Nickel tris(pyrazolyl)borate β-diketonate complexes

Mixed ligand tris(pyrazolyl)borate and β-diketonate complexes have been prepared by reacting [Tp^Ph2NiBr] with a β-diketone and then adding 1,8-diazabicycloundec-7-ene to yield [Tp^Ph2Ni(β-dkt)] {β-dkt = hexafluoroacetylacetonate (hfac) 1, phenylbutanedionate (pbd) 2, diphenylpropanedionate (dbm) 3, tetramethylheptanedionate (tmhd) 4}. The green solids have been characterized by IR, UV–Vis, and ¹H NMR spectroscopy. Crystallographic studies of [Tp^Ph2Ni(dbm)] reveal a five-coordinate, square pyramidal nickel centre with a κ³-coordinated Tp^Ph2 ligand and a bidentate β-diketonate ligand.     

Hydrogen-bonded mononuclear nickel(II) benzoate complexes: synthesis and structural studies

[Tp^Ph,MeNi(Cl)Pz^Ph,MeH] (1) has been synthesized by the reaction of hydrotris(3-phenyl-5-methyl-pyrazol-1-yl) borate [Tp^Ph,Me], NiCl₂ · 6H₂O and 3-phenyl-5-methyl-pyrazole [Pz^Ph,MeH]. The reaction of 1 with variously substituted sodium p–X–benzoates resulted in the formation of complexes of the type [Tp^Ph,MeNi(p–X–OBz)Pz^Ph,MeH] (X = H for 2, F for 3, Cl for 4, NO₂ for 5, Me for 6, OMe for 7, OH for 8, CHO for 9 and CN for 10). Single crystal X-ray studies suggest that all these complexes have a five-coordinate metal center and the benzoate groups are monodentate in a square pyramidal geometry. The X-ray studies also reveal that the uncoordinated oxygen atom of the benzoate forms intramolecular hydrogen-bonds with the NH group of the coordinated pyrazole. The substituents present on the benzoate ring are involved in different types of intermolecular interactions and the complexes exhibit different crystal packing. Complexes 2–10 were tested for superoxide dismutase activity. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Iron Pentacarbonyl Promoted Addition of CO and MeOH to 1,4-Disubstituted-1,3-butadiyne and Formation of Vinylallyl and Butatriene Ligand Systems

Abstract  Photochemical reaction of methanol solution containing 1,4-diferrocenyl- or 1,4-diphenyl-1,3-butadiynes and iron pentacarbonyl into which CO was constantly bubbled, yielded diiron hexacarbonyl complexes of cumulene ligand systems, [η¹: η³-{RCHC₂CR(COOMe)}Fe₂(CO)₆] (1; E, R = Fc, 2; Z, R = Fc, 5; E, R = Ph, 6; Z, R = Ph) and [η³: η³-{RCHC₂CR(COOMe)}Fe₂(CO)₆] (3; E, R = Fc, 7; E, R = Ph), formed by 1,4-addition of –COOMe and –H to the butadiynes. Additionally, diferrole, [Fe(CO)₄{C(O)CC(Fc)C(O)}₂],4 was obtained in minor quantity. Compounds 1, 2, 5 and 6 contain vinylallyl carbon framework which is stabilized by MeOC=O → Fe bond along with η¹: η³ coordinated Fe₂(CO)₆ unit. Compounds 3 and 7 contain butatriene units which are stabilized by η³: η³ coordinated Fe₂(CO)₆ unit. Characterization of the new compounds was carried out by IR and ¹H and ¹³C NMR spectroscopy and by mass spectrometry. Molecular structures of 2–7 were established by single crystal X-ray diffraction methods. Graphical Abstract  Diiron hexacarbonyl complexes of cumulene ligand systems, [η¹: η³ {RCHC₂CR(COOMe)}] (1; E, R = Fc, 2; Z, R = Fc, 5; E, R = Ph, 6; Z, R = Ph) and [η³: η³-{RCHC₂CR(COOMe)}] (3; E, R = Fc, 7; E, R = Ph) were obtained from photochemical reactions between Fe(CO)₅, CO and methanol. Yield of the minor product, the diferrole, 4, was improved when the photoreaction was carried out in hexane in place of methanol      

