond. The molecular structures of 4b and 4c were determined by X-ray diffraction analyses. The intermetallic communicative effects and the interplay of Fc and η²-alkene moieties of 4a and 4b were assessed by cyclovoltammetry. All complexes were also characterized in solution by one- and two-dimensional NMR spectroscopy (¹H, ¹³C, ¹H NOE, ¹H/¹H COSY, ¹³C/¹H HETCOR).     

Self-assembly syntheses and crystal structures of triorganotin(IV) pyridinecarboxylate: 1D polymers and a 42-membered macrocycle

A series of new triorganotin(IV) pyridinecarboxylates with 6-hydroxynicotinic acid (6-OH-3-nicH), 5-hydroxynicotinic acid (5-OH-3-nicH) and 2-hydroxyisonicotinic acid (2-OH-4-isonicH) of the types: [R₃Sn (6-OH-3-nic)·L]_n (I) (R = Ph, L = Ph·EtOH, 1; R = Bn, L = H₂O·EtOH, 2; R = Me, L = 0, 3; R = n-Bu, L = 0, 4), [R₃Sn (5-OH-3-nic)]_n (II) (R = Ph, 5; R = Bn, 6; R = Me, 7; R = n-Bu, 8), [R₃Sn (2-OH-4-isonic·L)]_n (III) (R = Bn, 9, L = MeOH; R = Me, L = 0, 10; R = Ph, 11, L = 0.5EtOH) have been synthesized. All the complexes were characterized by elemental analysis, TGA, IR and NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy analyses. Among them, except for complexes 5 and 6, all complexes were also characterized by X-ray crystallography diffraction analysis. Crystal structures show that complexes 1-10 adopt 1D infinite chain structures which are generated by the bidentate O, O or N, O and the five-coordinated tin centers. Significant O-H?O, and N-H?O intermolecular hydrogen bonds stabilize these structures. Complex 11 is a 42-membered macrocycle containing six tin atoms, and forms a 2D network by intermolecular N-H?O hydrogen.     

Mono and dinuclear half-sandwich platinum group metal complexes bearing pyrazolyl-pyrimidine ligands: Syntheses and structural studies

Reactions of 0.5 eq. of the dinuclear complexes [(η⁶-arene)Ru(μ-Cl)Cl]₂ (arene = η⁶-C₆H₆, η⁶-p-ⁱPrC₆H₄Me) and [(Cp∗)M(μ-Cl)Cl]₂ (M = Rh, Ir; Cp∗ = η⁵-C₅Me₅) with 4,6-disubstituted pyrazolyl-pyrimidine ligands (L) viz. 4,6-bis(pyrazolyl)pyrimidine (L1), 4,6-bis(3-methyl-pyrazolyl)pyrimidine (L2), 4,6-bis(3,5-dimethyl-pyrazolyl)pyrimidine (L3) lead to the formation of the cationic mononuclear complexes [(η⁶-C₆H₆)Ru(L)Cl]⁺ (L = L1, 1; L2, 2; L3, 3), [(η⁶-p-ⁱPrC₆H₄Me)Ru(L)Cl]⁺ (L = L1, 4; L2, 5; L3, 6), [(Cp∗)Rh(L)Cl]⁺ (L = L1, 7; L2, 8; L3, 9) and [(Cp∗)Ir(L)Cl]⁺ (L = L1, 10; L2, 11; L3, 12), while reactions with 1.0 eq. of the dinuclear complexes [(η⁶-arene)Ru(μ-Cl)Cl]₂ and [(Cp∗)M(μ-Cl)Cl]₂ give rise to the dicationic dinuclear complexes [{(η⁶-C₆H₆)RuCl}₂(L)]²⁺ (L = L1, 13; L2, 14; L3, 15), [{(η⁶-p-ⁱPrC₆H₄Me)RuCl}₂(L)]²⁺ (L = L1, 16; L2, 17; L3, 18), [{(Cp∗)RhCl}₂(L)]²⁺ (L = L1, 19; L2, 20; L3, 21) and [{(Cp∗)IrCl}₂(L)]²⁺ (L = L1 22; L2, 23; L3 24). The molecular structures of [3]PF₆, [6]PF₆, [7]PF₆ and [18](PF₆)₂ have been established by single crystal X-ray structure analysis.     