Modification of Yttrium Silyl-Bridged Amide Alkyl Complexes through Si−H/C−H Cross-Dehydrocoupling of Silanes with a Silylamino Ligand: Synthesis,Reactivity, and Mechanism

A new method for the modification of a silylamino ligand has been developed through mono and dual C(sp³)−H/Si−H cross-dehydrocoupling with silanes. The reaction of [LY{η²-(C,N)-CH₂Si(Me₂)NSiMe₃}] (L=bis(2,6-diisopropylphenyl)-β-diketiminato, L′ ( 1^L ′); L=tris(3,5-dimethylpyrazolyl)borate, Tp^Me2 ( 1^TpMe2 )) with 2 equivalents of PhSiH₃ in toluene gave the complexes [LY{η²-(C,N)-C(SiH₂Ph)₂Si(Me₂)NSiMe₃}] (L=L′ ( 2^L’ ); L=Tp^Me2 ( 2^TpMe2 )). Moreover, 1^TpMe2 reacted with the secondary silanes Ph₂SiH₂ and Et₂SiH₂ to afford the corresponding mono C−H activation products [Tp^Me2Y{η²-(C,N)-CH(SiHR₂)Si(Me₂)NSiMe₃}] (R=Ph ( 4 b ); R=Et ( 4 c )). The equimolar reaction of 1^TpMe2 with PhSiH₃ also produced the mono C−H activation product 4 a ([Tp^Me2Y{η²-(C,N)-CH(SiH₂Ph)Si(Me₂)NSiMe₃}(thf)]). A study of their reactivity showed that 4 a facilely reacted with 2 equivalents of benzothiazole by an unusual 1,1-addition of the C=N bond of the benzothiazolyl unit to the Si−H bond to give the C−H/Si−H cross-dehydrocoupling product [(Tp^Me2)Y{η³-(N,N,N)-N(SiMe₃)SiMe₂CH₂Si(Ph)(CSC₆H₄N)(CHSC₆H₄N)}] ( 5 ). These results indicate that this modification endows the silylamino ligand with novel reactivity.     

Potential Precursors for Terminal Methylidene Rare-Earth-Metal Complexes Supported by a Superbulky Tris(pyrazolyl)borato Ligand

A series of solvent-free heteroleptic terminal rare-earth-metal alkyl complexes stabilized by a superbulky tris(pyrazolyl)borato ligand with the general formula [Tp^tBu,MeLnMeR] have been synthesized and fully characterized. Treatment of the heterobimetallic mixed methyl/tetramethylaluminate compounds [Tp^tBu,MeLnMe(AlMe₄)] (Ln=Y, Lu) with two equivalents of the mild halogenido transfer reagents SiMe₃X (X=Cl, I) gave [Tp^tBu,MeLnX₂] in high yields. The addition of only one equivalent of SiMe₃Cl to [Tp^tBu,MeLuMe(AlMe₄)] selectively afforded the desired mixed methyl/chloride complex [Tp^tBu,MeLuMeCl]. Further reactivity studies of [Tp^tBu,MeLuMeCl] with LiR or KR (R=CH₂Ph, CH₂SiMe₃) through salt metathesis led to the monomeric mixed-alkyl derivatives [Tp^tBu,MeLuMe(CH₂SiMe₃)] and [Tp^tBu,MeLuMe(CH₂Ph)], respectively, in good yields. The SiMe₄ elimination protocols were also applicable when using SiMe₃X featuring more weakly coordinating moieties (here X=OTf, NTf₂). X-ray structure analyses of this diverse set of new [Tp^tBu,MeLnMeR/X] compounds were performed to reveal any electronic and steric effects of the varying monoanionic ligands R and X, including exact cone-angle calculations of the tridentate tris(pyrazolyl)borato ligand. Deeper insights into the reactivity of these potential precursors for terminal alkylidene rare-earth-metal complexes were gained through NMR spectroscopic studies.     

Bismuth(III) dication trapped on a chlorobismuthate

Abstract

Metal cations observed with tetrachloroaluminate anion provide insights into the structure and stability of reactive cations. Addition of tris(3,5-dimethylpyrazolyl)borate anion (Tp^Me2) to [BiCl₂][AlCl₄] traps a bismuth(III) dication, [Tp^Me2Bi]²⁺, possessing a highly electrophilic bismuth center with short coordinate Bi―N bonds. [Tp^Me2Bi]²⁺ has weak interactions with the chlorides of [Bi₃Cl₁₃]_∞. Strong affinity of [Tp^Me2Bi]²⁺ with the triflate (OTf) observed in [Tp^Me2Bi(OTf)₃]^- demonstrates the high electrophilicity at bismuth.     

Tris(mercaptoimidazolyl)hydroborato complexes of cobalt and iron, [TmPh]2M (M=Fe,Co): structural comparisons with their tris(pyrazolyl)hydroborato counterparts

The tris(mercaptophenylimidazolyl)borate iron and cobalt complexes [Tm^Ph]₂M (M=Fe, Co) have been synthesized by reaction of [Tm^Ph]Tl with MI₂. Structural characterization by X-ray diffraction demonstrates that the potentially tridentate [Tm^Ph] ligand binds through only two sulfur donors in these ‘sandwich’ complexes and that the ‘tetrahedral’ metal centers supplement the bonding by interactions with the two B–H groups. Comparison of the structures of [Tm^Ph]₂M (M=Fe, Co) with the related tris(pyrazolyl)borate [Tp^Ph]₂M counterparts indicates that the tris(mercaptoimidazolyl) ligand favors lower primary coordination numbers in divalent metal complexes. The trivalent complexes, {[Tp^Ph]₂Fe}[ClO₄] and {[pzBm^Me]₂Co}I, however, exhibit octahedral coordination, with the ligands binding using their full complement of donor atoms.     

A long-standing structural puzzle resolved: the crystal structure of [Ag2(TpMe,Me)2] [where TpMe,Me is hydrotris(3,5-dimethyl-pyrazolyl)borate]

The crystal structure of the simple 1:1 complex of Ag(I) with hydrotris(3,5-dimethylpyrazolyl)borate (Tp^Me,Me) has been shown to be an asymmetric dimer, in which each Tp^Me,Me ligand bridges both metals by coordinating two pyrazolyl donors to one Ag(I) centre and one to the other, such that to a first approximation one Ag(I) is four coordinate and the other is two coordinate. However two of the pyrazolyl donors around the `four-coordinate' metal centres are also involved in weak, asymmetric bridging interactions with the `two-coordinate' metal centres. This is in contrast to the structure of the Cu(I) analogue [Cu₂(Tp^Me,Me)₂] in which both Cu(I) ions are three coordinate.     

Catenated Gallium Compounds Supported by a<Emphasis Type="Italic"> Tris</Emphasis>(pyrazolyl)hydroborato Ligand