Dihalogen-halogenomethyl complexes of indium(III) X2InCH2X (X = Br, I): Simultaneous coordination of soft and hard ligands

Halogenomethyl-dihalogen-indium(III) compounds X₂InCH₂X (X = Br, I) obtained from indium monohalides and methylene dihalides were reacted with the soft donor ligands dialkylsulfides, R₂S (R = CH₃, CH₂Ph) to afford the corresponding dialkylsulfonium methylide complexes of InX₃, X₃InCH₂SR₂ (X = Br, R = CH₃, 1; X = I, R = CH₃, 2; X= I, R = CH₂Ph, 3). Compound 1 was reacted with the hard donor ligands dimethylsulfoxide or triphenylphosphine oxide to give the corresponding 1:1 adduct, Br₃(L)InCH₂S(CH₃)₂ (L = (CH₃)₂SO, 4; L = (C₆H₅)₃PO, 5). Compounds 1-5 were fully characterized in solution by NMR spectroscopy and in the solid state by X-ray methods.     

Formation of niobium and tantalum ylide complexes

The reactions of tri(bis(ethyl)amino)phosphorus ylide (Et₂N)₃PCH₂ with cyclopentadienyl (Cp) metal (V) tetrachloride CpMCl₄ (M = Nb 1; Ta 3) and pentamethylcycopentadienyl (Cp^∗) metal (V) tetrachloride Cp^∗MCl₄ (M = Nb 2; Ta 4) were investigated. The hexa-coordinate ylide adducts complexes 5 (CpNbCl₄(H₂CP(NEt₂)₃)), 6 (Cp^∗NbCl₄(H₂CP(NEt₂)₃)) and 8 (Cp^∗TaCl₄(H₂CP(NEt₂)₃)) with pseudo-octahedral geometry were structurally analyzed with X-ray diffraction. Compound 4 (Cp^∗TaCl₄) reacted with three molar equivalent of phosphorus ylide to form one ionic complex 9 ([H₃C-P(NEt₂)₃][Cp^∗TaCl₅]) which was also structurally analyzed with X-ray diffraction. The possible formation mechanism of compound 9 has been discussed.     

Preparation, structural characterisation and electrochemical properties of iron(0) and tungsten(0) carbonyl complexes with 1-(diphenylphosphanyl)-1′-vinylferrocene and 1-(diphenylphosphanyl)-1′-(dimethylvinylsilyl)ferrocene as P-monodentate ligands

A new organometallic phosphanylalkene, 1-(diphenylphosphanyl)-1′-(dimethylvinylsilyl)ferrocene (2) was prepared and—together with 1-(diphenylphosphanyl)-1′-vinylferrocene (1)—studied as a ligand in iron- and tungsten-carbonyl complexes. The following complexes featuring the mentioned phosphanylalkenes as P-monodentate donors were isolated and characterised by spectral methods: [Fe(CO)₄(L-κP)] (4, L = 1; 5, L = 2) and trans-[W(CO)₄(L-κP)₂] (6, L = 1; 7, L = 2). In addition, the solid-state structures of 4 and 6 have been determined by single-crystal X-ray diffraction and the electrochemical properties of compounds 1, 2, 4 and 6 were studied by cyclic voltammetry at platinum electrode.     

Titanium and zirconium complexes with novel phenoxy-phosphinimine ligands

A series of novel phenoxy-phosphinimine ligands (L): L = 2-(Ph₂PNR), 4, 6-(CMe₃)₂-C₆H₂OH [2, R = SiMe₃; 3, R = Ph] have been prepared in the yield of 65-71%. And bis(phenoxy-phosphinimide) group 4 complexes of the type L₂MCl₂ [4, M = Ti, R = SiMe₃; 5, M = Zr, R = SiMe₃; 6, M = Ti, R = Ph; 7, M = Zr, R = Ph] have been synthesized by the reaction of the ligands with TiCl₄ and ZrCl₄. The structure of complex 7 has been determined by X-ray crystallography. The complexes 4-7 showed inactive to ethylene polymerization in the presence of modified methylaluminoxane (MMAO) and i-Bu₃Al/Ph₃CB(C₆ F₅)₄. These results should be caused by overdoing the steric congestion around central metal.     

Synthesis,structural characterization and reactivity of copper(I)-nitrile complexes: Crystal and molecular structure of [Cu(BzCN)4][BF4]

Complexes of general formula [CuL₄][BF₄] (L = benzonitrile – PhCN 2 or phenylacetonitrile – BzCN 3) have been prepared and structurally characterized by NMR spectroscopy and X-ray crystallography. Their structure and reactivity have been compared to the well known [Cu(MeCN)₄][BF₄] (1). The ⁶³Cu line width and the ⁶³Cu chemical shift have been evaluated by varying the temperature and the concentration of the complex 2 in benzonitrile solutions. The phenylacetonitrile solutions of the complex 3 give extremely broad signals which are beyond detection. Accordingly, compound 3 has been studied by ⁶³Cu MAS NMR spectroscopy. The solution NMR data are consistent to the prevalence of dynamic equilibrium between tetra- and low-coordinated species in both complexes. The X-ray structure of 3 revealed that the copper(I) atom sits in a slightly distorted tetrahedral geometry, surrounded by four BzCN ligands.     