[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]M (M = K, Tl) reacts with “GaI” to give a series of compounds that feature Ga–Ga bonds, namely [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaI₃, [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]GaGaI₂GaI₂( \textHpz^\textMe₂ {\text{Hpz}}^{{{\text{Me}}_{2} }} ) and [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga(GaI₂)₂Ga[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ], in addition to the cationic, mononuclear Ga(III) complex {[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]₂Ga}⁺. Likewise, [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]M (M = K, Tl) reacts with (HGaCl₂) ₂ and Ga[GaCl₄] to give [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaCl₃, {[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]₂Ga}[GaCl₄], and {[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]GaGa[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]}[GaCl₄]₂. The adduct [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→B(C₆F₅)₃ may be obtained via treatment of [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]K with “GaI” followed by addition of B(C₆F₅)₃. Comparison of the deviation from planarity of the GaY₃ ligands in [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaY₃ (Y = Cl, I) and [ \textTm^{\textBu\textt} {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga→GaY₃, as evaluated by the sum of the Y–Ga–Y bond angles, Σ(Y–Ga–Y), indicates that the [ \textTm^{\textBu\textt} {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga moiety is a marginally better donor than [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga. In contrast, the displacement from planarity for the B(C₆F₅)₃ ligand of [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→B(C₆F₅)₃ is greater than that of [ \textTm^{\textBu\textt} {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga→B(C₆F₅)₃, an observation that is interpreted in terms of interligand steric interactions in the former complex compressing the C–B–C bond angles.     

B-Alkylation and Arylation of [(η5-C5Me5Mo)2B5H9]: Synthesis and Characterization of Isomeric [(η5-C5Me5Mo)2B5H9-nRn] (When R = n-Bu, n = 2, 1; R = Ph, n = 2, 1)

Abstract  Reaction of [(η⁵-C₅Me₅Mo)₂B₅H₉], 1 with 5-fold excess of n-BuLi at −70 °C followed by excess of RI (R = n-Bu or Ph) at room temperature yielded B-R inserted metallaboranes [(η⁵-C₅Me₅Mo)₂B₅H₈R] (2: R = n-Bu, 5: R = Ph), [(η⁵-C₅Me₅Mo)₂B₅H₇R₂] (3, 4: R = n-Bu; 6, 7: R = Ph). Isolated yields of mono-alkyl/arylated species are better than di-alkyl/arylated ones. All the new cluster compounds have been characterized by IR, ¹H, ¹¹B, ¹³C NMR and mass spectroscopy as simple substitution derivatives of [(η⁵-C₅Me₅Mo)₂B₅H₉] and the structural types of one of these species, 2 was established by X-ray crystallographic analysis. Graphical Abstract  Reaction of [(η⁵-C₅Me₅Mo)₂B₅H₉], with 5-fold excess of n-BuLi at −70 °C followed by excess of RI (R = n-Bu or Ph) at room temperature yielded B-R inserted metallaboranes [(η⁵-C₅Me₅Mo)₂B₅H_9-nR_n] (When R = n-Bu, n = 2, 1; R = Ph, n = 2, 1).      

Ruthenium Tris(pyrazolyl)borate Complexes. Part 20 [1]. Synthesis,Characterization, and Reactivity of Neutral Trispyrazolylborate Ruthenium Vinylidene Complexes

Summary. The reaction of RuTp(COD)Cl (1) with PPh₂Prⁱ and terminal alkynes HCCR (R=C₆H₅, C₄H₃S, C₆H₄OMe, Fc, C₆H₄–Fc, C₆H₉) affords the neutral vinylidene complexes RuTp(PPh₂Prⁱ) (Cl)(=C=CHR) (2a–2f) in high yields. These complexes do not react with MeOH to give methoxy carbene complexes of the type RuTp(PPh₂Prⁱ)(Cl)(=C(OMe)CH₂R), but react with oxygen to yield the CO complex RuTp(PPh₂R)(Cl)(CO) (3). The structures of 2b, 2f, and 3 have been determined by X-ray crystallography.     

Ruthenium Tris(pyrazolyl)borate Complexes. Part 20 [1]. Synthesis, Characterization, and Reactivity of Neutral Trispyrazolylborate Ruthenium Vinylidene Complexes

The reaction of RuTp(COD)Cl (1) with PPh₂Prⁱ and terminal alkynes HCCR (R=C₆H₅, C₄H₃S, C₆H₄OMe, Fc, C₆H₄–Fc, C₆H₉) affords the neutral vinylidene complexes RuTp(PPh₂Prⁱ) (Cl)(=C=CHR) (2a–2f) in high yields. These complexes do not react with MeOH to give methoxy carbene complexes of the type RuTp(PPh₂Prⁱ)(Cl)(=C(OMe)CH₂R), but react with oxygen to yield the CO complex RuTp(PPh₂R)(Cl)(CO) (3). The structures of 2b, 2f, and 3 have been determined by X-ray crystallography.     

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.     

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.     

Ligand Substitution Reactions on Aquapentachloro‐ and Hexachloroplatinic Acid — Synthesis and Characterization of Tetrachloroplatinum(IV) Complexes with Heterocyclic N,N Donors

Reactions of aquapentachloroplatinic acid, (H₃O)[PtCl₅(H₂O)]·2(18C6)·6H₂O ( 1 ) (18C6 = 18‐crown‐6), and H₂[PtCl₆]·6H₂O ( 2 ) with heterocyclic N, N donors (2, 2′‐bipyridine, bpy; 4, 4′‐di‐tert‐butyl‐2, 2′‐bipyridine, tBu₂bpy; 1, 10‐phenanthroline, phen; 4, 7‐diphenyl‐1, 10‐phenanthroline, Ph₂phen; 2, 2′‐bipyrimidine, bpym) afforded with ligand substitution platinum(IV) complexes [PtCl₄(N∩N)] (N∩N = bpy, 3a ; tBu₂bpy, 3b ; Ph₂phen, 5 ; bpym, 7 ) and/or with protonation of N, N donor yielding (R₂phenH)₂[PtCl₆] (R = H, 4a ; Ph, 4b ) and (bpymH)⁺ ( 8 ). With UV irradiation Ph₂phen and bpym reacted with reduction yielding platinum(II) complexes [PtCl₂(N∩N)] (N∩N = Ph₂phen, 6 ; bpym, 9 ). Identities of all complexes were established by microanalysis as well as by NMR (¹H, ¹³C, ¹⁹⁵Pt) and IR spectroscopic investigations. Molecular structures of [PtCl₄(bpym)]·MeOH ( 7 ) and [PtCl₂(Ph₂phen)] ( 6 ) were determined by X‐ray diffraction analyses. Differences in reactivity of bpy/bpym and phen ligands are discussed in terms of calculated structures of complexes [PtCl₅(N∩N)]^— with monodentately bound N, N ligands (N∩N = bpy, 10a ; phen, 10b ; bpym, 10c ).     

Syntheses, structures, and properties of metal complexes involving π-conjugated tetrathiafulvalene-pyridine ligand

Four metal complexes based on the phenyl-bridged pyridine ligand with tetrathiafulvalene unit (TTF-Ph-Py, L), Ni^II(acac)₂(L)₂ (1, acac = acetylacetonate), M(hfac)₂(L)₂ (M = Ni^II, 2; M = Cu^II, 3; hfac = hexafluoroacetylacetonato) and [Co^II(Tp^Ph2)(OAc)(L)]·H₂O (4, Tp^Ph2 = hydridotri(3,5-diphenylpyrazol-1-yl) borate), have been synthesized and structurally characterized. The absorption spectra and redox behaviors of these new compounds have been studied. Optimized conformation and molecular orbital diagram of L has been calculated with density functional theory (DFT).     

Versatile Reactivity of Scorpionate‐Anchored Yttrium?Dialkyl Complexes towards Unsaturated Substrates