Alkynylphosphanes as supports for mixed-metal Co4M (M = Ru, Os) fluoride complexes: Syntheses, structures and thermolysis studies

Treatment of the tetrameric group eight fluoride complexes [MF(μ-F)(CO)₃]₄ [M = Ru (1a), Os (1b)] with the alkynylphosphane, Ph₂PCCPh, results in fluoride-bridge cleavage and the formation of the air-sensitive monomeric octahedral complexes [MF₂(CO)₂(PPh₂CCPh)₂] [M = Ru (2a), Os (2b)] in high yield. The molecular structure of 2b reveals a cis, cis, trans configuration for each pair of ligands, respectively. The free alkyne moieties in 2 can be readily complexed to hexacarbonyldicobalt fragments by treatment with dicobalt octacarbonyl to afford [MF₂(CO)₂(μ-η¹:η²-PPh₂CCPh)₂{Co₂(CO)₆}₂] [M = Ru (3a), Os (3b)]. Evidence for an intramolecular non-bonded contact between a bound fluoride and a cobalt carbonyl carbon atom is seen in the molecular structure of 3a. Thermolysis of 3a at 50 °C results in fluoride dissociation to give [RuF(CO)₂(μ-η¹:η²-PPh₂CCPh)₂{Co₂(CO)₆}₂]⁺ (4), while no reaction occurred with the osmium analogue. Prolonged thermolysis at 120 °C in a sealed vessel of both 3a and 3b gave only insoluble decomposition products.     

The role of phosphine in cobalt-catalyzed carbonylative polymerization of N-alkylaziridine

A series of CH₃COCo(CO)₃L complexes (1, L = PCy₃; 2, L = PMe₂Ph; 3, L = PPh₃; 4, L = P(para-F-Ph)₃; 5, L = P(meta-F-Ph)₃; and 6, L = P(ortho-tolyl)₃) were studied as precatalyst for the title polymerization. The Co-P bond length primarily responds to the cone angle of the phosphine ligand (6 > 1 > 2 ≈ 3 ≈ 4 ≈ 5), while the back-donation to the axial acetyl ligand and the equatorial CO ligand depends on the electron-donating ability of the phosphine and increases in the order 1 > 6 > 2 > 3 > 4 > 5. The equilibrium constant for CH₃COCo(CO)₃L + CO ↔ CH₃COCo(CO)₄ + L depends on the electron-donating ability of the phosphine ligand except for 6 and follows the order 6 ? 5 > 4 > 3 > 2 > 1. The catalytic activity follows the order 6 > 5 > 4 > 3 > 1 > 2. The activity difference cannot be explained solely by the above equilibrium and is consistent with the competition for the acyl site by the phosphine as nucleophile against aziridine. The production of the β-lactam byproduct is attributed to catalyst decomposition, which is accelerated to the basicity/nucleophilicity of the phosphine ligand.     

Olefin-aminocarbyne coupling in diiron complexes: Synthesis of new bridging aminoallylidene complexes