A series of unusual chemical‐bond transformations were observed in the reactions of high active yttrium? dialkyl complexes with unsaturated small molecules. The reaction of scorpionate‐anchored yttrium? dibenzyl complex [Tp^Me2Y(CH₂Ph)₂(thf)] ( 1 , Tp^Me2=tri(3,5‐dimethylpyrazolyl)borate) with phenyl isothiocyanate led to C?S bond cleavage to give a cubane‐type yttrium–sulfur cluster, {Tp^Me2Y(μ₃‐S)}₄ ( 2 ), accompanied by the elimination of PhN?C(CH₂Ph)₂. However, compound 1 reacted with phenyl isocyanate to afford a C(sp³)? H activation product, [Tp^Me2Y(thf){μ‐η¹:η³‐OC(CHPh)NPh}{μ‐η³:η²‐OC(CHPh)NPh}YTp^Me2] ( 3 ). Moreover, compound 1 reacted with phenylacetonitrile at room temperature to produce γ‐deprotonation product [(Tp^Me2)₂Y]⁺[Tp^Me2Y(N=C?CHPh)₃]^? ( 6 ), in which the newly formed N?C?CHPh ligands bound to the metal through the terminal nitrogen atoms. When this reaction was carried out in toluene at 120 °C, it gave a tandem γ‐deprotonation/insertion/partial‐Tp^Me2‐degradation product, [(Tp^Me2Y)₂(μ‐Pz)₂{μ‐η¹:η³‐NC(CH₂Ph)CHPh}] ( 7 , Pz=3,5‐dimethylpyrazolyl).     

New diruthenium vinyliminium complexes from the insertion of alkynes into bridging aminocarbynes

Primary alkynes R′CCH [R′ = Me₃Si, Tol, CH₂OH, CO₂Me, (CH₂)₄CCH, Me] insert into the metal-carbon bond of diruthenium μ-aminocarbynes [Ru₂{μ-CN(Me)(R)}(μ-CO)(CO)(MeCN)(Cp)₂][SO₃CF₃] [R = 2,6-Me₂C₆H₃ (Xyl), 1a; CH₂Ph (Bz), 1b; Me, 1c] to give the vinyliminium complexes [Ru₂{μ-η¹:η³-C(R′)CHCN(Me)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] [R = Xyl, R′ = Me₃Si, 2a; R = Bz, R′ = Me₃Si, 2b; R = Me, R′ = Me₃Si, 2c; R = Xyl, R′ = Tol, 3a; R = Bz, R′ = Tol, 3b; R = Bz, R′ = CH₂OH, 4; R = Bz, R′ = CO₂Me, 5a; R = Me, R′ = CO₂Me, 5b; R = Xyl, R′ = (CH₂)₄CCH, 6; R = Xyl, R′ = Me, 7a; R = Bz, R′ = Me, 7b; R = Me, R′ = Me, 7c]. The related compound [Ru₂{μ-η¹:η³-C[C(Me)CH₂]CHCN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂][SO₃CF₃], (9) is better prepared by reacting [Ru₂{μ-CN(Me)(Xyl)}(μ-CO)(CO)(Cl)(Cp)₂] (8) with AgSO₃CF₃ in the presence of HCCC(Me)CH₂ in CH₂Cl₂ at low temperature.In a similar way, also secondary alkynes can be inserted to give the new complexes [Ru₂{μ-η¹:η³-C(R′)C(R′)CN(Me)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = Bz, R′ = CO₂Me, 11; R = Xyl, R′ = Et, 12a; R = Bz, R′ = Et, 12b; R = Xyl, R′ = Me, 13). The reactions of 2-7, 9, 11-13 with hydrides (i.e., NaBH₄, NaH) have been also studied, affording μ-vinylalkylidene complexes [Ru₂{μ-η¹:η³-C(R′)C(R″)C(H)N(Me)(R)}(μ-CO)(CO)(Cp)₂] (R = Bz, R′ = Me₃Si, R″ = H, 14a; R = Me, R′ = Me₃Si, R″ = H, 14b; R = Bz, R′ = Tol, R″ = H, 15; R = Bz, R′ = R″ = Et, 16), bis-alkylidene complexes [Ru₂{μ-η¹:η²-C(R′)C(H)(R″)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂] (R′ = Me₃Si, R″ = H, 17; R′ = R″ = Et, 18), acetylide compounds [Ru₂{μ-CN(Me)(R)}(μ-CO)(CO)(CCR′)(Cp)₂] (R = Xyl, R′ = Tol, 19; R = Bz, R′ = Me₃Si, 20; R = Xyl, R′ = Me, 21) or the tetranuclear species [Ru₂{μ-η¹:η²-C(Me)CCN(Me)(Bz)}(μ-CO)(CO)(Cp)₂]₂ (23) depending on the properties of the hydride and the substituents on the complex. Chromatography of 21 on alumina results in its conversion into [Ru₂{μ-η³:η¹-C[N(Me)(Xyl)]C(H)CCH₂}(μ-CO)(CO)(Cp)₂] (22). The crystal structures of 2a[CF₃SO₃] · 0.5CH₂Cl₂, 12a[CF₃SO₃] and 22 have been determined by X-ray diffraction studies.     