The bridging aminocarbyne complexes [Fe₂{μ-CN(Me)(R)}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃] (R = Me, 1a; Xyl, 1b; 4-C₆H₄OMe, 1c; Xyl = 2,6-Me₂C₆ H₃) react with acrylonitrile or methyl acrylate, in the presence of Me₃NO and NaH, to give the corresponding μ-allylidene complexes [Fe₂{μ-η¹:η³- C_α(N(Me)(R))C_β(H)C_γ(H)(R′)}(μ-CO)(CO)(Cp)₂] (R = Me, R′ = CN, 3a; R = Xyl, R′ = CN, 3b; R = 4-C₆H₄OMe, R′ = CN, 3c; R = Me, R′ = CO₂Me, 3d; R = 4-C₆H₄OMe, R′ = CO₂Me, 3e). Likewise, 1a reacts with styrene or diethyl maleate, under the same reaction conditions, affording the complexes [Fe₂{μ-η¹:η³-C_α(NMe₂)C_β(R′)C_γ(H)(R″)}(μ-CO)(CO)(Cp)₂] (R′ = H, R″ = C₆H₅, 3f; R′ = R″ = CO₂Et, 3g). The corresponding reactions of [Ru₂{μ-CN(Me)(CH₂Ph)}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃] (1d) with acrylonitrile or methyl acrylate afford the complexes [Ru₂{μ-η¹:η³-C_α(N(Me)(CH₂Ph))C_β(H)C_γ(H)(R′)}(μ-CO)(CO)(Cp)₂] (R′ = CN, 3h; CO₂Me, 3i), respectively.The coupling reaction of olefin with the carbyne carbon is regio- and stereospecific, leading to the formation of only one isomer. C-C bond formation occurs selectively between the less substituted alkene carbon and the aminocarbyne, and the C_β-H, C_γ-H hydrogen atoms are mutually trans.The reactions with acrylonitrile, leading to 3a-c and 3h involve, as intermediate species, the nitrile complexes [M₂{μ-CN(Me)(R)}(μ-CO)(CO)(NC-CHCH₂)(Cp)₂][SO₃CF₃] (M = Fe, R = Me, 4a; M = Fe, R = Xyl, 4b; M = Fe, R = 4-C₆H₄OMe, 4c; M = Ru, R = CH₂C₆H₅, 4d).Compounds 3a, 3d and 3f undergo methylation (by CH₃SO₃CF₃) and protonation (by HSO₃CF₃) at the nitrogen atom, leading to the formation of the cationic complexes [Fe₂{μ-η¹:η³-C_α(N(Me)₃)C_β(H)C_γ(H)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = CN, 5a; R = CO₂Me, 5b; R = C₆H₅, 5c) and [Fe₂{μ-η¹:η³-C_α(N(H)(Me)₂)C_β(H)C_γ(H)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = CN, 6a; R = CO₂Me, 6b; R = C₆H₅, 6c), respectively.Complex 3a, adds the fragment [Fe(CO)₂(THF)(Cp)]⁺, through the nitrile functionality of the bridging ligand, leading to the formation of the complex [Fe₂{μ-η¹:η³-C_α(NMe₂)C_β(H)C_γ(H)(CNFe(CO)₂Cp)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (9).In an analogous reaction, 3a and [Fe₂{μ-CN(Me)(R)}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃], in the presence of Me₃NO, are assembled to give the tetrameric species [Fe₂{μ-η¹:η³-C_α(NMe₂)C_β(H)C_γ(H)(CN[Fe₂{μ- CN(Me)(R)}(μ-CO)(CO)(Cp)₂])}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = Me, 10a; R = Xyl, 10b; R = 4-C₆H₄OMe, 10c).The molecular structures of 3a and 3b have been determined by X-ray diffraction studies.     

Fe(II) and Co(II) pyridinebisimine complexes bearing different substituents on ortho- and para-position of imines: synthesis, characterization and behavior of ethylene polymerization

A series of 2,6-bis(imino)pyridyl iron(II) and cobalt(II) complexes [2,6-(ArNCMe)₂C₅H₃N]MCl₂ (Ar = 2,6-i-Pr₂C₆H₃, M = Fe: 3a, M = Co: 4a; Ar = 2,4,6-i-Pr₃C₆H₂, M = Fe: 3b, M = Co: 4b; Ar = 2,6-i-Pr₂-4-BrC₆H₂, M = Fe: 3c, M = Co: 4c; Ar = 2,4-i-Pr₂-6-BrC₆H₂, M = Fe: 3d, M = Co: 4d) has been synthesized, characterized, and investigated as precatalysts for the polymerization of ethylene in the presence of modified methylaluminoxane (MMAO). The substituents of pyridinebisimine ligands and their positions located significantly influence catalyst activity and polymer property. It is found that the catalytic activities of the iron complexes/MMAO systems are mainly dominated by electronical effect, while those of the cobalt complexes/MMAO systems are primarily controlled by hindering effect.     

Synthesis and crystal structures of boratranes with methyl substituents on the atrane cage

Three monomeric boratranes B[(OCH₂CH₂)_nN(CH₂CMe₂O)_3−n] (n = 0, 1; n = 1, 2; n = 2, 3) have been synthesized by the reaction of B(OMe)₃ with a series of triethanolateamines such as [(OCH₂CH₂)_nN(CH₂CMe₂O)_3−n]³⁻ (n = 0, L1; n = 1, L2; n = 2, L3), where the number of CMe₂ groups adjacent to the OH functionality varied from 3 (L1H₃) to 2 (L2H₃) to 1 (L3H₃). These boratranes 1-3 have been characterized by solution ¹H, ¹³C{¹H} and ¹¹B NMR, and the crystal structures of 1 and 2 have been determined by single crystal X-ray diffraction.