Use of bis-aminoalcohol benzoquinones and dihydroxybenzoquinones in the formation of mono and polymeric structures of diorganotin(IV) derivatives

Reaction of three hexadentate ligands (L1-L3) derived from 1,4-benzoquinone bis(aminoalcohols) with diorganotin oxides (R₂Sn-O)_n (with R = Me, nBu, Ph) in 1:2 stoichiometric proportions lead to the formation of dinuclear tin compounds of the composition [(R₂Sn)₂(L)], wherein the five-coordinate metal centers are embedded in distorted trigonal-bipyramidal polyhedra. X-ray diffraction analysis revealed that diorganotin complexes carrying n-butyl groups tend to associate further through intermolecular O?Sn interactions to give 1D polymeric chains, while diphenyltin analogues tend to be monomeric. On the other hand, using 2,5-dihydroxy-3,6-dichloro-1,4-benzoquinone as ligand (L4) in 1:1 reactions with the diorganotin oxide derivatives, 1D polymeric complexes of the composition [R₂Sn(L4)(DMSO)]_n with seven-coordinate metal centers in distorted pentagonal-bipyramidal coordination polyhedra were obtained. In this case, the presence of different substituents attached to the tin atoms (Me, nBu, Ph) had no influence on the molecular composition of the products, but on the conformation of the polymeric chain, which was either planar (R = Me), slightly distorted from planarity (R = nBu) or ondulated (R = Ph).     

Synthesis and structures of o-phenylene-bridged Cp/phosphinoamide titanium complexes

Addition of R′₂PCl to anilines substituted with di- or trimethylcyclopentadienyl unit at ortho-position affords ortho-phenylene-bridged Me₂Cp or Me₃Cp/phosophinoamide ligands, 2-(RMe₂C₅H₂)C₆H₄NHPR′₂ (R = Me or H; R′ = Ph, iPr, or Cyclohexyl). Successive addition of Ti(NMe₂)₄ and Me₂SiCl₂ to the ligands affords the desired dichlorotitanium complexes, [2-(η⁵-RMe₂C₅H)C₆H₄NPR′ ₂− κ²N,P]TiCl₂ (R = H, R′ = Ph, 9; R = Me, R′ = Ph, 10; R = H, R′ = iPr, 11; R = Me, R′ = iPr, 12; R = H, R′ = Cy, 13; R = Me, R′ = Cy, 14). By using Zr(NMe₂)₄ instead of Ti(NMe₂)₄, a zirconium complex, [2-(η⁵-Me₃C₅H)C₆H₄NP(iPr)₂−κ²N,P]ZrCl₂ (15) is prepared. Molecular structures of 10, 14 and [2-(η⁵-Me₂C₅H₂)C₆H₄NPPh₂− κN]Ti(NMe₂)₂ (16) were determined. The metric parameters determined on the X-ray crystallographic studies and the chemical shifts of the ³¹P NMR signal indicate that the phosphorous atom coordinates to the titanium in the dichloro-complexes 9-15. The titanium and zirconium complexes show negligible activity in ethylene and ethylene/1-hexene (co)polymerization when activated with MAO or iBu₃Al/[Ph₃C][B(C₆F₅)₄].